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Sample records for low-mass eclipsing binaries

  1. VizieR Online Data Catalog: ASAS low-mass eclipsing binaries light curves (Helminiak+, 2011)

    NASA Astrophysics Data System (ADS)

    Helminiak, K. G.; Konacki, M.

    2010-09-01

    Photometric observations of two newly-discovered low-mass eclipsing binaries: ASAS J045304-0700.4 (ASAS-04) and ASAS J082552-1622.8 (ASAS-08). V and I band curves were obtained in January 2008 with the 1.0-m Elizabeth telescope and its STE4 camera at the South African Astronomical Observatory (SAAO). (4 data files).

  2. LOW-MASS ECLIPSING BINARIES IN THE INITIAL KEPLER DATA RELEASE

    SciTech Connect

    Coughlin, J. L.; Harrison, T. E.; Ule, N.; Lopez-Morales, M.; Hoffman, D. I.

    2011-03-15

    We identify 231 objects in the newly released Cycle 0 data set from the Kepler Mission as double-eclipse, detached eclipsing binary systems with T{sub eff} < 5500 K and orbital periods shorter than {approx}32 days. We model each light curve using the JKTEBOP code with a genetic algorithm to obtain precise values for each system. We identify 95 new systems with both components below 1.0 M{sub sun} and eclipses of at least 0.1 mag, suitable for ground-based follow-up. Of these, 14 have periods less than 1.0 day, 52 have periods between 1.0 and 10.0 days, and 29 have periods greater than 10.0 days. This new sample of main-sequence, low-mass, double-eclipse, detached eclipsing binary candidates more than doubles the number of previously known systems and extends the sample into the completely heretofore unexplored P > 10.0 day period regime. We find preliminary evidence from these systems that the radii of low-mass stars in binary systems decrease with period. This supports the theory that binary spin-up is the primary cause of inflated radii in low-mass binary systems, although a full analysis of each system with radial-velocity and multi-color light curves is needed to fully explore this hypothesis. Also, we present seven new transiting planet candidates that do not appear among the list of 706 candidates recently released by the Kepler team, or in the Kepler False Positive Catalog, along with several other new and interesting systems. We also present novel techniques for the identification, period analysis, and modeling of eclipsing binaries.

  3. Hot subdwarfs in (eclipsing) binaries with brown dwarf or low-mass main-sequence companions

    NASA Astrophysics Data System (ADS)

    Schaffenroth, Veronika; Geier, Stephan; Heber, Uli

    2014-09-01

    The formation of hot subdwarf stars (sdBs), which are core helium-burning stars located on the extended horizontal branch, is not yet understood. Many of the known hot subdwarf stars reside in close binary systems with short orbital periods of between a few hours and a few days, with either M-star or white-dwarf companions. Common-envelope ejection is the most probable formation channel. Among these, eclipsing systems are of special importance because it is possible to constrain the parameters of both components tightly by combining spectroscopic and light-curve analyses. They are called HW Virginis systems. Soker (1998) proposed that planetary or brown-dwarf companions could cause the mass loss necessary to form an sdB. Substellar objects with masses greater than >10 M_J were predicted to survive the common-envelope phase and end up in a close orbit around the stellar remnant, while planets with lower masses would entirely evaporate. This raises the question if planets can affect stellar evolution. Here we report on newly discovered eclipsing or not eclipsing hot subdwarf binaries with brown-dwarf or low-mass main-sequence companions and their spectral and photometric analysis to determine the fundamental parameters of both components.

  4. GJ 3236: A NEW BRIGHT, VERY LOW MASS ECLIPSING BINARY SYSTEM DISCOVERED BY THE MEARTH OBSERVATORY

    SciTech Connect

    Irwin, Jonathan; Charbonneau, David; Berta, Zachory K.; Quinn, Samuel N.; Latham, David W.; Torres, Guillermo; Blake, Cullen H.; Burke, Christopher J.; Esquerdo, Gilbert A.; Fueresz, Gabor; Mink, Douglas J.; Nutzman, Philip; Szentgyorgyi, Andrew H.; Calkins, Michael L.; Falco, Emilio E.; Bloom, Joshua S.; Starr, Dan L.

    2009-08-20

    We report the detection of eclipses in GJ 3236, a bright (I = 11.6), very low mass binary system with an orbital period of 0.77 days. Analysis of light and radial velocity curves of the system yielded component masses of 0.38 {+-} 0.02 M{sub sun} and 0.28 {+-} 0.02 M{sub sun}. The central values for the stellar radii are larger than the theoretical models predict for these masses, in agreement with the results for existing eclipsing binaries, although the present 5% observational uncertainties limit the significance of the larger radii to approximately 1{sigma}. Degeneracies in the light curve models resulting from the unknown configuration of surface spots on the components of GJ 3236 currently dominate the uncertainties in the radii, and could be reduced by obtaining precise, multiband photometry covering the full orbital period. The system appears to be tidally synchronized and shows signs of high activity levels as expected for such a short orbital period, evidenced by strong H{alpha} emission lines in the spectra of both components. These observations probe an important region of mass-radius parameter space around the predicted transition to fully convective stellar interiors, where there are a limited number of precise measurements available in the literature.

  5. Physical Properties of the Low-mass Eclipsing Binary NSVS 02502726

    NASA Astrophysics Data System (ADS)

    Lee, Jae Woo; Youn, Jae-Hyuck; Kim, Seung-Lee; Lee, Chung-Uk

    2013-01-01

    NSVS 02502726 has been known as a double-lined, detached eclipsing binary that consists of two low-mass stars. We obtained BVRI photometric follow-up observations in 2009 and 2011 to measure improved physical properties of the binary star. Each set of light curves, including the 2008 data given by Çakirli et al., was simultaneously analyzed with the previously published radial velocity curves using the Wilson-Devinney binary code. The conspicuous seasonal light variations of the system are satisfactorily modeled by a two-spot model with one starspot on each component and by changes of the spot parameters with time. Based on 23 eclipse timings calculated from the synthetic model and one ephemeris epoch, an orbital period study of NSVS 02502726 reveals that the period has experienced a continuous decrease of -5.9 × 10-7 day yr-1 or a sinusoidal variation with a period and semi-amplitude of 2.51 yr and 0.0011 days, respectively. The timing variations could be interpreted as either the light-travel-time effect due to the presence of an unseen third body, or as the combination of this effect and angular momentum loss via magnetic stellar wind braking. Individual masses and radii of both components are determined to be M 1 = 0.689 ± 0.016 M ⊙, M 2 = 0.341 ± 0.009 M ⊙, R 1 = 0.707 ± 0.007 R ⊙, and R 2 = 0.657 ± 0.008 R ⊙. The results are very different from those of Çakirli et al. with the primary's radius (0.674 ± 0.006 R ⊙) smaller the secondary's (0.763 ± 0.007 R ⊙). We compared the physical parameters presented in this paper with current low-mass stellar models and found that the measured values of the primary star are best fitted to a 79 Myr isochrone. The primary is in good agreement with the empirical mass-radius relation from low-mass binaries, but the secondary is oversized by about 85%.

  6. Optical flare activity in the low-mass eclipsing binary GJ 3236

    NASA Astrophysics Data System (ADS)

    Parimucha, Š.; Dubovský, P.; Vaňko, M.; Čokina, M.

    2016-09-01

    We present our observations of the low-mass eclipsing binary GJ 3236. We have analyzed a phased RC light-curve and confirmed previously determined fundamental parameters of the components. We detected evolution of the spot(s) and found that there exists a large spot near a polar region of the primary component and another spot either on the primary or the secondary component. We also observed 7 flare events and determined a flare rate of about 0.1 flares per hour. We observed two high energy, long-term flares with a complex light curve and possibly four weak short-term flaring events. A majority of the flares was detected in the RC filter, which indicate their high energy.

  7. DETECTABILITY OF TRANSITING JUPITERS AND LOW-MASS ECLIPSING BINARIES IN SPARSELY SAMPLED PAN-STARRS-1 SURVEY DATA

    SciTech Connect

    Dupuy, Trent J.; Liu, Michael C.

    2009-10-20

    We present detailed simulations of the Pan-STARRS-1 (PS1) multi-epoch, multiband 3pi Survey in order to assess its potential yield of transiting planets and eclipsing binaries. This survey differs from dedicated transit surveys in that it will cover the entire northern sky but provide only sparsely sampled light curves. Since most eclipses would be detected at only a single epoch, the 3pi Survey will be most sensitive to deep eclipses (approx>0.10 mag) caused by Jupiters transiting M dwarfs and eclipsing stellar/substellar binaries. The survey will measure parallaxes for the approx4 x 10{sup 5} stars within 100 pc, which will enable a volume-limited eclipse search, reducing the number of astrophysical false positives compared with previous magnitude-limited searches. Using the best available empirical data, we constructed a model of the extended solar neighborhood that includes stars, brown dwarfs, and a realistic binary population. We computed the yield of deeply eclipsing systems using both a semianalytic and a full Monte Carlo approach. We examined statistical tests for detecting single-epoch eclipses in sparsely sampled data and assessed their vulnerability to false positives due to stellar variability. Assuming a short-period planet frequency of 0.5% for M dwarfs, our simulations predict that about a dozen transiting Jupiters around low-mass stars (M {sub *} < 0.3 M {sub sun}) within 100 pc are potentially detectable in the PS1 3pi Survey, along with approx300 low-mass eclipsing binaries (both component masses <0.5 M {sub sun}), including approx10 eclipsing field brown dwarfs. Extensive follow-up observations would be required to characterize these candidate eclipsing systems, thereby enabling comprehensive tests of structural models and novel insights into the planetary architecture of low-mass stars.

  8. IGR J17451–3022: a dipping and eclipsing low mass X-ray binary

    NASA Astrophysics Data System (ADS)

    Bozzo, E.

    2016-06-01

    We report on the available X-ray data collected by INTEGRAL, Swift, and XMM-Newton during the first outburst of the INTEGRAL transient IGR J17451-3022, discovered in 2014 August. The emission of the source during the 9 months-long outburst was dominated by a thermal component (kT˜1.2 keV), most likely produced by an accretion disk. The XMM-Newton observation carried out during the outburst revealed the presence of multiple absorption features in the soft X-ray emission that could be associated to the presence of an ionized absorber lying above the accretion disk, as observed in many high-inclination low mass X-ray binaries. The XMM-Newton data also revealed the presence of partial and rectangular X-ray eclipses (lasting about 820 s), together with dips. The latter can be associated with increases in the overall absorption column density in the direction of the source. The detection of two consecutive X-ray eclipses in the XMM-Newton data allowed us to estimate the source orbital period at Porb=22620.5(‑1.8,+2.0) s (1σ c.l.).

  9. A SuperWASP Benchmark Eclipsing Binary with a Very Low-Mass Secondary in the Brown Dwarf Desert

    NASA Astrophysics Data System (ADS)

    Gomez Maqueo Chew, Yilen; Garcia-Melendo, Enrique; Hebb, Leslie; Faedi, Francesca; Lopez-Morales, Mercedes; Pollacco, Don

    2012-08-01

    We will obtain eclipse light curves of a newly discovered eclipsing binary composed of a Sun-like primary with a secondary companion which can be either a very low mass M-dwarf (less than ~0.15 Msun) or a brown dwarf. The objects orbit each other with a period of ~14.3 days in an eccentric orbit, which as been confirmed with a high- precision radial velocity curve for the system. Therefore, these eclipse light curves will allow us to constrain the radii of the eclipsing components and orbital inclination of the system. Furthermore, the depth of the secondary eclipse which can only be observed in the near-infrared, directly constrains the temperature ratio between the components. In combination with the the masses derived from the radial velocity curve, our light curve analysis will unveil the true nature of the secondary. Whether it is a very-low mass star or a brown dwarf, direct measurements of the fundamental properties (masses, radii and temperatures) of such objects are very scarce and will provide key tests to current evolutionary models. Thus, we request two nights with FLAMINGOS at the KPNO 2.1m to observe a complete secondary eclipse of the system at near-infrared wavelengths in order to fully characterize the very low-mass component of the system.

  10. KEPLER STUDIES OF LOW-MASS ECLIPSING BINARIES. I. PARAMETERS OF THE LONG-PERIOD BINARY KIC 6131659

    SciTech Connect

    Bass, Gideon; Orosz, Jerome A.; Welsh, William F.; Windmiller, Gur; Gregg, Trevor Ames; Fetherolf, Tara; Wade, Richard A.; Quinn, Samuel N.

    2012-12-20

    KIC 6131659 is a long-period (17.5 days) eclipsing binary discovered by the Kepler mission. We analyzed six quarters of Kepler data along with supporting ground-based photometric and spectroscopic data to obtain accurate values for the mass and radius of both stars, namely, M{sub 1} = 0.922 {+-} 0.007 M{sub Sun }, R{sub 1} = 0.8800 {+-} 0.0028 R{sub Sun }, and M{sub 2} = 0.685 {+-} 0.005 M{sub Sun }, R{sub 2} = 0.6395 {+-} 0.0061 R{sub Sun }. There is a well-known issue with low-mass (M {approx}< 0.8 M{sub Sun }) stars (in cases where the mass and radius measurement uncertainties are smaller than 2% or 3%) where the measured radii are almost always 5% to 15% larger than expected from evolutionary models, i.e., the measured radii are all above the model isochrones in a mass-radius plane. In contrast, the two stars in KIC 6131659 were found to sit on the same theoretical isochrone in the mass-radius plane. Until recently, all of the well-studied eclipsing binaries with low-mass stars had periods of less than about three days. The stars in such systems may have been inflated by high levels of stellar activity induced by tidal effects in these close binaries. KIC 6131659 shows essentially no evidence of enhanced stellar activity, and our measurements support the hypothesis that the unusual mass-radius relationship observed in most low-mass stars is influenced by strong magnetic activity created by the rapid rotation of the stars in tidally locked, short-period systems. Finally, using short cadence data, we show that KIC 6131657 has one of the smallest measured non-zero eccentricities of a binary with two main-sequence stars, where ecos {omega} (4.57 {+-} 0.02) Multiplication-Sign 10{sup -5}.

  11. Detection of a very low mass star in an eclipsing binary system

    NASA Astrophysics Data System (ADS)

    Chaturvedi, Priyanka; Chakraborty, Abhijit; Anandarao, B. G.; Roy, Arpita; Mahadevan, Suvrath

    2016-10-01

    We report the detection of a very low mass star (VLMS) companion to the primary star 1SWASP J234318.41+295556.5A (J2343+29A), using radial velocity (RV) measurements from the PARAS (PRL Advanced Radial-velocity Abu-sky Search) high-resolution echelle spectrograph. The periodicity of the single-lined eclipsing binary (SB1) system, as determined from 20 sets of RV observations from PARAS and 6 supporting sets of observations from SOPHIE data, is found to be 16.953 d as against the 4.24 d period reported from SuperWASP photometry. It is likely that inadequate phase coverage of the transit with SuperWASP photometry led to the incorrect determination of the period for this system. We derive the spectral properties of the primary star from the observed stellar spectra: Teff = 5125 ± 67 K, [Fe/H] = 0.1 ± 0.14 and logg = 4.6 ± 0.14, indicating a K1V primary. Applying the Torres relation to the derived stellar parameters, we estimate a primary mass 0.864_{-0.098}^{+0.097} M⊙ and a radius of 0.854_{-0.060}^{+0.050} R⊙. We combine RV data with SuperWASP photometry to estimate the mass of the secondary, MB = 0.098 ± 0.007 M⊙, and its radius, RB = 0.127 ± 0.007 R⊙, with an accuracy of ˜7 per cent. Although the observed radius is found to be consistent with the Baraffe's theoretical models, the uncertainties on the mass and radius of the secondary reported here are model dependent and should be used with discretion. Here, we establish this system as a potential benchmark for the study of VLMS objects, worthy of both photometric follow-up and the investment of time on high-resolution spectrographs paired with large-aperture telescopes.

  12. Photometric monitoring of open clusters: Low-mass eclipsing binary stars and the stellar mass-luminosity-radius relation

    NASA Astrophysics Data System (ADS)

    Hebb, Leslie

    2006-06-01

    This thesis describes a photometric monitoring survey of Galactic star clusters designed to detect low-mass eclipsing binary star systems through variations in their relative lightcurves. The aim is to use cluster eclipsing binaries to measure the masses and radii of M-dwarf stars with ages and metallicities known from studies of brighter cluster stars. This information will provide an improved calibration of the mass-luminosity-radius relation for low-mass stars, be used to test stellar structure and evolution models, and help quantify the contribution of low-mass stars to the global mass census in the Galaxy. The survey is designed to detect eclipse events in stars of ~0.3 M_sun and consists of 600 Gbytes of raw imaging data on six open clusters with a range of ages (~ 0.15 - 4 Gyr) and metallicites (~ -0.2 - 0.0 dex). The clusters NGC 1647 and M 35 contain excellent candidate systems showing eclipse like variations in brightness and photometry consistent with cluster membership. The analysis of these clusters and the eclipsing M-dwarf stars detected in them are presented. Analysis of the candidate system in NGC 1647 confirms the object as a newly discovered M-dwarf eclipsing binary in the cluster with compenent masses of M 1 = 0.47 ± 0.05[Special characters omitted.] and M 2 = 0.19 ± 0.02[Special characters omitted.] . The small mass ratio ( M 2 / M 1 ) and low secondary mass of this object provide an unprecedented opportunity to test stellar models. We find that no stellar evolution models are consistent with all the properties of both M-dwarf stars in the eclipsing binary. The candidate in M 35 has been confirmed as an M-dwarf eclipsing binary, and the masses of the individual components are estimated to be M 1 ~ 0.25 M_sun and M 2 ~ 0.15 M_sun . Additional high resolution spectroscopic and photometric observations, for which we have applied and been awarded time, are necessary to accurately derive the intrinsic properties of the individual stellar

  13. NSVS 06507557: a low-mass double-lined eclipsing binary

    NASA Astrophysics Data System (ADS)

    Çakırlı, Ö.; Ibanoǧlu, C.

    2010-01-01

    In this paper, we present the results of a detailed spectroscopic and photometric analysis of the V = 13.4 mag low-mass eclipsing binary NSVS 06507557 with an orbital period of 0.515d. We have obtained a series of mid-resolution spectra covering nearly the entire orbit of the system. In addition, we have obtained simultaneous VRI broad-band photometry using a small aperture telescope. From these spectroscopic and photometric data, we have derived the system's orbital parameters and we have determined the fundamental stellar parameters of the two components. Our results indicate that NSVS 06507557 consists of a K9 pre-main-sequence star and an M3 pre-main-sequence star. These have masses of 0.66 +/- 0.09 Msolar and 0.28 +/- 0.05 Msolar and radii of 0.60 +/- 0.03 and 0.44 +/- 0.02 Rsolar, respectively, and are located at a distance of 111 +/- 9 pc. The radius of the less massive secondary component is larger than that of a zero-age main-sequence (ZAMS) star having the same mass. While the radius of the primary component is in agreement with ZAMS, the secondary component appears to be larger by about 35 per cent with respect to its ZAMS counterpart. Night-to-night intrinsic light variations up to 0.2 mag have been observed. In addition, the Hα and Hβ lines and the forbidden line of [OI] are seen in emission. The LiI 6708 Å absorption line is seen in most of the spectra. These features are taken to be signs of the characteristics of classic T Tauri stars. The parameters we have derived are consistent with an age of about 20 Myr, according to stellar evolutionary models. The spectroscopic and photometric results are in agreement with those obtained using theoretical predictions. Based on spectroscopic observations collected at TÜBİTAK (Turkey). E-mail: omur.cakirli@ege.edu.tr

  14. ECLIPSE TIMINGS OF THE TRANSIENT LOW-MASS X-RAY BINARY EXO 0748-676. IV. THE ROSSI X-RAY TIMING EXPLORER ECLIPSES

    SciTech Connect

    Wolff, Michael T.; Ray, Paul S.; Wood, Kent S.; Hertz, Paul L. E-mail: Paul.Ray@nrl.navy.mil E-mail: Paul.Hertz@nasa.gov

    2009-07-01

    We report our complete database of X-ray eclipse timings of the low-mass X-ray binary EXO 0748-676 observed by the Rossi X-Ray Timing Explorer (RXTE) satellite. As of this writing we have accumulated 443 full X-ray eclipses, 392 of which have been observed with the Proportional Counter Array on RXTE. These include both observations where an eclipse was specifically targeted and those eclipses found in the RXTE data archive. Eclipse cycle count has been maintained since the discovery of the EXO 0748-676 system in 1985 February. We describe our observing and analysis techniques for each eclipse and describe improvements we have made since the last compilation by Wolff et al. The principal result of this paper is the database containing the timing results from a seven-parameter fit to the X-ray light curve for each observed eclipse along with the associated errors in the fitted parameters. Based on the standard O - C analysis, EXO 0748-676 has undergone four distinct orbital period epochs since its discovery. In addition, EXO 0748-676 shows small-scale events in the O - C curve that are likely due to short-lived changes in the secondary star.

  15. KIC 1571511B: a benchmark low-mass star in an eclipsing binary system in the Kepler field

    NASA Astrophysics Data System (ADS)

    Ofir, A.; Gandolfi, D.; Buchhave, Lars; Lacy, C. H. S.; Hatzes, A. P.; Fridlund, Malcolm

    2012-06-01

    KIC 1571511 is a 14-d eclipsing binary (EB) in the Kepler data set. The secondary of this EB is a very low mass star with a mass of ? and a radius of ? (statistical errors only). The overall system parameters make KIC 1571511B an ideal 'benchmark object': among the smallest, lightest and best-described stars known, smaller even than some known exoplanet. Currently available photometry encompasses only a small part of the total: future Kepler data releases promise to constrain many of the properties of KIC 1571511B to unprecedented level. However, as in many spectroscopic single-lined systems, the current error budget is dominated by the modelling errors of the primary and not by the above statistical errors. We conclude that detecting the RV signal of the secondary component is crucial to achieving the full potential of this possible benchmark object for the study of low-mass stars. Footnotes<label>1</label>Kepler Data Processing Handbook section 9.3, document number KSCI-19081-001 of 2011 April 1.<label>2</label>See Kepler Instrument Handbook, document KSCI-19033, for full description.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21394205','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21394205"><span id="translatedtitle">THE EFFECT OF STARSPOTS ON ACCURATE RADIUS DETERMINATION OF THE <span class="hlt">LOW-MASS</span> DOUBLE-LINED <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> GU Boo</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Windmiller, G.; Orosz, J. A.; Etzel, P. B. E-mail: orosz@sciences.sdsu.ed</p> <p>2010-04-01</p> <p>GU Boo is one of only a relatively small number of well-studied double-lined <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> that contain <span class="hlt">low-mass</span> stars. Lopez-Morales and Ribas present a comprehensive analysis of multi-color light and radial velocity curves for this system. The GU Boo light curves presented by Lopez-Morales and Ribas had substantial asymmetries, which were attributed to large spots. In spite of the asymmetry, Lopez-Morales and Ribas derived masses and radii accurate to {approx_equal}2%. We obtained additional photometry of GU Boo using both a CCD and a single-channel photometer and modeled the light curves with the ELC software to determine if the large spots in the light curves give rise to systematic errors at the few percent level. We also modeled the original light curves from the work of Lopez-Morales and Ribas using models with and without spots. We derived a radius of the primary of 0.6329 +- 0.0026 R{sub sun}, 0.6413 +- 0.0049 R{sub sun}, and 0.6373 +- 0.0029 R{sub sun} from the CCD, photoelectric, and Lopez-Morales and Ribas data, respectively. Each of these measurements agrees with the value reported by Lopez-Morales and Ribas (R{sub 1} = 0.623 +- 0.016 R{sub sun}) at the level of {approx}2%. In addition, the spread in these values is {approx}1%-2% from the mean. For the secondary, we derive radii of 0.6074 +- 0.0035 R{sub sun}, 0.5944 +- 0.0069 R{sub sun}, and 0.5976 +- 0.0059 R{sub sun} from the three respective data sets. The Lopez-Morales and Ribas value is R{sub 2} = 0.620 +- 0.020 R{sub sun}, which is {approx}2%-3% larger than each of the three values we found. The spread in these values is {approx}2% from the mean. The systematic difference between our three determinations of the secondary radius and that of Lopez-Morales and Ribas might be attributed to differences in the modeling process and codes used. Our own fits suggest that, for GU Boo at least, using accurate spot modeling of a single set of multi-color light curves results in radii determinations</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950048261&hterms=hertz&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dhertz','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950048261&hterms=hertz&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dhertz"><span id="translatedtitle"><span class="hlt">Eclipse</span> timings of the <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> EXO 0748-676: Statistical arguments against orbital period changes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hertz, Paul; Wood, Kent S.; Cominsky, Lynn</p> <p>1995-01-01</p> <p>EXO 0748-676, an <span class="hlt">eclipsing</span> <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span>, is one of only about four or five <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> for which orbital period evolution has been reported. We observed a single <span class="hlt">eclipse</span> egress with ROSAT . The time of this egress is consistent with the apparent increase in P(sub orb) previously reported on the basis of EXOSAT and Ginga observations. Standard analysis, in which O-C (observed minus calculated) timing residuals are examined for deviations from a constant period, implicitly assume that the only uncertainty in each residual is measurement error and that these errors are independent. We argue that the variable <span class="hlt">eclipse</span> durations and profiles observed in EXO 0748-676 imply that there is an additional source of uncertainty in timing measurements, that this uncertainty is intrinsic to the <span class="hlt">binary</span> system, and that it is correlated from observation to observation with a variance which increases as a function of the number of <span class="hlt">binary</span> cycles between observations. This intrinsic variability gives rise to spurious trends in O-C residuals which are misinterpreted as changes in the orbital period. We describe several statistics tests which can be used to test for the presence of intrinsic variability. We apply those statistical tests which are suitable to the EXO 0748-676 observations. The apparent changes in the orbital period of EXO 0748-676 can be completely accounted for by intrinsic variability with an rms variability of approximately 0.35 s per orbital cycle. The variability appears to be correlated from cycle-to-cycle on timescales of less than 1 yr. We suggest that the intrinsic variability is related to slow changes in either the source's X-ray luminosity or the structure of the companion star's atmosphere. We note that several other X-ray <span class="hlt">binaries</span> and cataclysmic variables have previously reported orbital period changes which may also be due to intrinsic variability rather than orbital period evolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PASJ...68S..15S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PASJ...68S..15S"><span id="translatedtitle">Peculiar lapse of periodic <span class="hlt">eclipsing</span> event at <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> GRS 1747-312 during Suzaku observation in 2009</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saji, Shigetaka; Mori, Hideyuki; Matsumoto, Hironori; Dotani, Tadayasu; Iwai, Masachika; Maeda, Yoshitomo; Mitsuishi, Ikuyuki; Ozaki, Masanobu; Tawara, Yuzuru</p> <p>2016-06-01</p> <p>GRS 1747-312 is a neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> in the globular cluster Terzan 6, located at a distance of 9.5 kpc from the Earth. During its outbursts, periodic <span class="hlt">eclipses</span> were known to occur. Observations for the outbursts were performed with Chandra in 2004 and Swift in 2013. XMM-Newton observed its quiescent state in 2004. In addition, when Suzaku observed it in 2009 as a part of Galactic center mapping observations, GRS 1747-312 was found to be in a low-luminosity state with Lx ˜ 1.2 × 1035 erg s-1. All of the observations except for XMM-Newton included the time of the <span class="hlt">eclipses</span> predicted. We analyzed archival data of these observations. During the Chandra and Swift observations, we found clear flux decreases at the expected time of the <span class="hlt">eclipses</span>. During the Suzaku observation, however, there were no clear signs for the predicted <span class="hlt">eclipses</span>. The lapse of the predicted <span class="hlt">eclipses</span> during the Suzaku observation can be explained by a contaminant source quite close to GRS 1747-312. When GRS 1747-312 is in the quiescent state, we observe X-rays from the contaminant source rather than from GRS 1747-312. However, we have no clear evidence for the contaminant source in our data. The lapse might also be explained by thick material (NH > 1024 cm-2) between the neutron star and the companion star, though the origin of the thick material is not clear.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009A%26A...503..873H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009A%26A...503..873H"><span id="translatedtitle">The triple system HIP 96515: a <span class="hlt">low-mass</span> <span class="hlt">eclipsing</span> <span class="hlt">binary</span> with a DB white dwarf companion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huélamo, N.; Vaz, L. P. R.; Torres, C. A. O.; Bergeron, P.; Melo, C. H. F.; Quast, G. R.; Barrado y Navascués, D.; Sterzik, M. F.; Chauvin, G.; Bouy, H.; Landin, N. R.</p> <p>2009-09-01</p> <p>Context: HIP 96515 A is a double-lined spectroscopic <span class="hlt">binary</span> included in the SACY catalog as a potential young star. It has a visual companion (CCDM 19371-5134 B, HIP 96515 B) at 8.6 arcsec. If bound to the primary, the optical and infrared colors of this wide companion are consistent with those of a white dwarf. Aims: We attempt to characterize the system HIP 96515 A&B by studying each of its components. Methods: We analyzed spectroscopic and photometric observations of HIP 96515 A and its visual companion, HIP 96515 B. To confirm the system as a common proper-motion pair, we analyzed the astrometry of the components using high-angular resolution infrared observations obtained within a time span of two years, and archival astrometry. Results: The high-resolution optical spectrum of HIP 96515 A was used to derive a mass ratio, M_2/M_1, close to 0.9. The optical lightcurve of HIP 96515 A shows periodic variations with P_orbital = 2.3456 days, revealing that HIP 96515 A is an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> with preliminary orbital parameters of i = 89.0° ± 0.2°, and M1 = 0.59 ± 0.03 M⊙ and M2 = 0.54 ± 0.03 M⊙, for the primary and secondary, respectively, at an estimated distance of 42 ± 3 pc. This is a new <span class="hlt">eclipsing</span> <span class="hlt">binary</span> with component masses below 0.6 M⊙. Multi-epoch observations of HIP 96515 A&B show that the system is a common proper-motion pair. The optical spectrum of HIP 96515 B is consistent with a pure helium atmosphere (DB) white dwarf. The comparison with evolutionary cooling sequence models provides Teff,WD = 19 126 ± 195 K, log gWD = 8.08, MWD/M⊙ = 0.6, and a distance of ~46 pc. The estimated WD cooling age is ~100 Myr and the total age of the object (including the main-sequence phase) is ~400 Myr. Finally, if HIP 96515 A&B are coeval, and assuming a common age of ~400 Myr, the comparison of the masses of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> members with evolutionary tracks shows that they are underestimated by ~15% and 10%, for the primary and secondary, respectively</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AAS...22321502S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AAS...22321502S"><span id="translatedtitle">Kepler's Cool <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Swift, Jonathan; Muirhead, P. S.; Johnson, J. A.; Gonzales, A.; Shporer, A.; Plavchan, P.; Lockwood, A.; Morton, T.</p> <p>2014-01-01</p> <p>Some of the most exciting exoplanet results to date have come from the smallest and coolest sample of stars in the Kepler field—the M dwarfs. These cool stars represent the largest stellar population in the Galaxy which in turn harbors one of the largest known exoplanet populations. However, an accurate understanding of their physical properties currently eludes us. Detached, M dwarf <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems provide an accurate and precise, model-independent means of measuring the fundamental properties of <span class="hlt">low-mass</span> stars shedding light on the rich physics embodied by this spectral class and refining our knowledge of their exoplanets. We have undertaken an observational campaign to obtain masses, radii, and effective temperatures of the Kepler <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> having an M dwarf primary with periods between 1 and 60 days. These data will allow detailed comparisons between stellar properties, <span class="hlt">binary</span> period, rotation, metallicity and activity levels.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li class="active"><span>1</span></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_1 --> <div id="page_2" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active"><span>2</span></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="21"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...587A..16V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...587A..16V"><span id="translatedtitle">Calibrating convective-core overshooting with <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems. The case of <span class="hlt">low-mass</span> main-sequence stars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Valle, G.; Dell'Omodarme, M.; Prada Moroni, P. G.; Degl'Innocenti, S.</p> <p>2016-03-01</p> <p>Context. Double-lined <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> have often been adopted in literature to calibrate the extension of the convective-core overshooting beyond the border defined by the Schwarzschild criterion. Aims: In a robust statistical way, we quantify the magnitude of the uncertainty that affects the calibration of the overshooting efficiency parameter β that is owing to the uncertainty on the observational data. We also quantify the biases on the β determination that is caused by the lack of constraints on the initial helium content and on the efficiencies of the superadiabatic convection and microscopic diffusion. Methods: We adopted a modified grid-based SCEPtER pipeline to recover the β parameter from synthetic stellar data. Our grid spans the mass range [1.1; 1.6] M⊙ and evolutionary stages from the zero-age main sequence (MS) to the central hydrogen depletion. The β estimates were obtained by generalising the maximum likelihood technique described in our previous works. As observational constraint, we adopted the effective temperatures, [Fe/H], masses, and radii of the two stars. Results: By means of Monte Carlo simulations, adopting a reference scenario of mild overshooting β = 0.2 for the synthetic data, and taking typical observational errors into account, we found both large statistical uncertainties and biases on the estimated values of β. For the first 80% of the MS evolution, β is biased by about -0.04, with the 1σ error practically unconstrained in the whole explored range [0.0; 0.4]. In the last 5% of the evolution the bias vanishes and the 1σ error is about 0.05. The 1σ errors are similar when adopting different reference values of β. Interestingly, for synthetic data computed without convective-core overshooting, the estimated β is biased by about 0.12 in the first 80% of the MS evolution, and by 0.05 afterwards. Assuming an uncertainty of ±1 in the helium-to-metal enrichment ratio ΔY/ ΔZ, we found a large systematic uncertainty in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...831...29C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...831...29C"><span id="translatedtitle">Orbital and Spin Parameter Variations of Partial <span class="hlt">Eclipsing</span> <span class="hlt">Low</span> <span class="hlt">Mass</span> X-Ray <span class="hlt">Binary</span> X 1822-371</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chou, Yi; Hsieh, Hung-En; Hu, Chin-Ping; Yang, Ting-Chang; Su, Yi-Hao</p> <p>2016-11-01</p> <p>We report our measurements for the orbital and spin parameters of X 1822-371 using its X-ray partial <span class="hlt">eclipsing</span> profile and pulsar timing from data collected by the Rossi X-ray Timing Explorer (RXTE). Four more X-ray <span class="hlt">eclipse</span> times obtained by the RXTE 2011 observations were combined with historical records to trace the evolution of the orbital period. We found that a cubic ephemeris likely better describes the evolution of the X-ray <span class="hlt">eclipse</span> times during a time span of about 34 years with a marginal second order derivative of {\\ddot{P}}{orb}=(-1.05+/- 0.59)× {10}-19 s‑1. Using the pulse arrival time delay technique, the orbital and spin parameters were obtained from RXTE observations from 1998 to 2011. The detected pulse periods show that the neutron star in X 1822-371 is continuously spun-up with a rate of {\\dot{P}}s=(-2.6288+/- 0.0095)× {10}-12 s s‑1. Although the evolution of the epoch of the mean longitude l = π/2 (i.e., T π/2) gives an orbital period derivative value consistent with that obtained from the quadratic ephemeris evaluated from the X-ray <span class="hlt">eclipse</span>, the detected T π/2 values are significantly and systematically earlier than the corresponding expected X-ray <span class="hlt">eclipse</span> times by 90 ± 11 s. This deviation is probably caused by asymmetric X-ray emissions. We also attempted to constrain the mass and radius of the neutron star using the spin period change rate and concluded that the intrinsic luminosity of X 1822-371 is likely more than 1038 erg s‑1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21452902','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21452902"><span id="translatedtitle">THIRTY NEW <span class="hlt">LOW-MASS</span> SPECTROSCOPIC <span class="hlt">BINARIES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shkolnik, Evgenya L.; Hebb, Leslie; Cameron, Andrew C.; Liu, Michael C.; Neill Reid, I. E-mail: Andrew.Cameron@st-and.ac.u E-mail: mliu@ifa.hawaii.ed</p> <p>2010-06-20</p> <p>As part of our search for young M dwarfs within 25 pc, we acquired high-resolution spectra of 185 <span class="hlt">low-mass</span> stars compiled by the NStars project that have strong X-ray emission. By cross-correlating these spectra with radial velocity standard stars, we are sensitive to finding multi-lined spectroscopic <span class="hlt">binaries</span>. We find a <span class="hlt">low-mass</span> spectroscopic <span class="hlt">binary</span> fraction of 16% consisting of 27 SB2s, 2 SB3s, and 1 SB4, increasing the number of known <span class="hlt">low-mass</span> spectroscopic <span class="hlt">binaries</span> (SBs) by 50% and proving that strong X-ray emission is an extremely efficient way to find M-dwarf SBs. WASP photometry of 23 of these systems revealed two <span class="hlt">low-mass</span> <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> (EBs), bringing the count of known M-dwarf EBs to 15. BD-22 5866, the ESB4, was fully described in 2008 by Shkolnik et al. and CCDM J04404+3127 B consists of two mid-M stars orbiting each other every 2.048 days. WASP also provided rotation periods for 12 systems, and in the cases where the synchronization time scales are short, we used P{sub rot} to determine the true orbital parameters. For those with no P{sub rot}, we used differential radial velocities to set upper limits on orbital periods and semimajor axes. More than half of our sample has near-equal-mass components (q > 0.8). This is expected since our sample is biased toward tight orbits where saturated X-ray emission is due to tidal spin-up rather than stellar youth. Increasing the samples of M-dwarf SBs and EBs is extremely valuable in setting constraints on current theories of stellar multiplicity and evolution scenarios for <span class="hlt">low-mass</span> multiple systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011A%26A...527A..14H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011A%26A...527A..14H"><span id="translatedtitle">Orbital and physical parameters of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> from the All-Sky Automated Survey catalogue. III. Two new <span class="hlt">low-mass</span> systems with rapidly evolving spots</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hełminiak, K. G.; Konacki, M.; Złoczewski, K.; Ratajczak, M.; Reichart, D. E.; Ivarsen, K. M.; Haislip, J. B.; Crain, J. A.; Foster, A. C.; Nysewander, M. C.; Lacluyze, A. P.</p> <p>2011-03-01</p> <p>Aims: We present the results of our spectroscopic and photometric analysis of two newly discovered <span class="hlt">low-mass</span> detached <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> found in the All-Sky Automated Survey (ASAS) catalogue: ASAS J093814-0104.4 and ASAS J212954-5620.1. Methods: Using the Grating Instrument for Radiation Analysis with a Fibre-Fed Echelle (GIRAFFE) on the 1.9-m Radcliffe telescope at the South African Astronomical Observatory (SAAO) and the University College London Echelle Spectrograph (UCLES) on the 3.9-m Anglo-Australian Telescope, we obtained high-resolution spectra of both objects and derived their radial velocities (RVs) at various orbital phases. The RVs of both objects were measured with the two-dimensional cross-correlation technique (TODCOR) using synthetic template spectra as references. We also obtained V and I band photometry using the 1.0-m Elizabeth telescope at SAAO and the 0.4-m Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes (PROMPT) located at the Cerro Tololo Inter-American Observatory (CTIO). The orbital and physical parameters of the systems were derived with PHOEBE and JKTEBOP codes. We compared our results with several sets of widely-used isochrones. Results: Our multi-epoch photometric observations demonstrate that both objects show significant out-of-<span class="hlt">eclipse</span> modulations, which vary in time. We believe that this effect is caused by stellar spots, which evolve on time scales of tens of days. For this reason, we constructed our models on the basis of photometric observations spanning short time scales (less than a month). Our modeling indicates that (1) ASAS J093814-0104.04 is a main sequence active system with nearly-twin components with masses of M1 = 0.771 ± 0.033 M⊙, M2 = 0.768 ± 0.021 M⊙ and radii of R1 = 0.772 ± 0.012 R⊙ and R2 = 0.769 ± 0.013 R⊙. (2) ASAS J212954-5620.1 is a main sequence active <span class="hlt">binary</span> with component masses of M1 = 0.833 ± 0.017 M⊙, M2 = 0.703 ± 0.013 M⊙ and radii of R1 = 0.845 ± 0.012 R⊙ and R2</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ApJ...797...31T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ApJ...797...31T"><span id="translatedtitle">The G+M <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> V530 Orionis: A Stringent Test of Magnetic Stellar Evolution Models for <span class="hlt">Low-mass</span> Stars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Torres, Guillermo; Sandberg Lacy, Claud H.; Pavlovski, Krešimir; Feiden, Gregory A.; Sabby, Jeffrey A.; Bruntt, Hans; Viggo Clausen, Jens</p> <p>2014-12-01</p> <p>We report extensive photometric and spectroscopic observations of the 6.1 day period, G+M-type detached double-lined <span class="hlt">eclipsing</span> <span class="hlt">binary</span> V530 Ori, an important new benchmark system for testing stellar evolution models for <span class="hlt">low-mass</span> stars. We determine accurate masses and radii for the components with errors of 0.7% and 1.3%, as follows: M A = 1.0038 ± 0.0066 M ⊙, M B = 0.5955 ± 0.0022 M ⊙, R A = 0.980 ± 0.013 R ⊙, and R B = 0.5873 ± 0.0067 R ⊙. The effective temperatures are 5890 ± 100 K (G1 V) and 3880 ± 120 K (M1 V), respectively. A detailed chemical analysis probing more than 20 elements in the primary spectrum shows the system to have a slightly subsolar abundance, with [Fe/H] = -0.12 ± 0.08. A comparison with theory reveals that standard models underpredict the radius and overpredict the temperature of the secondary, as has been found previously for other M dwarfs. On the other hand, models from the Dartmouth series incorporating magnetic fields are able to match the observations of the secondary star at the same age as the primary (~3 Gyr) with a surface field strength of 2.1 ± 0.4 kG when using a rotational dynamo prescription, or 1.3 ± 0.4 kG with a turbulent dynamo approach, not far from our empirical estimate for this star of 0.83 ± 0.65 kG. The observations are most consistent with magnetic fields playing only a small role in changing the global properties of the primary. The V530 Ori system thus provides an important demonstration that recent advances in modeling appear to be on the right track to explain the long-standing problem of radius inflation and temperature suppression in <span class="hlt">low-mass</span> stars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22370081','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22370081"><span id="translatedtitle">The G+M <span class="hlt">eclipsing</span> <span class="hlt">binary</span> V530 Orionis: a stringent test of magnetic stellar evolution models for <span class="hlt">low-mass</span> stars</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Torres, Guillermo; Lacy, Claud H. Sandberg; Pavlovski, Krešimir; Feiden, Gregory A.; Sabby, Jeffrey A.; Bruntt, Hans; Clausen, Jens Viggo</p> <p>2014-12-10</p> <p>We report extensive photometric and spectroscopic observations of the 6.1 day period, G+M-type detached double-lined <span class="hlt">eclipsing</span> <span class="hlt">binary</span> V530 Ori, an important new benchmark system for testing stellar evolution models for <span class="hlt">low-mass</span> stars. We determine accurate masses and radii for the components with errors of 0.7% and 1.3%, as follows: M {sub A} = 1.0038 ± 0.0066 M {sub ☉}, M {sub B} = 0.5955 ± 0.0022 M {sub ☉}, R {sub A} = 0.980 ± 0.013 R {sub ☉}, and R {sub B} = 0.5873 ± 0.0067 R {sub ☉}. The effective temperatures are 5890 ± 100 K (G1 V) and 3880 ± 120 K (M1 V), respectively. A detailed chemical analysis probing more than 20 elements in the primary spectrum shows the system to have a slightly subsolar abundance, with [Fe/H] = –0.12 ± 0.08. A comparison with theory reveals that standard models underpredict the radius and overpredict the temperature of the secondary, as has been found previously for other M dwarfs. On the other hand, models from the Dartmouth series incorporating magnetic fields are able to match the observations of the secondary star at the same age as the primary (∼3 Gyr) with a surface field strength of 2.1 ± 0.4 kG when using a rotational dynamo prescription, or 1.3 ± 0.4 kG with a turbulent dynamo approach, not far from our empirical estimate for this star of 0.83 ± 0.65 kG. The observations are most consistent with magnetic fields playing only a small role in changing the global properties of the primary. The V530 Ori system thus provides an important demonstration that recent advances in modeling appear to be on the right track to explain the long-standing problem of radius inflation and temperature suppression in <span class="hlt">low-mass</span> stars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NewA...36...56T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NewA...36...56T"><span id="translatedtitle">Cyclic period changes and the light-time effect in <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>: A <span class="hlt">low-mass</span> companion around the system VV Ursae Majoris</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tanrıver, Mehmet</p> <p>2015-04-01</p> <p>In this article, a period analysis of the late-type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> VV UMa is presented. This work is based on the periodic variation of <span class="hlt">eclipse</span> timings of the VV UMa <span class="hlt">binary</span>. We determined the orbital properties and mass of a third orbiting body in the system by analyzing the light-travel time effect. The O-C diagram constructed for all available minima times of VV UMa exhibits a cyclic character superimposed on a linear variation. This variation includes three maxima and two minima within approximately 28,240 orbital periods of the system, which can be explained as the light-travel time effect (LITE) because of an unseen third body in a triple system that causes variations of the <span class="hlt">eclipse</span> arrival times. New parameter values of the light-time travel effect because of the third body were computed with a period of 23.22 ± 0.17 years in the system. The cyclic-variation analysis produces a value of 0.0139 day as the semi-amplitude of the light-travel time effect and 0.35 as the orbital eccentricity of the third body. The mass of the third body that orbits the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars is 0.787 ± 0.02 M⊙, and the semi-major axis of its orbit is 10.75 AU.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22078405','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22078405"><span id="translatedtitle">A POSSIBLE SIGNATURE OF LENSE-THIRRING PRECESSION IN DIPPING AND <span class="hlt">ECLIPSING</span> NEUTRON-STAR <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARIES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Homan, Jeroen</p> <p>2012-12-01</p> <p>Relativistic Lense-Thirring precession of a tilted inner accretion disk around a compact object has been proposed as a mechanism for low-frequency ({approx}0.01-70 Hz) quasi-periodic oscillations (QPOs) in the light curves of X-ray <span class="hlt">binaries</span>. A substantial misalignment angle ({approx}15 Degree-Sign -20 Degree-Sign ) between the inner-disk rotation axis and the compact-object spin axis is required for the effects of this precession to produce observable modulations in the X-ray light curve. A consequence of this misalignment is that in high-inclination X-ray <span class="hlt">binaries</span> the precessing inner disk will quasi-periodically intercept our line of sight to the compact object. In the case of neutron-star systems, this should have a significant observational effect, since a large fraction of the accretion energy is released on or near the neutron-star surface. In this Letter, I suggest that this specific effect of Lense-Thirring precession may already have been observed as {approx}1 Hz QPOs in several dipping/<span class="hlt">eclipsing</span> neutron-star X-ray <span class="hlt">binaries</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ATel.9072....1B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ATel.9072....1B"><span id="translatedtitle">Outburst from <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> GRS 1747-312 in Terzan 6</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bahramian, A.; Heinke, C. O.; Sivakoff, G. R.; Kennea, J. A.; Wijnands, R.; Altamirano, D.</p> <p>2016-05-01</p> <p>GRS 1747-312 is an <span class="hlt">eclipsing</span> transient <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> in the core of the globular cluster Terzan 6. This source shows regular outbursts ~ every 6 months and, due to its <span class="hlt">eclipsing</span> behaviour, has an accurately-constrained orbital period (12.36 hrs, in't Zand et al. 2003, A & A, 406, 233).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPhCS.728g2023Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPhCS.728g2023Z"><span id="translatedtitle">Substellar objects around the sdB <span class="hlt">eclipsing</span> <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, Liying; Qian, Shengbang; Liao, Wenping; Zhao, Ergang; Li, Linjia</p> <p>2016-07-01</p> <p>The sdB-type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> consists a very hot subdwarf B (sdB) type primary and a <span class="hlt">low</span> <span class="hlt">mass</span> secondary with short period. They are detached <span class="hlt">binaries</span> and show very narrow <span class="hlt">eclipse</span> profiles, which benefits the determination of the precise <span class="hlt">eclipse</span> times. With the precise times of light minimum, we can detected small mass objects around them by analyzing the observed-calculated (O-C) curve based on the light time effect. For searching the substellar objects orbiting around the <span class="hlt">binaries</span>, we have monitored sdB-type <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> for decades. A group of brown dwarfs and planets have been detected since then. In the present paper, we focus on the target NSVS07826147, which may be another exoplanet host candidate among the group of the sdB-type <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ASPC..496...76H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ASPC..496...76H"><span id="translatedtitle">Multiples Among Detached <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> from the ASAS Catalog</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hełminiak, K. G.; Konacki, M.; Ratajczak, M.; Jordán, A.; Espinoza, N.; Brahm, R.; Kambe, E.; Ukita, N.</p> <p>2015-07-01</p> <p>We have been conducting a spectroscopic survey of detached <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> (DEBs) from the All-Sky Automated Survey (ASAS) database for more than three years. Thousands of high-resolution spectra of >300 systems have been secured, and used for radial velocity measurements and spectral analysis. We have found a zoo of multiple systems in our sample, such as spectroscopic triples and quadruples, visual <span class="hlt">binaries</span> with <span class="hlt">eclipsing</span> components, and circumbinary <span class="hlt">low-mass</span> companions, including sub-stellar-mass candidates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985ASSL..113...61M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985ASSL..113...61M"><span id="translatedtitle"><span class="hlt">Low-mass</span> X-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McClintock, J. E.; Rappaport, S. A.</p> <p></p> <p>A review is given of current understanding of <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs), which are luminous X-ray sources composed of a late-type optical companion (mass less than about 1 solar mass) and a neutron star (or possibly a black hole). Thirty-two LMXBs have been identified with optical counterparts in the Galaxy and one in the Large Magellanic Cloud (Brad and McClintock, 1983). It is unlikely that there are more than about 100 active LMXBs in the Galaxy, compared with about 200,000 cataclysmic variables. Topics covered in the review are: typical X-ray and optical properties; orbital periods; the nature of the compact source; accretion disks; formation; mass transfer mechanisms; and globular clusters and bright bulge X-ray sources.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ascl.soft06002P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ascl.soft06002P"><span id="translatedtitle">PHOEBE: PHysics Of <span class="hlt">Eclipsing</span> <span class="hlt">BinariEs</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prsa, Andrej; Matijevic, Gal; Latkovic, Olivera; Vilardell, Francesc; Wils, Patrick</p> <p>2011-06-01</p> <p>PHOEBE (PHysics Of <span class="hlt">Eclipsing</span> <span class="hlt">BinariEs</span>) is a modeling package for <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars, built on top of the widely used WD program (Wilson & Devinney 1971). This introductory paper overviews most important scientific extensions (incorporating observational spectra of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> into the solution-seeking process, extracting individual temperatures from observed color indices, main-sequence constraining and proper treatment of the reddening), numerical innovations (suggested improvements to WD's Differential Corrections method, the new Nelder & Mead's downhill Simplex method) and technical aspects (back-end scripter structure, graphical user interface). While PHOEBE retains 100% WD compatibility, its add-ons are a powerful way to enhance WD by encompassing even more physics and solution reliability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AJ....129.2806Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AJ....129.2806Z"><span id="translatedtitle">Deep, <span class="hlt">Low</span> <span class="hlt">Mass</span> Ratio Overcontact <span class="hlt">Binaries</span>. II. IK Persei</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, L.-Y.; Qian, S.-B.; Soonthornthum, B.; Yang, Y.-G.</p> <p>2005-06-01</p> <p>BV photometric light curves of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> IK Per were obtained during three nights in 2002 December. The photometric elements were computed using the Wilson-Devinney code. The results reveal that IK Per is an A-type overcontact <span class="hlt">binary</span> system with a <span class="hlt">low</span> <span class="hlt">mass</span> ratio of q=0.17 and a large degree of overcontact of 60%. The asymmetry of the light curves (i.e., the O'Connell effect) is explained by spot models. The observed long-term orbital period decrease [dP/dt=-(2.5+/-0.09)×10-7 days yr-1] is probably influenced by the presence of a third body in the system. The <span class="hlt">low</span> <span class="hlt">mass</span> ratio, high degree of overcontact, and secular orbital decrease all indicate that the situation of IK Per resembles those of FG Hya, GR Vir, and AW UMa. Because of the decrease of their orbital periods, the shrinking of the inner and outer critical Roche lobes will lead the common envelopes to overlap more, and finally the systems will evolve into single rapid-rotation stars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MNRAS.454.2946L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MNRAS.454.2946L"><span id="translatedtitle">Properties of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> from all-sky surveys - II. Detached <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in Catalina Sky Surveys</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee ( ), Chien-Hsiu</p> <p>2015-12-01</p> <p><span class="hlt">Eclipsing</span> <span class="hlt">binaries</span> play pivotal roles in our understanding of stellar properties. In the era of all-sky surveys, thousands of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> have been charted, yet their light curves remain unexplored. The goal of this work is to use time series and colour information to extract physical parameters of the <span class="hlt">binary</span> systems when the spectroscopic information is not available. Inspired by the work of Devor et al., we use the Detached <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Light curve fitter (DEBiL) and the Method for <span class="hlt">Eclipsing</span> Component Identification (MECI) to derive basic properties of the <span class="hlt">binary</span> systems identified by the Catalina Sky Surveys. We derive the mass, fractional radius, and age for 2170 <span class="hlt">binary</span> systems. We report 211 eccentric systems and compare their properties to the tidal circularization theory. From the mass estimate, we present a subsample of <span class="hlt">low-mass</span> M-dwarfs which warrant further follow-up to test the stellar models at the <span class="hlt">low-mass</span> regime. With MECI, we are able to estimate the distance to individual <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system and use them to probe the large-scale structure of the Milky Way. We demonstrate that DEBiL and MECI are instrumental to investigate <span class="hlt">eclipsing</span> <span class="hlt">binary</span> light curves in the era of all-sky surveys, and provide estimates of stellar parameters when the spectroscopic information is not available.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013MNRAS.429..256P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013MNRAS.429..256P"><span id="translatedtitle"><span class="hlt">Eclipsing</span> post-common envelope <span class="hlt">binaries</span> from the Catalina surveys</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parsons, S. G.; Gänsicke, B. T.; Marsh, T. R.; Drake, A. J.; Dhillon, V. S.; Littlefair, S. P.; Pyrzas, S.; Rebassa-Mansergas, A.; Schreiber, M. R.</p> <p>2013-02-01</p> <p>We analyse the Catalina Real-time Transient Survey light curves of 835 spectroscopically confirmed white dwarf plus main-sequence <span class="hlt">binaries</span> from the Sloan Digital Sky Survey (SDSS) with g < 19, in search of new <span class="hlt">eclipsing</span> systems. We identify 29 <span class="hlt">eclipsing</span> systems, 12 of which were previously unknown. This brings the total number of <span class="hlt">eclipsing</span> white dwarf plus main-sequence <span class="hlt">binaries</span> to 49. Our set of new <span class="hlt">eclipsing</span> systems contains two with periods of 1.9 and 2.3 d, making them the longest period <span class="hlt">eclipsing</span> white dwarf <span class="hlt">binaries</span> known. We also identify one system which shows very large ellipsoidal modulation (almost 0.3 mag), implying that the system is both very close to Roche lobe overflow and at high inclination. However, our follow-up photometry failed to firmly detect an <span class="hlt">eclipse</span>, meaning that either this system contains a cool white dwarf and hence the <span class="hlt">eclipse</span> is very shallow and undetectable in our red-sensitive photometry or that it is non-<span class="hlt">eclipsing</span>. Radial velocity measurements for the main-sequence stars in three of our newly identified <span class="hlt">eclipsing</span> systems imply that their white dwarf masses are lower than those inferred from modelling their SDSS spectra. 13 non-<span class="hlt">eclipsing</span> post-common envelope <span class="hlt">binaries</span> were also identified, from either reflection or ellipsoidal modulation effects. The white dwarfs in our newly discovered <span class="hlt">eclipsing</span> systems span a wide range of parameters, including <span class="hlt">low-mass</span> (˜0.3 M⊙), very hot (80 000 K) and a DC white dwarf. The spectral types of the main-sequence stars range from M2 to M6. This makes our sample ideal for testing white dwarf and <span class="hlt">low-mass</span> star mass-radius relationships as well as close <span class="hlt">binary</span> evolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22520068','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22520068"><span id="translatedtitle">KEPLER <span class="hlt">ECLIPSING</span> <span class="hlt">BINARIES</span> WITH STELLAR COMPANIONS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gies, D. R.; Matson, R. A.; Guo, Z.; Lester, K. V.; Orosz, J. A.; Peters, G. J. E-mail: rmatson@chara.gsu.edu E-mail: lester@chara.gsu.edu E-mail: gjpeters@mucen.usc.edu</p> <p>2015-12-15</p> <p>Many short-period <span class="hlt">binary</span> stars have distant orbiting companions that have played a role in driving the <span class="hlt">binary</span> components into close separation. Indirect detection of a tertiary star is possible by measuring apparent changes in <span class="hlt">eclipse</span> times of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> as the <span class="hlt">binary</span> orbits the common center of mass. Here we present an analysis of the <span class="hlt">eclipse</span> timings of 41 <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> observed throughout the NASA Kepler mission of long duration and precise photometry. This subset of <span class="hlt">binaries</span> is characterized by relatively deep and frequent <span class="hlt">eclipses</span> of both stellar components. We present preliminary orbital elements for seven probable triple stars among this sample, and we discuss apparent period changes in seven additional <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> that may be related to motion about a tertiary in a long period orbit. The results will be used in ongoing investigations of the spectra and light curves of these <span class="hlt">binaries</span> for further evidence of the presence of third stars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21224439','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21224439"><span id="translatedtitle">KOI-126: a triply <span class="hlt">eclipsing</span> hierarchical triple with two <span class="hlt">low-mass</span> stars.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Carter, Joshua A; Fabrycky, Daniel C; Ragozzine, Darin; Holman, Matthew J; Quinn, Samuel N; Latham, David W; Buchhave, Lars A; Van Cleve, Jeffrey; Cochran, William D; Cote, Miles T; Endl, Michael; Ford, Eric B; Haas, Michael R; Jenkins, Jon M; Koch, David G; Li, Jie; Lissauer, Jack J; MacQueen, Phillip J; Middour, Christopher K; Orosz, Jerome A; Rowe, Jason F; Steffen, Jason H; Welsh, William F</p> <p>2011-02-01</p> <p>The Kepler spacecraft has been monitoring the light from 150,000 stars in its primary quest to detect transiting exoplanets. Here, we report on the detection of an <span class="hlt">eclipsing</span> stellar hierarchical triple, identified in the Kepler photometry. KOI-126 [A, (B, C)], is composed of a <span class="hlt">low-mass</span> <span class="hlt">binary</span> [masses M(B) = 0.2413 ± 0.0030 solar mass (M(⊙)), M(C) = 0.2127 ± 0.0026 M(⊙); radii R(B) = 0.2543 ± 0.0014 solar radius (R(⊙)), R(C) = 0.2318 ± 0.0013 R(⊙); orbital period P(1) = 1.76713 ± 0.00019 days] on an eccentric orbit about a third star (mass M(A) = 1.347 ± 0.032 M(⊙); radius R(A) = 2.0254 ± 0.0098 R(⊙); period of orbit around the <span class="hlt">low-mass</span> <span class="hlt">binary</span> P(2) = 33.9214 ± 0.0013 days; eccentricity of that orbit e(2) = 0.3043 ± 0.0024). The <span class="hlt">low-mass</span> pair probe the poorly sampled fully convective stellar domain offering a crucial benchmark for theoretical stellar models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016nova.pres..940K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016nova.pres..940K"><span id="translatedtitle">Record-Breaking <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kohler, Susanna</p> <p>2016-05-01</p> <p>A new record holder exists for the longest-period <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star system: TYC-2505-672-1. This intriguing system contains a primary star that is <span class="hlt">eclipsed</span> by its companion once every 69 years with each <span class="hlt">eclipse</span> lasting several years!120 Years of ObservationsIn a recent study, a team of scientists led by Joseph Rodriguez (Vanderbilt University) characterizes the components of TYC-2505-672-1. This <span class="hlt">binary</span> star system consists of an M-type red giant star that undergoes a ~3.45-year-long, near-total <span class="hlt">eclipse</span> with a period of ~69.1 years. This period is more than double that of the previous longest-period <span class="hlt">eclipsing</span> <span class="hlt">binary</span>!Rodriguez and collaborators combined photometric observations of TYC-2505-672-1 by the Kilodegree Extremely Little Telescope (KELT) with a variety of archival data, including observations by the American Association of Variable Star Observers (AAVSO) network and historical data from the Digital Access to a Sky Century @ Harvard (DASCH) program.In the 120 years spanned by these observations, two <span class="hlt">eclipses</span> are detected: one in 1942-1945 and one in 2011-2015. The authors use the observations to analyze the components of the system and attempt to better understand what causes its unusual light curve.Characterizing an Unusual SystemObservations of TYC-2505-672-1 plotted from 1890 to 2015 reveal two <span class="hlt">eclipses</span>. (The blue KELT observations during the <span class="hlt">eclipse</span> show upper limits only.) [Rodriguez et al. 2016]By modeling the systems emission, Rodriguez and collaborators establish that TYC-2505-672-1 consists of a 3600-K primary star thats the M giant orbited by a small, hot, dim companion thats a toasty 8000 K. But if the companion is small, why does the <span class="hlt">eclipse</span> last several years?The authors argue that the best model of TYC-2505-672-1 is one in which the small companion star is surrounded by a large, opaque circumstellar disk. Rodriguez and collaborators suggest that the companion could be a former red giant whose atmosphere was stripped from it, leaving behind</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AAS...20915102T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AAS...20915102T"><span id="translatedtitle">The <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> MY Cygni</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tucker, Rebecca; Sowell, J. R.; Williamon, R. M.</p> <p>2006-12-01</p> <p>Differential UBV photoelectric photometry for the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> MY Cyg is presented. The Wilson-Devinney program is used to solve simultaneously the three light curves together with previously published radial velocities. We determine absolute dimensions and estimate the age of the system. We compute color indices for the two stars and estimate color excesses. A comparison is made with the previous solution found with the Russell-Merrill method.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active"><span>2</span></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_2 --> <div id="page_3" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="41"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SASS...32..179S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SASS...32..179S"><span id="translatedtitle"><span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> with Possible Tertiary Components</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Snyder, LeRoy F.</p> <p>2013-05-01</p> <p>Many <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star systems (EBS) show long-term variations in their orbital periods which are evident in their O-C (observed minus calculated period) diagrams. This research carried out an analysis of 324 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems taken from the systems analyzed in the Bob Nelson's O-C Files database. Of these 18 systems displayed evidence of periodic variations of the arrival times of the <span class="hlt">eclipses</span>. These rates of period changes are sinusoidal variations. The sinusoidal character of these variations is suggestive of Keplerian motion caused by an orbiting companion. The reason for these changes is unknown, but mass loss, apsidal motion, magnetic activity and the presence of a third body have been proposed. This paper has assumed light time effect as the cause of the sinusoidal variations caused by the gravitational pull of a tertiary companion orbiting around the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems. An observed minus calculated (O-C) diagram of the 324 systems was plotted using a quadratic ephemeris to determine if the system displayed a sinusoidal trend in theO-C residuals. After analysis of the 18 systems, seven systems, AW UMa, BB PEG, OO Aql, V508 Oph, VW Cep, WCrv and YY ERI met the benchmark of the criteria of a possible orbiting companion. The other 11 systems displayed a sinusoidal variation in the O-C residuals of the primary <span class="hlt">eclipses</span> but these systems in the Bob Nelson's O-C Files did not contain times of minimum (Tmin) of the secondary <span class="hlt">eclipses</span> and therefore not conclusive in determining the presents of the effects of a tertiary companion. An analysis of the residuals of the seven systems yields a light-time semi-amplitude, orbital period, eccentricity and mass of the tertiary companion as the amplitude of the variation is proportional to the mass, period and inclination of the 3rd orbiting body. Knowing the <span class="hlt">low</span> <span class="hlt">mass</span> of the tertiary body in the seven cases the possibility of five of these tertiary companions being brown dwarfs is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22365202','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22365202"><span id="translatedtitle">Radius constraints from high-speed photometry of 20 <span class="hlt">low-mass</span> white dwarf <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hermes, J. J.; Brown, Warren R.; Kilic, Mukremin; Gianninas, A.; Chote, Paul; Sullivan, D. J.; Winget, D. E.; Bell, Keaton J.; Falcon, R. E.; Winget, K. I.; Harrold, Samuel T.; Montgomery, M. H.; Mason, Paul A.</p> <p>2014-09-01</p> <p>We carry out high-speed photometry on 20 of the shortest-period, detached white dwarf <span class="hlt">binaries</span> known and discover systems with <span class="hlt">eclipses</span>, ellipsoidal variations (due to tidal deformations of the visible white dwarf), and Doppler beaming. All of the <span class="hlt">binaries</span> contain <span class="hlt">low-mass</span> white dwarfs with orbital periods of less than four hr. Our observations identify the first eight tidally distorted white dwarfs, four of which are reported for the first time here. We use these observations to place empirical constraints on the mass-radius relationship for extremely <span class="hlt">low-mass</span> (≤0.30 M {sub ☉}) white dwarfs. We also detect Doppler beaming in several of these <span class="hlt">binaries</span>, which confirms their high-amplitude radial-velocity variability. All of these systems are strong sources of gravitational radiation, and long-term monitoring of those that display ellipsoidal variations can be used to detect spin-up of the tidal bulge due to orbital decay.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22011953','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22011953"><span id="translatedtitle">ROTATIONAL DOPPLER BEAMING IN <span class="hlt">ECLIPSING</span> <span class="hlt">BINARIES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Groot, Paul J.</p> <p>2012-01-20</p> <p>In <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> the stellar rotation of the two components will cause a rotational Doppler beaming during <span class="hlt">eclipse</span> ingress and egress when only part of the <span class="hlt">eclipsed</span> component is covered. For <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> with fast spinning components this photometric analog of the well-known spectroscopic Rossiter-McLaughlin effect can exceed the strength of the orbital effect. Example light curves are shown for a detached double white dwarf <span class="hlt">binary</span>, a massive O-star <span class="hlt">binary</span> and a transiting exoplanet case, similar to WASP-33b. Inclusion of the rotational Doppler beaming in <span class="hlt">eclipsing</span> systems is a prerequisite for deriving the correct stellar parameters from fitting high-quality photometric light curves and can be used to determine stellar obliquities as well as, e.g., an independent measure of the rotational velocity in those systems that may be expected to be fully synchronized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016IBVS.6167....1P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016IBVS.6167....1P"><span id="translatedtitle">Minima Times of Selected <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parimucha, S.; Dubovsky, P.; Kudak, V.; Perig, V.</p> <p>2016-05-01</p> <p>We present 221 CCD minima times of the 76 selected <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> obtained during 2013-2016 at Observatory at Kolonica Saddle in Slovakia and Observatory of Laboratory of Space Research, Uzhhorod National University in Ukraine</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JAVSO..43..238S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JAVSO..43..238S"><span id="translatedtitle">Recent Minima of 171 <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Stars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Samolyk, G.</p> <p>2015-12-01</p> <p>This paper continues the publication of times of minima for 171 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars from observations reported to the AAVSO EB section. Times of minima from observations received by the author from March 2015 thru October 2015 are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005HiA....13..451U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005HiA....13..451U"><span id="translatedtitle"><span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> in the Magellanic Clouds</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Udalski, Andrzej</p> <p>2005-01-01</p> <p>We present results of the search for <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in the Magellanic Cloud fields covering central parts of these galaxies. The data were collected during the second phase of the Optical Gravitational Lensing Experiment survey (OGLE-II) in 1997-2000. In total about 1500 and 3000 <span class="hlt">eclipsing</span> stars were found in the Small and Large Magellanic Cloud respectively. The photometric data of all objects are available to the astronomical community from the OGLE Internet archive. We also discuss observational prospects for the <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> field in relation with the third phase of the OGLE project (OGLE-III) which started in 2001.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...830..153J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...830..153J"><span id="translatedtitle">Evolution of <span class="hlt">Low-mass</span> X-Ray <span class="hlt">Binaries</span>: The Effect of Donor Evaporation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jia, Kun; Li, Xiang-Dong</p> <p>2016-10-01</p> <p>Millisecond pulsars (MSPs) are thought to originate from <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs). The discovery of <span class="hlt">eclipsing</span> radio MSPs, including redbacks and black widows, indicates that evaporation of the donor star by the MSP’s irradiation takes place during the LMXB evolution. In this work, we investigate the effect of donor evaporation on the secular evolution of LMXBs, considering different evaporation efficiencies and related angular momentum loss. We find that for widening LMXBs, the donor star leaves a less massive white dwarf than without evaporation; for contracting systems, evaporation can speed up the evolution, resulting in dynamically unstable mass transfer and possibly the formation of isolated MSPs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AN....331..397P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AN....331..397P"><span id="translatedtitle"><span class="hlt">Eclipsing</span> <span class="hlt">binaries</span> in the MOST satellite fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pribulla, T.; Rucinski, S. M.; Latham, D. W.; Quinn, S. N.; Siwak, M.; Matthews, J. M.; Kuschnig, R.; Rowe, J. F.; Guenther, D. B.; Moffat, A. F. J.; Sasselov, D.; Walker, G. A. H.; Weiss, W. W.</p> <p>2010-04-01</p> <p>Sixteen new <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> have been discovered by the MOST satellite among guide stars used to point its telescope in various fields. Several previously known <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> were also observed by MOST with unprecedented quality. Among the objects we discuss in more detail are short-period <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> with eccentric orbits in young open clusters: V578 Mon in NGC 2244 and HD 47934 in NGC 2264. Long nearly-continuous photometric runs made it possible to discover three long-period <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> with orbits seen almost edge-on: HD 45972 with P = 28.1 days and two systems (GSC 154 1247 and GSC 2141 526) with P > 25 days. The high precision of the satellite data led to discoveries of <span class="hlt">binaries</span> with very shallow <span class="hlt">eclipses</span> (e.g., HD 46180 with A = 0.016 mag, and HD 47934 with A = 0.025 mag). Ground-based spectroscopy to support the space-based photometry was used to refine the models of several of the systems. Based on photometric data from MOST, a Canadian Space Agency mission (jointly operated by Microsat Systems Canada Inc. (formerly the Space Division of Dynacon Inc.), the University of Toronto Institute for Aerospace Studies - SpaceFlight Lab and the University of British Columbia, with the assistance of the University of Vienna), and on spectroscopic data from the David Dunlap Observatory, University of Toronto, and Las Campanas Observatory, Carnegie Institute Washington.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AAS...22315522G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AAS...22315522G"><span id="translatedtitle">Characterizing the <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> KOI 1120</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gonzales, Alexandria; Swift, J.; Shporer, A.; Sanchis Ojeda, R.; Johnson, J. A.</p> <p>2014-01-01</p> <p>Because the NASA Kepler Mission is primarily a search for exoplanetary objects, its exquisite photometric precision has also opened scientific frontiers in stellar astrophysics. As part of the cool Kepler <span class="hlt">eclipsing</span> <span class="hlt">binary</span> program, we present a case study of a particularly interesting KOI false positive—KOI-1120. This K giant/G dwarf <span class="hlt">eclipsing</span> <span class="hlt">binary</span> pair reveals a deep secondary <span class="hlt">eclipse</span> of 16% and a 7% primary <span class="hlt">eclipse</span> depth with multiple star spot crossing events over the Kepler time baseline. Kepler data supplemented with Keck/HIRES radial velocity measurements, Keck/NIRC2 adaptive optics imaging, and Palomar/TripleSpec near infrared spectra enable precise and accurate modeling of the system. Characterizing this distinctive system will provide important insights into stellar astrophysics and stellar evolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013RAA....13.1471Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013RAA....13.1471Y"><span id="translatedtitle">The <span class="hlt">low-mass</span> classic Algol-type <span class="hlt">binary</span> UU Leo revisited</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Yuan-Gui</p> <p>2013-12-01</p> <p>New multi-color photometry of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> UU Leo, acquired from 2010 to 2013, was carried out by using the 60-cm and 85-cm telescopes at the Xinglong station, which is administered by National Astronomical Observatories, Chinese Academy of Sciences. With the updated Wilson-Devinney code, the photometric solution was derived from BVR light curves. The results imply that UU Leo is a semi-detached Algol-type <span class="hlt">binary</span>, with a mass ratio of q = 0.100(±0.002). The change in orbital period was reanalyzed based on all available <span class="hlt">eclipsing</span> times. The O - C curve could be described by an upward parabola superimposed on a quasi-sinusoidal curve. The period and semi-amplitudes are Pmod = 54.5(±1.1) yr and A = 0.0273d(±0.0015d), which may be attributed to the light-time effect via the presence of an invisible third body. The long-term period increases at a rate of dP/dt = +4.64(±0.14) × 10-7d yr-1, which may be interpreted by the conserved mass being transferred from the secondary to the primary. With mass being transferred, the <span class="hlt">low-mass</span> Algol-type <span class="hlt">binary</span> UU Leo may evolve into a <span class="hlt">binary</span> system with a main sequence star and a helium white dwarf.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AAS...22040601P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AAS...22040601P&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> with the Kepler Mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prsa, Andrej; Kepler Eclipsing Binary Working Group</p> <p>2012-05-01</p> <p>Kepler has revolutionized the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> field by providing us essentially uninterrupted data of unprecedented quality. Out of 160,000 targets, we detected over 2500 <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>. These range in orbital periods from as short as 0.3 days, all the way to several years, and encompass stellar types across the H-R diagram. In this talk I will present the collaborative effort of the Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Working Group to study and characterize these systems on a statistical level: their distribution in periods, galactic latitude, spectral type, fundamental stellar properties and multiplicity as evidenced by <span class="hlt">eclipse</span> timing variations. I will further show the gems that have sprung from this sample, which were modeled and interpreted to reveal intrinsically pulsating components, runaway encounters with massive tertiaries, stellar objects that populate the lowest end of the main sequence and circumbinary planets. I will critically review and discuss the causes of data systematics and detrending, and introduce a novel algorithm to classify light curves into morphological types using Locally Linear Embedding. Finally, I will touch on the dark side of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> as the primary cause of false positives in extrasolar planet detections with Kepler.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015RAA....15..889G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015RAA....15..889G"><span id="translatedtitle">Discovery of a deep, <span class="hlt">low</span> <span class="hlt">mass</span> ratio overcontact <span class="hlt">binary</span> GSC 03517-00663</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guo, Di-Fu; Li, Kai; Hu, Shao-Ming; Jiang, Yun-Guo; Gao, Dong-Yang; Chen, Xu</p> <p>2015-06-01</p> <p>When observing blazars, we identified a new <span class="hlt">eclipsing</span> <span class="hlt">binary</span> named GSC 03517-00663. The light curves of GSC 03517-00663 are typical of EW-type light curves. Based on the observation using the 1 m telescope at the Weihai Observatory of Shandong University, complete VRI light curves were determined. Then, we analyzed the multiple light curves using the Wilson-Devinney program. It was found that GSC 03517-00663 has a mass ratio of q = 0.164 and a degree of contact of f = 69.2%. GSC 03517-00663 is a deep, <span class="hlt">low</span> <span class="hlt">mass</span> ratio overcontact <span class="hlt">binary</span>. The light curves of GSC 03517-00663 show a strong O'Connell effect, which was explained by employing a dark spot on the secondary component. Supported by the National Natural Science Foundation of China.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22034561','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22034561"><span id="translatedtitle">ROTATIONAL VELOCITIES OF INDIVIDUAL COMPONENTS IN VERY <span class="hlt">LOW</span> <span class="hlt">MASS</span> <span class="hlt">BINARIES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Konopacky, Q. M.; Macintosh, B. A.; Ghez, A. M.; Fabrycky, D. C.; White, R. J.; Barman, T. S.; Rice, E. L.; Hallinan, G.; Duchene, G. E-mail: konopacky@di.utoronto.ca E-mail: fabrycky@ucolick.org E-mail: barman@lowell.edu E-mail: gh@astro.caltech.edu</p> <p>2012-05-01</p> <p>We present rotational velocities for individual components of 11 very <span class="hlt">low</span> <span class="hlt">mass</span> (VLM) <span class="hlt">binaries</span> with spectral types between M7 and L7.5. These results are based on observations taken with the near-infrared spectrograph, NIRSPEC, and the Keck II laser guide star adaptive optics system. We find that the observed sources tend to be rapid rotators (v sin i > 10 km s{sup -1}), consistent with previous seeing-limited measurements of VLM objects. The two sources with the largest v sin i, LP 349-25B and HD 130948C, are rotating at {approx}30% of their break-up speed, and are among the most rapidly rotating VLM objects known. Furthermore, five <span class="hlt">binary</span> systems, all with orbital semimajor axes {approx}<3.5 AU, have component v sin i values that differ by greater than 3{sigma}. To bring the <span class="hlt">binary</span> components with discrepant rotational velocities into agreement would require the rotational axes to be inclined with respect to each other, and that at least one component is inclined with respect to the orbital plane. Alternatively, each component could be rotating at a different rate, even though they have similar spectral types. Both differing rotational velocities and inclinations have implications for <span class="hlt">binary</span> star formation and evolution. We also investigate possible dynamical evolution in the triple system HD 130948A-BC. The close <span class="hlt">binary</span> brown dwarfs B and C have significantly different v sin i values. We demonstrate that components B and C could have been torqued into misalignment by the primary star, A, via orbital precession. Such a scenario can also be applied to another triple system in our sample, GJ 569A-Bab. Interactions such as these may play an important role in the dynamical evolution of VLM <span class="hlt">binaries</span>. Finally, we note that two of the <span class="hlt">binaries</span> with large differences in component v sin i, LP 349-25AB and 2MASS 0746+20AB, are also known radio sources.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AAS...21642303H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AAS...21642303H"><span id="translatedtitle">Spectroscopic Survey of Detached <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> from the ASAS Catalog</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Helminiak, Krzysztof; Konacki, M.; Kaluzny, J.; Rozyczka, M.; Zloczewski, K.; Ratajczak, M.; Muterspaugh, M. W.; Reichart, D. E.; Ivarsen, K. M.; Haislip, J. B.; Crain, A.; Foster, A. C.; Nysewander, M. C.; LaCluyze, A. P.</p> <p>2010-05-01</p> <p>We present the most interesting results from our survey of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> from the All-Sky Automated Survey (ASAS) catalog. Radial velocities were calculated from high-resolution spectra obtained with Keck I/HIRES, Radcliffe/GIRAFFE and AAT/UCLES telescopes/spectrographs. A novel iodine cell technique for double-lined <span class="hlt">binaries</span> was also involved. Photometry was taken directly from the ASAS or from dedicated observations at the Elizabeth telescope (SAAO) and fully-automated PROMPT facility. For a sample of systems we derived very precise absolute values of fundamental parameters. In our sample we found 6 new <span class="hlt">low-mass</span> systems, 4 pre-main-sequence candidates, and several other <span class="hlt">binaries</span> interesting from the evolutionary point of view.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22270771','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22270771"><span id="translatedtitle">THE RADIUS DISCREPANCY IN <span class="hlt">LOW-MASS</span> STARS: SINGLE VERSUS <span class="hlt">BINARIES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Spada, F.; Demarque, P.; Kim, Y.-C.; Sills, A.</p> <p>2013-10-20</p> <p>A long-standing issue in the theory of <span class="hlt">low-mass</span> stars is the discrepancy between predicted and observed radii and effective temperatures. In spite of the increasing availability of very precise radius determinations from <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> and interferometric measurements of radii of single stars, there is no unanimous consensus on the extent (or even the existence) of the discrepancy and on its connection with other stellar properties (e.g., metallicity, magnetic activity). We investigate the radius discrepancy phenomenon using the best data currently available (accuracy ∼< 5%). We have constructed a grid of stellar models covering the entire range of <span class="hlt">low-mass</span> stars (0.1-1.25 M{sub ☉}) and various choices of the metallicity and mixing length parameter, α. We used an improved version of the Yale Rotational stellar Evolution Code, implementing surface boundary conditions based on the most up-to-date PHOENIX atmosphere models. Our models are in good agreement with others in the literature and improve and extend the <span class="hlt">low</span> <span class="hlt">mass</span> end of the Yale-Yonsei isochrones. Our calculations include rotation-related quantities, such as moments of inertia and convective turnover timescales, useful in studies of magnetic activity and rotational evolution of solar-like stars. Consistent with previous works, we find that both <span class="hlt">binaries</span> and single stars have radii inflated by about 3% with respect to the theoretical models; among <span class="hlt">binaries</span>, the components of short orbital period systems are found to be the most deviant. We conclude that both <span class="hlt">binaries</span> and single stars are comparably affected by the radius discrepancy phenomenon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1980A%26AS...42...15M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1980A%26AS...42...15M"><span id="translatedtitle">Revised photometric elements of eight <span class="hlt">eclipsing</span> <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mezzetti, M.; Predolin, F.; Giuricin, G.; Mardirossian, F.</p> <p>1980-10-01</p> <p>Photoelectric lightcurves of eight <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>, known as detached systems, have been reanalysed by means of Wood's model in order to obtain homogeneous photometric elements. All <span class="hlt">binaries</span> are confirmed to be detached. TU Cam, CW CMa, YZ Cas, CW Eri, CO Lac and EE Peg appear to be normal main-sequence (or near main-sequence) detached systems, but only the absolute elements of CO Lac are well-known. The detached <span class="hlt">binaries</span> EK Cep and IQ Per are shown to be anomalous.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AAN...507....1T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AAN...507....1T"><span id="translatedtitle">Observations of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> b Persei</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Templeton, Matthew R.</p> <p>2015-01-01</p> <p>Dr. Robert Zavala (USNO-Flagstaff) et al. request V time-series observations of the bright variable star b Persei 7-21 January 2015 UT, in hopes of catching a predicted <span class="hlt">eclipse</span> on January 15. This is a follow-up to the February 2013 campaign announced in Alert Notice 476, and will be used as a photometric comparison for upcoming interferometric observations with the Navy Precision Optical Interferometer (NPOI) in Arizona. b Per (V=4.598, B-V=0.054) is ideal for photoelectric photometers or DSLR cameras. Telescopic CCD observers may observe by stopping down larger apertures. Comparison and check stars assigned by PI: Comp: SAO 24412, V=4.285, B-V = -0.013; Check: SAO 24512, V=5.19, B-V = -0.05. From the PI: "[W]e wanted to try and involve AAVSO observers in a follow up to our successful detection of the b Persei <span class="hlt">eclipse</span> of Feb 2013, AAVSO Alert Notice 476 and Special Notice 333. Our goal now is to get good time resolution photometry as the third star passes in front of the close ellipsoidal <span class="hlt">binary</span>. The potential for multiple <span class="hlt">eclipses</span> exists. The close <span class="hlt">binary</span> has a 1.5 day orbital period, and the <span class="hlt">eclipsing</span> C component requires about 4 days to pass across the close <span class="hlt">binary</span> pair. The primary <span class="hlt">eclipse</span> depth is 0.15 magnitude. Photometry to 0.02 or 0.03 mags would be fine to detect this <span class="hlt">eclipse</span>. <span class="hlt">Eclipse</span> prediction date (JD 2457033.79 = 2015 01 11 UT, ~+/- 1 day) is based on one orbital period from the 2013 <span class="hlt">eclipse</span>." More information is available at PI's b Persei <span class="hlt">eclipse</span> web page: http://inside.warren-wilson.edu/~dcollins/bPersei/. Finder charts with sequence may be created using the AAVSO Variable Star Plotter (https://www.aavso.org/vsp). Observations should be submitted to the AAVSO International Database. See full Alert Notice for more details and information on the targets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NewA...46...73E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NewA...46...73E"><span id="translatedtitle">The <span class="hlt">low</span> <span class="hlt">mass</span> ratio contact <span class="hlt">binary</span> system V728 Herculis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Erkan, N.; Ulaş, B.</p> <p>2016-07-01</p> <p>We present the orbital period study and the photometric analysis of the contact <span class="hlt">binary</span> system V728 Her. Our orbital period analysis shows that the period of the system increases (dP / dt = 1.92 ×10-7 dyr-1) and the mass transfer rate from the less massive component to more massive one is 2.51 ×10-8 M⊙y-1 . In addition, an advanced sinusoidal variation in period can be attributed to the light-time effect by a tertiary component or the Applegate mechanism triggered by the secondary component. The simultaneous multicolor BVR light and radial velocity curves solution indicates that the physical parameters of the system are M1 = 1.8M⊙ , M2 = 0.28M⊙ , R1 = 1.87R⊙ , R2 = 0.82R⊙ , L1 = 5.9L⊙ , and L2 = 1.2L⊙ . We discuss the evolutionary status and conclude that V728 Her is a deep (f = 81%), <span class="hlt">low</span> <span class="hlt">mass</span> ratio (q = 0.16) contact <span class="hlt">binary</span> system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21582794','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21582794"><span id="translatedtitle">KEPLER <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> STARS. II. 2165 <span class="hlt">ECLIPSING</span> <span class="hlt">BINARIES</span> IN THE SECOND DATA RELEASE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Slawson, Robert W.; Doyle, Laurance R.; Prsa, Andrej; Engle, Scott G.; Conroy, Kyle; Coughlin, Jared; Welsh, William F.; Orosz, Jerome A.; Gregg, Trevor A.; Fetherolf, Tara; Short, Donald R.; Windmiller, Gur; Rucker, Michael; Batalha, Natalie; Fabrycky, Daniel C.; Jenkins, Jon M.; Mullally, F.; Seader, Shawn E.</p> <p>2011-11-15</p> <p>The Kepler Mission provides nearly continuous monitoring of {approx}156,000 objects with unprecedented photometric precision. Coincident with the first data release, we presented a catalog of 1879 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems identified within the 115 deg{sup 2} Kepler field of view (FOV). Here, we provide an updated catalog augmented with the second Kepler data release which increases the baseline nearly fourfold to 125 days. Three hundred and eighty-six new systems have been added, ephemerides and principal parameters have been recomputed. We have removed 42 previously cataloged systems that are now clearly recognized as short-period pulsating variables and another 58 blended systems where we have determined that the Kepler target object is not itself the <span class="hlt">eclipsing</span> <span class="hlt">binary</span>. A number of interesting objects are identified. We present several exemplary cases: four <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> that exhibit extra (tertiary) <span class="hlt">eclipse</span> events; and eight systems that show clear <span class="hlt">eclipse</span> timing variations indicative of the presence of additional bodies bound in the system. We have updated the period and galactic latitude distribution diagrams. With these changes, the total number of identified <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems in the Kepler FOV has increased to 2165, 1.4% of the Kepler target stars. An online version of this catalog is maintained at http://keplerEBs.villanova.edu.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AAS...22734413T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AAS...22734413T"><span id="translatedtitle"><span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> B-Star Mass Determinations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Townsend, Amanda; Eikenberry, Stephen S.</p> <p>2016-01-01</p> <p>B-stars in <span class="hlt">binary</span> pairs provide a laboratory for key astrophysical measurements of massive stars, including key insights for the formation of compact objects (neutron stars and black holes). In their paper, Martayan et al (2004) find 23 Be <span class="hlt">binary</span> star pairs in NGC2004 in the Large Magellanic Cloud, five of which are both <span class="hlt">eclipsing</span> and spectroscopic <span class="hlt">binaries</span> with archival data from VLT-Giraffe and photometric data from MACHO. By using the Wilson <span class="hlt">eclipsing</span> <span class="hlt">binary</span> code (e.g., Wilson, 1971), we can determine preliminary stellar masses of the <span class="hlt">binary</span> components. We present the first results from this analysis. This study also serves as proof-of-concept for future observations with the Photonic Synthesis Telescope Array (Eikenberry et al., in prep) that we are currently building for low-cost, precision spectroscopic observations. With higher resolution and dedicated time for observations, we can follow-up observations of these Be stars as well as Be/X-ray <span class="hlt">binaries</span>, for improved mass measurements of neutron stars and black holes and better constraints on their origin/formation.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21394314','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21394314"><span id="translatedtitle">HIGH-PRECISION DYNAMICAL MASSES OF VERY <span class="hlt">LOW</span> <span class="hlt">MASS</span> <span class="hlt">BINARIES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Konopacky, Q. M.; Ghez, A. M.; McLean, I. S.; Barman, T. S.; Rice, E. L.; Bailey, J. I.; White, R. J.; Duchene, G. E-mail: ghez@astro.ucla.ed E-mail: barman@lowell.ed E-mail: white@chara.gsu.ed</p> <p>2010-03-10</p> <p>We present the results of a three year monitoring program of a sample of very <span class="hlt">low</span> <span class="hlt">mass</span> (VLM) field <span class="hlt">binaries</span> using both astrometric and spectroscopic data obtained in conjunction with the laser guide star adaptive optics system on the W. M. Keck II 10 m telescope. Among the 24 systems studied, 15 have undergone sufficient orbital motion, allowing us to derive their relative orbital parameters and hence their total system mass. These measurements more than double the number of mass measurements for VLM objects, and include the most precise mass measurement to date (<2%). Among the 11 systems with both astrometric and spectroscopic measurements, six have sufficient radial velocity variations to allow us to obtain individual component masses. This is the first derivation of the component masses for five of these systems. Altogether, the orbital solutions of these <span class="hlt">low</span> <span class="hlt">mass</span> systems show a correlation between eccentricity and orbital period, consistent with their higher mass counterparts. In our primary analysis, we find that there are systematic discrepancies between our dynamical mass measurements and the predictions of theoretical evolutionary models (TUCSON and LYON) with both models either underpredicting or overpredicting the most precisely determined dynamical masses. These discrepancies are a function of spectral type, with late-M through mid-L systems tending to have their masses underpredicted, while one T-type system has its mass overpredicted. These discrepancies imply that either the temperatures predicted by evolutionary and atmosphere models are inconsistent for an object of a given mass, or the mass-radius relationship or cooling timescales predicted by the evolutionary models are incorrect. If these spectral-type trends are correct and hold into the planetary mass regime, the implication is that the masses of directly imaged extrasolar planets are overpredicted by the evolutionary models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPC.1722d0007Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPC.1722d0007Y"><span id="translatedtitle">Apsidal motion in <span class="hlt">eclipsing</span> <span class="hlt">binary</span> GG Orionis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yilan, E.; Bulut, I.</p> <p>2016-03-01</p> <p>The study of apsidal motion in <span class="hlt">binary</span> stars with eccentric orbit is well known as an important source of information for the stellar internal structure as well as the possibility of verification of general relativity. In this study, the apsidal motion of the eccentric <span class="hlt">eclipsing</span> <span class="hlt">binary</span> GG Ori (P = 6.631 days, e = 0.22) has been analyzed using the times of minimum light taken from the literature and databases and the elements of apsidal motion have been computed. The method described by Giménez and García-Pelayo (1983) has been used for the apsidal motion analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009MNRAS.395..593P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009MNRAS.395..593P"><span id="translatedtitle">Spectroscopic survey of ASAS <span class="hlt">eclipsing</span> variables: search for chromospherically active <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars - I</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parihar, Padmakar; Messina, S.; Bama, P.; Medhi, B. J.; Muneer, S.; Velu, C.; Ahmad, A.</p> <p>2009-05-01</p> <p>We have started a spectroscopic survey to identify new chromospherically active components and <span class="hlt">low-mass</span> pre-main sequence (PMS) stars in recently discovered All Sky Automated Survey (ASAS) <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>. In this paper, we briefly describe our scientific motivation, the observing tools and the results obtained from the first phase of this survey. Using the available observing facilities in India, the spectroscopic observations of a sample of 180 candidate <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars selected from ASAS-I&II releases were carried out during 2004-2006. The strength of Hα emission was used to characterize the level of chromospheric activity. Our spectroscopic survey reveals that out of 180 stars about 36 <span class="hlt">binary</span> systems show excess Hα emission. One of the objects in our sample, ASAS 081700-4243.8, displays very strong Hα emission. Follow-up high-resolution spectroscopic observations reveal that this object is indeed very interesting and most likely a classical Be-type system with K0III companion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014xru..confE.227B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014xru..confE.227B"><span id="translatedtitle">A Unified Model of <span class="hlt">Low</span> <span class="hlt">Mass</span> X-ray <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Balucinska-Church, M.; Church, M.</p> <p>2014-07-01</p> <p>We present a unified physical model of <span class="hlt">Low</span> <span class="hlt">Mass</span> X-ray <span class="hlt">Binaries</span> explaining the basic Atoll and Z-track types of source. In all LMXB with luminosity above 1-2.10^{37} erg/s, we have a new fundamental result that the temperature of the Comptonizing ADC corona equals that of the neutron star, i.e. there is thermal equilibrium. This equilibrium explains the properties of the basic Banana State of Atoll sources. Below this luminosity, equilibrium breaks down, T_ADC rising towards 100 keV by an unknown heating mechanism, explaining the Island State. Above 5.10^{37} erg/s flaring begins in the GX-Atolls which we show is unstable nuclear burning. Above 1.10^{38} erg/s, LMXB are seen as Z-track sources. Flaring in these and the GX-Atolls occurs when the mass accretion rate to the neutron star falls to the critical value for unstable nuclear burning on the star. Below 2.10^{37} erg/s, a different unstable burning: X-ray bursting, takes over. We show that the Normal Branch of the Z-track consists simply of increasing mass accretion rate, as is the Banana State in Atolls. In the Horizontal Branch, a measured, strongly increasing radiation pressure of the neutron star disrupts the inner disk launching the relativistic jets seen on this branch.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22521875','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22521875"><span id="translatedtitle">EVOLUTION OF TRANSIENT <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARIES</span> TO REDBACK MILLISECOND PULSARS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jia, Kun; Li, Xiang-Dong</p> <p>2015-11-20</p> <p>Redback millisecond pulsars (MSPs; hereafter redbacks) are a subpopulation of <span class="hlt">eclipsing</span> MSPs in close <span class="hlt">binaries</span>. The formation processes of these systems are not clear. The three pulsars showing transitions between rotation- and accretion-powered states belong to both redbacks and transient <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs), suggesting a possible evolutionary link between them. Through <span class="hlt">binary</span> evolution calculations, we show that the accretion disks in almost all LMXBs are subject to the thermal-viscous instability during certain evolutionary stages, and the parameter space for the disk instability covers the distribution of known redbacks in the orbital period—companion mass plane. We accordingly suggest that the abrupt reduction of the mass accretion rate during quiescence of transient LMXBs provides a plausible way to switch on the pulsar activity, leading to the formation of redbacks, if the neutron star has been spun up to be an energetic MSP. We investigate the evolution of redbacks, taking into account the evaporation feedback, and discuss its possible influence on the formation of black widow MSPs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AJ....151..101A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AJ....151..101A"><span id="translatedtitle">Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Stars. VIII. Identification of False Positive <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> and Re-extraction of New Light Curves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Abdul-Masih, Michael; Prša, Andrej; Conroy, Kyle; Bloemen, Steven; Boyajian, Tabetha; Doyle, Laurance R.; Johnston, Cole; Kostov, Veselin; Latham, David W.; Matijevič, Gal; Shporer, Avi; Southworth, John</p> <p>2016-04-01</p> <p>The Kepler mission has provided unprecedented, nearly continuous photometric data of ∼200,000 objects in the ∼105 deg2 field of view (FOV) from the beginning of science operations in May of 2009 until the loss of the second reaction wheel in May of 2013. The Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Catalog contains information including but not limited to ephemerides, stellar parameters, and analytical approximation fits for every known <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system in the Kepler FOV. Using target pixel level data collected from Kepler in conjunction with the Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Catalog, we identify false positives among <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>, i.e., targets that are not <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> themselves, but are instead contaminated by <span class="hlt">eclipsing</span> <span class="hlt">binary</span> sources nearby on the sky and show <span class="hlt">eclipsing</span> <span class="hlt">binary</span> signatures in their light curves. We present methods for identifying these false positives and for extracting new light curves for the true source of the observed <span class="hlt">binary</span> signal. For each source, we extract three separate light curves for each quarter of available data by optimizing the signal-to-noise ratio, the relative percent <span class="hlt">eclipse</span> depth, and the flux <span class="hlt">eclipse</span> depth. We present 289 new <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in the Kepler FOV that were not targets for observation, and these have been added to the catalog. An online version of this catalog with downloadable content and visualization tools is maintained at http://keplerEBs.villanova.edu.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016OEJV..176...35A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016OEJV..176...35A"><span id="translatedtitle">Phenomenological modelling of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Andronov, I. L.; Tkachenko, M. G.; Chinarova, L. L.</p> <p>2016-03-01</p> <p>We review the method NAV ("New Algol Variable") first introduced in (2012Ap.....55..536A) which uses the locally-dependent shapes of <span class="hlt">eclipses</span> in an addition to the trigonometric polynomial of the second order (which typically describes the "out-of-<span class="hlt">eclipse</span>" part of the light curve with effects of reflection, ellipticity and O'Connell). <span class="hlt">Eclipsing</span> <span class="hlt">binary</span> stars are believed to show distinct <span class="hlt">eclipses</span> only if belonging to the EA (Algol) type. With a decreasing <span class="hlt">eclipse</span> width, the statistically optimal value of the trigonometric polynomial s(2003ASPC..292..391A) drastically increases from ~2 for elliptic (EL) variables without <span class="hlt">eclipses</span>, ~6-8 for EW and up to ~30-50 for some EA with narrow <span class="hlt">eclipses</span>. In this case of large number of parameters, the smoothing curve becomes very noisy and apparent waves (the Gibbs phenomenon) may be seen. The NAV set of the parameters may be used for classification in the GCVS, VSX and similar catalogs. The maximal number of parameters is m=12, which corresponds to s=5, if correcting both the period and the initial epoch. We have applied the method to few stars, also in a case of multi-color photometry (2015JASS...32..127A), when it is possible to use the phenomenological parameters from the NAV fit to estimate physical parameters using statistical dependencies. For the one-color observations, one may estimate the ratio of the surface brightnesses of the components. We compiled a catalog of phenomenological characteristics based on published observations. We conclude that the NAV approximation is better than the TP one even for the case of EW-type stars with much wider <span class="hlt">eclipses</span>. It may also be used to determine timings (see 2005ASPC..335...37A for a review of methods) or to determine parameters in the case of variable period, using a complete light curve modeling the phase variations. The method is illustrated on 2MASS J11080447-6143290 (EA-type), USNO-B1.0 1265-0306001 and USNO-B1.01266-0313413 (EW-type) and compared to various other methods</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22348233','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22348233"><span id="translatedtitle">Properties of an <span class="hlt">eclipsing</span> double white dwarf <span class="hlt">binary</span> NLTT 11748</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kaplan, David L.; Walker, Arielle N.; Marsh, Thomas R.; Bours, Madelon C. P.; Breedt, Elmé; Bildsten, Lars; Copperwheat, Chris M.; Dhillon, Vik S.; Littlefair, Stuart P.; Howell, Steve B.; Shporer, Avi; Steinfadt, Justin D. R.</p> <p>2014-01-10</p> <p>We present high-quality ULTRACAM photometry of the <span class="hlt">eclipsing</span> detached double white dwarf <span class="hlt">binary</span> NLTT 11748. This system consists of a carbon/oxygen white dwarf and an extremely <span class="hlt">low</span> <span class="hlt">mass</span> (<0.2 M {sub ☉}) helium-core white dwarf in a 5.6 hr orbit. To date, such extremely <span class="hlt">low-mass</span> white dwarfs, which can have thin, stably burning outer layers, have been modeled via poorly constrained atmosphere and cooling calculations where uncertainties in the detailed structure can strongly influence the eventual fates of these systems when mass transfer begins. With precise (individual precision ≈1%), high-cadence (≈2 s), multicolor photometry of multiple primary and secondary <span class="hlt">eclipses</span> spanning >1.5 yr, we constrain the masses and radii of both objects in the NLTT 11748 system to a statistical uncertainty of a few percent. However, we find that overall uncertainty in the thickness of the envelope of the secondary carbon/oxygen white dwarf leads to a larger (≈13%) systematic uncertainty in the primary He WD's mass. Over the full range of possible envelope thicknesses, we find that our primary mass (0.136-0.162 M {sub ☉}) and surface gravity (log (g) = 6.32-6.38; radii are 0.0423-0.0433 R {sub ☉}) constraints do not agree with previous spectroscopic determinations. We use precise <span class="hlt">eclipse</span> timing to detect the Rømer delay at 7σ significance, providing an additional weak constraint on the masses and limiting the eccentricity to ecos ω = (– 4 ± 5) × 10{sup –5}. Finally, we use multicolor data to constrain the secondary's effective temperature (7600 ± 120 K) and cooling age (1.6-1.7 Gyr).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JAVSO..43...54B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JAVSO..43...54B"><span id="translatedtitle">A Photometric Study of ASAS J184708-3340.2: an <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> with Total <span class="hlt">Eclipses</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berrington, R. C.; Tuhey, E. M.</p> <p>2015-06-01</p> <p>We present new multi-band differential aperture photometry of the <span class="hlt">eclipsing</span> variable star ASAS J184708-3340.2. The light curves are analyzed with the Wilson-Devinney model to determine best-fit stellar models. Our models show that ASAS J184708-3340.2 is consistent with an overcontact <span class="hlt">eclipsing</span> <span class="hlt">binary</span> (W Ursae Majoris) system with total <span class="hlt">eclipses</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AAS...22734516R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AAS...22734516R"><span id="translatedtitle">Propertires of K/M Dwarf <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Riddle, Andrew; Kraus, Adam L.</p> <p>2016-01-01</p> <p>Stellar models of <span class="hlt">low-mass</span> stars (M < 0.8 M_Sun) have been found to be in disagreement with observed properties, the observed radii being larger and the observed temperatures being lower. To characterize this discrepancy and search for possible confounding parameters, we are observing a sample of <span class="hlt">low-mass</span> <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> using the McDonald 2.7-m telescope and archival Keck data for spectroscopic observations as well as the 0.8-m telescope at McDonald. This study will greatly increase the number of well-characterized <span class="hlt">low-mass</span> stars, allowing for a better understanding of how fundamental stellar parameters (T_eff, R_*, M_*, abundances, activity, luminosity, etc.) depend on one another. We are using IGRINS, a high resolution (R=40,000) IR (H+K) spectrograph on the McDonald 2.7-m, to measure T_eff and abundances of the sample to a higher precision than previously capable. Relationships between the stellar parameters could reveal the influence of extra parameters on the mass-radius relation, indicating the additional physics that must be added to stellar evolutionary models to bring them into agreement with observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AJ....146...35Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AJ....146...35Y"><span id="translatedtitle">Deep, <span class="hlt">Low</span> <span class="hlt">Mass</span> Ratio Overcontact <span class="hlt">Binary</span> Systems. XIII. DZ Piscium with Intrinsic Light Variability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Y.-G.; Qian, S.-B.; Zhang, L.-Y.; Dai, H.-F.; Soonthornthum, B.</p> <p>2013-08-01</p> <p>New multi-color photometry for the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> DZ Psc was performed in 2011 and 2012 using the 85 cm telescope at the Xinglong Station of the National Astronomical Observatories of China. Using the updated Wilson-Devinney (W-D) code, we deduced two sets of photometric solutions. The overcontact degree is f = 89.7(± 1.0)%, identifying DZ Psc as a deep, <span class="hlt">low</span> <span class="hlt">mass</span> ratio overcontact <span class="hlt">binary</span>. The asymmetric light curves (i.e., LC2 in 2012) were modeled by a hot spot on the primary star. Based on all of the available light minimum times, we discovered that the orbital period of DZ Psc may be undergoing a secular period increase with a cyclic variation. The modulated period and semi-amplitude of this oscillation are P mod = 11.89(± 0.19) yr and A = 0.0064(± 0.0006) days, which may be possibly attributed to either cyclic magnetic activity or light-time effect due to the third body. The long-term period increases at a rate of dP/dt=+7.43(+/- 0.17)\\times 10^{-7}{\\,days\\, yr^{-1}}, which may be interpreted as conserved mass transfer from the less massive component to the more massive one. With mass transferring, DZ Psc will finally merge into a rapid-rotation single star when J spin/J orb > 1/3.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ASPC..496..311R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ASPC..496..311R"><span id="translatedtitle">Studies of Long Period <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ratajczak, M.; Hełminiak, K. G.; Konacki, M.</p> <p>2015-07-01</p> <p>The survey of long period <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> from the All Sky Automated Survey (ASAS) catalog aims at searching for and characterizing subgiants and red giants in double-lined detached <span class="hlt">binary</span> systems. Absolute physical and orbital parameters are presented based on radial velocities from high-quality optical spectra obtained with the following telescope/instrument combinations: 8.2 m Subaru/HDS, ESO 3.6 m/HARPS, 1.9 m Radcliffe/GIRAFFE, CTIO 1.5 m/CHIRON, and 1.2 m Euler/CORALIE. Photometric data from ASAS, SuperWASP, and the Solaris Project were also used. We discuss the derived uncertainties for the individual masses and radii of the components (better than 3% for several systems), as well as results from the spectral analysis performed for components of systems whose spectra we disentangled.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AJ....142..124Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AJ....142..124Z"><span id="translatedtitle">Deep, <span class="hlt">Low</span> <span class="hlt">Mass</span> Ratio Overcontact <span class="hlt">Binary</span> Systems. XI. V1191 Cygni</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, L. Y.; Qian, S. B.; Soonthornthum, B.; He, J. J.; Liu, L.</p> <p>2011-10-01</p> <p>Complete CCD photometric light curves in BV(RI) c bands obtained on one night in 2009 for the short-period close-<span class="hlt">binary</span> system V1191 Cygni are presented. A new photometric analysis with the 2003 version of the Wilson-Van Hamme code shows that V1191 Cyg is a W-type overcontact <span class="hlt">binary</span> system and suggests that it has a high degree of overcontact (f = 68.6%) with very <span class="hlt">low</span> <span class="hlt">mass</span> ratio, implying that it is at the late stage of overcontact evolution. The absolute parameters of V1191 Cyg are derived using spectroscopic and photometric solutions. Combining new determined times of light minimum with others published in the literature, the period change of the <span class="hlt">binary</span> star is investigated. A periodic variation, with a period of 26.7 years and an amplitude of 0.023 days, was discovered to be superimposed on a long-term period increase (dP/dt = +4.5(± 0.1) × 10-7 days yr-1). The cyclic period oscillation may be caused by the magnetic activity cycles of either of the components or the light-time effect due to the presence of a third body with a mass of m 3 = 0.77 M sun and an orbital radius of a 3 = 7.6 AU, when this body is coplanar to the orbit of the <span class="hlt">eclipsing</span> pair. The secular orbital period increase can be interpreted as a mass transfer from the less massive component to the more massive one. With the period increases, V1191 Cyg will evolve from its present <span class="hlt">low</span> <span class="hlt">mass</span> ratio, high filled overcontact state to a rapidly rotating single star when its orbital angular momentum is less than three times the total spin angular momentum. V1191 Cyg is too blue for its orbital period and it is an unusual W-type overcontact system with such a <span class="hlt">low</span> <span class="hlt">mass</span> ratio and high fill-out overcontact configuration, which is worth monitoring continuously in the future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22340008','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22340008"><span id="translatedtitle">Kepler <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars. IV. Precise <span class="hlt">eclipse</span> times for close <span class="hlt">binaries</span> and identification of candidate three-body systems</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Conroy, Kyle E.; Stassun, Keivan G.; Prša, Andrej; Orosz, Jerome A.; Welsh, William F.; Fabrycky, Daniel C.</p> <p>2014-02-01</p> <p>We present a catalog of precise <span class="hlt">eclipse</span> times and analysis of third-body signals among 1279 close <span class="hlt">binaries</span> in the latest Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Catalog. For these short-period <span class="hlt">binaries</span>, Kepler's 30 minute exposure time causes significant smearing of light curves. In addition, common astrophysical phenomena such as chromospheric activity, as well as imperfections in the light curve detrending process, can create systematic artifacts that may produce fictitious signals in the <span class="hlt">eclipse</span> timings. We present a method to measure precise <span class="hlt">eclipse</span> times in the presence of distorted light curves, such as in contact and near-contact <span class="hlt">binaries</span> which exhibit continuously changing light levels in and out of <span class="hlt">eclipse</span>. We identify 236 systems for which we find a timing variation signal compatible with the presence of a third body. These are modeled for the light travel time effect and the basic properties of the third body are derived. This study complements J. A. Orosz et al. (in preparation), which focuses on <span class="hlt">eclipse</span> timing variations of longer period <span class="hlt">binaries</span> with flat out-of-<span class="hlt">eclipse</span> regions. Together, these two papers provide comprehensive <span class="hlt">eclipse</span> timings for all <span class="hlt">binaries</span> in the Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Catalog, as an ongoing resource freely accessible online to the community.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006JASS...23..189L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006JASS...23..189L"><span id="translatedtitle"><span class="hlt">Low</span> <span class="hlt">Mass</span> Ratio Contact <span class="hlt">Binary</span> Systems HN UMa and II UMa - III</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Woo-Baik; Kim, Ho-Il; Kang, Young Woon; Oh, Kyu-Dong</p> <p>2006-09-01</p> <p>We present newly observed BVRI CCD light curves for <span class="hlt">low</span> <span class="hlt">mass</span> ratio contact <span class="hlt">binaries</span>, HN UMa and II UMa. The absolute dimensions of these objects were obtained by applying the Wilson-Devinney program to previously published spectroscopic analysis and to our observed photometric data. The evolutionary status of all 21 <span class="hlt">low</span> <span class="hlt">mass</span> ratio contact <span class="hlt">binary</span> system including HN UMa and II UMa was then considered. The secondaries of all <span class="hlt">low</span> <span class="hlt">mass</span> ratio contact <span class="hlt">binaries</span> are located below the zero age main sequence in HR diagram. This phenomenon could be explained by mass loss from the secondary component in the <span class="hlt">low</span> <span class="hlt">mass</span> contact <span class="hlt">binary</span> system because even small mass loss affects luminosity decrease in the <span class="hlt">low</span> <span class="hlt">mass</span> stars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MNRAS.453.3474L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MNRAS.453.3474L"><span id="translatedtitle">Properties of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> from all-sky surveys - I. Detached <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in ASAS, NSVS, and LINEAR</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee ( ), Chien-Hsiu</p> <p>2015-11-01</p> <p><span class="hlt">Eclipsing</span> <span class="hlt">binaries</span> provide a unique opportunity to measure fundamental properties of stars. With the advent of all-sky surveys, thousands of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> have been reported, yet their light curves are not fully exploited. The goal of this work is to make use of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> light curves delivered by all-sky surveys. We attempt to extract physical parameters of the <span class="hlt">binary</span> systems from their light curves and colour. Inspired by the work of Devor et al., we use the Detached <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Light curve fitter (DEBIL) and the Method for <span class="hlt">Eclipsing</span> Component Identification (MECI) to derive basic properties of the <span class="hlt">binary</span> systems reported by the All Sky Automated Survey, the Northern Sky Variability Survey, and the Lincoln Near Earth Asteroids Research. We derive the mass, fractional radius, and age for 783 <span class="hlt">binary</span> systems. We report a subsample of eccentric systems and compare their properties to the tidal circularization theory. With MECI, we are able to estimate the distance of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems and use them to probe the structure of the Milky Way. Following the approach of Devor et al., we demonstrate that DEBIL and MECI are instrumental to investigate <span class="hlt">eclipsing</span> <span class="hlt">binary</span> light curves in the era of all-sky surveys, and provide estimates of stellar parameters of both <span class="hlt">binary</span> components without spectroscopic information.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AAS...21537103B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AAS...21537103B"><span id="translatedtitle">The Behavior of Accretion Disks in <span class="hlt">Low</span> <span class="hlt">Mass</span> X-ray <span class="hlt">Binaries</span>: Disk Winds and Alpha Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bayless, Amanda J.</p> <p>2010-01-01</p> <p>This dissertation presents research on two <span class="hlt">low</span> <span class="hlt">mass</span> X-ray <span class="hlt">binaries</span>. The <span class="hlt">eclipsing</span> <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> 4U 1822-371 is the prototypical accretion disk corona (ADC) system. We have obtained new time-resolved UV spectroscopy with the ACS/SBC on the Hubble Space Telescope and new V- and J-band photometry with the 1.3-m SMARTS telescope at CTIO. We show that the accretion disk in the system has a strong wind with projected velocities up to 4000 km/s as determined from the Doppler width of the C IV emission line. The broad and shallow <span class="hlt">eclipse</span> indicates that the disk has a vertically-extended, optically-thick component at optical wavelengths. This component extends almost to the edge of the disk and has a height equal to 50% of the disk radius. As it has a low brightness temperature, we identify it as the optically-thick base of the disk wind. V1408 Aql (=4U 1957+115) is a <span class="hlt">low</span> <span class="hlt">mass</span> X-ray <span class="hlt">binary</span> which continues to be a black hole candidate. We have new photometric data of this system from the Otto Struve 2.1-m telescope's high speed CCD photometer at McDonald Observatory. The light curve is largely sinusoidal which we model with two components: a constant light source from the disk and a sinusoidal modulation at the orbital period from the irradiated face of the companion star. This is a radical re-interpretation of the orbital light curve. We do not require a large or asymmetric disk rim to account for the modulation in the light curve. Thus, the orbital inclination is unconstrained in our new model, removing the foundation for any claims of the compact object being a black hole.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920074057&hterms=Teff&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DTeff','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920074057&hterms=Teff&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DTeff"><span id="translatedtitle">The hot subdwarf in the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> HD 185510</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jeffery, C. S.; Simon, Theodore; Evans, T. L.</p> <p>1992-01-01</p> <p>High-resolution spectroscopic measurements of radial velocity are employed to characterize the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> HD 185510 in terms of masses and evolutionary status. The IUE is used to obtain the radial velocities which indicate a large mass ratio Mp/Ms of 7.45 +/- 0.15, and Teff is given at 25,000 +/- 1000 K based on Ly alpha and UV spectrophotometry. Photometric observations are used to give an orbital inclination of between 90 and 70 deg inclusive, leading to masses of 0.31-0.37 and 2.3-2.8 solar mass for the hot star and the K star, respectively. The surface gravity of HD 185510B is shown to be higher than those values for sdB stars suggesting that the object is a <span class="hlt">low-mass</span> white dwarf that has not reached its fully degenerate configuration. The object is theorized to be a <span class="hlt">low-mass</span> helium main-sequence star or a nascent helium degenerate in a post-Algol system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060053342&hterms=kepler&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dkepler','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060053342&hterms=kepler&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dkepler"><span id="translatedtitle">The Kepler Mission and <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Koch, David; Borucki, William; Lissauer, J.; Basri, Gibor; Brown, Timothy; Caldwell, Douglas; Cochran, William; Jenkins, Jon; Dunham, Edward; Gautier, Nick</p> <p>2006-01-01</p> <p>The Kepler Mission is a photometric mission with a precision of 14 ppm (at R=12) that is designed to continuously observe a single field of view (FOV) of greater 100 sq deg in the Cygnus-Lyra region for four or more years. The primary goal of the mission is to monitor greater than 100,000 stars for transits of Earth-size and smaller planets in the habitable zone of solar-like stars. In the process, many <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> (EB) will also be detected and light curves produced. To enhance and optimize the mission results, the stellar characteristics for all the stars in the FOV with R less than 16 will have been determined prior to launch. As part of the verification process, stars with transit candidates will have radial velocity follow-up observations performed to determine the component masses and thereby separate <span class="hlt">eclipses</span> caused by stellar companions from transits caused by planets. The result will be a rich database on EBs. The community will have access to the archive for further analysis, such as, for EB modeling of the high-precision light curves. A guest observer program is also planned to allow for photometric observations of objects not on the target list but within the FOV, since only the pixels of interest from those stars monitored will be transmitted to the ground.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997AAS...190.2803C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997AAS...190.2803C"><span id="translatedtitle">CCD Photometry of Apsidal Motion <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caton, D.; Templeton, S.</p> <p>1997-05-01</p> <p>At Appalachian State University's Dark Sky Observatory we have maintained a program of monitoring the times of minimum light for apsidal motion <span class="hlt">binaries</span>. In the last two years that program has largely migrated to the CCD detector, from the photoelectric photometer used previously. Most of the work has also moved from the 18-inch telescope to the new 32-inch telescope. Some observations were also made using the 36-inch SARA telescope at Kitt Peak. We have concentrated on observing <span class="hlt">eclipses</span> of fainter systems as well as those that have been neglected by other observers. We will report here on the observations over the last few years. This work has been supported by grants from the National Science Foundation, the American Astronomical Society, and the Fund for Astrophysical Research. We are also grateful for the assistance from the U.S. Naval Observatory library, the Yerkes Observatory library, the SIMBAD data base, and the Digitized Sky Survey internet service.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E1626R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E1626R"><span id="translatedtitle">B-type stars in <span class="hlt">eclipsing</span> <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ratajczak, Milena; Pigulski, Andrzej</p> <p>2016-07-01</p> <p>B-type stars in <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems are unique astrophysical tools to test several aspects of stellar evolution. Such objects can be used e.g. to determine the masses of Beta Cephei variable stars, as well as help to place tighter constraints on the value of the convective core overshooting parameter α. Both precise photometry and high-resolution spectroscopy with high SNR are required to achieve these goals, but since many of the targets are bright enough, the challenge is fair. Following this assumption, we shall explain how we plan to examine both the aforementioned aspects of stellar evolution using observations of B-type stars obtained with a wide range of spectrographs, as well as BRITE-Constellation satellites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AJ....130.1206Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AJ....130.1206Q"><span id="translatedtitle">Deep, <span class="hlt">Low</span> <span class="hlt">Mass</span> Ratio Overcontact <span class="hlt">Binary</span> Systems. V. The Lowest Mass Ratio <span class="hlt">Binary</span> V857 Herculis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qian, S.-B.; Zhu, L.-Y.; Soonthornthum, B.; Yuan, J.-Z.; Yang, Y.-G.; He, J.-J.</p> <p>2005-09-01</p> <p>Charge-coupled device (CCD) photometric light curves in the B, V, and R bands of the complete <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star V857 Her are presented. It is shown that the light curves of the W UMa-type <span class="hlt">binary</span> are symmetric and of A type according to Binnendijk's classification. Our four epochs of light minimum along with others compiled from the literature were used to revise the period and study the period change. Weak evidence indicates that the orbital period of V857 Her may show a continuous increase at a rate of dP/dt=+2.90×10-7 days yr-1. The photometric parameters of the system were determined with the 2003 version of the Wilson-Devinney code. It is shown that V857 Her is a deep overcontact <span class="hlt">binary</span> system with f=83.8%+/-5.1%. The derived mass ratio of q=0.06532+/-0.0002 suggests that it has the lowest mass ratio among overcontact <span class="hlt">binary</span> systems. As the orbital period increases, the decrease of the mass ratio will cause it to evolve into a single rapidly rotating star when it meets the more familiar criterion that the orbital angular momentum be less than 3 times the total spin angular momentum. To understand the evolutionary state of the system, long-term photometric monitoring and spectroscopic observations will be required.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PASA...33...43S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PASA...33...43S"><span id="translatedtitle">Precise Orbital Solutions for KEPLER <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> of W UMa Type Showing Total <span class="hlt">Eclipses</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Şenavcı, H. V.; Doǧruel, M. B.; Nelson, R. H.; Yılmaz, M.; Selam, S. O.</p> <p>2016-09-01</p> <p>We aim to discover the accuracy of photometric mass ratios (q ph) determined for <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars, in the case of the system having at least one `flat bottom' as a minimum profile, as well as the accuracy of data used in that sense. Within this context, we present the results of two-dimensional grid search (q - i) for some W UMa-type <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> showing total <span class="hlt">eclipses</span>, based on the high precision photometric data provided by the KEPLER Mission. The radial velocity data obtained for KIC10618253 in this study, enables us to compare both q ph and the corresponding spectroscopic mass ratio (q sp) values. The results indicate that the high precision photometric data for overcontact <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> showing total <span class="hlt">eclipses</span> allow us to obtain the photometric mass ratios as accurate as the spectroscopic values.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/886668','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/886668"><span id="translatedtitle">Evolution of Intermediate and <span class="hlt">Low</span> <span class="hlt">Mass</span> <span class="hlt">Binary</span> Systems</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Eggleton, P P</p> <p>2005-10-25</p> <p>There are a number of <span class="hlt">binaries</span>, fairly wide and with one or even two evolved giant components, that do not agree very well with conventional stellar evolution: the secondaries are substantially larger (oversized) than they should be because their masses are quite low compared with the primaries. I discuss the possibility that these <span class="hlt">binaries</span> are former triples, in which a merger has occurred fairly recently in a short-period <span class="hlt">binary</span> sub-component. Some mergers are expected, and may follow a phase of contact evolution. I suggest that in contact there is substantial transfer of luminosity between the components due to differential rotation, of the character observed by helioseismology in the Sun's surface convection zone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/964527','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/964527"><span id="translatedtitle">Evolution of Very Close <span class="hlt">Binaries</span> of <span class="hlt">Low</span> <span class="hlt">Mass</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Eggleton, P</p> <p>2009-07-17</p> <p><span class="hlt">Binaries</span> of low total mass (say 1-3 M{sub {circle_dot}}) and very short period (say {approx}< 4 d) are subject to a number of evolutionary processes, such as nuclear evolution, Roche-Lobe overflow, mass loss by stellar wind enhanced by rapid rotation, angular momentum loss by stellar wind with magnetic braking and tidal friction, mass transfer in contact (potentially in either direction), and heat transport from one component to the other during contact. Unfortunately all of these phenomena can be expected to occur on something like the same timescale. This makes it especially difficult to tie a particular system to a particular set of evolutionary processes. Theory suggests that very close <span class="hlt">binaries</span> should appear in four morphological forms: detached <span class="hlt">binaries</span>, semidetached <span class="hlt">binaries</span> in which the more massive component is the one that fills its Roche lobe (reverse Algols), semidetached <span class="hlt">binaries</span> in which the less massive component is the one that fills its Roche lobe (normal Algols), and contact, or, as some would say, overcontact <span class="hlt">binaries</span>, where both components overfill their Roche lobes up to the same equipotential surface. This is not to say that perhaps some other configuration may be important, but I am not sure that any has yet been put forward that is incontrovertible. I have developed an evolutionary code in which the two components are solved simultaneously, and subject in principle to all six of the processes in the first paragraph. All four morphological forms are achievable by the code, as the physics demands. The code is still preliminary, partly at least because of the difficulty of quantifying all six processes. I will illustrate some possibly peculiar evolutionary scenarios that can emerge; but I will mainly argue, on the basis of observed data from a variety of systems, that it is indeed necessary to include all these processes, and not, for example, to ignore mass loss by stellar wind by claiming that it cannot be strong enough to be significant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22126742','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22126742"><span id="translatedtitle">MICROLENSING DISCOVERY OF A POPULATION OF VERY TIGHT, VERY <span class="hlt">LOW</span> <span class="hlt">MASS</span> <span class="hlt">BINARY</span> BROWN DWARFS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Choi, J.-Y.; Han, C.; Udalski, A.; Sumi, T.; Gaudi, B. S.; Gould, A.; Bennett, D. P.; Dominik, M.; Beaulieu, J.-P.; Tsapras, Y.; Bozza, V.; Abe, F.; Furusawa, K.; Itow, Y.; Bond, I. A.; Ling, C. H.; Botzler, C. S.; Freeman, M.; Chote, P.; Fukui, A.; Collaboration: MOA Collaboration; OGLE Collaboration; muFUN Collaboration; MiNDSTEp Consortium; PLANET Collaboration; RoboNet Collaboration; and others</p> <p>2013-05-10</p> <p>Although many models have been proposed, the physical mechanisms responsible for the formation of <span class="hlt">low-mass</span> brown dwarfs (BDs) are poorly understood. The multiplicity properties and minimum mass of the BD mass function provide critical empirical diagnostics of these mechanisms. We present the discovery via gravitational microlensing of two very <span class="hlt">low</span> <span class="hlt">mass</span>, very tight <span class="hlt">binary</span> systems. These <span class="hlt">binaries</span> have directly and precisely measured total system masses of 0.025 M{sub Sun} and 0.034 M{sub Sun }, and projected separations of 0.31 AU and 0.19 AU, making them the lowest-mass and tightest field BD <span class="hlt">binaries</span> known. The discovery of a population of such <span class="hlt">binaries</span> indicates that BD <span class="hlt">binaries</span> can robustly form at least down to masses of {approx}0.02 M{sub Sun }. Future microlensing surveys will measure a mass-selected sample of BD <span class="hlt">binary</span> systems, which can then be directly compared to similar samples of stellar <span class="hlt">binaries</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997JAVSO..26...14C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997JAVSO..26...14C"><span id="translatedtitle">CCD Photometry of Five Neglected <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Stars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cook, Stephen P.</p> <p></p> <p>Differential V-magnitude CCD photometric data are presented for five neglected <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars with shallow <span class="hlt">eclipses</span>. An improved period is derived for SV Equ, past O-C trends are confirmed for AN And and DL Vir, and an unexpectedly large O-C values are found for BW DEL nad CS Lac.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22370093','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22370093"><span id="translatedtitle">Properties OF M31. V. 298 <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> from PAndromeda</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lee, C.-H.; Koppenhoefer, J.; Seitz, S.; Bender, R.; Riffeser, A.; Kodric, M.; Hopp, U.; Snigula, J.; Gössl, C.; Kudritzki, R.-P.; Burgett, W.; Chambers, K.; Hodapp, K.; Kaiser, N.; Waters, C.</p> <p>2014-12-10</p> <p>The goal of this work is to conduct a photometric study of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in M31. We apply a modified box-fitting algorithm to search for <span class="hlt">eclipsing</span> <span class="hlt">binary</span> candidates and determine their period. We classify these candidates into detached, semi-detached, and contact systems using the Fourier decomposition method. We cross-match the position of our detached candidates with the photometry from Local Group Survey and select 13 candidates brighter than 20.5 mag in V. The relative physical parameters of these detached candidates are further characterized with the Detached <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Light curve fitter (DEBiL) by Devor. We will follow up the detached <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> spectroscopically and determine the distance to M31.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004MNRAS.351..110W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004MNRAS.351..110W"><span id="translatedtitle">The effect of star-spots on <span class="hlt">eclipse</span> timings of <span class="hlt">binary</span> stars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Watson, C. A.; Dhillon, V. S.</p> <p>2004-06-01</p> <p>We investigate the effects that star-spots have on the light curves of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>, and in particular how they may affect the accurate measurement of <span class="hlt">eclipse</span> timings. Concentrating on systems containing a <span class="hlt">low-mass</span> main-sequence star and a white dwarf, we find that if star-spots exhibit the Wilson depression they can alter the times of primary <span class="hlt">eclipse</span> ingress and egress by several seconds for typical <span class="hlt">binary</span> parameters and star-spot depressions. In addition, we find that the effect on the <span class="hlt">eclipse</span> ingress/egress times becomes more profound for lower orbital inclinations. We show how it is possible, in principle, to determine estimates of both the <span class="hlt">binary</span> inclination and the depth of the Wilson depression from light curve analysis The effect of depressed star-spots on the O-C diagrams of <span class="hlt">eclipsing</span> systems is also investigated. It is found that the presence of star-spots will introduce a jitter in the O-C residuals and can cause spurious orbital period changes to be observed. Despite this, we show that the period can still be accurately determined even for heavily spotted systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21467163','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21467163"><span id="translatedtitle">OGLE-2005-BLG-153: MICROLENSING DISCOVERY AND CHARACTERIZATION OF A VERY <span class="hlt">LOW</span> <span class="hlt">MASS</span> <span class="hlt">BINARY</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hwang, K.-H.; Han, C.; Ryu, Y.-H.; Udalski, A.; Kubiak, M.; Szymanski, M. K.; Pietrzynski, G.; Soszynski, I.; Szewczyk, O.; Ulaczyk, K.; Wyrzykowski, L.; Bond, I. A.; Beaulieu, J.-P.; Dominik, M.; Horne, K.; Gould, A.; Gaudi, B. S.; Abe, F.; Botzler, C. S.; Hearnshaw, J. B.</p> <p>2010-11-01</p> <p>The mass function and statistics of <span class="hlt">binaries</span> provide important diagnostics of the star formation process. Despite this importance, the mass function at <span class="hlt">low</span> <span class="hlt">masses</span> remains poorly known due to observational difficulties caused by the faintness of the objects. Here we report the microlensing discovery and characterization of a <span class="hlt">binary</span> lens composed of very <span class="hlt">low</span> <span class="hlt">mass</span> stars just above the hydrogen-burning limit. From the combined measurements of the Einstein radius and microlens parallax, we measure the masses of the <span class="hlt">binary</span> components of 0.10 {+-} 0.01 M{sub sun} and 0.09 {+-} 0.01 M{sub sun}. This discovery demonstrates that microlensing will provide a method to measure the mass function of all Galactic populations of very <span class="hlt">low</span> <span class="hlt">mass</span> <span class="hlt">binaries</span> that is independent of the biases caused by the luminosity of the population.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010ATel.2778....1S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010ATel.2778....1S"><span id="translatedtitle">No <span class="hlt">eclipses</span> in the double WD <span class="hlt">binary</span> SDSS J125733.63+542850.5</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shporer, A.; Kaplan, D.; Bildsten, L.; Howell, S.; Steinfadt, J.</p> <p>2010-08-01</p> <p>We have carried out a search with the Faulkes Telescope North (FTN) for <span class="hlt">eclipses</span> in the <span class="hlt">binary</span> white dwarf (WD) system SDSS J125733.63+542850.5, resulting in a non-detection. SDSS J125733.63+542850.5 was identified by Marsh et al. (2010) and Kulkarni & van Kerkwijk (2010) as a <span class="hlt">binary</span> system consisting of a <span class="hlt">low-mass</span> He WD (the primary) and a high-mass CO WD (the secondary), with an orbital period of 4.56 hours.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21367475','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21367475"><span id="translatedtitle">STATE TRANSITIONS IN <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARIES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bradley, Charles K.; Frank, Juhan</p> <p>2009-10-10</p> <p>We investigate the model of disk/coronal accretion into a black hole. We show that the inner regions of an accretion disk in X-ray <span class="hlt">binaries</span> can transform from a cool standard disk to an advection-dominated flow through the known properties of Coulomb interaction in a two-temperature plasma, viscous heating, radiative processes, and thermal conduction. A hot, diffuse corona covering the disk is powered by accretion, but it exchanges mass with the underlying cold disk. If the accretion rate in the system is low enough, we show that the corona evaporates the disk away, leaving an advective flow to continue toward the hole. In the soft/hard transition commonly seen in X-ray <span class="hlt">binaries</span>, we show that this advective flow can recondense back onto the underlying disk if the change in the system's accretion rate is slow enough due to thermal conduction. Unabsorbed spectra are produced to test against observations as well as prediction of the location of truncation radii of the accretion disk.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20050240876&hterms=kepler&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dkepler','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20050240876&hterms=kepler&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dkepler"><span id="translatedtitle"><span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> from the Kepler Mission</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Koch, David; Borucki, William; Lissauer, J.; Basri, Gibor; Brown, Timothy; Caldwell, Douglas; Cochran, William; Jenkins, Jon; Dunham, Edward; Gautier, Nick</p> <p>2005-01-01</p> <p>The Kepler Mission is a photometric space mission that will continuously observe a single 100 sq deg field of view (FOV) of greater than 100,000 stars in the Cygnus-Lyra region for 4 or more years with a precision of 14 ppm (R=12). The primary goal of the mission is to detect Earth-size planets in the habitable zone of solar-like stars. In the process, many <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> (EB) will also be detected. Prior to launch, the stellar characteristics will have been detennined for all the stars in the FOV with R<16. As part of the verification process, stars with transits <5% will need to have follow-up radial velocity observations performed to determine the component masses and thereby separate transits caused by stellar companions from those caused by planets. The result will be a rich database on EBs. The community will have access to the archive for uses such as for EB modeling of the high-precision light curves. A guest observer program is also planned for objects not already on the target list.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AN....337..512P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AN....337..512P"><span id="translatedtitle">High ionisation absorption in <span class="hlt">low</span> <span class="hlt">mass</span> X-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ponti, G.; Bianchi, S.; Muñoz-Darias, T.; De, K.; Fender, R.; Merloni, A.</p> <p>2016-05-01</p> <p>The advent of the new generation of X-ray telescopes yielded a significant step forward in our understanding of ionised absorption generated in the accretion discs of X-ray <span class="hlt">binaries</span>. It has become evident that these relatively weak and narrow absorption features, sporadically present in the X-ray spectra of some systems, are actually the signature of equatorial outflows, which might carry away more matter than that being accreted. Therefore, they play a major role in the accretion phenomenon. These outflows (or ionised atmospheres) are ubiquitous during the softer states but absent during the power-law dominated, hard states, suggesting a strong link with the state of the inner accretion disc, presence of the radio-jet and the properties of the central source. Here, we discuss the current understanding of this field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AJ....150...69Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AJ....150...69Y"><span id="translatedtitle">Deep, <span class="hlt">Low</span> <span class="hlt">Mass</span> Ratio Overcontact <span class="hlt">Binary</span> Systems. XIV. A Statistical Analysis of 46 Sample <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Yuan-Gui; Qian, Sheng-Bang</p> <p>2015-09-01</p> <p>A sample of 46 deep, <span class="hlt">low</span> <span class="hlt">mass</span> ratio (DLMR) overcontact <span class="hlt">binaries</span> (i.e., q≤slant 0.25 and f≥slant 50%) is statistically analyzed in this paper. It is found that five relations possibly exist among some physical parameters. The primary components are little-evolved main sequence stars that lie between the zero-age main sequence line and the terminal-age main sequence (TAMS) line. Meanwhile, the secondary components may be evolved stars above the TAMS line. The super-luminosities and large radii may result from energy transfer, which causes their volumes to expand. The equations of M-L and M-R for the components are also determined. The relation of P-Mtotal implies that mass may escape from the central system when the orbital period decreases. The minimum mass ratio may preliminarily be {q}{min}=0.044(+/- 0.007) from the relations of q-f and q-Jspin/Jorb. With mass and angular momentum loss, the orbital period decreases, which finally causes this kind of DLMR overcontact <span class="hlt">binary</span> to merge into a rapid-rotating single star.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EAS....64..433Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EAS....64..433Z"><span id="translatedtitle">The role of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in open cluster research</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zejda, M.; Paunzen, E.; Mikulášek, Z.; Janík, J.; Liška, J.; Chrastina, M.</p> <p>2013-02-01</p> <p><span class="hlt">Eclipsing</span> <span class="hlt">binaries</span> (EBs) are a key which opens the door to a chamber of knowledge. Thus the research of EBs in open clusters (OCs) is very promising. However, only several lists of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> known in OCs have been published, the last one almost three decades ago. We introduce a new catalogue of EBs in the field of open clusters. In addition we establish a new program for skilled amateur astronomers who are able to produce a significant amount of photometric data of sufficient accuracy. Photometry as well as spectroscopy of selected EBs in OCs will be used to determine stellar parameters of components in <span class="hlt">binaries</span> and cluster parameters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...818..155B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...818..155B"><span id="translatedtitle">The ELM Survey. VII. Orbital Properties of <span class="hlt">Low-Mass</span> White Dwarf <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brown, Warren R.; Gianninas, A.; Kilic, Mukremin; Kenyon, Scott J.; Allende Prieto, Carlos</p> <p>2016-02-01</p> <p>We present the discovery of 15 extremely <span class="hlt">low-mass</span> (5\\lt {log}g\\lt 7) white dwarf (WD) candidates, 9 of which are in ultra-compact double-degenerate <span class="hlt">binaries</span>. Our targeted extremely <span class="hlt">low-mass</span> Survey sample now includes 76 <span class="hlt">binaries</span>. The sample has a lognormal distribution of orbital periods with a median period of 5.4 hr. The velocity amplitudes imply that the <span class="hlt">binary</span> companions have a normal distribution of mass with 0.76 M⊙ mean and 0.25 M⊙ dispersion. Thus extremely <span class="hlt">low-mass</span> WDs are found in <span class="hlt">binaries</span> with a typical mass ratio of 1:4. Statistically speaking, 95% of the WD <span class="hlt">binaries</span> have a total mass below the Chandrasekhar mass, and thus are not type Ia supernova progenitors. Yet half of the observed <span class="hlt">binaries</span> will merge in less than 6 Gyr due to gravitational wave radiation; probable outcomes include single massive WDs and stable mass transfer AM CVn <span class="hlt">binaries</span>. Based on observations obtained at the MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21562556','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21562556"><span id="translatedtitle">A DEEPLY <span class="hlt">ECLIPSING</span> DETACHED DOUBLE HELIUM WHITE DWARF <span class="hlt">BINARY</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Parsons, S. G.; Marsh, T. R.; Gaensicke, B. T.; Drake, A. J.; Koester, D.</p> <p>2011-07-10</p> <p>Using Liverpool Telescope+RISE photometry we identify the 2.78 hr period <span class="hlt">binary</span> star CSS 41177 as a detached <span class="hlt">eclipsing</span> double white dwarf <span class="hlt">binary</span> with a 21,100 K primary star and a 10,500 K secondary star. This makes CSS 41177 only the second known <span class="hlt">eclipsing</span> double white dwarf <span class="hlt">binary</span> after NLTT 11748. The 2 minute long primary <span class="hlt">eclipse</span> is 40% deep and the secondary <span class="hlt">eclipse</span> 10% deep. From Gemini+GMOS spectroscopy, we measure the radial velocities of both components of the <span class="hlt">binary</span> from the H{alpha} absorption line cores. These measurements, combined with the light curve information, yield white dwarf masses of M{sub 1} = 0.283 {+-} 0.064 M{sub sun} and M{sub 2} = 0.274 {+-} 0.034 M{sub sun}, making them both helium core white dwarfs. As an <span class="hlt">eclipsing</span>, double-lined spectroscopic <span class="hlt">binary</span>, CSS 41177 is ideally suited to measuring precise, model-independent masses and radii. The two white dwarfs will merge in roughly 1.1 Gyr to form a single sdB star.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22130660','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22130660"><span id="translatedtitle">PERIOD ERROR ESTIMATION FOR THE KEPLER <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> CATALOG</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mighell, Kenneth J.; Plavchan, Peter</p> <p>2013-06-15</p> <p>The Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Catalog (KEBC) describes 2165 <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> identified in the 115 deg{sup 2} Kepler Field based on observations from Kepler quarters Q0, Q1, and Q2. The periods in the KEBC are given in units of days out to six decimal places but no period errors are provided. We present the PEC (Period Error Calculator) algorithm, which can be used to estimate the period errors of strictly periodic variables observed by the Kepler Mission. The PEC algorithm is based on propagation of error theory and assumes that observation of every light curve peak/minimum in a long time-series observation can be unambiguously identified. The PEC algorithm can be efficiently programmed using just a few lines of C computer language code. The PEC algorithm was used to develop a simple model that provides period error estimates for <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in the KEBC with periods less than 62.5 days: log {sigma}{sub P} Almost-Equal-To - 5.8908 + 1.4425(1 + log P), where P is the period of an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> in the KEBC in units of days. KEBC systems with periods {>=}62.5 days have KEBC period errors of {approx}0.0144 days. Periods and period errors of seven <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems in the KEBC were measured using the NASA Exoplanet Archive Periodogram Service and compared to period errors estimated using the PEC algorithm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MNRAS.446..510K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MNRAS.446..510K"><span id="translatedtitle">Photometry and Hα studies of a <span class="hlt">low-mass</span>-ratio overcontact <span class="hlt">binary</span> ASAS J082243+1927.0</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kandulapati, S.; Devarapalli, S. P.; Pasagada, V. R.</p> <p>2015-01-01</p> <p>Both high-precision CCD photometric and Hα line studies are presented for an overcontact <span class="hlt">binary</span> ASAS J082243+1927.0. The light curve exhibits a total <span class="hlt">eclipse</span> at secondary minima along with an O'Connell effect. The light curve was modelled using the Wilson-Devinney code and the best solution provides the mass ratio q ˜ 0.106 and fill-out factor f ˜ 72 per cent. These parameters indicate that the system is a <span class="hlt">low-mass</span>-ratio overcontact <span class="hlt">binary</span> with a high degree of geometrical contact. The Hα line equivalent width varied at different phases and it is found that the line is possibly filled in at secondary minima. From a small sample of overcontact <span class="hlt">binaries</span>, we found a correlation between the orbital period and Hα line equivalent width of the primary component. Based on a sample of high filling factor and <span class="hlt">low-mass</span>-ratio contact <span class="hlt">binaries</span>, a mass ratio cut-off is observed at qcritical = 0.085 in the mass-ratio-period plane. It was observed that for qcritical < 0.085, the period decreases with an increase of q, and above it the period increases as the mass ratio increases. Interestingly, the observed mass ratio cut-off value lies close to the critical mass ratio range as predicted in the literature. The observational evidence of the cut-off of the mass ratio and its variation with orbital period are discussed in terms of mass transfer and angular momentum loss. Based on the results, we suggest that, ASAS J082243+1927.0 is at the verge of merger, eventually forming a fast rotating star.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014bsee.confP..24H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014bsee.confP..24H"><span id="translatedtitle"><span class="hlt">Eclipsing</span> <span class="hlt">binaries</span> in the Gaia era: automated detection performance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Holl, Berry; Mowlavi, Nami; Lecoeur-Taïbi, Isabelle; Geneva Gaia CU7 Team members</p> <p>2014-09-01</p> <p><span class="hlt">Binary</span> systems can have periods from a fraction of a day to several years and exist in a large range of possible configurations at various evolutionary stages. About 2% of them are oriented such that <span class="hlt">eclipses</span> can be observed. Such observations provide unique opportunities for the determination of their orbital and stellar parameters. Large-scale multi-epoch photometric surveys produce large sets of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> that allow for statistical studies of <span class="hlt">binary</span> systems. In this respect the ESA Gaia mission, launched in December 2013, is expected to deliver an unprecedented sample of millions of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>. Their detection from Gaia photometry and estimation of their orbital periods are essential for their subclassification and orbital and stellar parameter determination. For a subset of these <span class="hlt">eclipsing</span> systems, Gaia radial velocities and astrometric orbital measurements will further complement the Gaia light curves. A key challenge of the detection and period determination of the expected millions of Gaia <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> is the automation of the procedure. Such an automated pipeline is being developed within the Gaia Data Processing Analysis Consortium, in the framework of automated detection and identification of various types of photometric variable objects. In this poster we discuss the performance of this pipeline on <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> using simulated Gaia data and the existing Hipparcos data. We show that we can detect a wide range of <span class="hlt">binary</span> systems and very often determine their orbital periods from photometry alone, even though the data sampling is relatively sparse. The results can further be improved for those objects for which spectroscopic and/or astrometric orbital measurements will also be available from Gaia.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22167327','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22167327"><span id="translatedtitle">A LONG-PERIOD TOTALLY <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> STAR AT THE TURNOFF OF THE OPEN CLUSTER NGC 6819 DISCOVERED WITH KEPLER</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sandquist, Eric L.; Orosz, Jerome A.; Jeffries, Mark W. Jr.; Brewer, Lauren N. E-mail: orosz@sciences.sdsu.edu; and others</p> <p>2013-01-01</p> <p>We present the discovery of the totally <span class="hlt">eclipsing</span> long-period (P = 771.8 days) <span class="hlt">binary</span> system WOCS 23009 in the old open cluster NGC 6819 that contains both an evolved star near central hydrogen exhaustion and a <span class="hlt">low-mass</span> (0.45 M {sub Sun }) star. This system was previously known to be a single-lined spectroscopic <span class="hlt">binary</span>, but the discovery of an <span class="hlt">eclipse</span> near apastron using data from the Kepler space telescope makes it clear that the system has an inclination that is very close to 90 Degree-Sign . Although the secondary star has not been identified in spectra, the mass of the primary star can be constrained using other <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in the cluster. The combination of the total <span class="hlt">eclipses</span> and a mass constraint for the primary star allows us to determine a reliable mass for the secondary star and radii for both stars, and to constrain the cluster age. Unlike well-measured stars of similar mass in field <span class="hlt">binaries</span>, the <span class="hlt">low-mass</span> secondary is not significantly inflated in radius compared to model predictions. The primary star characteristics, in combination with cluster photometry and masses from other cluster <span class="hlt">binaries</span>, indicate a best age of 2.62 {+-} 0.25 Gyr, although stellar model physics may introduce systematic uncertainties at the {approx}10% level. We find preliminary evidence that the asteroseismic predictions for red giant masses in this cluster are systematically too high by as much as 8%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21107425','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21107425"><span id="translatedtitle">The dynamical mass of a classical Cepheid variable star in an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pietrzyński, G; Thompson, I B; Gieren, W; Graczyk, D; Bono, G; Udalski, A; Soszyński, I; Minniti, D; Pilecki, B</p> <p>2010-11-25</p> <p>Stellar pulsation theory provides a means of determining the masses of pulsating classical Cepheid supergiants-it is the pulsation that causes their luminosity to vary. Such pulsational masses are found to be smaller than the masses derived from stellar evolution theory: this is the Cepheid mass discrepancy problem, for which a solution is missing. An independent, accurate dynamical mass determination for a classical Cepheid variable star (as opposed to type-II Cepheids, <span class="hlt">low-mass</span> stars with a very different evolutionary history) in a <span class="hlt">binary</span> system is needed in order to determine which is correct. The accuracy of previous efforts to establish a dynamical Cepheid mass from Galactic single-lined non-<span class="hlt">eclipsing</span> <span class="hlt">binaries</span> was typically about 15-30% (refs 6, 7), which is not good enough to resolve the mass discrepancy problem. In spite of many observational efforts, no firm detection of a classical Cepheid in an <span class="hlt">eclipsing</span> double-lined <span class="hlt">binary</span> has hitherto been reported. Here we report the discovery of a classical Cepheid in a well detached, double-lined <span class="hlt">eclipsing</span> <span class="hlt">binary</span> in the Large Magellanic Cloud. We determine the mass to a precision of 1% and show that it agrees with its pulsation mass, providing strong evidence that pulsation theory correctly and precisely predicts the masses of classical Cepheids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21107425','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21107425"><span id="translatedtitle">The dynamical mass of a classical Cepheid variable star in an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pietrzyński, G; Thompson, I B; Gieren, W; Graczyk, D; Bono, G; Udalski, A; Soszyński, I; Minniti, D; Pilecki, B</p> <p>2010-11-25</p> <p>Stellar pulsation theory provides a means of determining the masses of pulsating classical Cepheid supergiants-it is the pulsation that causes their luminosity to vary. Such pulsational masses are found to be smaller than the masses derived from stellar evolution theory: this is the Cepheid mass discrepancy problem, for which a solution is missing. An independent, accurate dynamical mass determination for a classical Cepheid variable star (as opposed to type-II Cepheids, <span class="hlt">low-mass</span> stars with a very different evolutionary history) in a <span class="hlt">binary</span> system is needed in order to determine which is correct. The accuracy of previous efforts to establish a dynamical Cepheid mass from Galactic single-lined non-<span class="hlt">eclipsing</span> <span class="hlt">binaries</span> was typically about 15-30% (refs 6, 7), which is not good enough to resolve the mass discrepancy problem. In spite of many observational efforts, no firm detection of a classical Cepheid in an <span class="hlt">eclipsing</span> double-lined <span class="hlt">binary</span> has hitherto been reported. Here we report the discovery of a classical Cepheid in a well detached, double-lined <span class="hlt">eclipsing</span> <span class="hlt">binary</span> in the Large Magellanic Cloud. We determine the mass to a precision of 1% and show that it agrees with its pulsation mass, providing strong evidence that pulsation theory correctly and precisely predicts the masses of classical Cepheids. PMID:21107425</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040033921','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040033921"><span id="translatedtitle">Relativistic Astrophysics in Black Hole and <span class="hlt">Low-Mass</span> Neutron Star X-ray <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2000-01-01</p> <p>During the five-year period, our study of "Relativistic Astrophysics in Black Hole and <span class="hlt">Low-Mass</span> Neutron Star X-ray <span class="hlt">Binaries</span>" has been focused on the following aspects: observations, data analysis, Monte-Carlo simulations, numerical calculations, and theoretical modeling. Most of the results of our study have been published in refereed journals and conference presentations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DDA....4720205C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DDA....4720205C"><span id="translatedtitle">Discovery of Triple Star Systems through Dynamical <span class="hlt">Eclipse</span> Timing Variations with Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Conroy, Kyle E.</p> <p>2016-05-01</p> <p>We present a catalog of precise <span class="hlt">eclipse</span> times and analysis of third-body signals among 1279 close <span class="hlt">binaries</span> in the latest Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Catalog. For these short-period <span class="hlt">binaries</span>, Kepler's 30 minute exposure time causes significant smearing of light curves. In addition, common astrophysical phenomena such as chromospheric activity, as well as imperfections in the light curve detrending process, can create systematic artifacts that may produce fictitious signals in the <span class="hlt">eclipse</span> timings. We present a method to measure precise <span class="hlt">eclipse</span> times in the presence of distorted light curves, such as in contact and near-contact <span class="hlt">binaries</span> which exhibit continuously changing light levels in and out of <span class="hlt">eclipse</span>. We identify 236 systems for which we find a timing variation signal compatible with the presence of a third body. These are modeled for the light travel time effect and the basic properties of the third body are derived. We summarize the overall distribution of mutual orbital inclination angles, which together now provide strong confirmation of the basic predictions of dynamical evolution through Kozai Cycles and Tidal Friction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6997518','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6997518"><span id="translatedtitle">A search for <span class="hlt">eclipses</span> of HD 114762 by a <span class="hlt">low-mass</span> companion</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Robinson, E.L.; Cochran, A.L.; Cochran, W.D.; Shafter, A.W.; Zhang, Erho Beijing Observatory )</p> <p>1990-02-01</p> <p>HD 114762 has an unseen companion with a dynamical mass that satisfies the constraint mass sin i = 2.5 x 10 to the 31st gm. The companion is a good candidate for a planetary-mass object, but the inclination of its orbit is unknown and its mass is indeterminate. Tests were conducted for the specific case of a nearly edge-on orbit by looking for <span class="hlt">eclipses</span> of HD 114762 by the companion. Although the a priori probability of an <span class="hlt">eclipse</span> is low, this is a crucial case because the companion has its minimum mass if the orbit is edge on. No <span class="hlt">eclipses</span> were found with a depth greater than 0.01 mag and, therefore, the inclination of the orbit of HD 114762 is less than 89 deg. 12 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007MNRAS.378..179B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007MNRAS.378..179B"><span id="translatedtitle">A new catalogue of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars with eccentric orbits</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bulut, I.; Demircan, O.</p> <p>2007-06-01</p> <p>A new catalogue of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars with eccentric orbits is presented. The catalogue lists the physical parameters (including apsidal motion parameters) of 124 <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> with eccentric orbits. In addition, the catalogue also contains a list of 150 candidate systems, about which not much is known at present. Full version of the catalogue is available online (see the Supplementary Material section at the end of this paper) and in electronic form at the CDS via http://cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/MNRAS/(vol)/ (page) E-mail: ibulut@comu.edu.tr</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AAS...204.0501B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AAS...204.0501B"><span id="translatedtitle">The <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> On-Line Atlas (EBOLA)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bradstreet, D. H.; Steelman, D. P.; Sanders, S. J.; Hargis, J. R.</p> <p>2004-05-01</p> <p>In conjunction with the upcoming release of \\it <span class="hlt">Binary</span> Maker 3.0, an extensive on-line database of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> is being made available. The purposes of the atlas are: \\begin {enumerate} Allow quick and easy access to information on published <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>. Amass a consistent database of light and radial velocity curve solutions to aid in solving new systems. Provide invaluable querying capabilities on all of the parameters of the systems so that informative research can be quickly accomplished on a multitude of published results. Aid observers in establishing new observing programs based upon stars needing new light and/or radial velocity curves. Encourage workers to submit their published results so that others may have easy access to their work. Provide a vast but easily accessible storehouse of information on <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> to accelerate the process of understanding analysis techniques and current work in the field. \\end {enumerate} The database will eventually consist of all published <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> with light curve solutions. The following information and data will be supplied whenever available for each <span class="hlt">binary</span>: original light curves in all bandpasses, original radial velocity observations, light curve parameters, RA and Dec, V-magnitudes, spectral types, color indices, periods, <span class="hlt">binary</span> type, 3D representation of the system near quadrature, plots of the original light curves and synthetic models, plots of the radial velocity observations with theoretical models, and \\it <span class="hlt">Binary</span> Maker 3.0 data files (parameter, light curve, radial velocity). The pertinent references for each star are also given with hyperlinks directly to the papers via the NASA Abstract website for downloading, if available. In addition the Atlas has extensive searching options so that workers can specifically search for <span class="hlt">binaries</span> with specific characteristics. The website has more than 150 systems already uploaded. The URL for the site is http://ebola.eastern.edu/.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ApJ...733..122D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ApJ...733..122D"><span id="translatedtitle">On the Distribution of Orbital Eccentricities for Very <span class="hlt">Low-mass</span> <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dupuy, Trent J.; Liu, Michael C.</p> <p>2011-06-01</p> <p>We have compiled a sample of 16 orbits for very <span class="hlt">low-mass</span> stellar (<0.1 M sun) and brown dwarf <span class="hlt">binaries</span>, including updated orbits for HD 130948BC and LP 415-20AB. This sample enables the first comprehensive study of the eccentricity distribution for such objects. We find that very <span class="hlt">low-mass</span> <span class="hlt">binaries</span> span a broad range of eccentricities from near-circular to highly eccentric (e ≈ 0.8), with a median eccentricity of 0.34. We have examined potential observational biases in this sample, and for visual <span class="hlt">binaries</span> we show through Monte Carlo simulations that if we choose appropriate selection criteria then all eccentricities are equally represented (lsim 5% difference between input and output eccentricity distributions). The orbits of this sample of very <span class="hlt">low-mass</span> <span class="hlt">binaries</span> show some significant differences from their solar-type counterparts. They lack a correlation between orbital period and eccentricity, and display a much higher fraction of near-circular orbits (e < 0.1) than solar-type stars, which together may suggest a different formation mechanism or dynamical history for these two populations. Very <span class="hlt">low-mass</span> <span class="hlt">binaries</span> also do not follow the e 2 distribution of Ambartsumian, which would be expected if their orbits were distributed in phase space according to a function of energy alone (e.g., the Boltzmann distribution). We find that current numerical simulations of very <span class="hlt">low-mass</span> star formation do not completely reproduce the observed properties of our <span class="hlt">binary</span> sample. The cluster formation model of Bate agrees very well with the overall e distribution, but the lack of any high-e (>0.6) <span class="hlt">binaries</span> at orbital periods comparable to our sample suggests that tidal damping due to gas disks may play too large of a role in the simulations. In contrast, the circumstellar disk fragmentation model of Stamatellos & Whitworth predicts only high-e <span class="hlt">binaries</span> and thus is highly inconsistent with our sample. These discrepancies could be explained if multiple formation processes are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21576713','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21576713"><span id="translatedtitle">ON THE DISTRIBUTION OF ORBITAL ECCENTRICITIES FOR VERY <span class="hlt">LOW-MASS</span> <span class="hlt">BINARIES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dupuy, Trent J.; Liu, Michael C.</p> <p>2011-06-01</p> <p>We have compiled a sample of 16 orbits for very <span class="hlt">low-mass</span> stellar (<0.1 M{sub sun}) and brown dwarf <span class="hlt">binaries</span>, including updated orbits for HD 130948BC and LP 415-20AB. This sample enables the first comprehensive study of the eccentricity distribution for such objects. We find that very <span class="hlt">low-mass</span> <span class="hlt">binaries</span> span a broad range of eccentricities from near-circular to highly eccentric (e {approx} 0.8), with a median eccentricity of 0.34. We have examined potential observational biases in this sample, and for visual <span class="hlt">binaries</span> we show through Monte Carlo simulations that if we choose appropriate selection criteria then all eccentricities are equally represented ({approx}< 5% difference between input and output eccentricity distributions). The orbits of this sample of very <span class="hlt">low-mass</span> <span class="hlt">binaries</span> show some significant differences from their solar-type counterparts. They lack a correlation between orbital period and eccentricity, and display a much higher fraction of near-circular orbits (e < 0.1) than solar-type stars, which together may suggest a different formation mechanism or dynamical history for these two populations. Very <span class="hlt">low-mass</span> <span class="hlt">binaries</span> also do not follow the e{sup 2} distribution of Ambartsumian, which would be expected if their orbits were distributed in phase space according to a function of energy alone (e.g., the Boltzmann distribution). We find that current numerical simulations of very <span class="hlt">low-mass</span> star formation do not completely reproduce the observed properties of our <span class="hlt">binary</span> sample. The cluster formation model of Bate agrees very well with the overall e distribution, but the lack of any high-e (>0.6) <span class="hlt">binaries</span> at orbital periods comparable to our sample suggests that tidal damping due to gas disks may play too large of a role in the simulations. In contrast, the circumstellar disk fragmentation model of Stamatellos and Whitworth predicts only high-e <span class="hlt">binaries</span> and thus is highly inconsistent with our sample. These discrepancies could be explained if multiple formation</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JApA...37...16L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JApA...37...16L"><span id="translatedtitle">Photometric Analysis and Period Investigation of the EW Type <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> V441 Lac</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, K.; Hu, S.-M.; Guo, D.-F.; Jiang, Y.-G.; Gao, D.-Y.; Chen, X.</p> <p>2016-09-01</p> <p>Four color light curves of the EW type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> V441 Lac were presented and analyzed by the W-D code. It is found that V441 Lac is an extremely <span class="hlt">low</span> <span class="hlt">mass</span> ratio ( q = 0.093±0.001) semi-detached <span class="hlt">binary</span> with the less massive secondary component filling the inner Roche lobe. Two dark spots on the primary component were introduced to explain the asymmetric light curves. By analyzing all times of light minimum, we determined that the orbital period of V441 Lac is continuously increasing at a rate of d P/d t = 5.874(±0.007) × 10-7 d yr-1. The semi-detached Algol type configuration of V441 Lac is possibly formed by a contact configuration destroyed shallow contact <span class="hlt">binary</span> due to mass transfer from the less massive component to the more massive one predicted by the thermal relaxation oscillation theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1982A%26AS...49..129B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1982A%26AS...49..129B"><span id="translatedtitle">Three colour photoelectric observations of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> TT HER</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burchi, R.; Dipaolantonio, A.; Mancuso, S.; Milano, L.; Vittone, A.</p> <p>1982-07-01</p> <p>Three color photoelectric observations of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> TT Her are presented. The observation sequence and the automation of the measurement cycle allowed 3742 points in each of the colors to be collected. The measurements were reduced to phase by means of an ephemeris and are shown. A preliminary analysis of the period variability is made.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012adap.prop..239P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012adap.prop..239P"><span id="translatedtitle">Towards a Fundamental Understanding of Short Period <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Systems Using Kepler Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prsa, Andrej</p> <p></p> <p>Kepler's ultra-high precision photometry is revolutionizing stellar astrophysics. We are seeing intrinsic phenomena on an unprecedented scale, and interpreting them is both a challenge and an exciting privilege. <span class="hlt">Eclipsing</span> <span class="hlt">binary</span> stars are of particular significance for stellar astrophysics because precise modeling leads to fundamental parameters of the orbiting components: masses, radii, temperatures and luminosities to better than 1-2%. On top of that, <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> are ideal physical laboratories for studying other physical phenomena, such as asteroseismic properties, chromospheric activity, proximity effects, mass transfer in close <span class="hlt">binaries</span>, etc. Because of the <span class="hlt">eclipses</span>, the basic geometry is well constrained, but a follow-up spectroscopy is required to get the dynamical masses and the absolute scale of the system. A conjunction of Kepler photometry and ground- based spectroscopy is a treasure trove for <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star astrophysics. This proposal focuses on a carefully selected set of 100 short period <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars. The fundamental goal of the project is to study the intrinsic astrophysical effects typical of short period <span class="hlt">binaries</span> in great detail, utilizing Kepler photometry and follow-up spectroscopy to devise a robust and consistent set of modeling results. The complementing spectroscopy is being secured from 3 approved and fully funded programs: the NOAO 4-m echelle spectroscopy at Kitt Peak (30 nights; PI Prsa), the 10- m Hobby-Eberly Telescope high-resolution spectroscopy (PI Mahadevan), and the 2.5-m Sloan Digital Sky Survey III spectroscopy (PI Mahadevan). The targets are prioritized by the projected scientific yield. Short period detached <span class="hlt">binaries</span> host <span class="hlt">low-mass</span> (K- and M- type) components for which the mass-radius relationship is sparsely populated and still poorly understood, as the radii appear up to 20% larger than predicted by the population models. We demonstrate the spectroscopic detection viability in the secondary</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AJ....151...68K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AJ....151...68K"><span id="translatedtitle">Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Stars. VII. The Catalog of <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> Found in the Entire Kepler Data Set</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kirk, Brian; Conroy, Kyle; Prša, Andrej; Abdul-Masih, Michael; Kochoska, Angela; Matijevič, Gal; Hambleton, Kelly; Barclay, Thomas; Bloemen, Steven; Boyajian, Tabetha; Doyle, Laurance R.; Fulton, B. J.; Hoekstra, Abe Johannes; Jek, Kian; Kane, Stephen R.; Kostov, Veselin; Latham, David; Mazeh, Tsevi; Orosz, Jerome A.; Pepper, Joshua; Quarles, Billy; Ragozzine, Darin; Shporer, Avi; Southworth, John; Stassun, Keivan; Thompson, Susan E.; Welsh, William F.; Agol, Eric; Derekas, Aliz; Devor, Jonathan; Fischer, Debra; Green, Gregory; Gropp, Jeff; Jacobs, Tom; Johnston, Cole; LaCourse, Daryll Matthew; Saetre, Kristian; Schwengeler, Hans; Toczyski, Jacek; Werner, Griffin; Garrett, Matthew; Gore, Joanna; Martinez, Arturo O.; Spitzer, Isaac; Stevick, Justin; Thomadis, Pantelis C.; Vrijmoet, Eliot Halley; Yenawine, Mitchell; Batalha, Natalie; Borucki, William</p> <p>2016-03-01</p> <p>The primary Kepler Mission provided nearly continuous monitoring of ∼200,000 objects with unprecedented photometric precision. We present the final catalog of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems within the 105 deg2 Kepler field of view. This release incorporates the full extent of the data from the primary mission (Q0-Q17 Data Release). As a result, new systems have been added, additional false positives have been removed, ephemerides and principal parameters have been recomputed, classifications have been revised to rely on analytical models, and <span class="hlt">eclipse</span> timing variations have been computed for each system. We identify several classes of systems including those that exhibit tertiary <span class="hlt">eclipse</span> events, systems that show clear evidence of additional bodies, heartbeat systems, systems with changing <span class="hlt">eclipse</span> depths, and systems exhibiting only one <span class="hlt">eclipse</span> event over the duration of the mission. We have updated the period and galactic latitude distribution diagrams and included a catalog completeness evaluation. The total number of identified <span class="hlt">eclipsing</span> and ellipsoidal <span class="hlt">binary</span> systems in the Kepler field of view has increased to 2878, 1.3% of all observed Kepler targets. An online version of this catalog with downloadable content and visualization tools is maintained at http://keplerEBs.villanova.edu.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJS..217...28Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJS..217...28Y"><span id="translatedtitle"><span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> From the CSTAR Project at Dome A, Antarctica</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Ming; Zhang, Hui; Wang, Songhu; Zhou, Ji-Lin; Zhou, Xu; Wang, Lingzhi; Wang, Lifan; Wittenmyer, R. A.; Liu, Hui-Gen; Meng, Zeyang; Ashley, M. C. B.; Storey, J. W. V.; Bayliss, D.; Tinney, Chris; Wang, Ying; Wu, Donghong; Liang, Ensi; Yu, Zhouyi; Fan, Zhou; Feng, Long-Long; Gong, Xuefei; Lawrence, J. S.; Liu, Qiang; Luong-Van, D. M.; Ma, Jun; Wu, Zhenyu; Yan, Jun; Yang, Huigen; Yang, Ji; Yuan, Xiangyan; Zhang, Tianmeng; Zhu, Zhenxi; Zou, Hu</p> <p>2015-04-01</p> <p>The Chinese Small Telescope ARray (CSTAR) has observed an area around the Celestial South Pole at Dome A since 2008. About 20,000 light curves in the i band were obtained during the observation season lasting from 2008 March to July. The photometric precision achieves about 4 mmag at i = 7.5 and 20 mmag at i = 12 within a 30 s exposure time. These light curves are analyzed using Lomb-Scargle, Phase Dispersion Minimization, and Box Least Squares methods to search for periodic signals. False positives may appear as a variable signature caused by contaminating stars and the observation mode of CSTAR. Therefore, the period and position of each variable candidate are checked to eliminate false positives. <span class="hlt">Eclipsing</span> <span class="hlt">binaries</span> are removed by visual inspection, frequency spectrum analysis, and a locally linear embedding technique. We identify 53 <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in the field of view of CSTAR, containing 24 detached <span class="hlt">binaries</span>, 8 semi-detached <span class="hlt">binaries</span>, 18 contact <span class="hlt">binaries</span>, and 3 ellipsoidal variables. To derive the parameters of these <span class="hlt">binaries</span>, we use the <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> via Artificial Intelligence method. The primary and secondary <span class="hlt">eclipse</span> timing variations (ETVs) for semi-detached and contact systems are analyzed. Correlated primary and secondary ETVs confirmed by false alarm tests may indicate an unseen perturbing companion. Through ETV analysis, we identify two triple systems (CSTAR J084612.64-883342.9 and CSTAR J220502.55-895206.7). The orbital parameters of the third body in CSTAR J220502.55-895206.7 are derived using a simple dynamical model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013giec.conf40102P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013giec.conf40102P&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Science through the Monocle of Kepler</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prsa, Andrej; Eclipsing Binary Working Group</p> <p>2013-07-01</p> <p>The notable success of space-borne missions such as MOST, CoRoT and Kepler triggered a surge of exciting new results in stellar astrophysics, ranging from asteroseismology, discoveries of new subclasses of objects such as heartbeat stars, to the literal firehose of extrasolar planets. The nearly continuous observing mode and an unprecedented photometric precision provide us with data that challenge even the most sophisticated models. <span class="hlt">Eclipsing</span> <span class="hlt">binary</span> stars play a major role since their accurate modeling provides fundamental stellar parameters (masses, radii, temperatures and luminosities) across the H-R diagram by relying on the uniquely favorable geometry that alleviates the need for any calibrations. NASA's Kepler mission is particularly well suited for the study of <span class="hlt">binaries</span>; the ~10-ppm precision and the ~105-square degree field of view yield a sample of ~2500 <span class="hlt">eclipsing</span> systems of varying types and morphologies, that have been observed uninterruptedly for 4 years in a row. I will present statistical results of the complete set of Kepler <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>, including the distributions of the periods, galactic latitudes, morphologies, orbital properties and fundamental stellar parameters. The mission provided us with ground-breaking observations of multiple components through the measurements of <span class="hlt">eclipse</span> timing variations. I will emphasize the pioneering efforts to detect and analyze stellar and substellar tertiaries orbiting <span class="hlt">binary</span> stars and explore the implications of multiplicity on the evolution of these systems. Several theoretical aspects of reliable modeling still elude our grasp, and I will provide a theorist's perspective of the direction that our field might take in the next several years. Lastly, I will focus on a few notable "head-scratchers", systems that deserve special attention because of their uniqueness and/or general importance to astrophysics. This presentation will encapsulate the results based on the work and dedication of the entire Kepler</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014MNRAS.441..343S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014MNRAS.441..343S&link_type=ABSTRACT"><span id="translatedtitle">The highly eccentric detached <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in ACVS and MACC</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shivvers, Isaac; Bloom, Joshua S.; Richards, Joseph W.</p> <p>2014-06-01</p> <p>Next-generation synoptic photometric surveys will yield unprecedented (for the astronomical community) volumes of data and the processes of discovery and rare-object identification are, by necessity, becoming more autonomous. Such autonomous searches can be used to find objects of interest applicable to a wide range of outstanding problems in astronomy, and in this paper we present the methods and results of a largely autonomous search for highly eccentric detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems in the Machine-learned All-Sky Automated Survey Classification Catalog. 106 detached <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> with eccentricities of e ≳ 0.1 are presented, most of which are identified here for the first time. We also present new radial-velocity curves and absolute parameters for six of those systems with the long-term goal of increasing the number of highly eccentric systems with orbital solutions, thereby facilitating further studies of the tidal circularization process in <span class="hlt">binary</span> stars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22342213','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22342213"><span id="translatedtitle">Photometric study of the pulsating, <span class="hlt">eclipsing</span> <span class="hlt">binary</span> OO DRA</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhang, X. B.; Deng, L. C.; Tian, J. F.; Wang, K.; Yan, Z. Z.; Luo, C. Q.; Sun, J. J.; Liu, Q. L.; Xin, H. Q.; Zhou, Q.; Luo, Z. Q.</p> <p>2014-12-01</p> <p>We present a comprehensive photometric study of the pulsating, <span class="hlt">eclipsing</span> <span class="hlt">binary</span> OO Dra. Simultaneous B- and V-band photometry of the star was carried out on 14 nights. A revised orbital period and a new ephemeris were derived from the data. The first photometric solution of the <span class="hlt">binary</span> system and the physical parameters of the component stars are determined. They reveal that OO Dra could be a detached system with a less-massive secondary component nearly filling its Roche lobe. By subtracting the <span class="hlt">eclipsing</span> light changes from the data, we obtained the intrinsic pulsating light curves of the hotter, massive primary component. A frequency analysis of the residual light yields two confident pulsation modes in both B- and V-band data with the dominant frequency detected at 41.865 c/d. A brief discussion concerning the evolutionary status and the pulsation nature of the <span class="hlt">binary</span> system is finally given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AJ....143..123M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AJ....143..123M"><span id="translatedtitle">Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Stars. III. Classification of Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Light Curves with Locally Linear Embedding</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matijevič, Gal; Prša, Andrej; Orosz, Jerome A.; Welsh, William F.; Bloemen, Steven; Barclay, Thomas</p> <p>2012-05-01</p> <p>We present an automated classification of 2165 Kepler <span class="hlt">eclipsing</span> <span class="hlt">binary</span> (EB) light curves that accompanied the second Kepler data release. The light curves are classified using locally linear embedding, a general nonlinear dimensionality reduction tool, into morphology types (detached, semi-detached, overcontact, ellipsoidal). The method, related to a more widely used principal component analysis, produces a lower-dimensional representation of the input data while preserving local geometry and, consequently, the similarity between neighboring data points. We use this property to reduce the dimensionality in a series of steps to a one-dimensional manifold and classify light curves with a single parameter that is a measure of "detachedness" of the system. This fully automated classification correlates well with the manual determination of morphology from the data release, and also efficiently highlights any misclassified objects. Once a lower-dimensional projection space is defined, the classification of additional light curves runs in a negligible time and the method can therefore be used as a fully automated classifier in pipeline structures. The classifier forms a tier of the Kepler EB pipeline that pre-processes light curves for the artificial intelligence based parameter estimator.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22034575','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22034575"><span id="translatedtitle">KEPLER <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> STARS. III. CLASSIFICATION OF KEPLER <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> LIGHT CURVES WITH LOCALLY LINEAR EMBEDDING</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Matijevic, Gal; Prsa, Andrej; Orosz, Jerome A.; Welsh, William F.; Bloemen, Steven; Barclay, Thomas E-mail: andrej.prsa@villanova.edu</p> <p>2012-05-15</p> <p>We present an automated classification of 2165 Kepler <span class="hlt">eclipsing</span> <span class="hlt">binary</span> (EB) light curves that accompanied the second Kepler data release. The light curves are classified using locally linear embedding, a general nonlinear dimensionality reduction tool, into morphology types (detached, semi-detached, overcontact, ellipsoidal). The method, related to a more widely used principal component analysis, produces a lower-dimensional representation of the input data while preserving local geometry and, consequently, the similarity between neighboring data points. We use this property to reduce the dimensionality in a series of steps to a one-dimensional manifold and classify light curves with a single parameter that is a measure of 'detachedness' of the system. This fully automated classification correlates well with the manual determination of morphology from the data release, and also efficiently highlights any misclassified objects. Once a lower-dimensional projection space is defined, the classification of additional light curves runs in a negligible time and the method can therefore be used as a fully automated classifier in pipeline structures. The classifier forms a tier of the Kepler EB pipeline that pre-processes light curves for the artificial intelligence based parameter estimator.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NewA...37...64T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NewA...37...64T"><span id="translatedtitle">The first light curve analysis of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> NR Cam</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tavakkoli, F.; Hasanzadeh, A.; Poro, A.</p> <p>2015-05-01</p> <p>New observations of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system NR Cam were carried out using a CCD in B, V, and R filters and new times of light minimum and new ephemeris were obtained. The B, V, and R light curves were analyzed using both the <span class="hlt">Binary</span> Maker 3.0 and PHOEBE 0.31 programs to determine some geometrical and physical parameters of the system. These results show that NR Cam is an overcontact <span class="hlt">binary</span> and that both components are Main Sequence stars. The O'Connell effect on NR Cam was studied and some variations in spot parameters were obtained over the different years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E1397N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E1397N"><span id="translatedtitle">Searching Planets Around Some Selected <span class="hlt">Eclipsing</span> Close <span class="hlt">Binary</span> Stars Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nasiroglu, Ilham; Slowikowska, Agnieszka; Krzeszowski, Krzysztof; Zejmo, M. Michal; Er, Hüseyin; Goździewski, Krzysztof; Zola, Stanislaw; Koziel-Wierzbowska, Dorota; Debski, Bartholomew; Ogloza, Waldemar; Drozdz, Marek</p> <p>2016-07-01</p> <p>We present updated O-C diagrams of selected short period <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> observed since 2009 with the T100 Telescope at the TUBITAK National Observatory (Antalya, Turkey), the T60 Telescope at the Adiyaman University Observatory (Adiyaman, Turkey), the 60cm at the Mt. Suhora Observatory of the Pedagogical University (Poland) and the 50cm Cassegrain telescope at the Fort Skala Astronomical Observatory of the Jagiellonian University in Krakow, Poland. All four telescopes are equipped with sensitive, back-illuminated CCD cameras and sets of wide band filters. One of the targets in our sample is a post-common envelope <span class="hlt">eclipsing</span> <span class="hlt">binary</span> NSVS 14256825. We collected more than 50 new <span class="hlt">eclipses</span> for this system that together with the literature data gives more than 120 <span class="hlt">eclipse</span> timings over the time span of 8.5 years. The obtained O-C diagram shows quasi-periodic variations that can be well explained by the existence of the third body on Jupiter-like orbit. We also present new results indicating a possible light time travel effect inferred from the O-C diagrams of two other <span class="hlt">binary</span> systems: HU Aqr and V470 Cam.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AJ....151..112D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AJ....151..112D"><span id="translatedtitle">New Pleiades <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> and a Hyades Transiting System Identified by K2</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>David, Trevor J.; Conroy, Kyle E.; Hillenbrand, Lynne A.; Stassun, Keivan G.; Stauffer, John; Rebull, Luisa M.; Cody, Ann Marie; Isaacson, Howard; Howard, Andrew W.; Aigrain, Suzanne</p> <p>2016-05-01</p> <p>We present the discovery in Kepler’s K2 mission observations and our follow-up radial velocity (RV) observations from Keck/HIRES for four <span class="hlt">eclipsing</span> <span class="hlt">binary</span> (EB) star systems in the young benchmark Pleiades and Hyades clusters. Based on our modeling results, we announce two new <span class="hlt">low</span> <span class="hlt">mass</span> ({M}{tot}\\lt 0.6 {M}⊙ ) EBs among Pleiades members (HCG 76 and MHO 9) and we report on two previously known Pleiades <span class="hlt">binaries</span> that are also found to be EB systems (HII 2407 and HD 23642). We measured the masses of the <span class="hlt">binary</span> HCG 76 to ≲2.5% precision, and the radii to ≲4.5% precision, which together with the precise effective temperatures yield an independent Pleiades distance of 132 ± 5 pc. We discuss another EB toward the Pleiades that is a possible but unlikely Pleiades cluster member (AK II 465). The two new confirmed Pleiades systems extend the mass range of Pleiades EB components to 0.2-2 {M}⊙ . Our initial measurements of the fundamental stellar parameters for the Pleiades EBs are discussed in the context of the current stellar models and the nominal cluster isochrone, finding good agreement with the stellar models of Baraffe et al. at the nominal Pleiades age of 120 Myr. Finally, in the Hyades, we report a new <span class="hlt">low</span> <span class="hlt">mass</span> <span class="hlt">eclipsing</span> system (vA 50) that was concurrently discovered and studied by Mann et al. We confirm that the <span class="hlt">eclipse</span> is likely caused by a Neptune-sized transiting planet, and with the additional RV constraints presented here we improve the constraint on the maximum mass of the planet to be ≲1.2 MJup.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AJ....141...83P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AJ....141...83P"><span id="translatedtitle">Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Stars. I. Catalog and Principal Characterization of 1879 <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> in the First Data Release</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prša, Andrej; Batalha, Natalie; Slawson, Robert W.; Doyle, Laurance R.; Welsh, William F.; Orosz, Jerome A.; Seager, Sara; Rucker, Michael; Mjaseth, Kimberly; Engle, Scott G.; Conroy, Kyle; Jenkins, Jon; Caldwell, Douglas; Koch, David; Borucki, William</p> <p>2011-03-01</p> <p>The Kepler space mission is devoted to finding Earth-size planets orbiting other stars in their habitable zones. Its large, 105 deg2 field of view features over 156,000 stars that are observed continuously to detect and characterize planet transits. Yet, this high-precision instrument holds great promise for other types of objects as well. Here we present a comprehensive catalog of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars observed by Kepler in the first 44 days of operation, the data being publicly available through MAST as of 2010 June 15. The catalog contains 1879 unique objects. For each object, we provide its Kepler ID (KID), ephemeris (BJD0, P 0), morphology type, physical parameters (T eff, log g, E(B - V)), the estimate of third light contamination (crowding), and principal parameters (T 2/T 1, q, fillout factor, and sin i for overcontacts, and T 2/T 1, (R 1 + R 2)/a, esin ω, ecos ω, and sin i for detached <span class="hlt">binaries</span>). We present statistics based on the determined periods and measure the average occurrence rate of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> to be ~1.2% across the Kepler field. We further discuss the distribution of <span class="hlt">binaries</span> as a function of galactic latitude and thoroughly explain the application of artificial intelligence to obtain principal parameters in a matter of seconds for the whole sample. The catalog was envisioned to serve as a bridge between the now public Kepler data and the scientific community interested in <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E1155L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E1155L"><span id="translatedtitle">Formation of Galactic Black Hole <span class="hlt">Low-Mass</span> X-ray <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Xiangdong</p> <p>2016-07-01</p> <p>Most of the Galactic black hole (BH) X-ray <span class="hlt">binary</span> systems are <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs). Although the formation of these systems has been extensively investigated, some crucial issues remain unresolved. The most noticeable one is that, the <span class="hlt">low-mass</span> companion has difficulties in ejecting the tightly bound envelope of the massive primary during the spiral-in process. While initially intermediate-mass <span class="hlt">binaries</span> are more likely to survive the common envelope (CE) evolution, the resultant BH LMXBs mismatch the observations. Here we use both stellar evolution and <span class="hlt">binary</span> population synthesis to study the evolutionary history of BH LMXBs. We test various assumptions and prescriptions for the supernova mechanisms that produce BHs, the binding energy parameter, the CE efficiency, and the initial mass distributions of the companion stars. We obtain the birthrate and the distributions of the donor mass, effective temperature and orbital period for the BH LMXBs in each case. By comparing the calculated results with the observations, we put useful constraints on the aforementioned parameters. In particular, we show that it is possible to form BH LMXBs with the standard CE scenario if most BHs are born through failed supernovae.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22365266','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22365266"><span id="translatedtitle">Formation of millisecond pulsars with <span class="hlt">low-mass</span> helium white dwarf companions in very compact <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jia, Kun; Li, X.-D.</p> <p>2014-08-20</p> <p><span class="hlt">Binary</span> millisecond pulsars (BMSPs) are thought to have evolved from <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs). If the mass transfer in LMXBs is driven by nuclear evolution of the donor star, the final orbital period is predicted to be well correlated with the mass of the white dwarf (WD), which is the degenerate He core of the donor. Here we show that this relation can be extended to very small WD mass (∼0.14-0.17 M {sub ☉}) and narrow orbital period (about a few hours), depending mainly on the metallicities of the donor stars. There is also discontinuity in the relation, which is due to the temporary contraction of the donor when the H-burning shell crosses the hydrogen discontinuity. BMSPs with <span class="hlt">low-mass</span> He WD companions in very compact <span class="hlt">binaries</span> can be accounted for if the progenitor <span class="hlt">binary</span> experienced very late Case A mass transfer. The WD companion of PSR J1738+0333 is likely to evolve from a Pop II star. For PSR J0348+0432, to explain its extreme compact orbit in the Roche-lobe-decoupling phase, even lower metallicity (Z = 0.0001) is required.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21583007','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21583007"><span id="translatedtitle">THE PALOMAR TRANSIENT FACTORY ORION PROJECT: <span class="hlt">ECLIPSING</span> <span class="hlt">BINARIES</span> AND YOUNG STELLAR OBJECTS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Van Eyken, Julian C.; Ciardi, David R.; Akeson, Rachel L.; Beichman, Charles A.; Von Braun, Kaspar; Gelino, Dawn M.; Kane, Stephen R.; Plavchan, Peter; RamIrez, Solange V.; Rebull, Luisa M.; Stauffer, John R.; Hoard, D. W.; Howell, Steve B.; Bloom, Joshua S.; Cenko, S. Bradley; Kasliwal, Mansi M.; Kulkarni, Shrinivas R.; Law, Nicholas M.; Nugent, Peter E.</p> <p>2011-08-15</p> <p>The Palomar Transient Factory (PTF) Orion project is one of the experiments within the broader PTF survey, a systematic automated exploration of the sky for optical transients. Taking advantage of the wide (3.{sup 0}5 x 2.{sup 0}3) field of view available using the PTF camera installed at the Palomar 48 inch telescope, 40 nights were dedicated in 2009 December to 2010 January to perform continuous high-cadence differential photometry on a single field containing the young (7-10 Myr) 25 Ori association. Little is known empirically about the formation of planets at these young ages, and the primary motivation for the project is to search for planets around young stars in this region. The unique data set also provides for much ancillary science. In this first paper, we describe the survey and the data reduction pipeline, and present some initial results from an inspection of the most clearly varying stars relating to two of the ancillary science objectives: detection of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> and young stellar objects. We find 82 new <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems, 9 of which are good candidate 25 Ori or Orion OB1a association members. Of these, two are potential young W UMa type systems. We report on the possible <span class="hlt">low-mass</span> (M-dwarf primary) <span class="hlt">eclipsing</span> systems in the sample, which include six of the candidate young systems. Forty-five of the <span class="hlt">binary</span> systems are close (mainly contact) systems, and one of these shows an orbital period among the shortest known for W UMa <span class="hlt">binaries</span>, at 0.2156509 {+-} 0.0000071 days, with flat-bottomed primary <span class="hlt">eclipses</span>, and a derived distance that appears consistent with membership in the general Orion association. One of the candidate young systems presents an unusual light curve, perhaps representing a semi-detached <span class="hlt">binary</span> system with an inflated <span class="hlt">low-mass</span> primary or a star with a warped disk, and may represent an additional young Orion member. Finally, we identify 14 probable new classical T-Tauri stars in our data, along with one previously known</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21451082','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21451082"><span id="translatedtitle">DISCOVERY OF THE <span class="hlt">ECLIPSING</span> DETACHED DOUBLE WHITE DWARF <span class="hlt">BINARY</span> NLTT 11748</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Steinfadt, Justin D. R.; Shporer, Avi; Bildsten, Lars; Kaplan, David L.; Howell, Steve B.</p> <p>2010-06-20</p> <p>We report the discovery of the first <span class="hlt">eclipsing</span> detached double white dwarf (WD) <span class="hlt">binary</span>. In a pulsation search, the <span class="hlt">low-mass</span> helium core WD NLTT 11748 was targeted for fast ({approx}1 minute) differential photometry with the Las Cumbres Observatory's Faulkes Telescope North. Rather than pulsations, we discovered {approx}180 s 3%-6% dips in the photometry. Subsequent radial velocity measurements of the primary white dwarf from the Keck telescope found variations with a semi-amplitude K{sub 1} = 271 {+-} 3 km s{sup -1} and confirmed the dips as <span class="hlt">eclipses</span> caused by an orbiting WD with a mass M{sub 2} = 0.648-0.771 M{sub sun} for M{sub 1} = 0.1-0.2 M{sub sun}. We detect both the primary and secondary <span class="hlt">eclipses</span> during the P{sub orb} = 5.64 hr orbit and measure the secondary's brightness to be 3.5% {+-} 0.3% of the primary at SDSS-g'. Assuming that the secondary follows the mass-radius relation of a cold C/O WD and including the effects of microlensing in the <span class="hlt">binary</span>, the primary <span class="hlt">eclipse</span> yields a primary radius of R{sub 1} = 0.043-0.039 R{sub sun} for M{sub 1} = 0.1-0.2 M{sub sun}, consistent with the theoretically expected values for a helium core WD with a thick, stably burning hydrogen envelope. Though nearby (at {approx}150 pc), the gravitational wave strain from NLTT 11748 is likely not adequate for direct detection by the Laser Interferometer Space Antenna. Future observational efforts will determine M{sub 1}, yielding accurate WD mass-radius measurement of both components, as well as a clearer indication of the <span class="hlt">binary</span>'s fate once contact is reached.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.462.1812R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.462.1812R"><span id="translatedtitle">A quintuple star system containing two <span class="hlt">eclipsing</span> <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rappaport, S.; Lehmann, H.; Kalomeni, B.; Borkovits, T.; Latham, D.; Bieryla, A.; Ngo, H.; Mawet, D.; Howell, S.; Horch, E.; Jacobs, T. L.; LaCourse, D.; Sódor, Á.; Vanderburg, A.; Pavlovski, K.</p> <p>2016-10-01</p> <p>We present a quintuple star system that contains two <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>. The unusual architecture includes two stellar images separated by 11 arcsec on the sky: EPIC 212651213 and EPIC 212651234. The more easterly image (212651213) actually hosts both <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> which are resolved within that image at 0.09 arcsec, while the westerly image (212651234) appears to be single in adaptive optics (AO), speckle imaging, and radial velocity (RV) studies. The `A' <span class="hlt">binary</span> is circular with a 5.1-d period, while the `B' <span class="hlt">binary</span> is eccentric with a 13.1-d period. The γ velocities of the A and B <span class="hlt">binaries</span> are different by ˜10 km s-1. That, coupled with their resolved projected separation of 0.09 arcsec, indicates that the orbital period and separation of the `C' <span class="hlt">binary</span> (consisting of A orbiting B) are ≃65 yr and ≃25 au, respectively, under the simplifying assumption of a circular orbit. Motion within the C orbit should be discernible via future RV, AO, and speckle imaging studies within a couple of years. The C system (i.e. 212651213) has an RV and proper motion that differ from that of 212651234 by only ˜1.4 km s-1 and ˜3 mas yr-1. This set of similar space velocities in three dimensions strongly implies that these two objects are also physically bound, making this at least a quintuple star system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007ApJ...667..520C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007ApJ...667..520C"><span id="translatedtitle">Southern Very <span class="hlt">Low</span> <span class="hlt">Mass</span> Stars and Brown Dwarfs in Wide <span class="hlt">Binary</span> and Multiple Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caballero, José Antonio</p> <p>2007-09-01</p> <p>The results of the Königstuhl survey in the Southern Hemisphere are presented. I have searched for common proper motion companions to 173 field very <span class="hlt">low</span> <span class="hlt">mass</span> stars and brown dwarfs with spectral types >M5.0 V and magnitudes J<~14.5 mag. I have measured for the first time the common proper motion of two new wide systems containing very <span class="hlt">low</span> <span class="hlt">mass</span> components, Königstuhl 2 AB and 3 A-BC. Together with Königstuhl 1 AB and 2M 0126-50 AB, they are among the widest systems in their respective classes (r=450-11,900 AU). I have determined the minimum frequency of field wide multiples (r>100 AU) with late-type components at 5.0%+/-1.8% and the frequency of field wide late-type <span class="hlt">binaries</span> with mass ratios q>0.5 at 1.2%+/-0.9%. These values represent a key diagnostic of evolution history and <span class="hlt">low-mass</span> star and brown dwarf formation scenarios. In addition, the proper motions of 62 field very <span class="hlt">low</span> <span class="hlt">mass</span> dwarfs are measured here for the first time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010MNRAS.407.2362P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010MNRAS.407.2362P"><span id="translatedtitle">Orbital period variations in <span class="hlt">eclipsing</span> post-common-envelope <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parsons, S. G.; Marsh, T. R.; Copperwheat, C. M.; Dhillon, V. S.; Littlefair, S. P.; Hickman, R. D. G.; Maxted, P. F. L.; Gänsicke, B. T.; Unda-Sanzana, E.; Colque, J. P.; Barraza, N.; Sánchez, N.; Monard, L. A. G.</p> <p>2010-10-01</p> <p>We present high-speed ULTRACAM photometry of the <span class="hlt">eclipsing</span> post-common-envelope <span class="hlt">binaries</span> DE CVn, GK Vir, NN Ser, QS Vir, RR Cae, RX J2130.6+4710, SDSS 0110+1326 and SDSS 0303+0054 and use these data to measure precise mid-<span class="hlt">eclipse</span> times in order to detect any period variations. We detect a large (~250 s) departure from linearity in the <span class="hlt">eclipse</span> times of QS Vir which Applegate's mechanism fails to reproduce by an order of magnitude. The only mechanism able to drive this period change is a third body in a highly elliptical orbit. However, the planetary/sub-stellar companion previously suggested to exist in this system is ruled out by our data. Our <span class="hlt">eclipse</span> times show that the period decrease detected in NN Ser is continuing, with magnetic braking or a third body the only mechanisms able to explain this change. The planetary/sub-stellar companion previously suggested to exist in NN Ser is also ruled out by our data. Our precise <span class="hlt">eclipse</span> times also lead to improved ephemerides for DE CVn and GK Vir. The width of a primary <span class="hlt">eclipse</span> is directly related to the size of the secondary star and variations in the size of this star could be an indication of Applegate's mechanism or Wilson (starspot) depressions which can cause jitter in the O-C curves. We measure the width of primary <span class="hlt">eclipses</span> for the systems NN Ser and GK Vir over several years but find no definitive variations in the radii of the secondary stars. However, our data are precise enough (Δ Rsec/Rsec < 10-5) to show the effects of Applegate's mechanism in the future. We find no evidence of Wilson depressions in either system. We also find tentative indications that flaring rates of the secondary stars depend on their mass rather than rotation rates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5557115','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5557115"><span id="translatedtitle">What is causing the <span class="hlt">eclipse</span> in the millisecond <span class="hlt">binary</span> pulsar</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rasio, F.A.; Shapiro, S.L.; Teukolsky, S.A. )</p> <p>1989-07-01</p> <p>Possible physical mechanisms for explaining the radio <span class="hlt">eclipses</span> in the millisecond <span class="hlt">binary</span> pulsar PSR 1957 + 20 are discussed. If, as recent observations suggest, the duration of the <span class="hlt">eclipses</span> depends on the observing frequency, a plausible mechanism is free-free absorption of the radio pulses by a low-density ionized wind surrounding the companion. Detailed numerical calculations are performed for this case, and it is found that all of the observations made at 430 MHz can be reliably reproduced, including the asymmetry in the excess time delay of the pulses. The model leads to definite predictions for the duration of the <span class="hlt">eclipse</span> at other observing frequencies, as well as the radio intensity and excess time delay of the pulses as a function of orbital phase. If the duration of the <span class="hlt">eclipses</span> were found to be independent of frequency, then the likely mechanism would be reflection of the radio signal at a contact discontinuity between a high-density wind and the pulsar radiation. In this case, however, it is difficult to explain the observed symmetry of the <span class="hlt">eclipse</span>. 12 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015BlgAJ..22...28B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015BlgAJ..22...28B"><span id="translatedtitle">Physical parameters of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> components, discovered by STEREO</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Belcheva, Maya; Markov, Haralambi; Tsvetanov, Zlatan; Iliev, Ilian; Stateva, Ivanka</p> <p>2015-01-01</p> <p>Using photometric observations made with the Heliospheric Imager 1 onboard NASA's STEREO mission a list of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems was prepared which can be observed with the Coude spectrograph of the National Astronomical Observatory of Bulgaria, Smolyan, Bulgaria. The epoch and orbital period of each system were determined. The full complement of data consist of light curves extracted from STEREO HI-1 cameras photometry, wide coverage Echelle spectra obtained with the ARCES spectrograph at Apache Point Observatory, New Mexico, USA, for stellar characterization and Coude spectra with R ≈ 15000 and R ≈ 30000 obtained at NAO Rozhen for radial velocity curves. Here we present preliminary results from applying the Wilson-Devinney models for the determination of some physical parameters of three SB2 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems - HD 103694, HD 185990, and HD 214688.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NewA...44...12K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NewA...44...12K"><span id="translatedtitle">Period change investigation of the <span class="hlt">low</span> <span class="hlt">mass</span> ratio contact <span class="hlt">binary</span> BO Ari</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kriwattanawong, W.; Tasuya, O.; Poojon, P.</p> <p>2016-04-01</p> <p>A photometric study and period change analysis for the A-type <span class="hlt">low</span> <span class="hlt">mass</span> ratio contact <span class="hlt">binary</span> BO Ari is presented. The BVR light curves were fitted by using the Wilson-Devinney method. The photometric solution yields a <span class="hlt">low</span> <span class="hlt">mass</span> ratio of q = 0.1754(±0.0016) with a contact degree of f = 27.72%(±2.37%). We found a long-term orbital period decrease at a rate of dPdt = - 3.49 ×10-7 d yr-1. This result indicates that the system is undergoing mass transfer from the primary component to the secondary with a mass transfer rate of m˙1m1 = - 7.77 ×10-8 yr-1. With the period decrease, the inner and outer critical Roche surfaces will tighten and cause the degree of contact to increase. Therefore, BO Ari may evolve into a deeper contact system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AAS...22312502P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AAS...22312502P"><span id="translatedtitle">Searching Kepler Variable Stars with the <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Factory Pipeline</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parvizi, Mahmoud; Paegert, M.</p> <p>2014-01-01</p> <p>Repositories of large survey data, such as the Mikulski Archive for Space Telescopes, provide an ideally sized sample from which to identify astrophysically interesting <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems (EBs). However, constraints on the rate of human analysis in solving for the characteristic parameters make mining this data using classical techniques prohibitive. The Kepler data set provides both the high precision simple aperture photometry necessary to detect EBs and a corresponding Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Catalog - V3 (KEBC3) of 2,406 EBs in the Kepler filed of view (FoV) as a benchmark. We developed a fully automated end-to-end computational pipeline known as the <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Factory (EBF) that employs pre-classification data processing modules, a feed-forward single layer perception neural network classifier (NNC), and a subsequent neural network solution estimator (NNSE). This paper focuses on the EBF component modules to include NNC, but excludes the NNSE, as a precursor to a fully automated pipeline that uses solution estimates of characteristic parameters to identify astrophysically interesting EBs. The EBF was found to recover ~94% of KEBC3 EBs contained in the Kepler “Q3” data release where the period is less than thirty days.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016AJ....151..139M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016AJ....151..139M&link_type=ABSTRACT"><span id="translatedtitle">Fundamental Parameters of Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span>. I. KIC 5738698</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matson, Rachel A.; Gies, Douglas R.; Guo, Zhao; Orosz, Jerome A.</p> <p>2016-06-01</p> <p><span class="hlt">Eclipsing</span> <span class="hlt">binaries</span> serve as a valuable source of stellar masses and radii that inform stellar evolutionary models and provide insight into additional astrophysical processes. The exquisite light curves generated by space-based missions such as Kepler offer the most stringent tests to date. We use the Kepler light curve of the 4.8 day <span class="hlt">eclipsing</span> <span class="hlt">binary</span> KIC 5739896 with ground based optical spectra to derive fundamental parameters for the system. We reconstruct the component spectra to determine the individual atmospheric parameters, and model the Kepler photometry with the <span class="hlt">binary</span> synthesis code <span class="hlt">Eclipsing</span> Light Curve to obtain accurate masses and radii. The two components of KIC 5738698 are F-type stars with {M}1\\=\\1.39+/- 0.04 {M}ȯ , {M}2\\=\\1.34+/- 0.06 {M}ȯ , and {R}1\\=\\1.84+/- 0.03 {R}ȯ , {R}2\\=\\1.72+/- 0.03 {R}ȯ . We also report a small eccentricity (e≲ 0.0017) and unusual albedo values that are required to match the detailed shape of the Kepler light curve. Comparison with evolutionary models indicate an approximate age of 2.3 Gyr for the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AJ....151..139M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AJ....151..139M"><span id="translatedtitle">Fundamental Parameters of Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span>. I. KIC 5738698</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matson, Rachel A.; Gies, Douglas R.; Guo, Zhao; Orosz, Jerome A.</p> <p>2016-06-01</p> <p><span class="hlt">Eclipsing</span> <span class="hlt">binaries</span> serve as a valuable source of stellar masses and radii that inform stellar evolutionary models and provide insight into additional astrophysical processes. The exquisite light curves generated by space-based missions such as Kepler offer the most stringent tests to date. We use the Kepler light curve of the 4.8 day <span class="hlt">eclipsing</span> <span class="hlt">binary</span> KIC 5739896 with ground based optical spectra to derive fundamental parameters for the system. We reconstruct the component spectra to determine the individual atmospheric parameters, and model the Kepler photometry with the <span class="hlt">binary</span> synthesis code <span class="hlt">Eclipsing</span> Light Curve to obtain accurate masses and radii. The two components of KIC 5738698 are F-type stars with {M}1\\=\\1.39+/- 0.04 {M}⊙ , {M}2\\=\\1.34+/- 0.06 {M}⊙ , and {R}1\\=\\1.84+/- 0.03 {R}⊙ , {R}2\\=\\1.72+/- 0.03 {R}⊙ . We also report a small eccentricity (e≲ 0.0017) and unusual albedo values that are required to match the detailed shape of the Kepler light curve. Comparison with evolutionary models indicate an approximate age of 2.3 Gyr for the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22270914','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22270914"><span id="translatedtitle">FORMATION OF BLACK WIDOWS AND REDBACKS—TWO DISTINCT POPULATIONS OF <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> MILLISECOND PULSARS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chen, Hai-Liang; Chen, Xuefei; Han, Zhanwen; Tauris, Thomas M.</p> <p>2013-09-20</p> <p><span class="hlt">Eclipsing</span> <span class="hlt">binary</span> millisecond pulsars (MSPs; the so-called black widows and redbacks) can provide important information about accretion history, pulsar irradiation of their companion stars, and the evolutionary link between accreting X-ray pulsars and isolated MSPs. However, the formation of such systems is not well understood, nor the difference in progenitor evolution between the two populations of black widows and redbacks. Whereas both populations have orbital periods between 0.1 and 1.0 days, their companion masses differ by an order of magnitude. In this paper, we investigate the formation of these systems via the evolution of converging <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> by employing the MESA stellar evolution code. Our results confirm that one can explain the formation of most of these <span class="hlt">eclipsing</span> <span class="hlt">binary</span> MSPs using this scenario. More notably, we find that the determining factor for producing either black widows or redbacks is the efficiency of the irradiation process, such that the redbacks absorb a larger fraction of the emitted spin-down energy of the radio pulsar (resulting in more efficient mass loss via evaporation) compared to that of the black widow systems. We argue that geometric effects (beaming) are responsible for the strong bimodality of these two populations. Finally, we conclude that redback systems do not evolve into black widow systems with time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...800...17F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...800...17F"><span id="translatedtitle">The Origin of Black Hole Spin in Galactic <span class="hlt">Low-mass</span> X-Ray <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fragos, T.; McClintock, J. E.</p> <p>2015-02-01</p> <p>Galactic field black hole (BH) <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs) are believed to form in situ via the evolution of isolated <span class="hlt">binaries</span>. In the standard formation channel, these systems survived a common envelope phase, after which the remaining helium core of the primary star and the subsequently formed BH are not expected to be highly spinning. However, the measured spins of BHs in LMXBs cover the whole range of spin parameters. We propose here that the BH spin in LMXBs is acquired through accretion onto the BH after its formation. In order to test this hypothesis, we calculated extensive grids of detailed <span class="hlt">binary</span> mass-transfer sequences. For each sequence, we examined whether, at any point in time, the calculated <span class="hlt">binary</span> properties are in agreement with their observationally inferred counterparts of 16 Galactic LMXBs. The "successful" sequences give estimates of the mass that the BH has accreted since the onset of Roche-Lobe overflow. We find that in all Galactic LMXBs with measured BH spin, the origin of the spin can be accounted for by the accreted matter, and we make predictions about the maximum BH spin in LMXBs where no measurement is yet available. Furthermore, we derive limits on the maximum spin that any BH can have depending on current properties of the <span class="hlt">binary</span> it resides in. Finally we discuss the implication that our findings have on the BH birth-mass distribution, which is shifted by ~1.5 M ⊙ toward lower masses, compared to the currently observed one.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.458.4188M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.458.4188M"><span id="translatedtitle">Tidal capture formation of <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> from wide <span class="hlt">binaries</span> in the field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Michaely, Erez; Perets, Hagai B.</p> <p>2016-06-01</p> <p>We present a dynamical formation scenario for <span class="hlt">low</span> <span class="hlt">mass</span> X-ray <span class="hlt">binaries</span> (LMXBs) in the field, focusing on black hole (BH) LMXBs. In this formation channel, LMXBs are formed from wide <span class="hlt">binaries</span> (>1000 au) with a BH component and a stellar companion. The wide <span class="hlt">binary</span> is perturbed by fly-bys of field stars, its orbit random walks, until driven into a sufficiently eccentric orbit such that the <span class="hlt">binary</span> components tidally interact and the <span class="hlt">binary</span> evolves to become a short period <span class="hlt">binary</span>, which eventually evolves into an LMXB. We consider several models for the formation and survival of such wide <span class="hlt">binaries</span>, and calculate the LMXB formation rates for each model. We find that models where BHs form through direct collapse with no/little natal kicks can give rise to high formation rates comparable with those inferred from observations. This formation scenario had several observational signatures: (1) the number density of LMXBs generally follows the background stellar density, beside the densest regions, where the dependence is stronger, (2) the mass function of the BH stellar companion should be comparable to the mass function of the background stellar population, likely peaking at 0.4-0.6 M⊙, and (3) the LMXBs orbit should not correlate with the spin of the BH. These aspects generally differ from the expectations from previously suggested LMXB formation models following common envelope <span class="hlt">binary</span> stellar evolution. We note that neutron star LMXBs can similarly form from wide <span class="hlt">binaries</span>, but their formation rate through this channel is likely significantly smaller due to their much higher natal kicks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014hst..prop13642D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014hst..prop13642D"><span id="translatedtitle">The evolutionary link between <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> and millisecond radio pulsars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Degenaar, Nathalie</p> <p>2014-10-01</p> <p><span class="hlt">Low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs) and millisecond radio pulsars (MSRPs) are two different manifestations of neutron stars in <span class="hlt">binary</span> systems. They are thought to be evolutionary linked, but many questions about their connection remain. Recent discoveries have opened up a new vista to investigate the LMXB/MSRP link. The neutron star XSS J12270-4859 was recently observed to switch between the two different manifestations. Here, we propose to exploit the unique UV capabilities of the HST to search for the presence of a quiescent accretion disk and to test if the neutron star is hot. This will give insight into its accretion history and the mechanism driving its metamorphosis, which will have direct implications for our understanding of the LMXB/MSRP evolutionary link.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AJ....151...69S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AJ....151...69S"><span id="translatedtitle">ASAS J083241+2332.4: A New Extreme <span class="hlt">Low</span> <span class="hlt">Mass</span> Ratio Overcontact <span class="hlt">Binary</span> System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sriram, K.; Malu, S.; Choi, C. S.; Vivekananda Rao, P.</p> <p>2016-03-01</p> <p>We present the R- and V-band CCD photometry and Hα line studies of an overcontact <span class="hlt">binary</span> ASAS J083241+2332.4. The light curves exhibit totality along with a trace of the O’Connell effect. The photometric solution indicates that this system falls into the category of extreme <span class="hlt">low-mass</span> ratio overcontact <span class="hlt">binaries</span> with a mass ratio, q ˜ 0.06. Although a trace of the O’ Connell effect is observed, constancy of the Hα line along various phases suggest that a relatively higher magnetic activity is needed for it to show a prominent fill-in effect. The study of O-C variations reveals that the period of the <span class="hlt">binary</span> shows a secular increase at the rate of dP/dt ˜ 0.0765 s years-1, which is superimposed by a low, but significant, sinusoidal modulation with a period of ˜8.25 years. Assuming that the sinusoidal variation is due to the presence of a third body, orbital elements have been derived. There exist three other similar systems, SX Crv, V857 Her, and E53, which have extremely <span class="hlt">low</span> <span class="hlt">mass</span> ratios and we conclude that ASAS J083241+2332.4 resembles SX Crv in many respects. Theoretical studies indicate that at a critical mass ratio range, qcritical = 0.07-0.09, overcontact <span class="hlt">binaries</span> should merge and form a fast rotating star, but it has been suggested that qcritical can continue to fall up to 0.05 depending on the primary's mass and structure. Moreover, the obtained fill-out factors (50%-70%) indicate that mass loss is considerable and hydrodynamical simulations advocate that mass loss from L2 is mandatory for a successful merging process. Comprehensively, the results indicate that ASAS J083241+2332.4 is at a stage of merger. The pivotal role played by the subtle nature of the derived mass ratio in forming a rapidly rotating star has been discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22522275','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22522275"><span id="translatedtitle">POTENTIAL GAMMA-RAY EMISSIONS FROM <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARY</span> JETS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhang, Jian-Fu; Gu, Wei-Min; Liu, Tong; Xue, Li; Lu, Ju-Fu E-mail: guwm@xmu.edu.cn</p> <p>2015-06-20</p> <p>By proposing a pure leptonic radiation model, we study the potential gamma-ray emissions from the jets of <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span>. In this model, the relativistic electrons that are accelerated in the jets are responsible for radiative outputs. Nevertheless, jet dynamics are dominated by magnetic and proton–matter kinetic energies. The model involves all kinds of related radiative processes and considers the evolution of relativistic electrons along the jet by numerically solving the kinetic equation. Numerical results show that the spectral energy distributions can extend up to TeV bands, in which synchrotron radiation and synchrotron self-Compton scattering are dominant components. As an example, we apply the model to the <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> GX 339–4. The results not only can reproduce the currently available observations from GX 339–4, but also predict detectable radiation at GeV and TeV bands by the Fermi and CTA telescopes. Future observations with Fermi and CTA can be used to test our model, which could be employed to distinguish the origin of X-ray emissions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21583272','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21583272"><span id="translatedtitle">ORBITAL SOLUTIONS FOR TWO YOUNG, <span class="hlt">LOW-MASS</span> SPECTROSCOPIC <span class="hlt">BINARIES</span> IN OPHIUCHUS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rosero, V.; Prato, L.; Wasserman, L. H.; Rodgers, B. E-mail: lprato@lowell.edu E-mail: brodgers@gemini.edu</p> <p>2011-01-15</p> <p>We report the orbital parameters for ROXR1 14 and RX J1622.7-2325Nw, two young, <span class="hlt">low-mass</span>, and double-lined spectroscopic <span class="hlt">binaries</span> recently discovered in the Ophiuchus star-forming region. Accurate orbital solutions were determined from over a dozen high-resolution spectra taken with the Keck II and Gemini South telescopes. These objects are T Tauri stars with mass ratios close to unity and periods of {approx}5 and {approx}3 days, respectively. In particular, RX J1622.7-2325Nw shows a non-circularized orbit with an eccentricity of 0.30, higher than any other short-period pre-main-sequence (PMS) spectroscopic <span class="hlt">binary</span> known to date. We speculate that the orbit of RX J1622.7-2325Nw has not yet circularized because of the perturbing action of a {approx}1'' companion, itself a close visual pair. A comparison of known young spectroscopic <span class="hlt">binaries</span> (SBs) and main-sequence (MS) SBs in the eccentricity-period plane shows an indistinguishable distribution of the two populations, implying that orbital circularization occurs in the first 1 Myr of a star's lifetime. With the results presented in this paper we increase by {approx}4% the small sample of PMS spectroscopic <span class="hlt">binary</span> stars with known orbital elements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SASS...28..107W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SASS...28..107W"><span id="translatedtitle">Revisiting the O'Connell Effect in <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilsey, Nicholas J.; Beaky, Mathew M.</p> <p>2009-05-01</p> <p>Many <span class="hlt">eclipsing</span> <span class="hlt">binary</span> light curves exhibit a feature known as the O'Connell effect, where the two out-of-<span class="hlt">eclipse</span> maxima are unequally high. The effect is entirely unexpected, because the two side-by-side configurations of the components should appear equally bright from our line of sight. Several theories have been proposed to explain the effect, including asymmetrically distributed starspots, clouds of circumstellar dust and gas, or a hot spot caused by the impact of a mass-transferring gas stream. Currently, most published models of systems with asymmetric maxima incorporate starspots to rectify their models to fit the observational data. However, the limitations of starspot solutions, as well as other possible explanations for the asymmetry, are rarely discussed. In order to revitalize the study the O'Connell effect, the astronomy program at Truman State University in Kirksville, Missouri has initiated a project to construct complete BVRI light curves of poorly studied <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems exhibiting the O'Connell effect, including V573 Lyr and UV Mon. We are also exploring methods of applying Fourier analysis to large, all-sky databases to extract correlations that may help to evaluate competing theories for explaining the effect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21583213','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21583213"><span id="translatedtitle">KEPLER <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> STARS. I. CATALOG AND PRINCIPAL CHARACTERIZATION OF 1879 <span class="hlt">ECLIPSING</span> <span class="hlt">BINARIES</span> IN THE FIRST DATA RELEASE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Prsa, Andrej; Engle, Scott G.; Conroy, Kyle; Batalha, Natalie; Rucker, Michael; Mjaseth, Kimberly; Slawson, Robert W.; Doyle, Laurance R.; Welsh, William F.; Orosz, Jerome A.; Seager, Sara; Jenkins, Jon; Caldwell, Douglas</p> <p>2011-03-15</p> <p>The Kepler space mission is devoted to finding Earth-size planets orbiting other stars in their habitable zones. Its large, 105 deg{sup 2} field of view features over 156,000 stars that are observed continuously to detect and characterize planet transits. Yet, this high-precision instrument holds great promise for other types of objects as well. Here we present a comprehensive catalog of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars observed by Kepler in the first 44 days of operation, the data being publicly available through MAST as of 2010 June 15. The catalog contains 1879 unique objects. For each object, we provide its Kepler ID (KID), ephemeris (BJD{sub 0}, P{sub 0}), morphology type, physical parameters (T{sub eff}, log g, E(B - V)), the estimate of third light contamination (crowding), and principal parameters (T{sub 2}/T{sub 1}, q, fillout factor, and sin i for overcontacts, and T{sub 2}/T{sub 1}, (R{sub 1} + R{sub 2})/a, esin {omega}, ecos {omega}, and sin i for detached <span class="hlt">binaries</span>). We present statistics based on the determined periods and measure the average occurrence rate of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> to be {approx}1.2% across the Kepler field. We further discuss the distribution of <span class="hlt">binaries</span> as a function of galactic latitude and thoroughly explain the application of artificial intelligence to obtain principal parameters in a matter of seconds for the whole sample. The catalog was envisioned to serve as a bridge between the now public Kepler data and the scientific community interested in <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AJ....138..540Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AJ....138..540Y"><span id="translatedtitle">Deep, <span class="hlt">Low</span> <span class="hlt">Mass</span> Ratio Overcontact <span class="hlt">Binary</span> Systems. IX. V345 Geminorum with a Bright Visual Pair</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Y.-G.; Qian, S.-B.; Zhu, L.-Y.; He, J.-J.</p> <p>2009-08-01</p> <p>CCD photometric observations of the visual <span class="hlt">binary</span>, V345 Geminorum, obtained from 2007 January 24 to 2009 March 22, are presented. When comparing the light curves in 2007 and 2008, it is found that there appears to be an O'Connell effect in the light curves of 2008. From those observations, two sets of photometric solutions were deduced using the 2003 version of the W-D program. The results indicated that V345 Gem is a <span class="hlt">low</span> <span class="hlt">mass</span> ratio overcontact <span class="hlt">binary</span> with f = 72.9%(±3.1%). The asymmetric light curves in 2008 may be attributed to the activity of starspot, whose area is up to 1.55% of the area of the more massive component. The contributions of the third light to the total light are approximately 20% in the BVR bands. The absolute physical parameters for V345 Gem were obtained first. From the log L-log M diagram of the <span class="hlt">binary</span>-star evolution, the primary component is an evolved star. From the O-C curve for V345 Gem, it is discovered that there exists a long-term period increase with a cyclic variation. The period and amplitude of the cyclic variation are P 3 = 646.7(±0.7) day and A = 0fd0019(±0fd0002), which may be caused by the light-time effect via the assumed third body. If it is true, the visual <span class="hlt">binary</span> V345 Gem may be a quadruple star. The kind of additional component may remove angular momentum from the central system, which may play an important role for the formation and evolution of the <span class="hlt">binary</span>. The secular period increases at a rate of dP/dt = +5.88 × 10-8 d yr-1, indicating that the mass transfers from the less massive component to the more massive component. With mass transferring, the orbital angular momentum decreases while the spin angular momentum increases. When J spin/J orb > 1/3, this kind of deep, <span class="hlt">low</span> <span class="hlt">mass</span> ratio overcontact <span class="hlt">binary</span> with secular period increase may evolve into a rapid-rotating single star.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950008094','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950008094"><span id="translatedtitle">Observations of hot stars and <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> with FRESIP</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gies, Douglas R.</p> <p>1994-01-01</p> <p>The FRESIP project offers an unprecedented opportunity to study pulsations in hot stars (which vary on time scales of a day) over a several year period. The photometric data will determine what frequencies are present, how or if the amplitudes change with time, and whether there is a connection between pulsation and mass loss episodes. It would initiate a new field of asteroseismology studies of hot star interiors. A search should be made for selected hot stars for inclusion in the list of project targets. Many of the primary solar mass targets will be <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>, and I present estimates of their frequency and typical light curves. The photometric data combined with follow up spectroscopy and interferometric observations will provide fundamental data on these stars. The data will provide definitive information on the mass ratio distribution of solar-mass <span class="hlt">binaries</span> (including the incidence of brown dwarf companions) and on the incidence of planets in <span class="hlt">binary</span> systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AN....328..154S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AN....328..154S"><span id="translatedtitle">Orbital period variation of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system TT Herculis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Selam, S. O.; Albayrak, B.</p> <p>2007-02-01</p> <p>% New photoelectric U BV observations were obtained for the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> TT Her at the Ankara University Observatory (AUO) and three new times of minima were calculated from these observations. The (O-C) diagram constructed for all available times of minima of TT Her exhibits a cyclic character superimposed on a quadratic variation. The quadratic character yields an orbital period decrease with a rate of dP/dt=-8.83×10-8 day yr-1 which can be attributed to the mass exchange/loss mechanism in the system. By assuming the presence of a gravitationally bound third body in the system, the analysis of the cyclic nature in the (O-C) diagram revealed a third body with a mass of 0.21 M\\sun orbiting around the <span class="hlt">eclipsing</span> pair. The possibility of magnetic activity cycle effect as a cause for the observed cyclic variation in the (O-C) diagram was also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IAUGA..2256653F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IAUGA..2256653F"><span id="translatedtitle">The origin of Black-Hole Spin in Galactic <span class="hlt">Low-Mass</span> X-ray <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fragos, Tassos; McClintock, Jeffrey</p> <p>2015-08-01</p> <p>Galactic field <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs), like the ones for which black hole (BH) spin measurements are available, are believed to form in situ via the evolution of isolated <span class="hlt">binaries</span>. In the standard formation channel, these systems survived a common envelope phase, after which the remaining helium core of the primary star and the subsequently formed BH are not expected to be highly spinning. However, the measured spins of BHs in LMXBs cover the whole range of spin parameters from a*~0 to a*1. In this talk I propose that the BH spin in LMXBs is acquired through accretion onto the BH during its long stable accretion phase. In order to test this hypothesis, I calculated extensive grids of <span class="hlt">binary</span> evolutionary sequences in which a BH accretes matter from a close companion. For each evolutionary sequence, I examined whether, at any point in time, the calculated <span class="hlt">binary</span> properties are in agreement with their observationally inferred counterparts of observed Galactic LMXBs with BH spin measurements. Mass-transfer sequences that simultaneously satisfy all observational constraints represent possible progenitors of the considered LMXBs and thus give estimates of the amount of matter that the BH has accreted since the onset of Roche-Lobe overflow. I find that in all Galactic LMXBs with measured BH spin, the origin of the spin can be accounted by the accreted matter. Furthermore, based on this hypothesis, I derive limits on the maximum spin that a BH can have depending on the orbital period of the <span class="hlt">binary</span> it resides in, and give predictions on the maximum possible BH spin of Galactic LMXBs where a BH spin measurement is not yet available. Finally I will discuss the implication that our findings have on the birth black hole mass distribution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014HEAD...1420505F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014HEAD...1420505F"><span id="translatedtitle">The Origin of Black-Hole Spin in Galactic <span class="hlt">Low-Mass</span> X-ray <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fragos, Tassos; McClintock, Jeffrey E.; Narayan, Ramesh</p> <p>2014-08-01</p> <p>Galactic field <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs), like the ones for which black hole (BH) spin measurements are available, are believed to form in situ via the evolution of isolated <span class="hlt">binaries</span>. In the standard formation channel, these systems survived a common envelope phase, after which the remaining helium core of the primary star and the subsequently formed BH are not expected to be highly spinning. However, the measured spins of BHs in LMXBs cover the whole range of spin parameters from a 0 to a*1. In this talk I propose that the BH spin in LMXBs is acquired through accretion onto the BH during its long stable accretion phase. In order to test this hypothesis, I calculated extensive grids of <span class="hlt">binary</span> evolutionary sequences in which a BH accretes matter from a close companion. For each evolutionary sequence, I examined whether, at any point in time, the calculated <span class="hlt">binary</span> properties are in agreement with their observationally inferred counterparts of observed Galactic LMXBs with BH spin measurements. Mass-transfer sequences that simultaneously satisfy all observational constraints represent possible progenitors of the considered LMXBs and thus give estimates of the amount of matter that the BH has accreted since the onset of Roche-Lobe overflow. I find that in all Galactic LMXBs with measured BH spin, the origin of the spin can be accounted by the accreted matter. Furthermore, based on this hypothesis, I derive limits on the maximum spin that a BH can have depending on the orbital period of the <span class="hlt">binary</span> it resides in, and give predictions on the maximum possible BH spin of Galactic LMXBs where a BH spin measurement is not yet available. Finally I will discuss the implication that our findings have on the birth black hole mass distribution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22364263','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22364263"><span id="translatedtitle">THE ORIGIN OF BLACK HOLE SPIN IN GALACTIC <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARIES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fragos, T.; McClintock, J. E.</p> <p>2015-02-10</p> <p>Galactic field black hole (BH) <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs) are believed to form in situ via the evolution of isolated <span class="hlt">binaries</span>. In the standard formation channel, these systems survived a common envelope phase, after which the remaining helium core of the primary star and the subsequently formed BH are not expected to be highly spinning. However, the measured spins of BHs in LMXBs cover the whole range of spin parameters. We propose here that the BH spin in LMXBs is acquired through accretion onto the BH after its formation. In order to test this hypothesis, we calculated extensive grids of detailed <span class="hlt">binary</span> mass-transfer sequences. For each sequence, we examined whether, at any point in time, the calculated <span class="hlt">binary</span> properties are in agreement with their observationally inferred counterparts of 16 Galactic LMXBs. The ''successful'' sequences give estimates of the mass that the BH has accreted since the onset of Roche-Lobe overflow. We find that in all Galactic LMXBs with measured BH spin, the origin of the spin can be accounted for by the accreted matter, and we make predictions about the maximum BH spin in LMXBs where no measurement is yet available. Furthermore, we derive limits on the maximum spin that any BH can have depending on current properties of the <span class="hlt">binary</span> it resides in. Finally we discuss the implication that our findings have on the BH birth-mass distribution, which is shifted by ∼1.5 M {sub ☉} toward lower masses, compared to the currently observed one.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NewA...35...48L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NewA...35...48L"><span id="translatedtitle">A comprehensive photometric study of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> EP Aurigae</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, H.-L.; Wei, J.-Y.; Yang, Y.-G.; Li, K.; Zhang, X.-B.</p> <p>2015-02-01</p> <p>We present new observations for the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> EP Aurigae, which were performed by using three small telescopes in China from 2003 December to 2014 January. With the updated 2003 version of the Wilson-Devinney code, the photometric elements were deduced from three sets of light curves. Based on all available <span class="hlt">eclipsing</span> times, the orbital period changes were investigated. It is discovered that the (O-C) curve may show an existence of light-time effect due to an unseen third body, which was weakly identified by the photometric solution. The modulated period and amplitude of the cyclic variation are P3=71.2(±8.0) yr and A=0.0101(±0.0008) day, respectively. In the co-planar orbit with the <span class="hlt">binary</span> system, the mass of the third body is M3=0.18(±0.02) M⊙. The photometric results imply that EP Aur is an Algol-type <span class="hlt">binary</span> with a mass ratio of q=0.831(±0.004). Its primary component almost fills its Roche lobe. Therefore, EP Aur may consist of a normal main-sequence star and a cool Roche-lobe filling subgiant, which may be undergoing rapid mass transfer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22356540','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22356540"><span id="translatedtitle">WISE detection of the galactic <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wang, Xuebing; Wang, Zhongxiang</p> <p>2014-06-20</p> <p>We report on the results from our search for the Wide-field Infrared Survey Explorer (WISE) detection of the Galactic <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs). Among 187 <span class="hlt">binaries</span> cataloged in Liu et al., we find 13 counterparts and 2 candidate counterparts. For the 13 counterparts, 2 (4U 0614+091 and GX 339–4) have already been confirmed by previous studies to have a jet and 1 (GRS 1915+105) to have a candidate circumbinary disk, from which the detected infrared emission arose. Having collected the broadband optical and near-infrared data in the literature and constructed flux density spectra for the other 10 <span class="hlt">binaries</span>, we identify that 3 (A0620–00, XTE J1118+480, and GX 1+4) are candidate circumbinary disk systems, 4 (Cen X-4, 4U 1700+24, 3A 1954+319, and Cyg X-2) had thermal emission from their companion stars, and 3 (Sco X-1, Her X-1, and Swift J1753.5–0127) are peculiar systems with the origin of their infrared emission rather uncertain. We discuss the results and WISE counterparts' brightness distribution among the known LMXBs, and suggest that more than half of the LMXBs would have a jet, a circumbinary disk, or both.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950036465&hterms=hertz&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dhertz','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950036465&hterms=hertz&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dhertz"><span id="translatedtitle">Searches for millisecond pulsations in <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span>, 2</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vaughan, B. A.; Van Der Klis, M.; Wood, K. S.; Norris, J. P.; Hertz, P.; Michelson, P. F.; Paradijs, J. Van; Lewin, W. H. G.; Mitsuda, K.; Penninx, W.</p> <p>1994-01-01</p> <p>Coherent millisecond X-ray pulsations are expected from <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs), but remain undetected. Using the single-parameter Quadratic Coherence Recovery Technique (QCRT) to correct for unknown <span class="hlt">binary</span> orbit motion, we have performed Fourier transform searches for coherent oscillations in all long, continuous segments of data obtained at 1 ms time resolution during Ginga observations of LMXB. We have searched the six known Z sources (GX 5-1, Cyg X-2, Sco X-1, GX 17+2, GX 340+0, and GX 349+2), seven of the 14 known atoll sources (GX 3+1. GX 9+1, GX 9+9, 1728-33. 1820-30, 1636-53 and 1608-52), the 'peculiar' source Cir X-1, and the high-mass <span class="hlt">binary</span> Cyg X-3. We find no evidence for coherent pulsations in any of these sources, with 99% confidence limits on the pulsed fraction between 0.3% and 5.0% at frequencies below the Nyquist frequency of 512 Hz. A key assumption made in determining upper limits in previous searches is shown to be incorrect. We provide a recipe for correctly setting upper limits and detection thresholds. Finally we discuss and apply two strategies to improve sensitivity by utilizing multiple, independent, continuous segments of data with comparable count rates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015yCat..74422620Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015yCat..74422620Z"><span id="translatedtitle">VizieR Online Data Catalog: VRI light curve of 5 <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> (Zhang+, 2014)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, L.-Y.; Pi, Q.-F.; Yang, Y.-G.</p> <p>2015-03-01</p> <p>In this paper, we carried out new photometric observations of the five <span class="hlt">low-mass</span> <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> from 2010 to 2012 (NSVS 02502726: 2010 November 26, 27, 28 and 29; 2011 January 29 and 31, and December 10, 11, and 13; 2012 February 18 and 20, and April 3, 6, 7 and 8; NSVS 07453183: 2011 March 22, 24, April 15, 17, and 18, and December 8, 9; NSVS 11868841: 2010 November 26, 27, 28, 29, and December 11, 12, 13, 15; GSC02314-00530: 2010 November 24; 2011 January 28, and February 1, and December 9; NSVS 10653195: 2012 April 3, 4, 6, 7, and 8) with an 85cm telescope at Xinglong station of National Astronomical Observatories of China (NAOC). The photometer was equipped with a 1024x1024 pixel CCD along with Johnson-Cousins B, V, R, I filters. Our observations were carried out in V, R and I passbands. (4 data files).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AAS...21823007B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AAS...21823007B"><span id="translatedtitle">Fundamental Parameters of 4 Massive <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> in Westerlund 1</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bonanos, Alceste Z.; Koumpia, E.</p> <p>2011-05-01</p> <p>We present fundamental parameters of 4 massive <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in the young massive cluster Westerlund 1. The goal is to measure accurate masses and radii of their component stars, which provide much needed constraints for evolutionary models of massive stars. Accurate parameters can further be used to determine a dynamical lower limit for the magnetar progenitor and to obtain an independent distance to the cluster. Our results confirm and extend the evidence for a high mass for the progenitor of the magnetar. The authors acknowledge research and travel support from the European Commission Framework Program Seven under the Marie Curie International Reintegration Grant PIRG04-GA-2008-239335.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003AAS...202.0805S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003AAS...202.0805S&link_type=ABSTRACT"><span id="translatedtitle">BVRI Photometry of the <span class="hlt">Eclipsing</span> Spectroscopic <span class="hlt">Binary</span> V1061 Cygni</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sheets, H. A.; Marschall, L. A.; Torres, G.</p> <p>2003-05-01</p> <p>A series of over 2000 images of the 9th magnitude <span class="hlt">eclipsing</span> <span class="hlt">binary</span> V1061 (HD235444, spectral type F8) was obtained during Autumn, 2002 using the 16-inch reflecting telescope of the Gettysburg College Observatory and a Photometrics 350 Camera equipped with a SITe 1024 x 1024 back-illuminated CCD chip. From the densely sampled BVRI light curves derived from these images, along with high-precision radial velocity data obtained at the Center for Astrophysics, we have computed a preliminary set of physical characteristics of the components of the V1061 Cygni system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1981A%26A....96..328M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1981A%26A....96..328M"><span id="translatedtitle">A comparison of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> models - Application to RT UMi</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Milano, L.; Russo, G.; Sollazzo, C.</p> <p>1981-03-01</p> <p>The computer models of Wood and Wilson-Devinney have been used to solve the light curve of RT UMi, an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> with unknown mass function and a small value of the inclination angle. The system turns out to be a normal semi detached system, showing the inadequacy of the Russell and Merrill method in this limit case. The good agreement of the two solutions obtained enforces the validity of methods based on light curve synthesis, even in the absence of good starting parameters.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E1485O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E1485O"><span id="translatedtitle">KIC11560447: An Active <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> From the Kepler Field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ozavci, Ibrahim; Hussain, Gaitee; Yılmaz, Mesut; O'Neal, Douglas; osman Selam, Selim; Şenavcı, Hakan Volkan</p> <p>2016-07-01</p> <p>We performed spectroscopic and photometric analysis of the detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> KIC11560447, in order to investigate the spot activity of the system. In this context, we reconstructed the surface maps with the help of the code DoTS, using time series spectra obtained at the 2.1m Otto Struve Telescope of the McDonald Observatory. We also analysed high precision Kepler light curves of the system simultaneously with the code DoTS to reveal the spot migration and activity behaviour.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004RMxAC..20..211M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004RMxAC..20..211M&link_type=ABSTRACT"><span id="translatedtitle">Rapidly evolving light curves of <span class="hlt">Low</span> <span class="hlt">Mass</span> X-Ray <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Muhli, P.; Hakala, P. J.; Hjalmarsdotter, L.; Hannikainen, D. C.; Schultz, J.</p> <p>2004-07-01</p> <p>A few Galactic <span class="hlt">Low</span> <span class="hlt">Mass</span> X-Ray <span class="hlt">Binaries</span> (LMXBs) have shown drastically evolving X-ray and/or optical orbital light curves. In two short-period LMXBs, MS 1603+2600 (= UW CrB, P[orb] = 111 min) and 4U 1916-053 (see e.g. Homer et al. 2001), the variations in the light curve morphology seem to be repeating in a periodic manner. We present first results of a photometric monitoring campaign of MS 1603+2600, showing evidence of a 5-day superorbital period in this yet unclassified source. The observations also unraveled optical flares, reminiscent of type I bursts, suggesting a neutron star primary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015sptz.prop11183F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015sptz.prop11183F"><span id="translatedtitle">V404 Cyg - an Interacting Black-Hole <span class="hlt">Low-Mass</span> X-ray <span class="hlt">Binary</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fox, Ori; Mauerhan, Jon; Graham, Melissa</p> <p>2015-07-01</p> <p>This DDT proposal is prompted by the June 15, 2015 outburst of V404 Cyg, a black-hole (BH) <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> (LMXB). This outburst stands out since it is the first black hole system with a measured parallax, lying at a distance of only 2.39+/-0.14 kpc. An extensive and loosely organized multi-wavelength campaign is already underway by the astronomical community. One of the missing pieces of the puzzle is the mid-infrared (IR). Combined with radio, optical, and X-ray data, the mid-IR will help to discriminate discriminate between an accretion disk, jet emission, or circumstellar dust scenarios. Spitzer offers a unique opportunity to observe at these wavelengths. Here we propose 4 very short (5-minutes at 3.6 and 4.5 micron) observations of IRAC hotometry to search for the presence of warm dust and, if present, constrain the heating mechanism.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E.752G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E.752G"><span id="translatedtitle">Testing nuclear physics from space with quiescent <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guillot, Sebastien</p> <p>2016-07-01</p> <p>X-ray observations of quiescent <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (qLMXBs) provide one of the methods to understand the internal structure of neutron stars and therefore place constraints on the nuclear physics of dense matter. The hot thermal emission from the surface of neutron stars in qLMXBs allows us to measure the neutron star radius. In the past few years, promising results were obtained from statistical analyses that combined the X-ray spectra of qLMXBs. In this talk, I will summarize the constraints on the internal structure of neutron star obtained from currently available observations of qLMXBs, as well as the most recent results. In an effort to be as conservative as possible with the observational constraints, I will present the current limitations of this method, and how these limitations can be overcome with more observations of qLXMBs with current and future instrumentation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930057229&hterms=White+dwarf+stars&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2528%2528White%2Bdwarf%2529%2Bstars%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930057229&hterms=White+dwarf+stars&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2528%2528White%2Bdwarf%2529%2Bstars%2529"><span id="translatedtitle">Hydrodynamics of winds from irradiated companion stars in <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tavani, Marco; London, Richard</p> <p>1993-01-01</p> <p>We study the hydrodynamics of evaporative winds driven by X-rays and/or soft gamma-rays irradiating the outer layers of companion stars in <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs). We consider several irradiating fluxes and spectra for LMXBs with white dwarf and main-sequence companion stars. The thermal structure of the base of the coronal region, the position of the sonic point, and the value of the mass-loss rate are calculated in the case of spherical geometry. We consider photospheric and coronal heating from both X-ray photoionization and Compton scattering of X-rays and soft gamma-rays with energy about 1 MeV possibly irradiating the companion star in LMXBs. Evaporative winds may play a relevant role for the evolution of a special class of radiation-driven LMXBs, and this study is a step toward a quantitative understanding of the mechanism driving LMXB evolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997AAS...190.2609G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997AAS...190.2609G"><span id="translatedtitle"><span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> as Astrophysical Laboratories: Evidence of a Jupiter-size Planet Orbiting the Short Period <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> CM Draconis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guinan, E. F.; McCook, G. P.; Wright, S. R.; Bradstreet, D. H.</p> <p>1997-05-01</p> <p>We report further on the possible photometric detection of a planetary transit <span class="hlt">eclipse</span> for the dM4.5+dM4.5 (P=1.268d) <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star CM Dra. CM Dra was selected as a target for a planetary transit search because its orbital plane is seen almost exactly edge-on and its component stars radii are small. A planet orbiting the <span class="hlt">binary</span> in the plane of its orbit would transit across the disks of the stars, producing a decrease in brightness proportional to the relative areas of the planet to the stars. Photoelectric photometry of CM Dra has been conducted from Arizona from 1995-1997 using the Four College Consortium 0.8m Automatic Photometric Telescope (APT). As reported in AC No.6423, during a 3.h interval on 01 June 1996 UT, CM Dra was fainter by 0.08 mag in the I-band. In this paper we present the modelling results of the observed light decrease assuming a planetary transit <span class="hlt">eclipse</span> of the limb-darkened (x=0.45) dM4.5 stars. Good fits of the light loss were obtained for a planet with a diameter = 0.94 +/-0.04Dj and having an orbital period of P = 2.2 +/-0.4 yrs. This estimated orbital period is close to the elapsed time interval of 2.01 yrs between the transit event reported here and that reported by Martin and Deeg (IAUC No. 6425). Upper limits of the mass of this possible planet of Mp < 5Mj were made by searching for systematic variations of the <span class="hlt">eclipse</span> arrival times of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> that would occur from the presence of a massive planet or brown dwarf. Observations of additional photometric transits are needed to confirm the presence of a planet in the CM Dra system.This research is supported by NSF grants AST-9315365 to Villanova University and AST-9528506 Four College Consortium. We gratefully acknowedge this support.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT........56M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT........56M"><span id="translatedtitle">Investigating <span class="hlt">Low-Mass</span> <span class="hlt">Binary</span> Stars And Brown Dwarfs with Near-Infrared Spectroscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mace, Gregory Nathan</p> <p></p> <p>The mass of a star at formation determines its subsequent evolution and demise. <span class="hlt">Low-mass</span> stars are the most common products of star formation and their long main-sequence lifetimes cause them to accumulate over time. Star formation also produces many substellar-mass objects known as brown dwarfs, which emerge from their natal molecular clouds and continually cool as they age, pervading the Milky Way. <span class="hlt">Low-mass</span> stars and brown dwarfs exhibit a wide range of physical characteristics and their abundance make them ideal subjects for testing formation and evolution models. I have examined a pair of pre-main sequence spectroscopic <span class="hlt">binaries</span> and used radial velocity variations to determine orbital solutions and mass ratios. Additionally, I have employed synthetic spectra to estimate their effective temperatures and place them on theoretical Hertzsprung-Russell diagrams. From this analysis I discuss the formation and evolution of young <span class="hlt">binary</span> systems and place bounds on absolute masses and radii. I have also studied the late-type T dwarfs revealed by the Wide-field Infrared Survey Explorer (WISE). This includes the exemplar T8 subdwarf Wolf 1130C, which has the lowest inferred metallicity in the literature and spectroscopic traits consistent with old age. Comparison to synthetic spectra implies that the dispersion in near-infrared colors of late-type T dwarfs is a result of age and/or thin sulfide clouds. With the updated census of the L, T, and Y dwarfs we can now study specific brown dwarf subpopulations. Finally, I present a number of future studies that would develop our understanding of the physical qualities of T dwarf color outliers and disentangle the tracers of age and atmospheric properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989A%26AS...81...81V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989A%26AS...81...81V"><span id="translatedtitle">Photometric study of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> RR Leporis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vyas, M. L.; Abhyankar, K. D.</p> <p>1989-11-01</p> <p>The <span class="hlt">eclipsing</span> <span class="hlt">binary</span> RR Leporis has been observed on 42 nights during 1982-1987 in standard U, B and V passbands. The complete light curves and photometric solutions for this <span class="hlt">binary</span> system are presented. The preliminary elements derived by Russell-Merrill method were used as inputs in Wilson-Devinney's Differential Corrections Program. All the three light curves in UBV were treated simultaneously. Two different Mode 5 solutions, in which the secondary fills its roche lobe, fitted the light curves equally well. On comparing these photometric elements with those given by Samec et al. (1988), it was found that the solution is indeterminate because i and q are strongly correlated. In the absence of any accurate spectroscopic data, it is premature to derive absolute dimensions of the system. The most likely parameters are given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770017081','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770017081"><span id="translatedtitle">A1540-53, an <span class="hlt">eclipsing</span> X-ray <span class="hlt">binary</span> pulsator</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Becker, R. H.; Swank, J. H.; Boldt, E. A.; Holt, S. S.; Pravdo, S. H.; Saba, J. R.; Serlemitsos, P. J.</p> <p>1977-01-01</p> <p>An <span class="hlt">eclipsing</span> X-ray <span class="hlt">binary</span> pulsator consistent with the location of A1540-53 was observed. The source pulse period was 528.93 plus or minus 0.10 seconds. The <span class="hlt">binary</span> nature is confirmed by a Doppler curve for the pulsation period. The <span class="hlt">eclipse</span> angle of 30.5 deg plus or minus 3 deg and the 4 h transition to and from <span class="hlt">eclipse</span> suggest an early type, giant or supergiant, primary star.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21451043','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21451043"><span id="translatedtitle">MASS CONSTRAINTS FROM <span class="hlt">ECLIPSE</span> TIMING IN DOUBLE WHITE DWARF <span class="hlt">BINARIES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kaplan, David L.</p> <p>2010-07-10</p> <p>I demonstrate that an effect similar to the Roemer delay, familiar from timing radio pulsars, should be detectable in the first <span class="hlt">eclipsing</span> double white dwarf (WD) <span class="hlt">binary</span>, NLTT 11748. By measuring the difference of the time between the secondary and primary <span class="hlt">eclipses</span> from one-half period (4.6 s), one can determine the physical size of the orbit and hence constrain the masses of the individual WDs. A measurement with uncertainty <0.1 s-possible with modern large telescopes-will determine the individual masses to {+-}0.02 M{sub sun} when combined with good-quality (<1 km s{sup -1}) radial velocity data, although the eccentricity must also be known to high accuracy ({+-}10{sup -3}). Mass constraints improve as P {sup -1/2} (where P is the orbital period), so this works best in wide <span class="hlt">binaries</span> and should be detectable even for non-degenerate stars, but such constraints require the mass ratio to differ from 1, as well as undistorted orbits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920030098&hterms=nn+models&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dnn%2Bmodels','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920030098&hterms=nn+models&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dnn%2Bmodels"><span id="translatedtitle">IUE spectra of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> NN Serpentis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wood, Janet H.; Marsh, Thomas R.</p> <p>1991-01-01</p> <p>Low-resolution SWP and LWP IUE spectra are used to fit the temperature and angular radius of the white dwarf in the detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> NN Ser. It is found that the redenning to the system has E(B-V) of 0.05 +/-0.05, the white dwarf temperature is 60,000 +/-10,000 K, and the age of the white dwarf is less than 10 exp 7. The shape of <span class="hlt">eclipse</span> and the K-magnitude of the secondary star are used to constrain the inclination of the <span class="hlt">binary</span> and the masses and radii of the two stars. The size of the secondary star relative to its Roche lobe and the age of the white dwarf indicate that mass transfer has not yet occurred and that the system is a precataclysmic variable rather than a cataclysmic variable which has entered the period gap. Fitting the observed magnitude of the sinusoidal modulation with a reprocessing model shows that only when i is approximately equal to 90 deg is the required temperature of the secondary star consistent with these results. For this solution the white dwarf temperature is also consistent with those obtained from the IUE spectra.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...802...37B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...802...37B"><span id="translatedtitle">Discovery and Characterization of Wide <span class="hlt">Binary</span> Systems with a Very <span class="hlt">Low</span> <span class="hlt">Mass</span> Component</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baron, Frédérique; Lafrenière, David; Artigau, Étienne; Doyon, René; Gagné, Jonathan; Davison, Cassy L.; Malo, Lison; Robert, Jasmin; Nadeau, Daniel; Reylé, Céline</p> <p>2015-03-01</p> <p>We report the discovery of 14 <span class="hlt">low-mass</span> <span class="hlt">binary</span> systems containing mid-M to mid-L dwarf companions with separations larger than 250 AU. We also report the independent discovery of nine other systems with similar characteristics that were recently discovered in other studies. We have identified these systems by searching for common proper motion sources in the vicinity of known high proper motion stars, based on a cross-correlation of wide area near-infrared surveys (2MASS, SDSS, and SIMP). An astrometric follow-up, for common proper motion confirmation, was made with SIMON and/or CPAPIR at the Observatoire du Mont Mégantic 1.6 m and CTIO 1.5 m telescopes for all the candidates identified. A spectroscopic follow-up was also made with GMOS or GNIRS at Gemini to determine the spectral types of 11 of our newly identified companions and 10 of our primaries. Statistical arguments are provided to show that all of the systems we report here are very likely to be physical <span class="hlt">binaries</span>. One of the new systems reported features a brown dwarf companion: LSPM J1259+1001 (M5) has an L4.5 (2M1259+1001) companion at ˜340 AU. This brown dwarf was previously unknown. Seven other systems have a companion of spectral type L0-L1 at a separation in the 250-7500 AU range. Our sample includes 14 systems with a mass ratio below 0.3.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PhDT........13R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PhDT........13R&link_type=ABSTRACT"><span id="translatedtitle">Red Giants in <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> as a Benchmark for Asteroseismology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rawls, Meredith L.</p> <p>2016-04-01</p> <p>Red giants with solar-like oscillations are astrophysical laboratories for probing the Milky Way. The Kepler Space Telescope revolutionized asteroseismology by consistently monitoring thousands of targets, including several red giants in <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>. Binarity allows us to directly measure stellar properties independently of asteroseismology. In this dissertation, we study a subset of eight red giant <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> observed by Kepler with a range of orbital periods, oscillation behavior, and stellar activity. Two of the systems do not show solar-like oscillations at all. We use a suite of modeling tools to combine photometry and spectroscopy into a comprehensive picture of each star's life. One noteworthy case is a double red giant <span class="hlt">binary</span>. The two stars are nearly twins, but have one main set of solar-like oscillations with unusually low-amplitude, wide modes, likely due to stellar activity and modest tidal forces acting over the 171 day eccentric orbit. Mixed modes indicate the main oscillating star is on the secondary red clump (a core-He-burning star), and stellar evolution modeling supports this with a coeval history for a pair of red clump stars. The other seven systems are all red giant branch stars (shell-H-burning) with main sequence companions. The two non-oscillators have the strongest magnetic signatures and some of the strongest lifetime tidal forces with nearly-circular 20–34 day orbits. One system defies this trend with oscillations and a 19 day orbit. The four long-period systems (>100 days) have oscillations, more eccentric orbits, and less stellar activity. They are all detached <span class="hlt">binaries</span> consistent with coevolution. We find the asteroseismic scaling laws are approximately correct, but fail the most for stars that are least like the Sun by systematically overestimating both mass and radius. Strong magnetic activity and tidal effects often occur in tandem and act to suppress solar-like oscillations. These red giant <span class="hlt">binaries</span> offer an</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhDT........13R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhDT........13R"><span id="translatedtitle">Red Giants in <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> as a Benchmark for Asteroseismology</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rawls, Meredith L.</p> <p>2016-04-01</p> <p>Red giants with solar-like oscillations are astrophysical laboratories for probing the Milky Way. The Kepler Space Telescope revolutionized asteroseismology by consistently monitoring thousands of targets, including several red giants in <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>. Binarity allows us to directly measure stellar properties independently of asteroseismology. In this dissertation, we study a subset of eight red giant <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> observed by Kepler with a range of orbital periods, oscillation behavior, and stellar activity. Two of the systems do not show solar-like oscillations at all. We use a suite of modeling tools to combine photometry and spectroscopy into a comprehensive picture of each star's life. One noteworthy case is a double red giant <span class="hlt">binary</span>. The two stars are nearly twins, but have one main set of solar-like oscillations with unusually low-amplitude, wide modes, likely due to stellar activity and modest tidal forces acting over the 171 day eccentric orbit. Mixed modes indicate the main oscillating star is on the secondary red clump (a core-He-burning star), and stellar evolution modeling supports this with a coeval history for a pair of red clump stars. The other seven systems are all red giant branch stars (shell-H-burning) with main sequence companions. The two non-oscillators have the strongest magnetic signatures and some of the strongest lifetime tidal forces with nearly-circular 20-34 day orbits. One system defies this trend with oscillations and a 19 day orbit. The four long-period systems (>100 days) have oscillations, more eccentric orbits, and less stellar activity. They are all detached <span class="hlt">binaries</span> consistent with coevolution. We find the asteroseismic scaling laws are approximately correct, but fail the most for stars that are least like the Sun by systematically overestimating both mass and radius. Strong magnetic activity and tidal effects often occur in tandem and act to suppress solar-like oscillations. These red giant <span class="hlt">binaries</span> offer an</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014A%26A...571A..45I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014A%26A...571A..45I"><span id="translatedtitle">The formation of <span class="hlt">low-mass</span> helium white dwarfs orbiting pulsars . Evolution of <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> below the bifurcation period</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Istrate, A. G.; Tauris, T. M.; Langer, N.</p> <p>2014-11-01</p> <p>Context. Millisecond pulsars (MSPs) are generally believed to be old neutron stars (NSs) that have been spun up to high rotation rates via accretion of matter from a companion star in a <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> (LMXB). This scenario has been strongly supported by various pieces of observational evidence. However, many details of this recycling scenario remain to be understood. Aims: Here we investigate <span class="hlt">binary</span> evolution in close LMXBs to study the formation of radio MSPs with <span class="hlt">low-mass</span> helium white dwarf companions (He WDs) in tight <span class="hlt">binaries</span> with orbital periods Porb ≃ 2-9h. In particular, we examine i) if the observed systems can be reproduced by theoretical modelling using standard prescriptions of orbital angular momentum losses (i.e. with respect to the nature and the strength of magnetic braking), ii) if our computations of the Roche-lobe detachments can match the observed orbital periods, and iii) if the correlation between WD mass and orbital period (MWD, Porb) is valid for systems with Porb< 2 days. Methods: Numerical calculations with a detailed stellar evolution code were used to trace the mass-transfer phase in ~400 close LMXB systems with different initial values of donor star mass, NS mass, orbital period, and the so-called γ-index of magnetic braking. Subsequently, we followed the orbital and the interior evolution of the detached <span class="hlt">low-mass</span> (proto) He WDs, including stages with residual shell hydrogen burning. Results: We find that severe fine-tuning is necessary to reproduce the observed MSPs in tight <span class="hlt">binaries</span> with He WD companions of mass <0.20 M⊙, which suggests that something needs to be modified or is missing in the standard input physics of LMXB modelling. Results from previous independent studies support this conclusion. We demonstrate that the theoretically calculated (MWD, Porb)-relation is in general also valid for systems with Porb< 2 days, although with a large scatter in He WD masses between 0.15-0.20 M⊙. The results of the thermal</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22364180','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22364180"><span id="translatedtitle">DISCOVERY OF PSR J1227−4853: A TRANSITION FROM A <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARY</span> TO A REDBACK MILLISECOND PULSAR</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Roy, Jayanta; Bhattacharyya, Bhaswati; Stappers, Ben; Ray, Paul S.; Wolff, Michael; Wood, Kent S.; Chengalur, Jayaram N.; Deneva, Julia; Camilo, Fernando; Johnson, Tyrel J.; Hessels, Jason W. T.; Bassa, Cees G.; Keane, Evan F.; Ferrara, Elizabeth C.; Harding, Alice K.</p> <p>2015-02-10</p> <p>XSS J12270−4859 is an X-ray <span class="hlt">binary</span> associated with the Fermi Large Area Telescope gamma-ray source 1FGL J1227.9−4852. In 2012 December, this source underwent a transition where the X-ray and optical luminosity dropped and the spectral signatures of an accretion disk disappeared. We report the discovery of a 1.69 millisecond pulsar (MSP), PSR J1227−4853, at a dispersion measure of 43.4 pc cm{sup −3} associated with this source, using the Giant Metrewave Radio Telescope (GMRT) at 607 MHz. This demonstrates that, post-transition, the system hosts an active radio MSP. This is the third system after PSR J1023+0038 and PSR J1824−2452I showing evidence of state switching between radio MSP and <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> states. We report timing observations of PSR J1227−4853 with the GMRT and Parkes, which give a precise determination of the rotational and orbital parameters of the system. The companion mass measurement of 0.17–0.46 M{sub ⊙} suggests that this is a redback system. PSR J1227−4853 is <span class="hlt">eclipsed</span> for about 40% of its orbit at 607 MHz with additional short-duration <span class="hlt">eclipses</span> at all orbital phases. We also find that the pulsar is very energetic, with a spin-down luminosity of ∼10{sup 35} erg s{sup −1}. We report simultaneous imaging and timing observations with the GMRT, which suggests that <span class="hlt">eclipses</span> are caused by absorption rather than dispersion smearing or scattering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...800L..12R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...800L..12R"><span id="translatedtitle">Discovery of Psr J1227-4853: A Transition from a <span class="hlt">Low-mass</span> X-Ray <span class="hlt">Binary</span> to a Redback Millisecond Pulsar</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Roy, Jayanta; Ray, Paul S.; Bhattacharyya, Bhaswati; Stappers, Ben; Chengalur, Jayaram N.; Deneva, Julia; Camilo, Fernando; Johnson, Tyrel J.; Wolff, Michael; Hessels, Jason W. T.; Bassa, Cees G.; Keane, Evan F.; Ferrara, Elizabeth C.; Harding, Alice K.; Wood, Kent S.</p> <p>2015-02-01</p> <p>XSS J12270-4859 is an X-ray <span class="hlt">binary</span> associated with the Fermi Large Area Telescope gamma-ray source 1FGL J1227.9-4852. In 2012 December, this source underwent a transition where the X-ray and optical luminosity dropped and the spectral signatures of an accretion disk disappeared. We report the discovery of a 1.69 millisecond pulsar (MSP), PSR J1227-4853, at a dispersion measure of 43.4 pc cm-3 associated with this source, using the Giant Metrewave Radio Telescope (GMRT) at 607 MHz. This demonstrates that, post-transition, the system hosts an active radio MSP. This is the third system after PSR J1023+0038 and PSR J1824-2452I showing evidence of state switching between radio MSP and <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> states. We report timing observations of PSR J1227-4853 with the GMRT and Parkes, which give a precise determination of the rotational and orbital parameters of the system. The companion mass measurement of 0.17-0.46 M⊙ suggests that this is a redback system. PSR J1227-4853 is <span class="hlt">eclipsed</span> for about 40% of its orbit at 607 MHz with additional short-duration <span class="hlt">eclipses</span> at all orbital phases. We also find that the pulsar is very energetic, with a spin-down luminosity of ˜1035 erg s-1. We report simultaneous imaging and timing observations with the GMRT, which suggests that <span class="hlt">eclipses</span> are caused by absorption rather than dispersion smearing or scattering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22004595','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22004595"><span id="translatedtitle">LSPM J1112+7626: DETECTION OF A 41 DAY M-DWARF <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> FROM THE MEARTH TRANSIT SURVEY</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Irwin, Jonathan M.; Quinn, Samuel N.; Berta, Zachory K.; Latham, David W.; Torres, Guillermo; Burke, Christopher J.; Charbonneau, David; Dittmann, Jason; Esquerdo, Gilbert A.; Stefanik, Robert P.; Oksanen, Arto; Buchhave, Lars A.; Nutzman, Philip; Berlind, Perry; Calkins, Michael L.; Falco, Emilio E.</p> <p>2011-12-01</p> <p>We report the detection of <span class="hlt">eclipses</span> in LSPM J1112+7626, which we find to be a moderately bright (I{sub C} = 12.14 {+-} 0.05) very <span class="hlt">low</span> <span class="hlt">mass</span> <span class="hlt">binary</span> system with an orbital period of 41.03236 {+-} 0.00002 days, and component masses M{sub 1} = 0.395 {+-} 0.002 M{sub Sun} and M{sub 2} = 0.275 {+-} 0.001 M{sub Sun} in an eccentric (e = 0.239 {+-} 0.002) orbit. A 65 day out-of-<span class="hlt">eclipse</span> modulation of approximately 2% peak-to-peak amplitude is seen in I-band, which is probably due to rotational modulation of photospheric spots on one of the <span class="hlt">binary</span> components. This paper presents the discovery and characterization of the object, including radial velocities sufficient to determine both component masses to better than 1% precision, and a photometric solution. We find that the sum of the component radii, which is much better determined than the individual radii, is inflated by 3.8{sup +0.9}{sub -0.5}% compared to the theoretical model predictions, depending on the age and metallicity assumed. These results demonstrate that the difficulties in reproducing observed M-dwarf <span class="hlt">eclipsing</span> <span class="hlt">binary</span> radii with theoretical models are not confined to systems with very short orbital periods. This object promises to be a fruitful testing ground for the hypothesized link between inflated radii in M-dwarfs and activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...822L..24N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...822L..24N"><span id="translatedtitle">Formation of Black Hole <span class="hlt">Low-mass</span> X-Ray <span class="hlt">Binaries</span> in Hierarchical Triple Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Naoz, Smadar; Fragos, Tassos; Geller, Aaron; Stephan, Alexander P.; Rasio, Frederic A.</p> <p>2016-05-01</p> <p>The formation of black hole (BH) <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXB) poses a theoretical challenge, as <span class="hlt">low-mass</span> companions are not expected to survive the common-envelope scenario with the BH progenitor. Here we propose a formation mechanism that skips the common-envelope scenario and relies on triple-body dynamics. We study the evolution of hierarchical triples following the secular dynamical evolution up to the octupole-level of approximation, including general relativity, tidal effects, and post-main-sequence evolution such as mass loss, changes to stellar radii, and supernovae. During the dynamical evolution of the triple system the “eccentric Kozai-Lidov” mechanism can cause large eccentricity excitations in the LMXB progenitor, resulting in three main BH-LMXB formation channels. Here we define BH-LMXB candidates as systems where the inner BH-companion star crosses its Roche limit. In the “eccentric” channel (˜81% of the LMXBs in our simulations) the donor star crosses its Roche limit during an extreme eccentricity excitation while still on a wide orbit. Second, we find a “giant” LMXB channel (˜11%), where a system undergoes only moderate eccentricity excitations but the donor star fills its Roche-lobe after evolving toward the giant branch. Third, we identify a “classical” channel (˜8%), where tidal forces and magnetic braking shrink and circularize the orbit to short periods, triggering mass-transfer. Finally, for the giant channel we predict an eccentric (˜0.3-0.6) preferably inclined (˜40°, ˜140°) tertiary, typically on a wide enough orbit (˜104 au) to potentially become unbound later in the triple evolution. While this initial study considers only one representative system and neglects BH natal kicks, we expect our scenario to apply across a broad region of parameter space for triple-star systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950030868&hterms=thermal+neutron+spectrum&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dthermal%2Bneutron%2Bspectrum','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950030868&hterms=thermal+neutron+spectrum&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dthermal%2Bneutron%2Bspectrum"><span id="translatedtitle">Oscillations of red dwarfs in evolved <span class="hlt">low-mass</span> <span class="hlt">binaries</span> with neutron stars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sarna, Marek J.; Lee, Umin; Muslimov, Alexander G.</p> <p>1994-01-01</p> <p>We investigate a novel aspect of a problem related to the properties of <span class="hlt">low-mass</span> <span class="hlt">binaries</span> (LMBs) with millisecond pulsars: the pulsations of the red dwarf (donor) companion of the neutron star (NS). The illumination of the donor star by the pulsar's high-energy nonthermal radiation and relativistic wind may substantially affect its structure. We present a quantitative analysis of the oscillation spectrum of a red dwarf which has evolved in an LMB and has undergone the stage of evaporation. We calculate the p- and g-modes for red dwarfs with masses in the interval (0.2-0.6) stellar mass. For comparison, similar calculations are presented for zero age main-sequence (ZAMS) stars of the same masses. For less massive donor stars (approximately 0.2 stellar mass) the oscillation spectrum becomes quantitatively different from that of their ZAMS counterparts. The differnce is due to the fact that a ZAMS star of 0.2 stellar mass is fully convective, while the donor star in an LMB is expected to be far from thermal equilibrium and not fully convective. As a result, in contrast to a <span class="hlt">low-mass</span> ZAMS star, a red dwarf of the same mass in an LMB allows the existence of g-modes. We also consider tidally forced g-modes, and perform a linear analysis of these oscillations for different degrees of nonsynchronism between the orbital and spin rotation of the red dwarf component. We demonstrate the existence of a series of reasonances for the low-order g-modes which may occur in LMBs at a late stage of their evolution. We discuss the possibility that these oscillations may trigger Roche lobe overflow and sudden mass loss by the donor star. Further implications of this effect for gamma- and X-ray burst phenomena are outlined.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvD..93d4019F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvD..93d4019F"><span id="translatedtitle"><span class="hlt">Low</span> <span class="hlt">mass</span> <span class="hlt">binary</span> neutron star mergers: Gravitational waves and neutrino emission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Foucart, Francois; Haas, Roland; Duez, Matthew D.; O'Connor, Evan; Ott, Christian D.; Roberts, Luke; Kidder, Lawrence E.; Lippuner, Jonas; Pfeiffer, Harald P.; Scheel, Mark A.</p> <p>2016-02-01</p> <p>Neutron star mergers are among the most promising sources of gravitational waves for advanced ground-based detectors. These mergers are also expected to power bright electromagnetic signals, in the form of short gamma-ray bursts, infrared/optical transients powered by r-process nucleosynthesis in neutron-rich material ejected by the merger, and radio emission from the interaction of that ejecta with the interstellar medium. Simulations of these mergers with fully general relativistic codes are critical to understand the merger and postmerger gravitational wave signals and their neutrinos and electromagnetic counterparts. In this paper, we employ the Spectral Einstein Code to simulate the merger of <span class="hlt">low</span> <span class="hlt">mass</span> neutron star <span class="hlt">binaries</span> (two 1.2 M⊙ neutron stars) for a set of three nuclear-theory-based, finite temperature equations of state. We show that the frequency peaks of the postmerger gravitational wave signal are in good agreement with predictions obtained from recent simulations using a simpler treatment of gravity. We find, however, that only the fundamental mode of the remnant is excited for long periods of time: emission at the secondary peaks is damped on a millisecond time scale in the simulated <span class="hlt">binaries</span>. For such <span class="hlt">low</span> <span class="hlt">mass</span> systems, the remnant is a massive neutron star which, depending on the equation of state, is either permanently stable or long lived (i.e. rapid uniform rotation is sufficient to prevent its collapse). We observe strong excitations of l =2 , m =2 modes, both in the massive neutron star and in the form of hot, shocked tidal arms in the surrounding accretion torus. We estimate the neutrino emission of the remnant using a neutrino leakage scheme and, in one case, compare these results with a gray two-moment neutrino transport scheme. We confirm the complex geometry of the neutrino emission, also observed in previous simulations with neutrino leakage, and show explicitly the presence of important differences in the neutrino luminosity, disk</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ATel.5647....1B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ATel.5647....1B"><span id="translatedtitle">A possible state transition in the <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> XSS J12270-4859</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bassa, C. G.; Patruno, A.; Hessels, J. W. T.; Archibald, A. M.; Mahony, E. K.; Monard, B.; Keane, E. F.; Bogdanov, S.; Stappers, B. W.; Janssen, G. H.; Tendulkar, S.</p> <p>2013-12-01</p> <p>Spurred by the recent state change in the "missing link" pulsar <span class="hlt">binary</span> system PSR J1023+0038 (ATel #5513, #5514, #5515, #5516; Stappers et al. 2013, arXiv:1311.7506; Patruno et al. 2013, arXiv:1310.7549) we report on optical, radio, X-ray and gamma-ray observations of the <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> XSS J12270-4859, conducted between 2012 March 29 and 2013 December 10.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011adap.prop...54H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011adap.prop...54H"><span id="translatedtitle">Lense-Thirring precession in neutron-star <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Homan, Jeroen</p> <p></p> <p>Quasi-periodic oscillations (QPOs) with low frequencies (0.01-70 Hz) have been observed in the X-ray light curves of most neutron-star and black-hole <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span>. Despite having been discovered more than 25 years ago, their origin is still not well understood. Similarities between the low-frequency QPOs in the two types of systems suggest that they have a common origin in the accretion flows around black holes and neutron stars. Some of the proposed models that attempt to explain low- frequency QPOs invoke a General Relativistic effect known as Lense-Thirring precession (or "frame dragging"). However, for Lense-Thirring precession to produce substantial modulations of the X-ray flux through relativistic beaming and gravitational lensing, the rotation axis of the inner part of the accretion disk needs to have a substantial tilt (10-20 degrees) with respect to the spin axis of the compact object. We argue that observational evidence for such titled inner accretion disks can be found in the variability of neutron- star <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> that are viewed at inclination angles of 60-80 degrees. In these systems low-frequency QPOs at ~0.1-15 Hz are observed that modulate the emission from the neutron star by quasi-periodic obscuration, presumably by a titled inner disc. The goal of our proposed program is to test whether the frequency evolution and spectral state dependence of these QPOs is similar to what is observed for the low-frequency QPOs that are observed in lower-inclination neutron-star X-ray <span class="hlt">binaries</span>. To make such a comparison, we need to better characterize the properties and behavior of these QPOs. Our study will make use of almost 1300 RXTE observations of 11 sources, totaling 5.7 Ms of data. Signatures of strong gravity have long been sought after in accreting compact objects. While strong evidence from spectral features has emerged in the last decade (e.g. gravitationally broadened iron emission lines), there have only been hints of such</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22522026','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22522026"><span id="translatedtitle">DISCOVERY AND CHARACTERIZATION OF WIDE <span class="hlt">BINARY</span> SYSTEMS WITH A VERY <span class="hlt">LOW</span> <span class="hlt">MASS</span> COMPONENT</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Baron, Frédérique; Lafrenière, David; Artigau, Étienne; Doyon, René; Gagné, Jonathan; Robert, Jasmin; Nadeau, Daniel; Davison, Cassy L.; Malo, Lison; Reylé, Céline</p> <p>2015-03-20</p> <p>We report the discovery of 14 <span class="hlt">low-mass</span> <span class="hlt">binary</span> systems containing mid-M to mid-L dwarf companions with separations larger than 250 AU. We also report the independent discovery of nine other systems with similar characteristics that were recently discovered in other studies. We have identified these systems by searching for common proper motion sources in the vicinity of known high proper motion stars, based on a cross-correlation of wide area near-infrared surveys (2MASS, SDSS, and SIMP). An astrometric follow-up, for common proper motion confirmation, was made with SIMON and/or CPAPIR at the Observatoire du Mont Mégantic 1.6 m and CTIO 1.5 m telescopes for all the candidates identified. A spectroscopic follow-up was also made with GMOS or GNIRS at Gemini to determine the spectral types of 11 of our newly identified companions and 10 of our primaries. Statistical arguments are provided to show that all of the systems we report here are very likely to be physical <span class="hlt">binaries</span>. One of the new systems reported features a brown dwarf companion: LSPM J1259+1001 (M5) has an L4.5 (2M1259+1001) companion at ∼340 AU. This brown dwarf was previously unknown. Seven other systems have a companion of spectral type L0–L1 at a separation in the 250–7500 AU range. Our sample includes 14 systems with a mass ratio below 0.3.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988PhDT.........5G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988PhDT.........5G"><span id="translatedtitle">An investigation of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star system, CK Bootes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gershon, Kae Pearson</p> <p></p> <p>Photoelectrically observed light curves of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star system CK Bootes was obtained using the sixteen inch reflecting telescope at Kitt Peak National Observatory. The data was gathered during June of 1983. A total of 258, 240, and 240 usable observations were obtained in ultraviolet, blue, and visual light respectively, corresponding to the colors in the (UBV) system of Johnson and Morgan (ApJ.117,313,1953). Computer programs were written to reduce the data to light curves. The primary <span class="hlt">eclipse</span> was found to be a transit. The light curves were reduced to system parameters using three methods of analysis; the Russell - Merrill Method, the Wood Model, (WINK), and the Wilson-DeVinney Model. The results from these models were then compared. The parameters of the systems were found, and they were compared between the three models. The system was found to be a very close system, only about four stellar radii apart. Mass streaming was indicated by the light curve. The derived parameters suggested that the larger star had filled its Roche Lobe, and it was spilling mass onto the smaller and brighter star. This, combined with a mass ratio about equal one, indicated that the system consists of one unevolved star and one star just beginning to evolve.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014MNRAS.441.1825B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014MNRAS.441.1825B"><span id="translatedtitle">A state change in the <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> XSS J12270-4859</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bassa, C. G.; Patruno, A.; Hessels, J. W. T.; Keane, E. F.; Monard, B.; Mahony, E. K.; Bogdanov, S.; Corbel, S.; Edwards, P. G.; Archibald, A. M.; Janssen, G. H.; Stappers, B. W.; Tendulkar, S.</p> <p>2014-06-01</p> <p>Millisecond radio pulsars acquire their rapid rotation rates through mass and angular momentum transfer in a <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> system. Recent studies of PSR J1824-2452I and PSR J1023+0038 have observationally demonstrated this link, and they have also shown that such systems can repeatedly transition back-and-forth between the radio millisecond pulsar and <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> states. This also suggests that a fraction of such systems are not newly born radio millisecond pulsars but are rather suspended in a back-and-forth, state-switching phase, perhaps for gigayears. XSS J12270-4859 has been previously suggested to be a <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span>, and until recently the only such system to be seen at MeV-GeV energies. We present radio, optical and X-ray observations that offer compelling evidence that XSS J12270-4859 is a <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> which transitioned to a radio millisecond pulsar state between 2012 November 14 and December 21. We use optical and X-ray photometry/spectroscopy to show that the system has undergone a sudden dimming and no longer shows evidence for an accretion disc. The optical observations constrain the orbital period to 6.913 ± 0.002 h.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22034343','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22034343"><span id="translatedtitle">ABSOLUTE PROPERTIES OF THE <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> STAR HY VIRGINIS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sandberg Lacy, Claud H.; Fekel, Francis C. E-mail: fekel@evans.tsuniv.edu</p> <p>2011-12-15</p> <p>HY Vir is found to be a double-lined F0m+F5 <span class="hlt">binary</span> star with relatively shallow (0.3 mag) partial <span class="hlt">eclipses</span>. Previous studies of the system are improved with 7509 differential photometric observations from the URSA WebScope and 8862 from the NFO WebScope, and 68 high-resolution spectroscopic observations from the Tennessee State University 2 m automatic spectroscopic telescope, and the 1 m coude-feed spectrometer at Kitt Peak National Observatory. Very accurate (better than 0.5%) masses and radii are determined from analysis of the new light curves and radial velocity curves. Theoretical models match the absolute properties of the stars at an age of about 1.35 Gy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22034370','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22034370"><span id="translatedtitle">ABSOLUTE PROPERTIES OF THE <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> STAR V335 SERPENTIS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lacy, Claud H. Sandberg; Fekel, Francis C.; Claret, Antonio E-mail: fekel@evans.tsuniv.edu</p> <p>2012-08-15</p> <p>V335 Ser is now known to be an eccentric double-lined A1+A3 <span class="hlt">binary</span> star with fairly deep (0.5 mag) partial <span class="hlt">eclipses</span>. Previous studies of the system are improved with 7456 differential photometric observations from the URSA WebScope and 5666 from the NFO WebScope, and 67 high-resolution spectroscopic observations from the Tennessee State University 2 m automatic spectroscopic telescope. From dates of minima, the apsidal period is about 880 years. Accurate (better than 2%) masses and radii are determined from analysis of the two new light curves and the radial velocity curve. Theoretical models match the absolute properties of the stars at an age of about 380 Myr, though the age agreement for the two components is poor. Tidal theory correctly confirms that the orbit should still be eccentric, but we find that standard tidal theory is unable to match the observed asynchronous rotation rates of the components' surface layers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22342151','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22342151"><span id="translatedtitle">Absolute properties of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star IM Persei</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lacy, Claud H. Sandberg; Torres, Guillermo; Fekel, Francis C.; Muterspaugh, Matthew W.; Southworth, John E-mail: gtorres@cfa.harvard.edu E-mail: matthew1@coe.tsuniv.edu</p> <p>2015-01-01</p> <p>IM Per is a detached A7 eccentric <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star. We have obtained extensive measurements of the light curve (28,225 differential magnitude observations) and radial velocity curve (81 spectroscopic observations) which allow us to fit orbits and determine the absolute properties of the components very accurately: masses of 1.7831 ± 0.0094 and 1.7741 ± 0.0097 solar masses, and radii of 2.409 ± 0.018 and 2.366 ± 0.017 solar radii. The orbital period is 2.25422694(15) days and the eccentricity is 0.0473(26). A faint third component was detected in the analysis of the light curves, and also directly observed in the spectra. The observed rate of apsidal motion is consistent with theory (U = 151.4 ± 8.4 year). We determine a distance to the system of 566 ± 46 pc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015A%26A...577A...5T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015A%26A...577A...5T"><span id="translatedtitle">Quiescent thermal emission from neutron stars in <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Turlione, A.; Aguilera, D. N.; Pons, J. A.</p> <p>2015-05-01</p> <p>Context. We monitored the quiescent thermal emission from neutron stars in <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> after active periods of intense activity in X-rays (outbursts). Aims: The theoretical modeling of the thermal relaxation of the neutron star crust may be used to establish constraints on the crust composition and transport properties, depending on the astrophysical scenarios assumed. Methods: We numerically simulated the thermal evolution of the neutron star crust and compared them with inferred surface temperatures for five sources: MXB 1659-29, KS 1731-260, XTE J1701-462, EXO 0748-676 and IGR J17480-2446. Results: We find that the evolution of MXB 1659-29, KS 1731-260 and EXO 0748-676 can be well described within a deep crustal cooling scenario. Conversely, we find that the other two sources can only be explained with models beyond crustal cooling. For the peculiar emission of XTE J1701-462 we propose alternative scenarios such as residual accretion during quiescence, additional heat sources in the outer crust, and/or thermal isolation of the inner crust due to a buried magnetic field. We also explain the very recent reported temperature of IGR J17480-2446 with an additional heat deposition in the outer crust from shallow sources.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...830L...5H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...830L...5H"><span id="translatedtitle">Evidence for Simultaneous Jets and Disk Winds in Luminous <span class="hlt">Low-mass</span> X-Ray <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Homan, Jeroen; Neilsen, Joseph; Allen, Jessamyn L.; Chakrabarty, Deepto; Fender, Rob; Fridriksson, Joel K.; Remillard, Ronald A.; Schulz, Norbert</p> <p>2016-10-01</p> <p>Recent work on jets and disk winds in <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs) suggests that they are to a large extent mutually exclusive, with jets observed in spectrally hard states and disk winds observed in spectrally soft states. In this paper we use existing literature on jets and disk winds in the luminous neutron star (NS) LMXB GX 13+1, in combination with archival Rossi X-ray Timing Explorer data, to show that this source is likely able to produce jets and disk winds simultaneously. We find that jets and disk winds occur in the same location on the source’s track in its X-ray color–color diagram. A further study of literature on other luminous LMXBs reveals that this behavior is more common, with indications for simultaneous jets and disk winds in the black hole LMXBs V404 Cyg and GRS 1915+105 and the NS LMXBs Sco X-1 and Cir X-1. For the three sources for which we have the necessary spectral information, we find that simultaneous jets/winds all occur in their spectrally hardest states. Our findings indicate that in LMXBs with luminosities above a few tens of percent of the Eddington luminosity, jets and disk winds are not mutually exclusive, and the presence of disk winds does not necessarily result in jet suppression.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997AAS...191.4411W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1997AAS...191.4411W&link_type=ABSTRACT"><span id="translatedtitle">A Dynamical Study of the <span class="hlt">Low</span> <span class="hlt">Mass</span> X-ray <span class="hlt">Binary</span> GX 349+2</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wachter, S.</p> <p>1997-12-01</p> <p>We have obtained simultaneous optical photometry and spectroscopy of the <span class="hlt">low</span> <span class="hlt">mass</span> X-ray <span class="hlt">binary</span> (and Z-source) GX 349+2 with the CTIO 0.9 m and 4 m telescopes in July 1997. The spectrum of GX 349+2 only shows strong, narrow Hα emission. The observed radial velocities indicate that our previously reported 22 hour photometric modulation is indeed the orbital period. We find gamma =-250+/-10 km s(-1) and K=65+/-6 km s(-1) for the systemic and semi-amplitude velocities respectively. The photometric light curve and radial velocity curve are offset by 0.25 in phase. Doppler tomography shows the Hα emission centered on the position of the neutron star. The relative phasing implies that the photometric variability is probably caused by the heated face of the companion star while the Hα emission may arise in an accretion disk and traces the motion of the neutron star. It also indicates that the emission region is symmetric around the neutron star. If the Hα emission does originate in the accretion disk, the narrowness of the line suggests a low inclination for the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..APRC14008F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..APRC14008F"><span id="translatedtitle"><span class="hlt">Low</span> <span class="hlt">mass</span> <span class="hlt">binary</span> neutron star mergers : gravitational waves and neutrino emission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Foucart, Francois; SXS Collaboration Collaboration</p> <p>2016-03-01</p> <p>We present numerical simulations of <span class="hlt">low</span> <span class="hlt">mass</span> <span class="hlt">binary</span> neutron star mergers (1 . 2M⊙ - 1 . 2M⊙) with the SpEC code for a set of three nuclear-theory based, finite temperature equations of state. The merger remnant is a massive neutron star which is either permanently stable or long-lived. We focus on the post-merger gravitational wave signal, and on neutrino-matter interactions in the merger remnant. We show that the frequency peaks of the post-merger gravitational wave signal are in good agreement with predictions obtained from simulations using a simpler treatment of gravity. We then estimate the neutrino emission of the remnant using a neutrino leakage scheme and, in one case, compare these results with a gray two-moment neutrino transport scheme. We confirm the complex geometry of the neutrino emission, also observed in previous simulations with neutrino leakage, and show explicitly the presence of important differences in the neutrino luminosity, disk composition, and outflow properties between the neutrino leakage and transport schemes. We discuss the impact of our results on our ability to measure the neutron star equation of state, and on the post-merger electromagnetic signal and r-process nucleosynthesis in neutron star mergers. Einstein Fellow.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22525277','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22525277"><span id="translatedtitle">ON THE GEOMETRIC NATURE OF LOW-FREQUENCY QUASI-PERIODIC OSCILLATIONS IN NEUTRON-STAR <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARIES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Homan, Jeroen; Remillard, Ronald A.; Fridriksson, Joel K.</p> <p>2015-10-10</p> <p>We report on a detailed analysis of the so-called ∼1 Hz quasi-periodic oscillation (QPO) in the <span class="hlt">eclipsing</span> and dipping neutron-star <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> EXO 0748–676. This type of QPO has previously been shown to have a geometric origin. Our study focuses on the evolution of the QPO as the source moves through the color–color diagram in which it traces out an atoll-source-like track. The QPO frequency increases from ∼0.4 Hz in the hard state to ∼25 Hz as the source approaches the soft state. Combining power spectra based on QPO frequency reveals additional features that strongly resemble those seen in non-dipping/<span class="hlt">eclipsing</span> atoll sources. We show that the low-frequency QPOs in atoll sources and the ∼1 Hz QPO in EXO 0748–676 follow similar relations with respect to the noise components in their power spectra. We conclude that the frequencies of both types of QPOs are likely set by (the same) precession of a misaligned inner accretion disk. For high-inclination systems like EXO 0748–676 this results in modulations of the neutron-star emission due to obscuration or scattering, while for lower-inclination systems the modulations likely arise from relativistic Doppler-boosting and light-bending effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ascl.soft03016M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ascl.soft03016M"><span id="translatedtitle">ellc: Light curve model for <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars and transiting exoplanets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maxted, P. F. L.</p> <p>2016-03-01</p> <p>ellc analyzes the light curves of detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars and transiting exoplanet systems. The model represents stars as triaxial ellipsoids, and the apparent flux from the <span class="hlt">binary</span> is calculated using Gauss-Legendre integration over the ellipses that are the projection of these ellipsoids on the sky. The code can also calculate the fluxweighted radial velocity of the stars during an <span class="hlt">eclipse</span> (Rossiter-McLaghlin effect). ellc can model a wide range of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars and extrasolar planetary systems, and can enable the use of modern Monte Carlo methods for data analysis and model testing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AAS...22810208S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AAS...22810208S"><span id="translatedtitle">Discovery and Characterization of <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Stars and Transiting Planets in Young Benchmark Clusters: The Pleiades and Hyades</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stassun, Keivan; David, Trevor J.; Conroy, Kyle E.; Hillenbrand, Lynne; Stauffer, John R.; Pepper, Joshua; Rebull, Luisa M.; Cody, Ann Marie</p> <p>2016-06-01</p> <p>Prior to K2, only one <span class="hlt">eclipsing</span> <span class="hlt">binary</span> in the Pleiades was known (HD 23642). We present the discovery and characterization of three additional <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> (EBs) in this ~120 Myr old benchmark open cluster. Unlike HD 23642, all three of the new EBs are <span class="hlt">low</span> <span class="hlt">mass</span> (Mtot < 1 M⊙) and thus their components are still undergoing pre-main-sequence contraction at the Pleiades age. <span class="hlt">Low</span> <span class="hlt">mass</span> EBs are rare, especially in the pre-main-sequence phase, and thus these systems are valuable for constraining theoretical stellar evolution models. One of the three new EBs is single-lined with a K-type primary (HII 2407). The second (HCG 76) comprises two nearly equal-mass 0.3 M⊙ stars, with masses and radii measured with precisions of better than 3% and 5%, respectively. The third (MHO 9) has an M-type primary with a secondary that is possibly quite close to the hydrogen-burning limit, but needs additional follow-up observations to better constrain its parameters. We use the precise parameters of HCG 76 to test the predictions of stellar evolution models, and to derive an independent distance to the Pleiades of 132±5 pc. Finally, we present tentative evidence for differential rotation in the primary component of the newly discovered Pleiades EB HII 2407, and we also characterize a newly discovered transiting Neptune-sized planet orbiting an M-dwarf in the Hyades.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AJ....151...25L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AJ....151...25L"><span id="translatedtitle">KIC 4739791: A New R CMa-type <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> with a Pulsating Component</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Jae Woo; Kim, Seung-Lee; Hong, Kyeongsoo; Koo, Jae-Rim; Lee, Chung-Uk; Youn, Jae-Hyuck</p> <p>2016-02-01</p> <p>The Kepler light curve of KIC 4739791 exhibits partial <span class="hlt">eclipses</span>, the inverse O’Connell effect, and multiperiodic pulsations. Including a starspot on either of the <span class="hlt">binary</span> components, the light-curve synthesis indicates that KIC 4739791 is in detached or semi-detached configuration with both a short orbital period and a <span class="hlt">low</span> <span class="hlt">mass</span> ratio. Multiple frequency analyses were performed in the light residuals after subtracting the binarity effects from the original Kepler data. We detected 14 frequencies: 6 in the low-frequency region (0.1-2.3 days-1) and 8 in the high-frequency region (18.2-22.0 days-1). Among these, six high frequencies with amplitudes of 0.62-1.97 mmag were almost constant over time for 200 days. Their pulsation periods and pulsation constants are in the ranges of 0.048-0.054 days and 0.025-0.031 days, respectively. In contrast, the other frequencies may arise from the alias effects caused by the orbital frequency or combination frequencies. We propose that KIC 4739791 is a short-period R CMa <span class="hlt">binary</span> with the lowest mass ratio in the known classical Algols and that its primary component is a δ Sct pulsating star. Only four R CMa stars have been identified, three of which exhibit δ Sct-type oscillations. These findings make KIC 4739791 an attractive target for studies of stellar interior structure and evolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JKAS...46..151H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JKAS...46..151H"><span id="translatedtitle">Orbital Period Variation Study of the Algol <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> DI Pegasi</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hanna, M. A.; Amin, S. M.</p> <p>2013-08-01</p> <p>We discuss the orbital period changes of the Algol semi-detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> DI Peg by constructing the (O-C) residual diagram via using all the available precise minima times. We conclude that the period variation can be explained by a sine-like variation due to the presence of a third body orbiting the <span class="hlt">binary</span>, together with a long-term orbital period increase ( dP/dt=0.17 sec/century) that can be interpreted to be due to mass transfer from the evolved secondary component (of rate 1.52×10^{-8} M_{⊙}/ yr) to the primary one. The detected <span class="hlt">low-mass</span> third body (M_{3 min.}=0.22±0.0006 M_{⊙}) is responsible for a periodic variation of about 55 years light time effect. We have determined the orbital parameters of the third component which show a considerable eccentricity e_{3}= 0.77±0.07 together with a longitude of periastron ω_{3}=300° ± 10°.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.456..314X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.456..314X"><span id="translatedtitle">The first Doppler images of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> SZ Piscium</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiang, Yue; Gu, Shenghong; Cameron, A. Collier; Barnes, J. R.; Zhang, Liyun</p> <p>2016-02-01</p> <p>We present the first Doppler images of the active <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system SZ Psc, based on the high-resolution spectral data sets obtained in 2004 November and 2006 September-December. The least-squares deconvolution technique was applied to derive high signal-to-noise profiles from the observed spectra of SZ Psc. Absorption features contributed by a third component of the system were detected in the LSD profiles at all observed phases. We estimated the mass and period of the third component to be about 0.9 M⊙ and 1283 ± 10 d, respectively. After removing the contribution of the third body from the least-squares deconvolved profiles, we derived the surface maps of SZ Psc. The resulting Doppler images indicate significant star-spot activities on the surface of the K subgiant component. The distributions of star-spots are more complex than that revealed by previous photometric studies. The cooler K component exhibited pronounced high-latitude spots as well as numerous low- and intermediate-latitude spot groups during the entire observing seasons, but did not show any large, stable polar cap, different from many other active RS CVn-type <span class="hlt">binaries</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014CoSka..43..422C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014CoSka..43..422C"><span id="translatedtitle">Solution of basic tasks in <span class="hlt">eclipsing</span> <span class="hlt">binary</span> period analysis by genetic and LSM algorithms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chrastina, M.; Mikulášek, Z.; Zejda, M.</p> <p>2014-03-01</p> <p>A period analysis of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> can be performed effectively when using fine-tuned phenomenological models. The combination of a regression analysis and genetic algorithms is a powerful tool for such astrophysical tasks as light curve analysis, mid-<span class="hlt">eclipse</span> time determination and O-C diagram investigation — even the apsidal motion and the light time effect can be resolved.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020081039','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020081039"><span id="translatedtitle">Dip Spectroscopy of the <span class="hlt">Low</span> <span class="hlt">Mass</span> X-Ray <span class="hlt">Binary</span> XB 1254-690</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smale, Alan P.; Church, M. J.; BalucinskaChurch, M.; White, Nicholas E. (Technical Monitor)</p> <p>2002-01-01</p> <p>We observed the <span class="hlt">low</span> <span class="hlt">mass</span> X-ray <span class="hlt">binary</span> XB 1254-690 with the Rossi X-ray Timing Explorer in 2001 May and December. During the first observation strong dipping on the 3.9-hr orbital period and a high degree of variability were observed, along with "shoulders" approx. 15% deep during extended intervals on each side of the main dips. The first observation also included pronounced flaring activity. The non-dip spectrum obtained using the PCA instrument was well-described by a two-component model consisting of a blackbody with kT = 1.30 +/- 0.10 keV plus a cut-off power law representation of Comptonized emission with power law photon index 1.10 +/- 0.46 and a cut-off energy of 5.9(sup +3.0, sub -1.4) keV. The intensity decrease in the shoulders of dipping is energy-independent, consistent with electron scattering in the outer ionized regions of the absorber. In deep dipping the depth of dipping reached 100%, in the energy band below 5 keV, indicating that all emitting regions were covered by absorber. Intensity-selected dip spectra were well-fit by a model in which the point-like blackbody is rapidly covered, while the extended Comptonized emission is progressively overlapped by the absorber, with the, covering fraction rising to 95% in the deepest portion of the dip. The intensity of this component in the dip spectra could be modeled by a combination of electron scattering and photoelectric absorption. Dipping did not occur during the 2001 December observation, but remarkably, both bursting and flaring were observed contemporaneously.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.461.3847G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.461.3847G"><span id="translatedtitle">Intermittent dipping in a <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Galloway, Duncan K.; Ajamyan, Alishan N.; Upjohn, James; Stuart, Matthew</p> <p>2016-10-01</p> <p>Periodic dips observed in ≈20 per cent of <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs) are thought to arise from obscuration of the neutron star by the outer edge of the accretion disc. We report the detection with the Rossi X-ray Timing Explorer of two dipping episodes in Aql X-1, not previously a known dipper. The X-ray spectrum during the dips exhibited an elevated neutral column density, by a factor between one and almost two orders of magnitude. Dips were not observed in every cycle of the 18.95-h orbit, so that the estimated frequency for these events is 0.10_{-0.05}^{+0.07} cycle-1. This is the first confirmed example of intermittent dipping in such a system. Assuming that the dips in Aql X-1 occur because the system inclination is intermediate between the non-dipping and dipping sources, implies a range of 72°-79° for the source. This result lends support for the presence of a massive (>2 M⊙) neutron star in Aql X-1, and further implies that ≈30 additional LMXBs may have inclinations within this range, raising the possibility of intermittent dips in those systems also. Thus, we searched for dips from 24 other bursting systems, without success. For the system with the largest number of dip phases covered, 4U 1820-303, the non-detection implies a 95 per cent upper limit to the dip frequency of 1.4 × 10-3 cycle-1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhRvD..90f3001G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhRvD..90f3001G"><span id="translatedtitle">Explaining observations of rapidly rotating neutron stars in <span class="hlt">low-mass</span> x-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gusakov, Mikhail E.; Chugunov, Andrey I.; Kantor, Elena M.</p> <p>2014-09-01</p> <p>In a previous paper [M. E. Gusakov, A. I. Chugunov, and E. M. Kantor, Phys. Rev. Lett. 112, 151101 (2014)], we introduced a new scenario that explains the existence of rapidly rotating warm neutron stars (NSs) observed in <span class="hlt">low-mass</span> x-ray <span class="hlt">binaries</span> (LMXBs). Here it is described in more detail. The scenario takes into account the interaction between superfluid inertial modes and the normal (quadrupole) m=2 r mode, which can be driven unstable by the Chandrasekhar-Friedman-Schutz (CFS) mechanism. This interaction can only occur at some fixed "resonance" stellar temperatures; it leads to formation of the "stability peaks" which stabilize a star in the vicinity of these temperatures. We demonstrate that a NS in LMXB spends a substantial fraction of time on the stability peak, that is, in the region of stellar temperatures and spin frequencies that has been previously thought to be CFS unstable with respect to excitation of r modes. We also find that the spin frequencies of NSs are limited by the CFS instability of normal (octupole) m=3 r mode rather than by m=2 r mode. This result agrees with the predicted value of the cutoff spin frequency ˜730 Hz in the spin distribution of accreting millisecond x-ray pulsars. In addition, we analyze evolution of a NS after the end of the accretion phase and demonstrate that millisecond pulsars can be born in LMXBs within our scenario. Besides millisecond pulsars, our scenario also predicts a new class of LMXB descendants—hot and rapidly rotating nonaccreting NSs ("hot widows"/HOFNARs). Further comparison of the proposed theory with observations of rotating NSs can impose new important constraints on the properties of superdense matter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22357244','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22357244"><span id="translatedtitle">Neutron star masses and radii from quiescent <span class="hlt">low-mass</span> x-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lattimer, James M.; Steiner, Andrew W. E-mail: steiner3@uw.edu</p> <p>2014-04-01</p> <p>We perform a systematic analysis of neutron star radius constraints from five quiescent <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> and examine how they depend on measurements of their distances and amounts of intervening absorbing material, as well as their assumed atmospheric compositions. We construct and calibrate to published results a semi-analytic model of the neutron star atmosphere which approximates these effects for the predicted masses and radii. Starting from mass and radius probability distributions established from hydrogen-atmosphere spectral fits of quiescent sources, we apply this model to compute alternate sets of probability distributions. We perform Bayesian analyses to estimate neutron star mass-radius curves and equation of state (EOS) parameters that best-fit each set of distributions, assuming the existence of a known low-density neutron star crustal EOS, a simple model for the high-density EOS, causality, and the observation that the neutron star maximum mass exceeds 2 M {sub ☉}. We compute the posterior probabilities for each set of distance measurements and assumptions about absorption and composition. We find that, within the context of our assumptions and our parameterized EOS models, some absorption models are disfavored. We find that neutron stars composed of hadrons are favored relative to those with exotic matter with strong phase transitions. In addition, models in which all five stars have hydrogen atmospheres are found to be weakly disfavored. Our most likely models predict neutron star radii that are consistent with current experimental results concerning the nature of the nucleon-nucleon interaction near the nuclear saturation density.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015A%26A...581A.106G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015A%26A...581A.106G"><span id="translatedtitle">The Araucaria project. Precise physical parameters of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> IO Aquarii</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Graczyk, D.; Maxted, P. F. L.; Pietrzyński, G.; Pilecki, B.; Konorski, P.; Gieren, W.; Storm, J.; Gallenne, A.; Anderson, R. I.; Suchomska, K.; West, R. G.; Pollacco, D.; Faedi, F.; Pojmański, G.</p> <p>2015-09-01</p> <p>Aims: Our aim is to precisely measure the physical parameters of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> IO Aqr and derive a distance to this system by applying a surface brightness - colour relation. Our motivation is to combine these parameters with future precise distance determinations from the Gaia space mission to derive precise surface brightness - colour relations for stars. Methods: We extensively used photometry from the Super-WASP and ASAS projects and precise radial velocities obtained from HARPS and CORALIE high-resolution spectra. We analysed light curves with the code JKTEBOP and radial velocity curves with the Wilson-Devinney program. Results: We found that IO Aqr is a hierarchical triple system consisting of a double-lined short-period (P = 2.37 d) spectroscopic <span class="hlt">binary</span> and a low-luminosity and <span class="hlt">low-mass</span> companion star orbiting the <span class="hlt">binary</span> with a period of ≳25 000 d (≳70 yr) on a very eccentric orbit. We derive high-precision (better than 1%) physical parameters of the inner <span class="hlt">binary</span>, which is composed of two slightly evolved main-sequence stars (F5 V-IV + F6 V-IV) with masses of M1 = 1.569 ± 0.004 and M2 = 1.655 ± 0.004 M⊙ and radii R1 = 2.19 ± 0.02 and R2 = 2.49 ± 0.02 R⊙. The companion is most probably a late K-type dwarf with mass ≈0.6 M⊙. The distance to the system resulting from applying a () surface brightness - colour relation is 255 ± 6 (stat.) ± 6 (sys.) pc, which agrees well with the Hipparcos value of 270+91-55 pc, but is more precise by a factor of eight.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009OEJV..118....1M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009OEJV..118....1M"><span id="translatedtitle">GSC 4181-0713 - a new W UMa type <span class="hlt">eclipsing</span> <span class="hlt">binary</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Monninger, Gerold</p> <p>2009-12-01</p> <p>GSC 4181-0713 is identifed as an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> for the first time. Ten times of primary and secondary minima were obtained. The shape and amplitude of the light curve and the period P=0.258742d implies that GSC 4181-0713 is a short-period W UMa type <span class="hlt">eclipsing</span> <span class="hlt">binary</span>. The system shows clearly an O'Connell effect delta m<0 in its light curve.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JASS...33..185K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JASS...33..185K"><span id="translatedtitle">The First Photometric Study of NSVS 1461538: A New W-subtype Contact <span class="hlt">Binary</span> with a <span class="hlt">Low</span> <span class="hlt">Mass</span> Ratio and Moderate Fill-out Factor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Hyoun-Woo; Kim, Chun-Hwey; Song, Mi-Hwa; Jeong, Min-Ji; Kim, Hye-Young</p> <p>2016-09-01</p> <p>New multiband BVRI light curves of NSVS 1461538 were obtained as a byproduct during the photometric observations of our program star PV Cas for three years from 2011 to 2013. The light curves indicate characteristics of a typical W-subtype W UMa <span class="hlt">eclipsing</span> system, displaying a flat bottom at primary <span class="hlt">eclipse</span> and the O’Connell effect, rather than those of an Algol/ b Lyrae <span class="hlt">eclipsing</span> variable classified by the northern sky variability survey (NSVS). A total of 35 times of minimum lights were determined from our observations (20 timings) and the SuperWASP measurements (15 ones). A period study with all the timings shows that the orbital period may vary in a sinusoidal manner with a period of about 5.6 yr and a small semiamplitude of about 0.008 day. The cyclical period variation can be interpreted as a light-time effect due to a tertiary body with a minimum mass of 0.71 M⊙. Simultaneous analysis of the multiband light curves using the 2003 version of the WilsonDevinney <span class="hlt">binary</span> model shows that NSVS 1461538 is a genuine W-subtype W UMa contact <span class="hlt">binary</span> with the hotter primary component being less massive and the system shows a <span class="hlt">low</span> <span class="hlt">mass</span> ratio of q(mc/mh)=3.51, a high orbital inclination of 88.7°, a moderate fill-out factor of 30 %, and a temperature difference of ΔT=412 K. The O’Connell effect can be similarly explained by cool spots on either the hotter primary star or the cool secondary star. A small third-light corresponding to about 5 % and 2 % of the total systemic light in the B and V bandpasses, respectively, supports the third-body hypothesis proposed by the period study. Preliminary absolute dimensions of the system were derived and used to look into its evolutionary status with other W UMa <span class="hlt">binaries</span> in the mass-radius and mass-luminosity diagrams. A possible evolution scenario of the system was also discussed in the context of the mass vs mass ratio diagram.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...594A..92G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...594A..92G"><span id="translatedtitle">A solar twin in the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> LL Aquarii</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Graczyk, D.; Smolec, R.; Pavlovski, K.; Southworth, J.; Pietrzyński, G.; Maxted, P. F. L.; Konorski, P.; Gieren, W.; Pilecki, B.; Taormina, M.; Suchomska, K.; Karczmarek, P.; Górski, M.; Wielgórski, P.; Anderson, R. I.</p> <p>2016-10-01</p> <p>Aims: In the course of a project to study <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars in vinicity of the Sun, we found that the cooler component of LL Aqr is a solar twin candidate. This is the first known star with properties of a solar twin existing in a non-interacting <span class="hlt">eclipsing</span> <span class="hlt">binary</span>, offering an excellent opportunity to fully characterise its physical properties with very high precision. Methods: We used extensive multi-band, archival photometry and the Super-WASP project and high-resolution spectroscopy obtained from the HARPS and CORALIE spectrographs. The spectra of both components were decomposed and a detailed LTE abundance analysis was performed. The light and radial velocity curves were simultanously analysed with the Wilson-Devinney code. The resulting highly precise stellar parameters were used for a detailed comparison with PARSEC, MESA, and GARSTEC stellar evolution models. Results: LL Aqr consists of two main-sequence stars (F9 V + G3 V) with masses of M1 = 1.1949 ± 0.0007 and M2 = 1.0337 ± 0.0007 M⊙, radii R1 = 1.321 ± 0.006 and R2 = 1.002 ± 0.005 R⊙, temperatures T1 = 6080 ± 45 and T2 = 5703 ± 50 K and solar chemical composition [M/H] = 0.02 ± 0.05. The absolute dimensions, radiative and photometric properties, and atmospheric abundances of the secondary are all fully consistent with being a solar twin. Both stars are cooler by about 3.5σ or less metal abundant by 5σ than predicted by standard sets of stellar evolution models. When advanced modelling was performed, we found that full agreement with observations can only be obtained for values of the mixing length and envelope overshooting parameters that are hard to accept. The most reasonable and physically justified model fits found with MESA and GARSTEC codes still have discrepancies with observations but only at the level of 1σ. The system is significantly younger that the Sun, with an age between 2.3 Gyr and 2.7 Gyr, which agrees well with the relatively high lithium abundance of the secondary, A</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005AAS...20718603F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005AAS...20718603F&link_type=ABSTRACT"><span id="translatedtitle">New Ephemeris and Model for the <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> DE CVn</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Flora, C. T.; Ezhkova, O.; Khruzina, T.; Samus, N. N.; Wilson, R. E.</p> <p>2005-12-01</p> <p>Past photometric observations (1,2) of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> DE CVn have suggested that it is a white dwarf/red dwarf pair. The data show a deep (1 mag) primary minimum in the U band with a very steep ingress and egress, a much shallower (0.1 mag) primary minimum in R, and lack of a secondary minimum. In May 2005, we obtained more accurate CCD photometry in the U band with the 31" Lowell Observatory telescope. Photometric points on both branches of the <span class="hlt">eclipse</span> and a well represented plateau at its bottom allowed for accurate determinations of the middles of the observed minima. By combining those with the times of minima from our previous observations in UBVR(2), from unpublished data of Robb & Greimel (priv. comm.), and from(1,3), we improved the ephemeris to HJD= 2450549.4697 + 0.36413865E. We used two independent programs (4,5) to model the <span class="hlt">binary</span>. The physical and geometrical parameters obtained from the two models are similar and close to those proposed in (1), except for the position of a dark spot (or collection of small spots) needed to explain the asymmetry of the wave seen in V and R and the inequality of light in quadratures. The authors thank R.M. Robb and R. Greimel for permission to use their unpublished data. This project was supported by the NSF/REU grant AST-0354056 and the Nantucket Maria Mitchell Association. REW's participation was supported by the NSF as part of grant 0307561. References: (1) Robb, R.M. & Greimel R. 1997, IBVS, No.4486. (2) Samus, N.N., Flora, C.T., Khruzina, T., Holms, S., Ezhkova, O. & Wilson, R.E. (in prep.). (3) Tas, G. et al. 2004, IBVS, No.5548. (4) Wilson R.E., Devinney E.J. 1971, ApJ, 166, 605. (5) Khruzina, T.S. 1998, Astronomy Reports, 42, 180; Khruzina, T.S. & Cherepashchuk, A.M. 1995, Astronomy Reports, 39, 178.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060047754&hterms=naked&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dnaked','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060047754&hterms=naked&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dnaked"><span id="translatedtitle">Discovery of a 3.6-hr <span class="hlt">Eclipsing</span> Luminous X-Ray <span class="hlt">Binary</span> in the Galaxy NGC 4214</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ghosh, Kajal K.; Rappaport, Saul; Tennant, Allyn F.; Swartz, Douglas A.; Pooley, David; Madhusudhan, N.</p> <p>2006-01-01</p> <p>We report the discovery of an <span class="hlt">eclipsing</span> X-ray <span class="hlt">binary</span> with a 3.62-hr period within 24 arcsec of the center of the dwarf starburst galaxy NGC 4214. The orbital period places interesting constraints on the nature of the <span class="hlt">binary</span>, and allows for a few very different interpretations. The most likely possibility is that the source lies within NGC 4214 and has an X-ray luminosity of up to 7e38. In this case the <span class="hlt">binary</span> may well be comprised of a naked He-burning donor star with a neutron-star accretor, though a stellar-mass black-hole accretor cannot be completely excluded. There is no obvious evidence for a strong stellar wind in the X-ray orbital light curve that would be expected from a massive He star; thus, the mass of the He star should be <3-4 solar masses. If correct, this would represent a new class of very luminous X-ray <span class="hlt">binary</span>----perhaps related to Cyg X-3. Other less likely possibilities include a conventional <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> that somehow manages to produce such a high X-ray luminosity and is apparently persistent over an interval of years; or a foreground AM Her <span class="hlt">binary</span> of much lower luminosity that fortuitously lies in the direction of NGC 4214. Any model for this system must accommodate the lack of an optical counterpart down to a limiting magnitude of 22.6 in the visible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IAUGA..2257059L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IAUGA..2257059L"><span id="translatedtitle">Suzaku spectra of the neutron-star <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> 4U 1608-52</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lei, Yajuan; Zhang, Haotong; zhang, Yanxia</p> <p>2015-08-01</p> <p>We present the spectral analysis of the neutron-star <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> 4U 1608-52 using data from four Suzaku observations in 2010 March. 4U 1608-52 is a transient atoll source, and the analyzed observations contain the “island” and “banana” states, corresponding transitional, and soft states. The spectra are fitted with the hybrid model for the soft states, which consists of two thermal components (a multicolor accretion disk and a single-temperature blackbody) plus a broken power law. The fitting results show that the continuum spectra evolve during the different states. Fe emission line is often detected in <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span>, however, no obviously Fe line is detected in the four observations of 4U 1608-52.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ARep...59..441B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ARep...59..441B&link_type=ABSTRACT"><span id="translatedtitle">Extracting multipole moments of neutron stars from quasi-periodic oscillations in <span class="hlt">low</span> <span class="hlt">mass</span> X-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Boshkayev, Kuantay; Rueda, Jorge; Muccino, Marco</p> <p>2015-06-01</p> <p>We consider the kilohertz quasi-periodic oscillations of <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> within the Hartle-Thorne spacetime. We show that the interpretation of the epicyclic frequencies of this spacetime with the observed kilohertz quasi-periodic oscillations, within the Relativistic Precession Model, allows us to extract the total mass M, angular momentum J, and quadrupole moment Q of the compact object in a <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span>. We exemplify this fact by analyzing the data of the Z-source GX 5-1. We show that the extracted multipole structure of the compact component of this source deviates from the one expected from a Kerr black hole and instead it points to a neutron star explanation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...806..148B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...806..148B"><span id="translatedtitle">Coordinated X-Ray, Ultraviolet, Optical, and Radio Observations of the PSR J1023+0038 System in a <span class="hlt">Low-mass</span> X-Ray <span class="hlt">Binary</span> State</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bogdanov, Slavko; Archibald, Anne M.; Bassa, Cees; Deller, Adam T.; Halpern, Jules P.; Heald, George; Hessels, Jason W. T.; Janssen, Gemma H.; Lyne, Andrew G.; Moldón, Javier; Paragi, Zsolt; Patruno, Alessandro; Perera, Benetge B. P.; Stappers, Ben W.; Tendulkar, Shriharsh P.; D'Angelo, Caroline R.; Wijnands, Rudy</p> <p>2015-06-01</p> <p>The PSR J1023+0038 <span class="hlt">binary</span> system hosts a neutron star and a <span class="hlt">low-mass</span>, main-sequence-like star. It switches on year timescales between states as an <span class="hlt">eclipsing</span> radio millisecond pulsar and a <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> (LMXB). We present a multi-wavelength observational campaign of PSR J1023+0038 in its most recent LMXB state. Two long XMM-Newton observations reveal that the system spends ˜70% of the time in a ≈3 × 1033 erg s-1 X-ray luminosity mode, which, as shown in Archibald et al., exhibits coherent X-ray pulsations. This emission is interspersed with frequent lower flux mode intervals with ≈ 5× {10}32 erg s-1 and sporadic flares reaching up to ≈1034 erg s-1, with neither mode showing significant X-ray pulsations. The switches between the three flux modes occur on timescales of order 10 s. In the UV and optical, we observe occasional intense flares coincident with those observed in X-rays. Our radio timing observations reveal no pulsations at the pulsar period during any of the three X-ray modes, presumably due to complete quenching of the radio emission mechanism by the accretion flow. Radio imaging detects highly variable, flat-spectrum continuum radiation from PSR J1023+0038, consistent with an origin in a weak jet-like outflow. Our concurrent X-ray and radio continuum data sets do not exhibit any correlated behavior. The observational evidence we present bears qualitative resemblance to the behavior predicted by some existing “propeller” and “trapped” disk accretion models although none can account for key aspects of the rich phenomenology of this system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AAS...207.2909D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AAS...207.2909D"><span id="translatedtitle">Artificial Intelligence and the Brave New World of <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Devinney, E.; Guinan, E.; Bradstreet, D.; DeGeorge, M.; Giammarco, J.; Alcock, C.; Engle, S.</p> <p>2005-12-01</p> <p>The explosive growth of observational capabilities and information technology over the past decade has brought astronomy to a tipping point - we are going to be deluged by a virtual fire hose (more like Niagara Falls!) of data. An important component of this deluge will be newly discovered <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars (EBs) and other valuable variable stars. As exploration of the Local Group Galaxies grows via current and new ground-based and satellite programs, the number of EBs is expected to grow explosively from some 10,000 today to 8 million as GAIA comes online. These observational advances will present a unique opportunity to study the properties of EBs formed in galaxies with vastly different dynamical, star formation, and chemical histories than our home Galaxy. Thus the study of these <span class="hlt">binaries</span> (e.g., from light curve analyses) is expected to provide clues about the star formation rates and dynamics of their host galaxies as well as the possible effects of varying chemical abundance on stellar evolution and structure. Additionally, minimal-assumption-based distances to Local Group objects (and possibly 3-D mapping within these objects) shall be returned. These huge datasets of <span class="hlt">binary</span> stars will provide tests of current theories (or suggest new theories) regarding <span class="hlt">binary</span> star formation and evolution. However, these enormous data will far exceed the capabilities of analysis via human examination. To meet the daunting challenge of successfully mining this vast potential of EBs and variable stars for astrophysical results with minimum human intervention, we are developing new data processing techniques and methodologies. Faced with an overwhelming volume of data, our goal is to integrate technologies of Machine Learning and Pattern Processing (Artificial Intelligence [AI]) into the data processing pipelines of the major current and future ground- and space-based observational programs. Data pipelines of the future will have to carry us from observations to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.456..578M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.456..578M"><span id="translatedtitle">Estimates of black hole natal kick velocities from observations of <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mandel, Ilya</p> <p>2016-02-01</p> <p>The birth kicks of black holes, arising from asymmetric mass ejection or neutrino emission during core-collapse supernovae, are of great interest for both observationally constraining supernova models and population-synthesis studies of <span class="hlt">binary</span> evolution. Recently, several efforts were undertaken to estimate black hole birth kicks from observations of black hole <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span>. We follow up on this work, specifically focusing on the highest estimated black hole kick velocities. We find that existing observations do not require black hole birth kicks in excess of approximately 80 km s-1, although higher kicks are not ruled out.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016RAA....16h..14G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016RAA....16h..14G"><span id="translatedtitle">Three X-ray flares near primary <span class="hlt">eclipse</span> of the RS CVn <span class="hlt">binary</span> XY UMa</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gong, Hang; Osten, Rachel; Maccarone, Thomas; Reale, Fabio; Liu, Ji-Feng; Heckert, Paul A.</p> <p>2016-08-01</p> <p>We report on an archival X-ray observation of the <span class="hlt">eclipsing</span> RS CVn <span class="hlt">binary</span> XY UMa (P orb ≈ 0.48 d). In two Chandra ACIS observations spanning 200 ks and almost five orbital periods, three flares occurred. We find no evidence for <span class="hlt">eclipses</span> in the X-ray flux. The flares took place around times of primary <span class="hlt">eclipse</span>, with one flare occurring shortly (< 0.125 P orb) after a primary <span class="hlt">eclipse</span>, and the other two happening shortly (< 0.05 P orb) before a primary <span class="hlt">eclipse</span>. Two flares occurred within roughly one orbital period (Δα ≈ 1.024 P orb) of each other. We analyze the light curve and spectra of the system, and investigate coronal length scales during both quiescence and flares, as well as the timing of the flares. We explore the possibility that the flares are orbit-induced by introducing a small orbital eccentricity, which is quite challenging for this close <span class="hlt">binary</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016yCat..51510068K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016yCat..51510068K"><span id="translatedtitle">VizieR Online Data Catalog: Kepler Mission. VII. <span class="hlt">Eclipsing</span> <span class="hlt">binaries</span> in DR3 (Kirk+, 2016)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kirk, B.; Conroy, K.; Prsa, A.; Abdul-Masih, M.; Kochoska, A.; Matijevic, G.; Hambleton, K.; Barclay, T.; Bloemen, S.; Boyajian, T.; Doyle, L. R.; Fulton, B. J.; Hoekstra, A. J.; Jek, K.; Kane, S. R.; Kostov, V.; Latham, D.; Mazeh, T.; Orosz, J. A.; Pepper, J.; Quarles, B.; Ragozzine, D.; Shporer, A.; Southworth, J.; Stassun, K.; Thompson, S. E.; Welsh, W. F.; Agol, E.; Derekas, A.; Devor, J.; Fischer, D.; Green, G.; Gropp, J.; Jacobs, T.; Johnston, C.; Lacourse, D. M.; Saetre, K.; Schwengeler, H.; Toczyski, J.; Werner, G.; Garrett, M.; Gore, J.; Martinez, A. O.; Spitzer, I.; Stevick, J.; Thomadis, P. C.; Vrijmoet, E. H.; Yenawine, M.; Batalha, N.; Borucki, W.</p> <p>2016-07-01</p> <p>The Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Catalog lists the stellar parameters from the Kepler Input Catalog (KIC) augmented by: primary and secondary <span class="hlt">eclipse</span> depth, <span class="hlt">eclipse</span> width, separation of <span class="hlt">eclipse</span>, ephemeris, morphological classification parameter, and principal parameters determined by geometric analysis of the phased light curve. The previous release of the Catalog (Paper II; Slawson et al. 2011, cat. J/AJ/142/160) contained 2165 objects, through the second Kepler data release (Q0-Q2). In this release, 2878 objects are identified and analyzed from the entire data set of the primary Kepler mission (Q0-Q17). The online version of the Catalog is currently maintained at http://keplerEBs.villanova.edu/. A static version of the online Catalog associated with this paper is maintained at MAST https://archive.stsci.edu/kepler/<span class="hlt">eclipsing_binaries</span>.html. (10 data files).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.........1S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.........1S"><span id="translatedtitle">Accretion flow properties in <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sanna, Andrea</p> <p>2013-02-01</p> <p>Accretieschijf dubbelstersystemen onderzocht In zijn proefschrift onderzoekt Andrea Sanna de eigenschappen van de accretiestroom in lage-massa röntgendubbelstersystemen (LMXBs, <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span>). Dat zijn systemen waarin een neutronenster of een stellair zwart gat zich via een zogenoemde accretieschijf voedt met materie afkomstig van een lage massa begeleidende ster. Röntgendubbelstersystemen vormen een uniek laboratorium voor onderzoek van de fysica in een sterk zwaartekrachtsveld en in zeer dichte materie; extreme condities die niet na te bootsen zijn op de Aarde. Effecten rond deze compacte objecten, die voorspeld worden in de algemene relativiteitstheorie, zijn vele ordes van grootte sterker dan die waarin de algemene relativiteitstheorie succesvol is getest (het zwakke veld domein). De precieze aard en de collectieve eigenschappen van de elementaire deeltjes waaruit de neutronenster is opgebouwd, zijn nog steeds niet goed genoeg begrepen om de toestandsvergelijkingen (die de toestand van de materie in de neutronenster beschrijven) te voorspellen. Door de baanbeweging rond een neutronenster te onderzoeken, kunnen zowel de massa als de straal van het object bepaald worden. Dat kan weer gebruikt worden om de toestandsvergelijking en vervolgens de fundamentele eigenschappen van het materiaal in de neutronenster vast te stellen. Om röntgendubbelstersystemen te begrijpen, bestudeerde Sanna fotonen die worden uitgezonden door deze systemen. Hij richt zich op röntgenemissie die zijn oorsprong vindt in de nabije omgeving van het compacte object. ‘Momenteel zijn we nog niet in staat om via directe beeldvormende technieken de LMXBs ruimtelijk op te lossen in het röntgengebied,’ zegt hij. ‘Daarom zijn spectrale- en tijdsanalyses van röntgenfotonen de voornaamste methodes die gebruikt worden om de spectrale evolutie van de röntgenbron te begrijpen en om de intrinsieke parameters van het compacte object te onthullen. In dit proefschrift richt ik me in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22340076','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22340076"><span id="translatedtitle">Absolute properties of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> VV CORVI</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fekel, Francis C.; Henry, Gregory W.; Sowell, James R. E-mail: gregory.w.henry@gmail.com</p> <p>2013-12-01</p> <p>We have obtained red-wavelength spectroscopy and Johnson B and V differential photoelectric photometry of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> VV Crv = HR 4821. The system is the secondary of the common proper motion double star ADS 8627, which has a separation of 5.''2. VV Crv has an orbital period of 3.144536 days and a low but non-zero eccentricity of 0.085. With the Wilson-Devinney program we have determined a simultaneous solution of our spectroscopic and photometric observations. Those orbital elements produce masses of M {sub 1} = 1.978 ± 0.010 M {sub ☉} and M {sub 2} = 1.513 ± 0.008 M {sub ☉}, and radii of R {sub 1} = 3.375 ± 0.010 R {sub ☉} and R {sub 2} = 1.650 ± 0.008 R {sub ☉} for the primary and secondary, respectively. The effective temperatures of the two components are 6500 K (fixed) and 6638 K, so the star we call the primary is the more massive but cooler and larger component. A comparison with evolutionary tracks indicates that the components are metal rich with [Fe/H] = 0.3, and the system has an age of 1.2 Gyr. The primary is near the end of its main-sequence lifetime and is rotating significantly faster than its pseudosynchronous velocity. The secondary is still well ensconced on the main sequence and is rotating more slowly than its pseudosynchronous rate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004JAD....10....1S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004JAD....10....1S&link_type=ABSTRACT"><span id="translatedtitle">Photometry of 20 <span class="hlt">eclipsing</span> and ellipsoidal <span class="hlt">binary</span> systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shobbrook, R. R.</p> <p>2004-12-01</p> <p>A total of almost 2000 V observations of 20 <span class="hlt">eclipsing</span> and ellipsoidal bright <span class="hlt">binary</span> stars was collected between 1991 and 2001 for the purpose of determining more recent epoch ephemerides for the light curves than are available in the literature. The original purpose was to provide the Sydney University Stellar Interferometer (SUSI) with orbital periods and particularly the accurate times of minimum separation (light curve minima), so that the SUSI observations need not be used to determine them. This paper provides the periods, the times of primary minima and the phases of secondary minima for the 20 stars at an epoch as near as possible to the year 2000. No attempt has been made in this report to determine other parameters such as {apsidal motion} or stellar radii. Since the program was started in 1991, data for these stars taken in the period from late 1989 to early 1993 has also been available from the Hipparcos satellite; the light curves shown here include both sets of observations.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005JAD....11....7S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005JAD....11....7S&link_type=ABSTRACT"><span id="translatedtitle">Photometry of 20 <span class="hlt">eclipsing</span> and ellipsoidal <span class="hlt">binary</span> systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shobbrook, R. R.</p> <p>2005-12-01</p> <p>ERRATUM: In the published paper the phase diagrams of pi Sco and AL Scl were ommitted. The version reproduced in JAD11, 7 is the complete version. A total of almost 2000 V observations of 20 <span class="hlt">eclipsing</span> and ellipsoidal bright <span class="hlt">binary</span> stars was collected between 1991 and 2001 for the purpose of determining more recent epoch ephemerides for the light curves than are available in the literature. The original purpose was to provide the Sydney University Stellar Interferometer (SUSI) with orbital periods and particularly the accurate times of minimum separation (light curve minima), so that the SUSI observations need not be used to determine them. This paper provides the periods, the times of primary minima and the phases of secondary minima for the 20 stars at an epoch as near as possible to the year 2000. No attempt has been made in this report to determine other parameters such as {apsidal motion} or stellar radii. Since the program was started in 1991, data for these stars taken in the period from late 1989 to early 1993 has also been available from the Hipparcos satellite; the light curves shown here include both sets of observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20030093531&hterms=fuse&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dfuse','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20030093531&hterms=fuse&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dfuse"><span id="translatedtitle">Doppler Imaging with FUSE: The Partially <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> VW Cep</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sonneborn, George (Technical Monitor); Brickhouse, Nancy</p> <p>2003-01-01</p> <p>This report covers the FUSE Guest Observer program. This project involves the study of emission line profiles for the partially <span class="hlt">eclipsing</span>, rapidly rotating <span class="hlt">binary</span> system VW Cep. Active regions on the surface of the star(s) produce observable line shifts as the stars move with respect to the observer. By studying the time-dependence of the line profile changes and centroid shifts, one can determine the location of the activity. FUSE spectra were obtained by the P.I. 27 Sept 2002 and data reduction is in progress. Since we are interested in line profile analysis, we are now investigating the wavelength scale calibration in some detail. We have also obtained and are analyzing Chandra data in order to compare the X-ray velocities with the FUV velocities. A complementary project comparing X-ray and Far UltraViolet (FUV) emission for the similar system 44i Boo is also underway. Postdoctoral fellow Ronnie Hoogerwerf has joined the investigation team and will perform the data analysis, once the calibration is optimized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22034456','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22034456"><span id="translatedtitle">ABSOLUTE PROPERTIES OF THE <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> STAR BF DRACONIS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sandberg Lacy, Claud H.; Torres, Guillermo; Fekel, Francis C.; Sabby, Jeffrey A.; Claret, Antonio E-mail: gtorres@cfa.harvard.edu E-mail: jsabby@siue.edu</p> <p>2012-06-15</p> <p>BF Dra is now known to be an eccentric double-lined F6+F6 <span class="hlt">binary</span> star with relatively deep (0.7 mag) partial <span class="hlt">eclipses</span>. Previous studies of the system are improved with 7494 differential photometric observations from the URSA WebScope and 9700 from the NFO WebScope, 106 high-resolution spectroscopic observations from the Tennessee State University 2 m automatic spectroscopic telescope and the 1 m coude-feed spectrometer at Kitt Peak National Observatory, and 31 accurate radial velocities from the CfA. Very accurate (better than 0.6%) masses and radii are determined from analysis of the two new light curves and four radial velocity curves. Theoretical models match the absolute properties of the stars at an age of about 2.72 Gyr and [Fe/H] = -0.17, and tidal theory correctly confirms that the orbit should still be eccentric. Our observations of BF Dra constrain the convective core overshooting parameter to be larger than about 0.13 H{sub p}. We find, however, that standard tidal theory is unable to match the observed slow rotation rates of the components' surface layers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21562474','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21562474"><span id="translatedtitle">A 12 MINUTE ORBITAL PERIOD DETACHED WHITE DWARF <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Brown, Warren R.; Kilic, Mukremin; Kenyon, Scott J.; Hermes, J. J.; Winget, D. E.; Prieto, Carlos Allende E-mail: mkilic@cfa.harvard.edu E-mail: jjhermes@astro.as.utexas.edu E-mail: callende@iac.es</p> <p>2011-08-10</p> <p>We have discovered a detached pair of white dwarfs (WDs) with a 12.75 minute orbital period and a 1315 km s{sup -1} radial velocity amplitude. We measure the full orbital parameters of the system using its light curve, which shows ellipsoidal variations, Doppler boosting, and primary and secondary <span class="hlt">eclipses</span>. The primary is a 0.25 M{sub sun} tidally distorted helium WD, only the second tidally distorted WD known. The unseen secondary is a 0.55 M{sub sun} carbon-oxygen WD. The two WDs will come into contact in 0.9 Myr due to loss of energy and angular momentum via gravitational wave radiation. Upon contact the systems may merge (yielding a rapidly spinning massive WD), form a stable interacting <span class="hlt">binary</span>, or possibly explode as an underluminous Type Ia supernova. The system currently has a gravitational wave strain of 10{sup -22}, about 10,000 times larger than the Hulse-Taylor pulsar; this system would be detected by the proposed Laser Interferometer Space Antenna gravitational wave mission in the first week of operation. This system's rapid change in orbital period will provide a fundamental test of general relativity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22342241','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22342241"><span id="translatedtitle">Absolute properties of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star V501 Herculis</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lacy, Claud H. Sandberg; Fekel, Francis C. E-mail: fekel@evans.tsuniv.edu</p> <p>2014-10-01</p> <p>V501 Her is a well detached G3 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star with a period of 8.597687 days for which we have determined very accurate light and radial-velocity curves using robotic telescopes. Results of these data indicate that the component stars have masses of 1.269 ± 0.004 and 1.211 ± 0.003 solar masses, radii of 2.001 ± 0.003 and 1.511 ± 0.003 solar radii, and temperatures of 5683 ± 100 K and 5720 ± 100 K, respectively. Comparison with the Yonsei-Yale series of evolutionary models results in good agreement at an age of about 5.1 Gyr for a somewhat metal-rich composition. Those models indicate that the more massive, larger, slightly cooler star is just beyond core hydrogen exhaustion while the less massive, smaller, slightly hotter star has not quite reached core hydrogen exhaustion. The orbit is not yet circularized, and the components are rotating at or near their pseudosynchronous velocities. The distance to the system is 420 ± 30 pc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...816...21D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...816...21D"><span id="translatedtitle">K2 Discovery of Young <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> in Upper Scorpius: Direct Mass and Radius Determinations for the Lowest Mass Stars and Initial Characterization of an <span class="hlt">Eclipsing</span> Brown Dwarf <span class="hlt">Binary</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>David, Trevor J.; Hillenbrand, Lynne A.; Cody, Ann Marie; Carpenter, John M.; Howard, Andrew W.</p> <p>2016-01-01</p> <p>We report the discovery of three <span class="hlt">low-mass</span> double-lined <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in the pre-main sequence Upper Scorpius association, revealed by K2 photometric monitoring of the region over ˜78 days. The orbital periods of all three systems are <5 days. We use the K2 photometry plus multiple Keck/HIRES radial velocities (RVs) and spectroscopic flux ratios to determine fundamental stellar parameters for both the primary and secondary components of each system, along with the orbital parameters. We present tentative evidence that EPIC 203868608 is a hierarchical triple system comprised of an <span class="hlt">eclipsing</span> pair of ˜25 MJup brown dwarfs with a wide M-type companion. If confirmed, it would constitute only the second double-lined <span class="hlt">eclipsing</span> brown dwarf <span class="hlt">binary</span> system discovered to date. The double-lined system EPIC 203710387 is composed of nearly identical M4.5-M5 stars with fundamentally determined masses and radii measured to better than 3% precision ({M}1=0.1183+/- 0.0028{M}⊙ , {M}2=0.1076+/- 0.0031{M}⊙ and {R}1=0.417+/- 0.010{R}⊙ , {R}2=0.450+/- 0.012{R}⊙ ) from combination of the light curve and RV time series. These stars have the lowest masses of any stellar mass double-lined <span class="hlt">eclipsing</span> <span class="hlt">binary</span> to date. Comparing our derived stellar parameters with evolutionary models, we suggest an age of ˜10-11 Myr for this system, in contrast to the canonical age of 3-5 Myr for the association. Finally, EPIC 203476597 is a compact single-lined system with a G8-K0 primary and a likely mid-K secondary whose lines are revealed in spectral ratios. Continued measurement of RVs and spectroscopic flux ratios will better constrain fundamental parameters and should elevate the objects to benchmark status. We also present revised parameters for the double-lined <span class="hlt">eclipsing</span> <span class="hlt">binary</span> UScoCTIO 5 ({M}1=0.3336+/- 0.0022{M}⊙ , {M}2=0.3200+/- 0.0022{M}⊙ and {R}1=0.862+/- 0.012, {R}2=0.852+/- 0.013{R}⊙ ), which are suggestive of a system age younger than previously reported. We discuss the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22270898','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22270898"><span id="translatedtitle">PSR J1723–2837: AN <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> RADIO MILLISECOND PULSAR</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Crawford, Fronefield; Lyne, Andrew G.; Stairs, Ingrid H.; Kaplan, David L.; McLaughlin, Maura A.; Lorimer, Duncan R.; Freire, Paulo C. C.; Kramer, Michael; Burgay, Marta; D'Amico, Nichi; Possenti, Andrea; Camilo, Fernando; Faulkner, Andrew; Manchester, Richard N.; Steeghs, Danny</p> <p>2013-10-10</p> <p>We present a study of PSR J1723–2837, an <span class="hlt">eclipsing</span>, 1.86 ms millisecond <span class="hlt">binary</span> radio pulsar discovered in the Parkes Multibeam survey. Radio timing indicates that the pulsar has a circular orbit with a 15 hr orbital period, a <span class="hlt">low-mass</span> companion, and a measurable orbital period derivative. The <span class="hlt">eclipse</span> fraction of ∼15% during the pulsar's orbit is twice the Roche lobe size inferred for the companion. The timing behavior is significantly affected by unmodeled systematics of astrophysical origin, and higher-order orbital period derivatives are needed in the timing solution to account for these variations. We have identified the pulsar's (non-degenerate) companion using archival ultraviolet, optical, and infrared survey data and new optical photometry. Doppler shifts from optical spectroscopy confirm the star's association with the pulsar and indicate a pulsar-to-companion mass ratio of 3.3 ± 0.5, corresponding to a companion mass range of 0.4 to 0.7 M{sub ☉} and an orbital inclination angle range of between 30° and 41°, assuming a pulsar mass range of 1.4-2.0 M{sub ☉}. Spectroscopy indicates a spectral type of G for the companion and an inferred Roche-lobe-filling distance that is consistent with the distance estimated from radio dispersion. The features of PSR J1723–2837 indicate that it is likely a 'redback' system. Unlike the five other Galactic redbacks discovered to date, PSR J1723–2837 has not been detected as a γ-ray source with Fermi. This may be due to an intrinsic spin-down luminosity that is much smaller than the measured value if the unmeasured contribution from proper motion is large.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AAS...22033303B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AAS...22033303B"><span id="translatedtitle">Time-Dependent Behavior of the O'Connell Effect in <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Star Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beaky, Matthew M.; Koju, V.</p> <p>2012-05-01</p> <p>The characteristic shape of an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> light curve consists of two out-of-<span class="hlt">eclipse</span> maxima and two mid-<span class="hlt">eclipse</span> minima. Many <span class="hlt">eclipsing</span> <span class="hlt">binary</span> light curves exhibit unequally high maxima, a feature known as the O'Connell effect. So far, this asymmetry has not been convincingly explained aside from a few individual systems. Most theories attribute the O'Connell effect to phenomena such as starspots, clouds of circumstellar gas and dust, or a hot spot caused by the impact of a mass-transferring gas stream. The high precision and nearly continuous temporal coverage of light curves produced by the Kepler Space Mission make it possible to detect variations in the O'Connell effect within individual systems that have not previously been observed via ground-based observations. Our analysis of Kepler light curves of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems reveals that in most cases the size and even the sign of the O'Connell effect changes significantly over time scales of weeks or months. Moreover, the magnitude difference between the <span class="hlt">eclipse</span> minima also varies, usually lagging behind the variations in the difference between the out-of-<span class="hlt">eclipse</span> maxima by several orbital cycles. We have created models of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems using <span class="hlt">Binary</span> Maker 3 that include starspots that migrate slowly in longitude, and have analyze the light curves generated by these model systems. Models with constant starspots at fixed latitude and models with starspots that vary in size and latitude both reproduce the qualitative behavior of the time-dependent O'Connell effect in the Kepler light curves very closely. These results provide support for the notion that the O'Connell effect, at least in some cases, is caused by migrating starspots on the surface of one or both components of the <span class="hlt">binary</span> star system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NewA...44...78M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NewA...44...78M"><span id="translatedtitle">Period and light-curve study of the contact <span class="hlt">eclipsing</span> <span class="hlt">binary</span> V523 Cas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mohammadi, Mahya; Abedi, Abbas; Riazi, Nematollah</p> <p>2016-04-01</p> <p>CCD photometry of the <span class="hlt">eclipsing</span> W Uma <span class="hlt">binary</span> system V523 Cas in U, B, V and RC filters was carried out during eight nights in 2012. The physical and geometrical parameters of this system are obtained. A possible pulsation period of one of the components is obtained by analyzing the residuals of the ephemeris light curve. Our observations contain 16 times of minimum light. We combined these with all available published times of minimum. By fitting a quadratic curve to the O-C values, a new ephemeris of the system is calculated. By attributing the period change to mass transfer, we find a mass transfer rate of 4 ×10-12 M⊙/yr. Also, Period (80.58 yr) and the minimum mass (0.3 M⊙) of a possible third body is estimated. In addition, the possible existence of a fourth body with a mass of order 0.15 M⊙ is discussed. These third and fourth bodies could be <span class="hlt">low-mass</span> main-sequence stars (red dwarfs).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16541067','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16541067"><span id="translatedtitle">Discovery of two young brown dwarfs in an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stassun, Keivan G; Mathieu, Robert D; Valenti, Jeff A</p> <p>2006-03-16</p> <p>Brown dwarfs are considered to be 'failed stars' in the sense that they are born with masses between the least massive stars (0.072 solar masses, M(o)) and the most massive planets (approximately 0.013M(o)); they therefore serve as a critical link in our understanding of the formation of both stars and planets. Even the most fundamental physical properties of brown dwarfs remain, however, largely unconstrained by direct measurement. Here we report the discovery of a brown-dwarf <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system, in the Orion Nebula star-forming region, from which we obtain direct measurements of mass and radius for these newly formed brown dwarfs. Our mass measurements establish both objects as brown dwarfs, with masses of 0.054 +/- 0.005M(o) and 0.034 +/- 0.003M(o). At the same time, with radii relative to the Sun's of 0.669 +/- 0.034R(o) and 0.511 +/- 0.026R(o), these brown dwarfs are more akin to <span class="hlt">low-mass</span> stars in size. Such large radii are generally consistent with theoretical predictions for young brown dwarfs in the earliest stages of gravitational contraction. Surprisingly, however, we find that the less-massive brown dwarf is the hotter of the pair; this result is contrary to the predictions of all current theoretical models of coeval brown dwarfs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014A%26A...564A..98S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014A%26A...564A..98S"><span id="translatedtitle"><span class="hlt">Binaries</span> discovered by the MUCHFUSS project. SDSS J162256.66+473051.1: An <span class="hlt">eclipsing</span> subdwarf B <span class="hlt">binary</span> with a brown dwarf companion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schaffenroth, V.; Geier, S.; Heber, U.; Kupfer, T.; Ziegerer, E.; Heuser, C.; Classen, L.; Cordes, O.</p> <p>2014-04-01</p> <p>Hot subdwarf B stars (sdBs) are core helium-burning stars located on the extreme horizontal branch. About half of the known sdB stars are found in close <span class="hlt">binaries</span>. Their short orbital periods of 1.2 h to a few days suggest that they are post common-envelope systems. <span class="hlt">Eclipsing</span> hot subdwarf <span class="hlt">binaries</span> are rare but are important in determining the fundamental stellar parameters. <span class="hlt">Low-mass</span> companions are identified by the reflection effect. In most cases, the companion is a main sequence star near the stellar mass limit. Here, we report the discovery of an <span class="hlt">eclipsing</span> hot subdwarf <span class="hlt">binary</span> SDSS J162256.66+473051.1 (J1622) with very short orbital period (0.0697 d), which has been found in the course of the MUCHFUSS project. The lightcurve shows grazing <span class="hlt">eclipses</span> and a prominent reflection effect. An analysis of the light- and radial velocity (RV) curves indicated a mass ratio of q = 0.1325, an RV semi-amplitude K = 47.2 km s-1, and an inclination of i = 72.33°. We show that a companion mass of 0.064 M⊙, which is well below the hydrogen-burning limit, is the most plausible solution, which implies a mass close to the canonical mass (0.47 M⊙) of the sdB star. Therefore, the companion is a brown dwarf, which has not only survived the engulfment by the red-giant envelope but also triggered its ejection and enabled the sdB star to form. The rotation of J1622 is expected to be tidally locked to the orbit. However, J1622 rotates too slowly (vrot = 74.5 ± 7 km s-1) to be synchronized, challenging tidal interaction models. Appendix A is available in electronic form at http://www.aanda.org</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930062289&hterms=white+dwarf&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dwhite%2Bdwarf','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930062289&hterms=white+dwarf&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dwhite%2Bdwarf"><span id="translatedtitle">Spectroscopic observations of V443 Herculis - A symbiotic <span class="hlt">binary</span> with a <span class="hlt">low</span> <span class="hlt">mass</span> white dwarf</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dobrzycka, Danuta; Kenyon, Scott J.; Mikolajewska, Joanna</p> <p>1993-01-01</p> <p>We present an analysis of new and existing photometric and spectroscopic observations of the symbiotic <span class="hlt">binary</span> V443 Herculis. This <span class="hlt">binary</span> system consists of a normal M5 giant and a hot compact star. These two objects have comparable luminosities: about 1500 solar for the M5 giant and about 1000 solar for the compact star. We identify three nebular regions in this <span class="hlt">binary</span>: a small, highly ionized volume surrounding the hot component, a modestly ionized shell close to the red giant photosphere, and a less dense region of intermediate ionization encompassing both <span class="hlt">binary</span> components. The system parameters for V443 Her suggest the hot component currently declines from a symbiotic nova eruption.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MNRAS.453.3341R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MNRAS.453.3341R"><span id="translatedtitle">Constraining the formation of black holes in short-period black hole <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Repetto, Serena; Nelemans, Gijs</p> <p>2015-11-01</p> <p>The formation of stellar-mass black holes (BHs) is still very uncertain. Two main uncertainties are the amount of mass ejected in the supernova (SN) event (if any) and the magnitude of the natal kick (NK) the BH receives at birth (if any). Repetto et al., studying the position of Galactic X-ray <span class="hlt">binaries</span> containing BHs, found evidence for BHs receiving high NKs at birth. In this paper, we extend that study, taking into account the previous <span class="hlt">binary</span> evolution of the sources as well. The seven short-period BH X-ray <span class="hlt">binaries</span> that we use are compact <span class="hlt">binaries</span> consisting of a <span class="hlt">low-mass</span> star orbiting a BH in a period less than 1 d. We trace their <span class="hlt">binary</span> evolution backwards in time, from the current observed state of mass transfer, to the moment the BH was formed, and we add the extra information on the kinematics of the <span class="hlt">binaries</span>. We find that several systems could be explained by no NK, just mass ejection, while for two systems (and possibly more) a high kick is required. So unless the latter have an alternative formation, such as within a globular cluster, we conclude that at least some BHs get high kicks. This challenges the standard picture that BH kicks would be scaled down from neutron star kicks. Furthermore, we find that five systems could have formed with a non-zero NK but zero mass ejected (i.e. no SN) at formation, as predicted by neutrino-driven NKs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009A%26A...502..905Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009A%26A...502..905Y"><span id="translatedtitle">An XMM-Newton view of the dipping <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> XTE J1710-281</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Younes, G.; Boirin, L.; Sabra, B.</p> <p>2009-08-01</p> <p>Context: Studying the spectral changes during the dips exhibited by almost edge-on, <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs) is a powerful means of probing the structure of accretion disks. The XMM-Newton, Chandra, or Suzaku discovery of absorption lines from Fe xxv and other highly-ionized species in many dippers has revealed a highly-ionized atmosphere above the disk. A highly (but less strongly) ionized plasma is also present in the vertical structure causing the dips, together with neutral material. Aims: We aim to investigate the spectral changes during the dips of XTE J1710-281, a still poorly studied LMXB known to exhibit bursts, dips, and <span class="hlt">eclipses</span>. Methods: We analyze the archived XMM-Newton observation of XTE J1710-281 performed in 2004 that covered one orbital period of the system (3.8 h). We modeled the spectral changes between persistent and dips in the framework of the partial covering model and the ionized absorber approach. Results: The persistent spectrum can be fit by a power law with a photon index of 1.94±0.02 affected by absorption from cool material with a hydrogen column density of (0.401±0.007)×1022 cm-2. The spectral changes from persistent to deep-dipping intervals are consistent with the partial covering of the power-law emission. Twenty-six percent of the continuum is covered during shallow dipping, and 78% during deep dipping. The column density decreases from 77_-38+67 × 1022 cm-2 during shallow dipping to (14 ± 2) × 1022 cm-2 during the deep-dipping interval. We do not detect any absorption line from highly ionized species such as Fe xxv. However, the upper-limits we derive on their equivalent width (EW) are not constraining. Despite not detecting any narrow spectral signatures of a warm absorber, we show that the spectral changes are consistent with an increase in column density and a decrease in ionization state of a highly-ionized absorber, associated with an increase in column density of a neutral absorber, in agreement with the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21562597','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21562597"><span id="translatedtitle">APSIDAL MOTION OF THE <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> AS CAMELOPARDALIS: DISCREPANCY RESOLVED</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pavlovski, K.; Kolbas, V.; Southworth, J.</p> <p>2011-06-20</p> <p>We present a spectroscopic study of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system AS Camelopardalis, the first such study based on phase-resolved CCD echelle spectra. Via a spectral disentangling analysis we measure the minimum masses of the stars to be M{sub A}sin {sup 3} i = 3.213 {+-} 0.032 M{sub sun} and M{sub B}sin {sup 3} i = 2.323 {+-} 0.032 M{sub sun}, their effective temperatures to be T{sub eff}(A) = 12, 840 {+-} 120 K and T{sub eff}(B) = 10, 580 {+-} 240 K, and their projected rotational velocities to be v{sub A}sin i{sub A} = 14.5 {+-} 0.1 km s{sup -1} and v{sub B}sin i{sub B} {<=} 4.6 {+-} 0.1 km s{sup -1}. These projected rotational velocities appear to be much lower than the synchronous values. We show that measurements of the apsidal motion of the system suffer from a degeneracy between orbital eccentricity and apsidal motion rate. We use our spectroscopically measured e = 0.164 {+-} 0.004 to break this degeneracy and measure {omega}-dot{sub obs} = 0{sup 0}.133{+-}0{sup 0}.010 yr{sup -1}. Subtracting the relativistic contribution of {omega}-dot{sub GR} = 0{sup 0}.0963{+-}0{sup 0}0002 yr{sup -1} yields the contribution due to tidal torques: {omega}-dot{sub cl} = 0{sup 0}.037{+-}0{sup 0}.010 yr{sup -1}. This value is much smaller than the rate predicted by stellar theory, 0.{sup 0}40-0.{sup 0}87 yr{sup -1}. We interpret this as a misalignment between the orbital axis of the close <span class="hlt">binary</span> and the rotational axes of its component stars, which also explains their apparently low rotational velocities. The observed and predicted apsidal motion rates could be brought into agreement if the stars were rotating three times faster than synchronous about axes perpendicular to the orbital axis. Measurement of the Rossiter-McLaughlin effect can be used to confirm this interpretation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011AAS...21830302P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011AAS...21830302P&link_type=ABSTRACT"><span id="translatedtitle">Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Stars. Scientific Harvest from the First 4 Months of Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prsa, Andrej; Orosz, J. A.; Welsh, W. F.; Slawson, R. W.; Batalha, N.; Rucker, M.; Doyle, L. R.</p> <p>2011-05-01</p> <p>The Kepler mission observed over 2200 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars in its 105-square degree field of view. Their importance in modern astrophysics cannot be overstated -- it ranges from deriving the fundamental stellar parameters across the Hertzsprung-Russell Diagram and calibrating the mass-radius-temperature relationships, to determining the distances in the Galaxy and beyond. Kepler observations provide a unique sample with a nearly continuous coverage and sub-millimag precision, allowing us to model <span class="hlt">binary</span> star light curves to unprecedented accuracy. In the context of planet hunting, the period and amplitude statistics derived from this sample are used to estimate the occurence rate of false positives: stellar sources that mimic planet transits due to third light contamination. I will present the results of the studies performed by the Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Working Group: 1) determining the physical parameters of <span class="hlt">binary</span> star components, 2) studying the <span class="hlt">eclipse</span> timing variations that attest to the presence of third bodies or arise due to component interaction, 3) performing statistical analysis of the whole sample, 4) estimating the occurence rate of background <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>, and 5) searching for tertiary events due to other <span class="hlt">eclipsing</span> objects. This work is supported by the NASA/SETI grant 08-SC-1041 and NSF RUI #AST-05-07542.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21443175','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21443175"><span id="translatedtitle">THE PHASES DIFFERENTIAL ASTROMETRY DATA ARCHIVE. II. UPDATED <span class="hlt">BINARY</span> STAR ORBITS AND A LONG PERIOD <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Muterspaugh, Matthew W.; O'Connell, J.; Hartkopf, William I.; Lane, Benjamin F.; Williamson, M.; Kulkarni, S. R.; Konacki, Maciej; Burke, Bernard F.; Colavita, M. M.; Shao, M.; Wiktorowicz, Sloane J. E-mail: wih@usno.navy.mi E-mail: maciej@ncac.torun.p</p> <p>2010-12-15</p> <p>Differential astrometry measurements from the Palomar High-precision Astrometric Search for Exoplanet Systems have been combined with lower precision single-aperture measurements covering a much longer timespan (from eyepiece measurements, speckle interferometry, and adaptive optics) to determine improved visual orbits for 20 <span class="hlt">binary</span> stars. In some cases, radial velocity observations exist to constrain the full three-dimensional orbit and determine component masses. The visual orbit of one of these <span class="hlt">binaries</span>-{alpha} Com (HD 114378)-shows that the system is likely to have <span class="hlt">eclipses</span>, despite its very long period of 26 years. The next <span class="hlt">eclipse</span> is predicted to be within a week of 2015 January 24.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22520119','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22520119"><span id="translatedtitle">TIME-SERIES SPECTROSCOPY OF THE <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> Y CAM WITH A PULSATING COMPONENT</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hong, Kyeongsoo; Lee, Jae Woo; Kim, Seung-Lee; Koo, Jae-Rim; Lee, Chung-Uk; Yushchenko, Alexander V.; Kang, Young-Woon</p> <p>2015-10-15</p> <p>We present the physical properties of the semi-detached Algol-type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> Y Cam based on high resolution spectra obtained using the Bohyunsan Optical Echelle Spectrograph. This is the first spectroscopic monitoring data obtained for this interesting <span class="hlt">binary</span> system, which has a δ Sct-type pulsating component. We obtained a total of 59 spectra over 14 nights from 2009 December to 2011 March. Double-lined spectral features from the hot primary and cool secondary components were well identified. We determined the effective temperatures of the two stars to be T{sub eff,1} = 8000 ± 250 K and T{sub eff,2} = 4629 ± 150 K. The projected rotational velocities are v{sub 1}sin i{sub 1} = 51 ± 4 km s{sup −1} and v{sub 2}sin i{sub 2} = 50 ± 10 km s{sup −1}, which are very similar to a synchronous rotation with the orbital motion. Physical parameters of each component were derived by analyzing our radial velocity data together with previous photometric light curves from the literature. The masses and radii are M{sub 1} = 2.08 ± 0.09 M{sub ⊙}, M{sub 2} = 0.48 ± 0.03 M{sub ⊙}, R{sub 1} = 3.14 ± 0.05 R{sub ⊙}, and R{sub 2} = 3.33 ± 0.05 R{sub ⊙}, respectively. A comparison of these parameters with the theoretical evolution tracks showed that the primary component is located between the zero-age main sequence and the terminal-age main sequence, while the <span class="hlt">low-mass</span> secondary is noticeably evolved. This indicates that the two components have experienced mass exchange with each other and the primary has undergone an evolution process different from that of single δ Sct-type pulsators.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016RAA....16...68Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016RAA....16...68Z"><span id="translatedtitle">A <span class="hlt">low-mass</span>-ratio and deep contact <span class="hlt">binary</span> as the progenitor of the merger V1309 Sco</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, Li-Ying; Zhao, Er-Gang; Zhou, Xiao</p> <p>2016-04-01</p> <p>Nova Sco 2008 (=V1309 Sco) is an example of a V838 Mon type eruption rather than a typical classical nova. This enigmatic object was recently shown to have resulted from the merger of two stars in a contact <span class="hlt">binary</span>. It is the first stellar merger that was identified to be undergoing a common envelope transient. To understand the properties of its <span class="hlt">binary</span> progenitor, the pre-outburst light curves were analyzed by using the W-D method. The photometric solution of the 2002 light curve shows that it is a deep contact <span class="hlt">binary</span> (f = 89.5(±40.5)%) with a mass ratio of 0.094. The asymmetry of the light curve is explained by the presence of a dark spot on the more massive component. The extremely high fill-out factor suggests that the merging of the contact <span class="hlt">binary</span> is driven by dynamical mass loss from the outer Lagrange point. However, the analysis of the 2004 light curve indicates that no solutions were obtained even at an extremely <span class="hlt">low</span> <span class="hlt">mass</span> ratio of q = 0.03. This suggests that the common convective envelope of the <span class="hlt">binary</span> system disappeared and the secondary component spiraled into the envelope of the primary in 2004. Finally, the ejection of the envelope of the primary produced the outburst.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ATel.5651....1D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ATel.5651....1D"><span id="translatedtitle">Spectroscopic observations of the peculiar <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> XSS J12270-4859</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Martino, D.; Velazquez, J. Casares; Mason, E.; Kotze, M.; Buckley, D. A. H.; Bonnet-Bidaud, J.-M.; Belloni, T.; Mouchet, M.; Falanga, M.</p> <p>2013-12-01</p> <p>The enigmatic <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> XSS J12270-4859 associated to the Fermi/LAT Gamma ray source 1FGL 1227.9-4852/2FGL 1227.7-4853 (de Martino et al. 2010, A&A 515, A25; Hill et al. 2011, MNRAS 415, 235; de Martino et al. 2013, A&A 550, A89) was extensively observed from radio to gamma rays but its orbital period is still unknown. Pretorius (2009, MNRAS, 395, 386) did not find a period in time resolved optical observations.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22356771','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22356771"><span id="translatedtitle">Calibrating the updated overshoot mixing model on <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars: HY Vir, YZ Cas, χ{sup 2} Hya, and VV Crv</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Meng, Y.; Zhang, Q. S.</p> <p>2014-06-01</p> <p>Detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars with convective cores provide a good tool to investigate convective core overshoot. It has been performed on some <span class="hlt">binary</span> stars to restrict the classical overshoot model which simply extends the boundary of the fully mixed region. However, the classical overshoot model is physically unreasonable and inconsistent with helioseismic investigations. An updated model of overshoot mixing was established recently. There is a key parameter in the model. In this paper, we use observations of four <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars, i.e., HY Vir, YZ Cas, χ{sup 2} Hya, and VV Crv, to investigate a suitable value for the parameter. It is found that the value suggested by calibrations on <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars is the same as the value recommended by other methods. In addition, we have studied the effects of the updated overshoot model on the stellar structure. The diffusion coefficient of convective/overshoot mixing is very high in the convection zone, then quickly decreases near the convective boundary, and exponentially decreases in the overshoot region. The low value of the diffusion coefficient in the overshoot region leads to weak mixing and a partially mixed overshoot region. Semi-convection, which appears in the standard stellar models of <span class="hlt">low-mass</span> stars with convective cores, is removed by partial overshoot mixing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22140310','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22140310"><span id="translatedtitle">DID THE ANCIENT EGYPTIANS RECORD THE PERIOD OF THE <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> ALGOL-THE RAGING ONE?</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jetsu, L.; Porceddu, S.; Lyytinen, J.; Kajatkari, P.; Lehtinen, J.; Markkanen, T.; Toivari-Viitala, J.</p> <p>2013-08-10</p> <p>The <span class="hlt">eclipses</span> in <span class="hlt">binary</span> stars give precise information of orbital period changes. Goodricke discovered the 2.867 day period in the <span class="hlt">eclipses</span> of Algol in the year 1783. The irregular orbital period changes of this longest known <span class="hlt">eclipsing</span> <span class="hlt">binary</span> continue to puzzle astronomers. The mass transfer between the two members of this <span class="hlt">binary</span> should cause a long-term increase of the orbital period, but observations over two centuries have not confirmed this effect. Here, we present evidence indicating that the period of Algol was 2.850 days three millennia ago. For religious reasons, the ancient Egyptians have recorded this period into the Cairo Calendar (CC), which describes the repetitive changes of the Raging one. CC may be the oldest preserved historical document of the discovery of a variable star.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013ApJ...773....1J&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013ApJ...773....1J&link_type=ABSTRACT"><span id="translatedtitle">Did the Ancient Egyptians Record the Period of the <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Algol—The Raging One?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jetsu, L.; Porceddu, S.; Lyytinen, J.; Kajatkari, P.; Lehtinen, J.; Markkanen, T.; Toivari-Viitala, J.</p> <p>2013-08-01</p> <p>The <span class="hlt">eclipses</span> in <span class="hlt">binary</span> stars give precise information of orbital period changes. Goodricke discovered the 2.867 day period in the <span class="hlt">eclipses</span> of Algol in the year 1783. The irregular orbital period changes of this longest known <span class="hlt">eclipsing</span> <span class="hlt">binary</span> continue to puzzle astronomers. The mass transfer between the two members of this <span class="hlt">binary</span> should cause a long-term increase of the orbital period, but observations over two centuries have not confirmed this effect. Here, we present evidence indicating that the period of Algol was 2.850 days three millennia ago. For religious reasons, the ancient Egyptians have recorded this period into the Cairo Calendar (CC), which describes the repetitive changes of the Raging one. CC may be the oldest preserved historical document of the discovery of a variable star.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008MNRAS.391..343P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008MNRAS.391..343P"><span id="translatedtitle">MOST satellite photometry of stars in the M67 field: <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>, blue stragglers and δ Scuti variables</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pribulla, Theodor; Rucinski, Slavek; Matthews, Jaymie M.; Kallinger, Thomas; Kuschnig, Rainer; Rowe, Jason F.; Guenther, David B.; Moffat, Anthony F. J.; Sasselov, Dimitar; Walker, Gordon A. H.; Weiss, Werner W.</p> <p>2008-11-01</p> <p>We present two series of MOST (Microvariability and Oscillations of STars) space-based photometry, covering nearly continuously 10 d in 2004 and 30 d in 2007, of selected variable stars in the upper main sequence of the old open cluster M67. New high-precision light curves were obtained for the blue straggler <span class="hlt">binary</span>/triple systems AH Cnc, ES Cnc and EV Cnc. The precision and phase coverage of ES Cnc and EV Cnc is by far superior to any previous observations. The light curve of ES Cnc is modelled in detail, assuming two dark photospheric spots and Roche geometry. An analysis of the light curve of AH Cnc indicates a <span class="hlt">low</span> <span class="hlt">mass</span> ratio (q ~ 0.13) and a high inclination angle for this system. Two new long-period <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>, GSC 814-323 and HD 75638 (non-members of M67) were discovered. We also present ground-based DDO spectroscopy of ES Cnc and of the newly found <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>. Especially interesting is HD 75638, a member of a visual <span class="hlt">binary</span>, which must itself be a triple or a higher multiplicity system. New light curves of two δ Scuti pulsators, EX Cnc and EW Cnc, have been analysed leading to detection of 26 and eight pulsation frequencies of high temporal stability. Based on photometric data from MOST, a Canadian Space Agency mission (jointly operated by Dynacon Inc., the University of Toronto Institute for Aerospace Studies and the University of British Columbia, with the assistance of the University of Vienna), and on spectroscopic data from the David Dunlap Observatory, University of Toronto. E-mail: pribulla@ta3.sk (TP); rucinski@astro.utoronto.ca (SR)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AAS...21934518D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012AAS...21934518D&link_type=ABSTRACT"><span id="translatedtitle">Wide <span class="hlt">Low-Mass</span> Tertiary Companions of <span class="hlt">Binary</span> Star Systems as a Test of Star Formation Theories</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Douglas, Stephanie; Allen, P.</p> <p>2012-01-01</p> <p>We will present the status of a common proper motion search for wide <span class="hlt">low-mass</span> stellar and sub-stellar companions to known white dwarf-M dwarf <span class="hlt">binary</span> systems. I-band observations were made using the 31" NURO telescope at Lowell Observatory. Candidate companions are selected using astrometry from our own data and 2MASS photometry. We have begun to spectroscopically confirm candidates that pass our selection criteria. The ultimate goal of the search is to test star formation theories which predict that close <span class="hlt">binary</span> systems form by transferring angular momentum to a third companion. To this end, we will model the physical companion population and perform Bayesian statistical analysis to determine the best-fit population model to our data. Here we will present our spectroscopically confirmed companions as well as the preliminary results of our population models and statistical analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010A%26A...509A..70V&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010A%26A...509A..70V&link_type=ABSTRACT"><span id="translatedtitle">The distance to the Andromeda galaxy from <span class="hlt">eclipsing</span> <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vilardell, F.; Ribas, I.; Jordi, C.; Fitzpatrick, E. L.; Guinan, E. F.</p> <p>2010-01-01</p> <p>The cosmic distance scale largely depends on distance determinations to galaxies of the Local Group. In this sense, the Andromeda galaxy (M 31) is a key rung to better constrain the cosmic distance ladder. A project was started in 1999 to firmly establish a direct and accurate distance to M 31 using <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> (EBs). After the determination of the first direct distance to M 31 from EBs, the second direct distance to an EB system is presented: M31V J00443610+4129194. Light and radial velocity curves were obtained and fitted to derive the masses and radii of the components. The acquired spectra were combined and disentangled to determine the temperature of the components. The analysis of the studied EB resulted in a distance determination to M 31 of (m-M)0 = 24.30 ± 0.11 mag. This result, when combined with the previous distance determination to M 31, results in a distance modulus of (m-M)0 = 24.36 ± 0.08 mag (744 ± 33 kpc), fully compatible with other distance determinations to M 31. With an error of only 4%, the obtained value firmly establishes the distance to this important galaxy and represents the fulfillment of the main goal of our project. Based on observations made with the Isaac Newton Telescope operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina)Original data are only available in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AAS...22211505S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AAS...22211505S"><span id="translatedtitle">Photometric Observations of the Totally <span class="hlt">Eclipsing</span>, Solar Type <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span>, DK Andromedae</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Samec, Ronald G.; Faulkner, D. R.; Van Hamme, W. V.; Kring, J.</p> <p>2013-06-01</p> <p>We present the first precision BVRI light curves, synthetic light curve solutions and a period study for the Sonneberg variable, DK And. Observations were taken with the NURO 0.81-m Lowell reflector on 24, 25 and 27 September and 26 October and 01 November 2011 with the SARA 0.9-m reflector. Our light curves were premodeled with <span class="hlt">Binary</span> Maker 3.0, and solved with the Wilson-Devinney program. Our observations included 374 B, 372 V, 392 R and 394 I individual and calibrated observations. These were taken with the NURO, Lowell 2KX2K NASACAM, and the SARA 1KX1K Apogee camera. Six mean times of minimum light were determined, includingHJDMin I= 2455866.8222(±0.0003), 2455828.6632(±0.0001), 2455829.6405(±0.0097), and HJDMin II=2455866.5782(±0.0007), 2455860.6970(±0.0053) and 2455828.9081(±0.0004). Thirty-one timings taken over 73 years are included in our ephemeris calculation: J.D. Hel Min I = 2451435.4330(±0.0011)d + 0.48922346(±0.00000015)×E + 2.4(±0.4)×10-11×E2 For conservative mass transfer, the positive quadratic term means that the more massive star is the gainer. Our light curves shows a time of constant light in the secondary <span class="hlt">eclipse</span> of 28 minutes making this an A-type W UMa system. The amplitude of the light curves are about 0.5 mags in V. The light curve solution reveals a rather extreme mass ratio of 0.32, a component temperature difference of ~300K, and an inclination of 82.5°. The curves show the effects of dark spot activity. We thank USC, Lancaster for their support of our membership in NURO for the past 8 years, the American Astronomical Society for its support through its small research program and Arizona Space grant for the partial support for our student’s travel.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22034369','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22034369"><span id="translatedtitle"><span class="hlt">LOW-MASS</span> TERTIARY COMPANIONS TO SPECTROSCOPIC <span class="hlt">BINARIES</span>. I. COMMON PROPER MOTION SURVEY FOR WIDE COMPANIONS USING 2MASS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Allen, Peter R.; Burgasser, Adam J.; Faherty, Jacqueline K.; Kirkpatrick, J. Davy</p> <p>2012-08-15</p> <p>We report the first results of a multi-epoch search for wide (separations greater than a few tens of AU), <span class="hlt">low-mass</span> tertiary companions of a volume-limited sample of 118 known spectroscopic <span class="hlt">binaries</span> within 30 pc of the Sun, using the Two Micron All Sky Survey Point Source Catalog and follow-up observations with the KPNO and CTIO 4 m telescopes. Note that this sample is not volume complete but volume limited, and, thus, there is incompleteness in our reported companion rates. We are sensitive to common proper motion companions with separations from roughly 200 AU to 10,000 AU ({approx}10'' {yields} {approx} 10'). From 77 sources followed-up to date, we recover 11 previously known tertiaries, 3 previously known candidate tertiaries, of which 2 are spectroscopically confirmed and 1 rejected, and 3 new candidates, of which 2 are confirmed and 1 rejected. This yields an estimated wide tertiary fraction of 19.5{sup +5.2}{sub -3.7}%. This observed fraction is consistent with predictions set out in star formation simulations where the fraction of wide, <span class="hlt">low-mass</span> companions to spectroscopic <span class="hlt">binaries</span> is >10%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22133965','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22133965"><span id="translatedtitle">HIGH RESOLUTION H{alpha} IMAGES OF THE <span class="hlt">BINARY</span> <span class="hlt">LOW-MASS</span> PROPLYD LV 1 WITH THE MAGELLAN AO SYSTEM</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wu, Y.-L.; Close, L. M.; Males, J. R.; Follette, K.; Morzinski, K.; Kopon, D.; Rodigas, T. J.; Hinz, P.; Puglisi, A.; Esposito, S.; Pinna, E.; Riccardi, A.; Xompero, M.; Briguglio, R.</p> <p>2013-09-01</p> <p>We utilize the new Magellan adaptive optics system (MagAO) to image the <span class="hlt">binary</span> proplyd LV 1 in the Orion Trapezium at H{alpha}. This is among the first AO results in visible wavelengths. The H{alpha} image clearly shows the ionization fronts, the interproplyd shell, and the cometary tails. Our astrometric measurements find no significant relative motion between components over {approx}18 yr, implying that LV 1 is a <span class="hlt">low-mass</span> system. We also analyze Large Binocular Telescope AO observations, and find a point source which may be the embedded protostar's photosphere in the continuum. Converting the H magnitudes to mass, we show that the LV 1 <span class="hlt">binary</span> may consist of one very-<span class="hlt">low-mass</span> star with a likely brown dwarf secondary, or even plausibly a double brown dwarf. Finally, the magnetopause of the minor proplyd is estimated to have a radius of 110 AU, consistent with the location of the bow shock seen in H{alpha}.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21583012','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21583012"><span id="translatedtitle">EXPECTED LARGE SYNOPTIC SURVEY TELESCOPE (LSST) YIELD OF <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> STARS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Prsa, Andrej; Pepper, Joshua; Stassun, Keivan G.</p> <p>2011-08-15</p> <p>In this paper, we estimate the Large Synoptic Survey Telescope (LSST) yield of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars, which will survey {approx}20,000 deg{sup 2} of the southern sky during a period of 10 years in six photometric passbands to r {approx} 24.5. We generate a set of 10,000 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> light curves sampled to the LSST time cadence across the whole sky, with added noise as a function of apparent magnitude. This set is passed to the analysis-of-variance period finder to assess the recoverability rate for the periods, and the successfully phased light curves are passed to the artificial-intelligence-based pipeline ebai to assess the recoverability rate in terms of the <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>' physical and geometric parameters. We find that, out of {approx}24 million <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> observed by LSST with a signal-to-noise ratio >10 in mission lifetime, {approx}28% or 6.7 million can be fully characterized by the pipeline. Of those, {approx}25% or 1.7 million will be double-lined <span class="hlt">binaries</span>, a true treasure trove for stellar astrophysics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015A%26A...578A.125H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015A%26A...578A.125H"><span id="translatedtitle">Search with UVES and X-Shooter for signatures of the <span class="hlt">low-mass</span> secondary in the post common-envelope <span class="hlt">binary</span> AA Doradus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hoyer, D.; Rauch, T.; Werner, K.; Hauschildt, P. H.; Kruk, J. W.</p> <p>2015-06-01</p> <p>Context. AA Dor is a close, totally <span class="hlt">eclipsing</span>, post common-envelope <span class="hlt">binary</span> with an sdOB-type primary star and an extremely <span class="hlt">low-mass</span> secondary star, located close to the mass limit of stable central hydrogen burning. Within error limits, it may either be a brown dwarf or a late M-type dwarf. Aims: We aim to extract the secondary's contribution to the phase-dependent composite spectra. The spectrum and identified lines of the secondary decide on its nature. Methods: In January 2014, we measured the phase-dependent spectrum of AA Dor with X-Shooter over one complete orbital period. Since the secondary's rotation is presumable synchronized with the orbital period, its surface strictly divides into a day and night side. Therefore, we may obtain the spectrum of its cool side during its transit and of its hot, irradiated side close to its occultation. We developed the Virtual Observatory (VO) tool TLISA to search for weak lines of a faint companion in a <span class="hlt">binary</span> system. We successfully applied it to the observations of AA Dor. Results: We identified 53 spectral lines of the secondary in the ultraviolet-blue, visual, and near-infrared X-Shooter spectra that are strongest close to its occultation. We identified 57 (20 additional) lines in available Ultraviolet and Visual Echelle Spectrograph (UVES) spectra from 2001. The lines are mostly from C ii-iii and O ii, typical for a <span class="hlt">low-mass</span> star that is irradiated and heated by the primary. We verified the orbital period of P = 22 597.033201 ± 0.00007 s and determined the orbital velocity K_sec = 232.9+16.6-6.5 km s-1 of the secondary. The mass of the secondary is M_sec = 0.081+0.018-0.010 M_⊙ and, hence, it is not possible to reliably determine a brown dwarf or an M-type dwarf nature. Conclusions: Although we identified many emission lines of the secondary's irradiated surface, the resolution and signal-to-noise ratio of our UVES and X-Shooter spectra are not good enough to extract a good spectrum of the secondary</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016IAUS..314...65F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016IAUS..314...65F"><span id="translatedtitle">A New, Young, <span class="hlt">Low-Mass</span> Spectroscopic <span class="hlt">Binary</span> Without a Home</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Flagg, Laura S.; Shkolnik, Evgenya L.; Weinberger, Alycia J.; Bowler, Brendan P.; Kraus, Adam L.; Liu, Michael C.</p> <p>2016-01-01</p> <p>We have discovered that 2MASS 08355977-3042306 is an accreting K7, double-lined, spectroscopic <span class="hlt">binary</span> younger than ~20 Myr. The age of a dispersed young star can best be determined if it is a member of a known young moving group. However, the three dimensional space velocities (UVW) we calculate using radial velocity measurements, proper motions, and plausible photometric distances make membership in any known young moving group unlikely.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22370378','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22370378"><span id="translatedtitle">SpeX spectroscopy of unresolved very <span class="hlt">low</span> <span class="hlt">mass</span> <span class="hlt">binaries</span>. II. Identification of 14 candidate <span class="hlt">binaries</span> with late-M/early-L and T dwarf components</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bardalez Gagliuffi, Daniella C.; Burgasser, Adam J.; Nicholls, Christine P.; Gelino, Christopher R.; Looper, Dagny L.; Schmidt, Sarah J.; Cruz, Kelle; West, Andrew A.; Gizis, John E.; Metchev, Stanimir</p> <p>2014-10-20</p> <p>Multiplicity is a key statistic for understanding the formation of very <span class="hlt">low</span> <span class="hlt">mass</span> (VLM) stars and brown dwarfs. Currently, the separation distribution of VLM <span class="hlt">binaries</span> remains poorly constrained at small separations (≤1 AU), leading to uncertainty in the overall <span class="hlt">binary</span> fraction. We approach this problem by searching for late-M/early-L plus T dwarf spectral <span class="hlt">binaries</span> whose combined light spectra exhibit distinct peculiarities, allowing for separation-independent identification. We define a set of spectral indices designed to identify these systems, and we use a spectral template fitting method to confirm and characterize spectral <span class="hlt">binary</span> candidates from a library of 815 spectra from the SpeX Prism Spectral Libraries. We present 11 new <span class="hlt">binary</span> candidates, confirm 3 previously reported candidates, and rule out 2 previously identified candidates, all with primary and secondary spectral types in the range M7-L7 and T1-T8, respectively. We find that subdwarfs and blue L dwarfs are the primary contaminants in our sample and propose a method for segregating these sources. If confirmed by follow-up observations, these systems may add to the growing list of tight separation <span class="hlt">binaries</span>, whose orbital properties may yield further insight into brown dwarf formation scenarios.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013A%26A...549A..95Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013A%26A...549A..95Z"><span id="translatedtitle">Origin of apparent period variations in <span class="hlt">eclipsing</span> post-common-envelope <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zorotovic, M.; Schreiber, M. R.</p> <p>2013-01-01</p> <p>Context. Apparent period variations detected in several <span class="hlt">eclipsing</span>, close-compact <span class="hlt">binaries</span> are frequently interpreted as being caused by circumbinary giant planets. This interpretation raises the question of the origin of the potential planets that must have either formed in the primordial circumbinary disk, together with the host <span class="hlt">binary</span> star, and survived its evolution into a close-compact <span class="hlt">binary</span> or formed in a post-common-envelope circumbinary disk that remained bound to the post-common-envelope <span class="hlt">binary</span> (PCEB). Aims: Here we combine current knowledge of planet formation and the statistics of giant planets around primordial and evolved <span class="hlt">binary</span> stars with the theory of close-compact <span class="hlt">binary</span> star evolution aiming to derive new constraints on possible formation scenarios. Methods: We compiled a comprehensive list of observed <span class="hlt">eclipsing</span> PCEBs, estimated the fraction of systems showing apparent period variations, reconstructed the evolutionary history of the PCEBs, and performed <span class="hlt">binary</span> population models of PCEBs to characterize their main sequence <span class="hlt">binary</span> progenitors. We reviewed the currently available constraints on the fraction of PCEB progenitors that host circumbinary giant planets. Results: We find that the progenitors of PCEBs are very unlikely to be frequent hosts of giant planets (≲10 per cent), while the frequency of PCEBs with observed apparent period variations is very high (~90 per cent). Conclusions: The variations in <span class="hlt">eclipse</span> timings measured in <span class="hlt">eclipsing</span> PCEBs are probably not caused by first-generation planets that survived common-envelope evolution. The remaining options for explaining the observed period variations are second-generation planet formation or perhaps variations in the shape of a magnetically active secondary star. We suggest observational tests for both options. Appendix A is available in electronic form at http://www.aanda.org</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.461.2896H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.461.2896H"><span id="translatedtitle">HIDES spectroscopy of bright detached <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> from the Kepler field - I. Single-lined objects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hełminiak, K. G.; Ukita, N.; Kambe, E.; Kozłowski, S. K.; Sybilski, P.; Ratajczak, M.; Maehara, H.; Konacki, M.</p> <p>2016-09-01</p> <p>We present results of our spectroscopic observations of nine detached <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> (DEBs), selected from the Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Catalog, that only show one set of spectral lines. Radial velocities (RVs) were calculated from the high-resolution spectra obtained with the HIgh-Dispersion Echelle Spectrograph (HIDES) instrument, attached to the 1.88-m telescope at the Okayama Astrophysical Observatory, and from the public Apache Point Observatory Galactic Evolution Experiment archive. In our sample, we found five single-lined <span class="hlt">binaries</span>, with one component dominating the spectrum. The orbital and light-curve solutions were found for four of them, and compared with isochrones, in order to estimate absolute physical parameters and evolutionary status of the components. For the fifth case, we only update the orbital parameters, and estimate the properties of the unseen star. Two other systems show orbital motion with a period known from the <span class="hlt">eclipse</span> timing variations (ETVs). For these we obtained parameters of outer orbits, by translating the ETVs to RVs of the centre of mass of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span>, and combining with the RVs of the outer star. Of the two remaining ones, one is most likely a blend of a faint background DEB with a bright foreground star, which lines we see in the spectra, and the last case is possibly a quadruple bearing a sub-stellar mass object. Where possible, we compare our results with literature, especially with results from asteroseismology. We also report possible detections of solar-like oscillations in our RVs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005Ap%26SS.296..251P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005Ap%26SS.296..251P"><span id="translatedtitle">A New Package of Computer Codes for Analyzing Light Curves of <span class="hlt">Eclipsing</span> Pre-Cataclysmic <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pustynski, V.-V.; Pustylnik, I. B.</p> <p>2005-04-01</p> <p>Using the new package of computer codes for analyzing light curves of the two <span class="hlt">eclipsing</span> pre-cataclysmic <span class="hlt">binary</span> systems (PCBs) UU Sge and V471 Lyr we find updated values of the physical parameters and discuss the evolutionary state of these PCBs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AAS...21541941B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AAS...21541941B"><span id="translatedtitle">Light Curves and Analyses of the <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> EG Cas and EP Cas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bradstreet, David H.; Sanders, S. J.; McClain, T. R.</p> <p>2010-01-01</p> <p>New precision V & Rc light curves of the <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> EG Cas and EP Cas have been obtained using the 41-cm telescope at the Eastern University Observatory equipped with an SBIG ST-10XME CCD. EG Cas (P = 0.6115 days, Vmax = 12.9) has no published light curves and only a few dozen (mostly visual) timings of minimum light. The system is being observed throughout the fall of 2009 and the current light curves distinctly show that the system is a totally <span class="hlt">eclipsing</span> overcontact <span class="hlt">binary</span>. The light curves are also significantly asymmetric (strong O'Connell effect) indicating the presence of large, cool starspots, most likely on both stars. Preliminary analysis indicates that the <span class="hlt">binary</span> is an A-type (the larger, more massive star is the hotter component), has a mass ratio of 0.32, very large temperature difference between the stars greater than 1600 K, and a fillout of 0.26. The modern timings of minimum light combined with those in the literature indicate that the <span class="hlt">binary</span>'s period is decreasing. The large temperature difference coupled to a significant fillout factor seems contradictory, and further data acquisition and analysis will hopefully resolve this seeming enigma. EP Cas (P = 0.8134 days, Vmax = 11.2) is a partially <span class="hlt">eclipsing</span> detached system with a relatively deep primary <span class="hlt">eclipse</span> of 1.0 mag in Rc. No published light curves exist for this system although many timings of minimum light have been published. The O-C curve indicates that the period for the <span class="hlt">binary</span> has remained relatively constant since observations were first published in 1936. Preliminary light curve models indicate a partially <span class="hlt">eclipsing</span> system consisting of detached but tidally distorted stars. The complete light curve analyses as well as a period study of all published times of minimum light will be presented for both systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23803845','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23803845"><span id="translatedtitle">Multi-periodic pulsations of a stripped red-giant star in an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Maxted, Pierre F L; Serenelli, Aldo M; Miglio, Andrea; Marsh, Thomas R; Heber, Ulrich; Dhillon, Vikram S; Littlefair, Stuart; Copperwheat, Chris; Smalley, Barry; Breedt, Elmé; Schaffenroth, Veronika</p> <p>2013-06-27</p> <p><span class="hlt">Low-mass</span> white-dwarf stars are the remnants of disrupted red-giant stars in <span class="hlt">binary</span> millisecond pulsars and other exotic <span class="hlt">binary</span> star systems. Some <span class="hlt">low-mass</span> white dwarfs cool rapidly, whereas others stay bright for millions of years because of stable fusion in thick surface hydrogen layers. This dichotomy is not well understood, so the potential use of <span class="hlt">low-mass</span> white dwarfs as independent clocks with which to test the spin-down ages of pulsars or as probes of the extreme environments in which <span class="hlt">low-mass</span> white dwarfs form cannot fully be exploited. Here we report precise mass and radius measurements for the precursor to a <span class="hlt">low-mass</span> white dwarf. We find that only models in which this disrupted red-giant star has a thick hydrogen envelope can match the strong constraints provided by our data. Very cool <span class="hlt">low-mass</span> white dwarfs must therefore have lost their thick hydrogen envelopes by irradiation from pulsar companions or by episodes of unstable hydrogen fusion (shell flashes). We also find that this <span class="hlt">low-mass</span> white-dwarf precursor is a type of pulsating star not hitherto seen. The observed pulsation frequencies are sensitive to internal processes that determine whether this star will undergo shell flashes. PMID:23803845</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23803845','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23803845"><span id="translatedtitle">Multi-periodic pulsations of a stripped red-giant star in an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Maxted, Pierre F L; Serenelli, Aldo M; Miglio, Andrea; Marsh, Thomas R; Heber, Ulrich; Dhillon, Vikram S; Littlefair, Stuart; Copperwheat, Chris; Smalley, Barry; Breedt, Elmé; Schaffenroth, Veronika</p> <p>2013-06-27</p> <p><span class="hlt">Low-mass</span> white-dwarf stars are the remnants of disrupted red-giant stars in <span class="hlt">binary</span> millisecond pulsars and other exotic <span class="hlt">binary</span> star systems. Some <span class="hlt">low-mass</span> white dwarfs cool rapidly, whereas others stay bright for millions of years because of stable fusion in thick surface hydrogen layers. This dichotomy is not well understood, so the potential use of <span class="hlt">low-mass</span> white dwarfs as independent clocks with which to test the spin-down ages of pulsars or as probes of the extreme environments in which <span class="hlt">low-mass</span> white dwarfs form cannot fully be exploited. Here we report precise mass and radius measurements for the precursor to a <span class="hlt">low-mass</span> white dwarf. We find that only models in which this disrupted red-giant star has a thick hydrogen envelope can match the strong constraints provided by our data. Very cool <span class="hlt">low-mass</span> white dwarfs must therefore have lost their thick hydrogen envelopes by irradiation from pulsar companions or by episodes of unstable hydrogen fusion (shell flashes). We also find that this <span class="hlt">low-mass</span> white-dwarf precursor is a type of pulsating star not hitherto seen. The observed pulsation frequencies are sensitive to internal processes that determine whether this star will undergo shell flashes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.455..739K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.455..739K"><span id="translatedtitle">Observational signatures of neutron stars in <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> climbing a stability peak</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kantor, E. M.; Gusakov, M. E.; Chugunov, A. I.</p> <p>2016-01-01</p> <p>In the recent papers by Gusakov et al., a new scenario describing evolution of rapidly rotating neutron stars (NSs) in <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> was proposed. The scenario accounts for a resonant interaction of normal r-modes with superfluid inertial modes at some specific internal stellar temperatures (`resonance temperatures'). This interaction results in an enhanced damping of r-mode and appearance of the `stability peaks' in the temperature - spin frequency plane, which split the r-mode instability window in the vicinity of the resonance temperatures. The scenario suggests that the hot and rapidly rotating NSs spend most of their life climbing up these peaks and, in particular, are observed there at the moment. We analyse in detail possible observational signatures of this suggestion. In particular, we show that these objects may exhibit `anti-glitches' - sudden frequency jumps on a time-scale of hours-months.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007AAS...211.0309M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007AAS...211.0309M&link_type=ABSTRACT"><span id="translatedtitle">The Infrared Variability of GX17+2 and <span class="hlt">Low-Mass</span> X-ray <span class="hlt">Binary</span> Jets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McNamara, Bernard J.; Bornak, J.; Harrison, T.; Rupen, M.</p> <p>2007-12-01</p> <p>GX17+2 is a <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span>. It is also classified as a Z-source since it exhibits a distinctive Z-pattern in its X-ray color-color plot. GX17+2 is located in the direction of the galactic center and is not detectable at optical wavelengths. Its emission varies by over 4 magnitudes in the infrared. A number of explanations have been advanced to explain this variabilty. Based upon KPNO and Smarts IR observations, we suggest that it arises from a sychrotron jet which is periodically visible along our line of sight. This circumstance provides a rather unique opportunity to quantify a number of jet properties such as its opening angle, the sharpness of the jet boundaries, its variability, and the infrared emission uniformity across the jet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910069004&hterms=hertz&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dhertz','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910069004&hterms=hertz&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dhertz"><span id="translatedtitle">Searches for millisecond pulsations in <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wood, K. S.; Hertz, P.; Norris, J. P.; Vaughan, B. A.; Michelson, P. F.; Mitsuda, K.; Lewin, W. H. G.; Van Paradijs, J.; Penninx, W.; Van Der Klis, M.</p> <p>1991-01-01</p> <p>High-sensitivity search techniques for millisecond periods are presented and applied to data from the Japanese satellite Ginga and HEAO 1. The search is optimized for pulsed signals whose period, drift rate, and amplitude conform with what is expected for low-class X-ray <span class="hlt">binary</span> (LMXB) sources. Consideration is given to how the current understanding of LMXBs guides the search strategy and sets these parameter limits. An optimized one-parameter coherence recovery technique (CRT) developed for recovery of phase coherence is presented. This technique provides a large increase in sensitivity over the method of incoherent summation of Fourier power spectra. The range of spin periods expected from LMXB phenomenology is discussed, the necessary constraints on the application of CRT are described in terms of integration time and orbital parameters, and the residual power unrecovered by the quadratic approximation for realistic cases is estimated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PASJ...67...30S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PASJ...67...30S"><span id="translatedtitle"><span class="hlt">Low-mass</span> X-ray <span class="hlt">binary</span> MAXI J1421-613 observed by MAXI GSC and Swift XRT</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Serino, Motoko; Shidatsu, Megumi; Ueda, Yoshihiro; Matsuoka, Masaru; Negoro, Hitoshi; Yamaoka, Kazutaka; Kennea, Jamie A.; Fukushima, Kosuke; Nagayama, Takahiro</p> <p>2015-04-01</p> <p>Monitor of All sky X-ray Image (MAXI) discovered a new outburst of an X-ray transient source named MAXI J1421-613. Because of the detection of three X-ray bursts from the source, it was identified as a neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span>. The results of data analyses of the MAXI GSC (Gas Slit Camera) and the Swift XRT (X-Ray Telescope) follow-up observations suggest that the spectral hardness remained unchanged during the first two weeks of the outburst. All the XRT spectra in the 0.5-10 keV band can be well explained by thermal Comptonization of multi-color disk blackbody emission. The photon index of the Comptonized component is ≈ 2, which is typical of <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> in the low/hard state. Since X-ray bursts have a maximum peak luminosity, it is possible to estimate the (maximum) distance from its observed peak flux. The peak flux of the second X-ray burst, which was observed by the GSC, is about 5 photons cm-2 s-1. By assuming a blackbody spectrum of 2.5 keV, the maximum distance to the source is estimated as 7 kpc. The position of this source is contained by the large error regions of two bright X-ray sources detected with Orbiting Solar Observatory-7 (OSO-7) in the 1970s. Besides this, no past activities at the XRT position are reported in the literature. If MAXI J1421-613 is the same source as (one of) these, the outburst observed with MAXI may have occurred after a quiescence of 30-40 years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014yCat.5144....0M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014yCat.5144....0M"><span id="translatedtitle">VizieR Online Data Catalog: Near-IR spectroscopy of <span class="hlt">low-mass</span> <span class="hlt">binaries</span> and brown dwarfs (Mace, 2014)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mace, G. N.</p> <p>2014-05-01</p> <p>The mass of a star at formation determines its subsequent evolution and demise. <span class="hlt">Low-mass</span> stars are the most common products of star formation and their long main-sequence lifetimes cause them to accumulate over time. Star formation also produces many substellar-mass objects known as brown dwarfs, which emerge from their natal molecular clouds and continually cool as they age, pervading the Milky Way. <span class="hlt">Low-mass</span> stars and brown dwarfs exhibit a wide range of physical characteristics and their abundance make them ideal subjects for testing formation and evolution models. I have examined a pair of pre-main sequence spectroscopic <span class="hlt">binaries</span> and used radial velocity variations to determine orbital solutions and mass ratios. Additionally, I have employed synthetic spectra to estimate their effective temperatures and place them on theoretical Hertzsprung-Russell diagrams. From this analysis I discuss the formation and evolution of young <span class="hlt">binary</span> systems and place bounds on absolute masses and radii. I have also studied the late-type T dwarfs revealed by the Wide-field Infrared Survey Explorer (WISE). This includes the exemplar T8 subdwarf Wolf 1130C, which has the lowest inferred metallicity in the literature and spectroscopic traits consistent with old age. Comparison to synthetic spectra implies that the dispersion in near-infrared colors of late-type T dwarfs is a result of age and/or thin sul de clouds. With the updated census of the L, T, and Y dwarfs we can now study specific brown dwarf subpopulations. Finally, I present a number of future studies that would develop our understanding of the physical qualities of T dwarf color outliers and disentangle the tracers of age and atmospheric properties. The thesis is available at: http://www.astro.ucla.edu/~gmace/thesis.html (7 data files).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AJ....143..122Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AJ....143..122Y"><span id="translatedtitle">Deep, <span class="hlt">Low-mass</span> Ratio Overcontact <span class="hlt">Binary</span> Systems. XII. CK Bootis with Possible Cyclic Magnetic Activity and Additional Companion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Y.-G.; Qian, S.-B.; Soonthornthum, B.</p> <p>2012-05-01</p> <p>We present precision CCD photometry, a period study, and a two-color simultaneous Wilson code solution of the short-period contact <span class="hlt">binary</span> CK Bootis. The asymmetric light curves were modeled by a dark spot on the primary component. The result identifies that CK Boo is an A-type W UMa <span class="hlt">binary</span> with a high fillout of f = 71.7(± 4.4)%. From the O - C curve, it is found that the orbital period changes in a complicated mode, i.e., a long-term increase with two sinusoidal variations. One cyclic oscillation with a period of 10.67(± 0.20) yr may result from magnetic activity cycles, which are identified by the variability of Max. I - Max. II. Another sinusoidal variation (i.e., A = 0.0131 days(± 0.0009 days) and P 3 = 24.16(± 0.64) yr) may be attributed to the light-time effect due to a third body. This kind of additional companion can extract angular momentum from the central <span class="hlt">binary</span> system. The orbital period secularly increases at a rate of dP/dt = +9.79 (±0.80) × 10-8 days yr-1, which may be interpreted by conservative mass transfer from the secondary to the primary. This kind of deep, <span class="hlt">low-mass</span> ratio overcontact <span class="hlt">binaries</span> may evolve into a rapid-rotating single star, only if the contact configuration do not break down at J spin > (1/3)J orb.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1982Msngr..28...30A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1982Msngr..28...30A"><span id="translatedtitle">A Long Period <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Project - Five Years of Observations at ESO</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ahlin, P.; Sundman, A.</p> <p>1982-06-01</p> <p>The star HO 161387 first caught our eyes when we were reading an article on ~ Aurigae stars by K. O. Wright in Vistas in Astronomy No. 12. This was some 8 or 9 years ago. Aurigae stars are <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> formed by a cool supergiant K star and a very much smaller and holter mainsequence (more or less normal) B star. Out of <span class="hlt">eclipse</span> the B star dominates the blue spectral region, but a pure K-type spectrum is found in <span class="hlt">eclipse</span>. The drastic spectral changes lor HO 161387 can be seen in Fig 1c and 1d. Periods for these <span class="hlt">binaries</span> are in the range of 2 to 10 years. The general benefit 01 ~ Aurigae star studies is the possibility of direct determination 01 physical parameters of the components such as masses and radii. In practice, what one does observe is the change in radial velocity of the stars as they orbit around their common centre 01 gravity and the change in magnitude as the light from the B star is <span class="hlt">eclipsed</span> by the K supergiant. There is also the possibility of studying the structure of the atmosphere of a K supergiant manifested by spectral changes occurring as the point light of the B star shines through the outer parts of the K star c1ose to the total <span class="hlt">eclipse</span>. Besides Aurigae itsell only the stars 31 and 32 Cygni have been studied in greater detail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013JAVSO..41...97A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013JAVSO..41...97A&link_type=ABSTRACT"><span id="translatedtitle">Simultaneous CCD Photometry of Two <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Stars in Pegasus - Part 1: KW Pegasi</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alton, K. B.</p> <p>2013-06-01</p> <p>The coincidental location of BX Peg and KW Peg in the same field-of-view captured by the primary imaging system at UnderOak Observatory (UO) provided an opportunity to study both variable stars from the same exposures. Herein new findings for the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> KW Peg will be presented while those from BX Peg will be discussed in a separate paper (Part 2). KW Peg, described as an "Algol type" <span class="hlt">eclipsing</span> variable (P = 0.816402 d), is only reported in a single work published over twenty years ago. Photometric data collected in three bandpasses (B, V, and Ic), produced eight new times of minimum for KW Peg. These were used to update the linear ephemeris and further analyze potential changes in orbital periodicity by examining the available history of <span class="hlt">eclipse</span> timings. In addition, synthetic fitting of light curves by Roche modeling was accomplished with programs employing the Wilson-Devinney code. Results from the present study provide a reasonable case for classifying KW Peg as a short-period RS CVn <span class="hlt">eclipsing</span> <span class="hlt">binary</span> rather than Algol-like. The primary star in KW Peg would appear to be a late stage G9V-K0V dwarf whereas the secondary is a slightly cooler K0-K1 companion. The <span class="hlt">eclipse</span>-timing diagram for KW Peg is quite simple and indicates that, on average, the orbital period for this system has remained fairly constant over the past two decades.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22122885','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22122885"><span id="translatedtitle">ANALYSIS OF DETACHED <span class="hlt">ECLIPSING</span> <span class="hlt">BINARIES</span> NEAR THE TURNOFF OF THE OPEN CLUSTER NGC 7142</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sandquist, Eric L.; Serio, Andrew W.; Orosz, Jerome; Shetrone, Matthew E-mail: aserio@gemini.edu E-mail: shetrone@astro.as.utexas.edu</p> <p>2013-08-01</p> <p>We analyze extensive BVR{sub C}I{sub C} photometry and radial velocity measurements for three double-lined deeply <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars in the field of the old open cluster NGC 7142. The short period (P = 1.9096825 days) detached <span class="hlt">binary</span> V375 Cep is a high probability cluster member, and has a total <span class="hlt">eclipse</span> of the secondary star. The characteristics of the primary star (M = 1.288 {+-} 0.017 M{sub Sun }) at the cluster turnoff indicate an age of 3.6 Gyr (with a random uncertainty of 0.25 Gyr), consistent with earlier analysis of the color-magnitude diagram. The secondary star (M = 0.871 {+-} 0.008 M{sub Sun }) is not expected to have evolved significantly, but its radius is more than 10% larger than predicted by models. Because this <span class="hlt">binary</span> system has a known age, it is useful for testing the idea that radius inflation can occur in short period <span class="hlt">binaries</span> for stars with significant convective envelopes due to the inhibition of energy transport by magnetic fields. The brighter star in the <span class="hlt">binary</span> also produces a precision estimate of the distance modulus, independent of reddening estimates: (m - M){sub V} = 12.86 {+-} 0.07. The other two <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems are not cluster members, although one of the systems (V2) could only be conclusively ruled out as a present or former member once the stellar characteristics were determined. That <span class="hlt">binary</span> is within 0. Degree-Sign 5 of edge-on, is in a fairly long-period eccentric <span class="hlt">binary</span>, and contains two almost indistinguishable stars. The other <span class="hlt">binary</span> (V1) has a small but nonzero eccentricity (e = 0.038) in spite of having an orbital period under 5 days.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013hell.confS..45P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013hell.confS..45P"><span id="translatedtitle">An automated search of O'Connell effect for Large Numbers of <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Papageorgiou, A.; Kleftogiannis, G.; Christopoulou, P. E.</p> <p>2013-09-01</p> <p>The O'Connell effect in <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems (unequally high maxima) has stood for many decades as one of the most perplexing challenges in <span class="hlt">binary</span> studies. So far, this simple asymmetry has not been convincingly explained, but most theories attribute the effect to dynamic phenomena such as migrating star-spots or swirling circumstellar gas and dust. Nevertheless there has been no clear demonstration of a correlation between the assumptions of any one theory and the morphology of physical parameters of <span class="hlt">binary</span> systems that exhibit O'Connell effect. We have developed an automated program that characterizes the morphology of light curves by depth of both minima, height of both maxima and curvature outside the <span class="hlt">eclipses</span>. In terms of programming it is being developed in FORTRAN and PYTHON. This project results from realization of two needs, both related to recent discoveries of large number of contact <span class="hlt">binaries</span>. Thus the first need is of a simple method to obtain essential parameters for these systems, without the necessity of full light-curve synthesis solution. The second is a statistical one: we would like to extract information from light curves with the use of coefficients that describe the asymmetry in the light curve maxima and the overall shape in the growing observational data of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> (OGLE, ASAS, KEPLER, GAIA). Before applying the automated program several complications must be addressed, as eccentricity, quality of data with many outlying points, limitations to the classification method already applied.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AN....330..504R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AN....330..504R"><span id="translatedtitle">Photometric analysis of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> 2MASS 19090585+4911585</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Raetz, St.; Vaňko, M.; Mugrauer, M.; Schmidt, T. O. B.; Roell, T.; Eisenbeiss, T.; Hohle, M. M.; Koeltzsch, A.; Ginski, Ch.; Marka, C.; Moualla, M.; Tetzlaff, N.; Broeg, Ch.; Neuhäuser, R.</p> <p>2009-05-01</p> <p>We report on observations of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> 2MASS 19090585+4911585 with the 25 cm auxiliary telescope of the University Observatory Jena. We show that a nearby brighter star (2MASS 19090783+4912085) was previously misclassified as the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> and find 2MASS 19090585+4911585 to be the true source of variation. We present photometric analysis of V RI light curves. The system is an overcontact <span class="hlt">binary</span> of W UMa type with an orbital period of (0.288374 ± 0.000010) d. Based on observations obtained with telescopes of the University Observatory Jena, which is operated by the Astrophysical Institute of the Friedrich-Schiller-University Jena.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22521892','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22521892"><span id="translatedtitle">HII 2407: AN <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> REVEALED BY K2 OBSERVATIONS OF THE PLEIADES</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>David, Trevor J.; Hillenbrand, Lynne A.; Zhang, Celia; Riddle, Reed L.; Stauffer, John; Rebull, L. M.; Cody, Ann Marie; Conroy, Kyle; Stassun, Keivan G.; Pope, Benjamin; Aigrain, Suzanne; Gillen, Ed; Cameron, Andrew Collier; Barrado, David; Isaacson, Howard; Marcy, Geoffrey W.; Ziegler, Carl; Law, Nicholas M.; Baranec, Christoph</p> <p>2015-11-20</p> <p>The star HII 2407 is a member of the relatively young Pleiades star cluster and was previously discovered to be a single-lined spectroscopic <span class="hlt">binary</span>. It is newly identified here within Kepler/K2 photometric time series data as an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system. Mutual fitting of the radial velocity and photometric data leads to an orbital solution and constraints on fundamental stellar parameters. While the primary has arrived on the main sequence, the secondary is still pre-main sequence and we compare our results for the M/M{sub ⊙} and R/R{sub ⊙} values with stellar evolutionary models. We also demonstrate that the system is likely to be tidally synchronized. Follow-up infrared spectroscopy is likely to reveal the lines of the secondary, allowing for dynamically measured masses and elevating the system to benchmark <span class="hlt">eclipsing</span> <span class="hlt">binary</span> status.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/940893','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/940893"><span id="translatedtitle"><span class="hlt">Eclipsing</span> <span class="hlt">binary</span> stars in the Large and Small Magellanic Clouds from the MACHO project: The Sample</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Faccioli, L; Alcock, C; Cook, K; Prochter, G; Protopapas, P; Syphers, D</p> <p>2007-03-29</p> <p>We present a new sample of 4634 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars in the Large Magellanic Cloud (LMC), expanding on a previous sample of 611 objects and a new sample of 1509 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars in the Small Magellanic Cloud (SMC), that were identified in the light curve database of the MACHO project. We perform a cross correlation with the OGLE-II LMC sample, finding 1236 matches. A cross correlation with the OGLE-II SMC sample finds 698 matches. We then compare the LMC subsamples corresponding to center and the periphery of the LMC and find only minor differences between the two populations. These samples are sufficiently large and complete that statistical studies of the <span class="hlt">binary</span> star populations are possible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AAS...204.0512B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AAS...204.0512B"><span id="translatedtitle">Six Years of HST/STIS Observations of the <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> VV Cephei</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bennett, P. D.; Brown, A.; Bauer, W. H.</p> <p>2004-05-01</p> <p>VV Cephei (M2 Iab + B0.5 V) is the brightest M supergiant in an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system in the sky (V=4.90). Its orbital period of 20.3 years is one of the longest known for an <span class="hlt">eclipsing</span> <span class="hlt">binary</span>. This system is of great interest because of the possible use of the <span class="hlt">eclipse</span>-mapping technique developed for the ζ Aurigae <span class="hlt">binaries</span> to construct empirical models of the M supergiant's extended atmosphere and wind. The method uses circumstellar absorption and scattering features seen superimposed on the early-type companion's continuum near <span class="hlt">eclipse</span> (when the hot companion passes behind the cool supergiant) to map absorber column densities along the line of sight. During ingress, the line of sight to the hot companion sweeps through increasingly thick layers of the M supergiant's chromosphere prior to second contact; this sequence proceeds again in reverse during egress. Observing in the ultraviolet is particularly advantageous since there the cool supergiant contributes negligibly to the flux, thereby avoiding the problem of disentangling composite spectra. To this end, we have obtained HST/STIS echelle observations of the ultraviolet spectrum of VV Cep at 21 epochs over a 6-year period from mid-<span class="hlt">eclipse</span> in late 1997 through quadrature in 2003. The application of the <span class="hlt">eclipse</span>-mapping technique to VV Cep is not straightforward. The high mass loss rate and corresponding massive wind column densities produce a complex, heavily blended forest of circumstellar absorption lines, mainly from singly-ionized iron group elements. Accretion near the hot companion produces additional absorption and a highly-variable accretion continuum. Nevertheless, the science objectives of the project have been realized: there are sufficient, unblended lines of appropriate strengths (near optical depth unity) to permit the reconstruction of column-density maps along the various sightlines, and thus the construction of detailed models of the supergiant's chromosphere and wind. We show some sample</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IAUGA..2256344Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IAUGA..2256344Y"><span id="translatedtitle">Doubled-lined <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system KIC~2306740 with pulsating component discovered from Kepler space photometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yakut, Kadri</p> <p>2015-08-01</p> <p>We present a detailed study of KIC 2306740, an eccentric double-lined <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system with a pulsating component.Archive Kepler satellite data were combined with newly obtained spectroscopic data with 4.2\\,m William Herschel Telescope(WHT). This allowed us to determine rather precise orbital and physical parameters of this long period, slightly eccentric, pulsating <span class="hlt">binary</span> system. Duplicity effects are extracted from the light curve in order to estimate pulsation frequencies from the residuals.We modelled the detached <span class="hlt">binary</span> system assuming non-conservative evolution models with the Cambridge STARS(TWIN) code.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985PASP...97..584B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985PASP...97..584B"><span id="translatedtitle">Absolute parameters of stars in semidetached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Budding, E.</p> <p>1985-06-01</p> <p>A number of questions concerning the absolute parameters of stars in semidetached <span class="hlt">binary</span> systems are addressed. Consideration is given to: similarities between Algol-type <span class="hlt">binaries</span> and unevolved detached <span class="hlt">binaries</span> with respect to the mass-luminosity law; and the single-line classical Algol candidates with known mass functions and photometric solutions for mass ratio. It is shown that the validity of the mass luminosity-law cannot be verified for individual Algol-type <span class="hlt">binaries</span> though it does hold well on average; and (2), the existence of a definite class of sd-<span class="hlt">binaries</span> not containing a proportion of significantly undersize types is apparent. The conclusions are found to be in general agreement with the observations of Hall and Neff (1979).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...826...70D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...826...70D"><span id="translatedtitle">The Reverberation Lag in the <span class="hlt">Low-mass</span> X-ray <span class="hlt">Binary</span> H1743-322</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>De Marco, Barbara; Ponti, Gabriele</p> <p>2016-07-01</p> <p>The evolution of the inner accretion flow of a black hole X-ray <span class="hlt">binary</span> during an outburst is still a matter of active research. X-ray reverberation lags are powerful tools for constraining disk-corona geometry. We present a study of X-ray lags in the black hole transient H1743-322. We compared the results obtained from analysis of all the publicly available XMM-Newton observations. These observations were carried out during two different outbursts that occurred in 2008 and 2014. During all the observations the source was caught in the hard state and at similar luminosities ({L}3-10{keV}/{L}{Edd}˜ 0.004). We detected a soft X-ray lag of ˜60 ms, most likely due to thermal reverberation. We did not detect any significant change of the lag amplitude among the different observations, indicating a similar disk-corona geometry at the same luminosity in the hard state. On the other hand, we observe significant differences between the reverberation lag detected in H1743-322 and in GX 339-4 (at similar luminosities in the hard state), which might indicate variations of the geometry from source to source.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012MNRAS.420.3281P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012MNRAS.420.3281P"><span id="translatedtitle">A precision study of two <span class="hlt">eclipsing</span> white dwarf plus M dwarf <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parsons, S. G.; Marsh, T. R.; Gänsicke, B. T.; Rebassa-Mansergas, A.; Dhillon, V. S.; Littlefair, S. P.; Copperwheat, C. M.; Hickman, R. D. G.; Burleigh, M. R.; Kerry, P.; Koester, D.; Nebot Gómez-Morán, A.; Pyrzas, S.; Savoury, C. D. J.; Schreiber, M. R.; Schmidtobreick, L.; Schwope, A. D.; Steele, P. R.; Tappert, C.</p> <p>2012-03-01</p> <p>We use a combination of X-shooter spectroscopy, ULTRACAM high-speed photometry and SOFI near-infrared photometry to measure the masses and radii of both components of the <span class="hlt">eclipsing</span> post common envelope <span class="hlt">binaries</span> SDSS J121258.25-012310.1 and GK Vir. For both systems, we measure the gravitational redshift of the white dwarf (WD) and combine it with light-curve model fits to determine the inclinations, masses and radii. For SDSS J1212-0123, we find an inclination of i= 85?7 ± 0?5, masses of MWD= 0.439 ± 0.002 M⊙ and Msec= 0.273 ± 0.002 M⊙, and radii RWD= 0.0168 ± 0.0003 R⊙ and Rsec= 0.306 ± 0.007 R⊙. For GK Vir, we find an inclination of i= 89?5°± 0?6, masses of MWD= 0.564 ± 0.014 M⊙ and Msec= 0.116 ± 0.003 M⊙ and radii RWD= 0.0170 ± 0.0004 R⊙ and Rsec= 0.155 ± 0.003 R⊙. The mass and radius of the WD in GK Vir are consistent with evolutionary models for a 50 000 K carbon-oxygen (CO) core WD. Although the mass and radius of the WD in SDSS J1212-0123 are consistent with CO core models, evolutionary models imply that a WD with such a <span class="hlt">low</span> <span class="hlt">mass</span> and in a short period <span class="hlt">binary</span> must have a helium core. The mass and radius measurements are consistent with helium core models but only if the WD has a very thin hydrogen envelope (MH/MWD≤ 10-6). Such a thin envelope has not been predicted by any evolutionary models. The mass and radius of the secondary star in GK Vir are consistent with evolutionary models after correcting for the effects of irradiation by the WD. The secondary star in SDSS J1212-0123 has a radius ˜9 per cent larger than predicted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...591A.111M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...591A.111M"><span id="translatedtitle">ellc: A fast, flexible light curve model for detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars and transiting exoplanets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maxted, P. F. L.</p> <p>2016-06-01</p> <p>Context. Very high quality light curves are now available for thousands of detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars and transiting exoplanet systems as a result of surveys for transiting exoplanets and other large-scale photometric surveys. Aims: I have developed a <span class="hlt">binary</span> star model (ellc) that can be used to analyse the light curves of detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars and transiting exoplanet systems that is fast and accurate, and that can include the effects of star spots, Doppler boosting and light-travel time within <span class="hlt">binaries</span> with eccentric orbits. Methods: The model represents the stars as triaxial ellipsoids. The apparent flux from the <span class="hlt">binary</span> is calculated using Gauss-Legendre integration over the ellipses that are the projection of these ellipsoids on the sky. The model can also be used to calculate the flux-weighted radial velocity of the stars during an <span class="hlt">eclipse</span> (Rossiter-McLaghlin effect). The main features of the model have been tested by comparison to observed data and other light curve models. Results: The model is found to be accurate enough to analyse the very high quality photometry that is now available from space-spaced instruments, flexible enough to model a wide range of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars and extrasolar planetary systems, and fast enough to enable the use of modern Monte Carlo methods for data analysis and model testing. The software package is available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/591/A111</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730008094','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730008094"><span id="translatedtitle">A computer program for modeling non-spherical <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star systems</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wood, D. B.</p> <p>1972-01-01</p> <p>The accurate analysis of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> light curves is fundamental to obtaining information on the physical properties of stars. The model described accounts for the important geometric and photometric distortions such as rotational and tidal distortion, gravity brightening, and reflection effect. This permits a more accurate analysis of interacting <span class="hlt">eclipsing</span> star systems. The model is designed to be useful to anyone with moderate computing resources. The programs, written in FORTRAN 4 for the IBM 360, consume about 80k bytes of core. The FORTRAN program listings are provided, and the computational aspects are described in some detail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010ASPC..435..101L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010ASPC..435..101L"><span id="translatedtitle">The Algol-Type <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> X Tri: BVRI modeling and O-C Diagram Analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liakos, A.; Zasche, P.; Niarchos, P.</p> <p>2010-12-01</p> <p>CCD photometric observations of the Algol-type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> X Tri have been obtained. The light curves are analyzed with the Wilson-Devinney (WD) code and new geometric and photometric elements are derived. A new O-C analysis of the system, based on the most reliable timings of minima found in the literature, is presented and apparent period changes are discussed with respect to possible and multiple Light-Time Effect (LITE) in the system. Moreover, the results for the existence of additional bodies around the <span class="hlt">eclipsing</span> pair, derived from the period study, are compared with those for extra luminosity, derived from the light curve analysis.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009CoAst.160....2L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009CoAst.160....2L&link_type=ABSTRACT"><span id="translatedtitle">Observations of candidate oscillating <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> and two newly discovered pulsating variables</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liakos, A.; Niarchos, P.</p> <p>2009-03-01</p> <p>CCD observations of 24 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems with spectral types ranging between A0-F0, candidate for containing pulsating components, were obtained. Appropriate exposure times in one or more photometric filters were used so that short-periodic pulsations could be detected. Their light curves were analyzed using the Period04 software in order to search for pulsational behaviour. Two new variable stars, namely GSC 2673-1583 and GSC 3641-0359, were discov- ered as by-product during the observations of <span class="hlt">eclipsing</span> variables. The Fourier analysis of the observations of each star, the dominant pulsation frequencies and the derived frequency spectra are also presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950030867&hterms=atomic+mass+spectra&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Datomic%2Bmass%2Bspectra','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950030867&hterms=atomic+mass+spectra&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Datomic%2Bmass%2Bspectra"><span id="translatedtitle">Emission lines from X-ray-heated accretion disks in <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ko, Yuan-Kuen; Kallman, Timothy R.</p> <p>1994-01-01</p> <p>We investigate the structure of accretion disks illuminated by X-rays from a central compact object in a <span class="hlt">binary</span> system. X-rays can photoionize the upper atmosphere of the disk and form an accretion disk corona (ADC) where emission lines can form. We construct a model to calculate the vertical structure and the emission spectrum of the ADC with parameters appropriate to <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span>. These models are made by nonlocal thermodynamic equilibrium calculations of ion and level populations and include a large number of atomic processes for 10 cosmically abundant elements. Transfer of radiation is treated by using the escape probability formalism. The vertical temperature profile of the ADC consists of a Compton-heated region and a mid-T zone where the temperature is approximately 10(exp 6) K. A thermal instability occurs close to the disk photosphere and causes the temperature of the ADC to drop abruptly from 10(exp 6) K to several times 10(exp 4) K. The emission spectrum in the optical, ultraviolet, extreme ultraviolet, and X-ray range is discussed and compared with the observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22133933','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22133933"><span id="translatedtitle">THE ANTICORRELATED NATURE OF THE PRIMARY AND SECONDARY <span class="hlt">ECLIPSE</span> TIMING VARIATIONS FOR THE KEPLER CONTACT <span class="hlt">BINARIES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tran, K.; Rappaport, S.; Levine, A.; Borkovits, T.; Csizmadia, Sz.; Kalomeni, B. E-mail: aml@space.mit.edu E-mail: szilard.csizmadia@dlr.de</p> <p>2013-09-01</p> <p>We report a study of the <span class="hlt">eclipse</span> timing variations in contact <span class="hlt">binary</span> systems, using long-cadence lightcurves from the Kepler archive. As a first step, observed minus calculated (O - C) curves were produced for both the primary and secondary <span class="hlt">eclipses</span> of some 2000 Kepler <span class="hlt">binaries</span>. We find {approx}390 short-period <span class="hlt">binaries</span> with O - C curves that exhibit (1) random walk-like variations or quasi-periodicities, with typical amplitudes of {+-}200-300 s, and (2) anticorrelations between the primary and secondary <span class="hlt">eclipse</span> timing variations. We present a detailed analysis and results for 32 of these <span class="hlt">binaries</span> with orbital periods in the range of 0.35 {+-} 0.05 days. The anticorrelations observed in their O - C curves cannot be explained by a model involving mass transfer, which, among other things, requires implausibly high rates of {approx}0.01 M{sub Sun} yr{sup -1}. We show that the anticorrelated behavior, the amplitude of the O - C delays, and the overall random walk-like behavior can be explained by the presence of a starspot that is continuously visible around the orbit and slowly changes its longitude on timescales of weeks to months. The quasi-periods of {approx}50-200 days observed in the O - C curves suggest values for k, the coefficient of the latitude dependence of the stellar differential rotation, of {approx}0.003-0.013.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22136569','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22136569"><span id="translatedtitle">WOCS 40007: A DETACHED <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> NEAR THE TURNOFF OF THE OPEN CLUSTER NGC 6819</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jeffries, Mark W. Jr.; Sandquist, Eric L.; Orosz, Jerome A.; Brewer, Lauren N. E-mail: erics@mintaka.sdsu.edu E-mail: lbrewer@rohan.sdsu.edu; and others</p> <p>2013-09-15</p> <p>We analyze extensive BVR{sub c}I{sub c} time-series photometry and radial-velocity measurements for WOCS 40007 (Auner 259; KIC 5113053), a double-lined detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> and a member of the open cluster NGC 6819. Utilizing photometric observations from the 1 m telescope at Mount Laguna Observatory and spectra from the WIYN 3.5 m telescope, we measure precise and accurate masses ({approx}1.6% uncertainty) and radii ({approx}0.5%) for the <span class="hlt">binary</span> components. In addition, we discover a third star orbiting the <span class="hlt">binary</span> with a period greater than 3000 days using radial velocities and Kepler <span class="hlt">eclipse</span> timings. Because the stars in the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> are near the cluster turnoff, they are evolving rapidly in size and are sensitive to age. With a metallicity of [Fe/H] = +0.09 {+-} 0.03, we find the age of NGC 6819 to be about 2.4 Gyr from color-magnitude diagram (CMD) isochrone fitting and 3.1 {+-} 0.4 Gyr by analyzing the mass-radius (M-R) data for this <span class="hlt">binary</span>. The M-R age is above previous determinations for this cluster, but consistent within 1{sigma} uncertainties. When the M-R data for the primary star of the additional cluster <span class="hlt">binary</span> WOCS 23009 is included, the weighted age estimate drops to 2.5 {+-} 0.2 Gyr, with a systematic uncertainty of at least 0.2 Gyr. The age difference between our CMD and M-R findings may be the result of systematic error in the metallicity or helium abundance used in models, or due to slight radius inflation of one or both stars in the WOCS 40007 <span class="hlt">binary</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010MNRAS.402.2591P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010MNRAS.402.2591P"><span id="translatedtitle">Precise mass and radius values for the white dwarf and <span class="hlt">low</span> <span class="hlt">mass</span> M dwarf in the pre-cataclysmic <span class="hlt">binary</span> NN Serpentis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parsons, S. G.; Marsh, T. R.; Copperwheat, C. M.; Dhillon, V. S.; Littlefair, S. P.; Gänsicke, B. T.; Hickman, R.</p> <p>2010-03-01</p> <p>Using the high resolution Ultraviolet and Visual Echelle Spectrograph (UVES) mounted on the Very Large Telescope in combination with photometry from the high-speed CCD camera ULTRACAM, we derive precise system parameters for the pre-cataclysmic <span class="hlt">binary</span> NN Ser. A model fit to the ULTRACAM light curves gives the orbital inclination as and the scaled radii, RWD/a and Rsec/a. Analysis of the HeII 4686 Å absorption line gives a radial velocity amplitude for the white dwarf of KWD = 62.3 +/- 1.9kms-1. We find that the irradiation-induced emission lines from the surface of the secondary star give a range of observed radial velocity amplitudes due to differences in optical depths in the lines. We correct these values to the centre of mass of the secondary star by computing line profiles from the irradiated face of the secondary star. We determine a radial velocity of Ksec = 301 +/- 3kms-1, with an error dominated by the systematic effects of the model. This leads to a <span class="hlt">binary</span> separation of a = 0.934 +/- 0.009Rsolar, radii of RWD = 0.0211 +/- 0.0002Rsolar and Rsec = 0.149 +/- 0.002Rsolar and masses of MWD = 0.535 +/- 0.012Msolar and Msec = 0.111 +/- 0.004Msolar. The masses and radii of both components of NN Ser were measured independently of any mass-radius relation. For the white dwarf, the measured mass, radius and temperature show excellent agreement with a `thick' hydrogen layer of fractional mass MH/MWD = 10-4. The measured radius of the secondary star is 10 per cent larger than predicted by models, however, correcting for irradiation accounts for most of this inconsistency, hence the secondary star in NN Ser is one of the first precisely measured very <span class="hlt">low</span> <span class="hlt">mass</span> objects (M <~ 0.3Msolar) to show good agreement with models. ULTRACAM r', i' and z' photometry taken during the primary <span class="hlt">eclipse</span> determines the colours of the secondary star as (r' - i')sec = 1.4 +/- 0.1 and (i' - z')sec = 0.8 +/- 0.1 which corresponds to a spectral type of M4 +/- 0.5. This is consistent with the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010A%26A...511A..84S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010A%26A...511A..84S"><span id="translatedtitle">The <span class="hlt">eclipsing</span>, double-lined, Of supergiant <span class="hlt">binary</span> Cygnus OB2-B17</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stroud, V. E.; Clark, J. S.; Negueruela, I.; Roche, P.; Norton, A. J.; Vilardell, F.</p> <p>2010-02-01</p> <p>Context. Massive, <span class="hlt">eclipsing</span>, double-lined, spectroscopic <span class="hlt">binaries</span> are not common but are necessary to understand the evolution of massive stars as they are the only direct way to determine stellar masses. They are also the progenitors of energetic phenomena such as X-ray <span class="hlt">binaries</span> and γ-ray bursts. Aims: We present a photometric and spectroscopic analysis of the candidate <span class="hlt">binary</span> system Cyg OB2-B17 to show that it is indeed a massive evolved <span class="hlt">binary</span>. Methods: We utilise V band and white-light photometry to obtain a light curve and period of the system, and spectra at different resolutions to calculate preliminary orbital parameters and spectral classes for the components. Results: Our results suggest that B17 is an <span class="hlt">eclipsing</span>, double-lined, spectroscopic <span class="hlt">binary</span> with a period of 4.0217±0.0004 days, with two massive evolved components with preliminary classifications of O7 and O9 supergiants. The radial velocity and light curves are consistent with a massive <span class="hlt">binary</span> containing components with similar luminosities, and in turn with the preliminary spectral types and age of the association.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994ExA.....5..163M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994ExA.....5..163M"><span id="translatedtitle">New Developments in <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Light Curve Modeling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Milone, E. F.; Stagg, C. R.</p> <p>1994-03-01</p> <p>The light curve modeling of <span class="hlt">binary</span> stars has continued to evolve since its founding by Henry Norris Russell (see Russell and Merrill 1952 and citations therein) nearly a century ago, accelerated in the 1950s by Kopal's introduction of Roche geometry into models and by the development of synthetic light curve computer code in the 1970's. Improved physics and the use of more kinds of observational input are providing another round of important advances that promise to enlarge our knowledge of both <span class="hlt">binary</span> stars and ensembles containing them. Here we discuss the newer horizons of light curve modeling and the steps being taken toward them.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014NewA...27...19O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014NewA...27...19O"><span id="translatedtitle">V380 Dra: New short-period totally <span class="hlt">eclipsing</span> active <span class="hlt">binary</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Özdarcan, O.</p> <p>2014-02-01</p> <p>In this study, first complete and standard BVR light curves and photometric analysis of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system V380 Dra are presented. Photometric analysis result indicates that the system has components which are cool main sequence stars. In light and color curves, remarkable asymmetry is observed, especially after secondary minimum, which is believed to be a result of chromospheric activity in one or both components. O-C diagram of available small number of <span class="hlt">eclipse</span> times, together with new <span class="hlt">eclipse</span> timings in this work, exhibits no significant variation. Preliminary light curve solution shows that the secondary minimum is total <span class="hlt">eclipse</span>. By using the advantage of total <span class="hlt">eclipse</span> and mass-luminosity relation, it is found that the system has a possible mass ratio of q = 0.81. First estimation of masses and radii of primary and secondary components are M1 = 0.77 M⊙,M2 = 0.62 M⊙ and R1 = 0.93 R⊙,R2 = 0.77 R⊙, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015A%26A...584A.128L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015A%26A...584A.128L"><span id="translatedtitle">An <span class="hlt">eclipsing</span> double-line spectroscopic <span class="hlt">binary</span> at the stellar/substellar boundary in the Upper Scorpius OB association</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lodieu, N.; Alonso, R.; González Hernández, J. I.; Sanchis-Ojeda, R.; Narita, N.; Kawashima, Y.; Kawauchi, K.; Suárez Mascareño, A.; Deeg, H.; Prieto Arranz, J.; Rebolo, R.; Pallé, E.; Béjar, V. J. S.; Ferragamo, A.; Rubiño-Martín, J. A.</p> <p>2015-12-01</p> <p>Aims: We aim at constraining evolutionary models at <span class="hlt">low</span> <span class="hlt">mass</span> and young ages by identifying interesting transiting system members of the nearest OB association to the Sun, Upper Scorpius (USco), which has been targeted by the Kepler mission. Methods: We produced light curves for M-dwarf members of the USco region that has been surveyed during the second campaign of the Kepler K2 mission. We identified by eye a transiting system, USco J161630.68-251220.1 (=EPIC 203710387) with a combined spectral type of M5.25, whose photometric, astrometric, and spectroscopic properties makes it a member of USco. We conducted an extensive photometric and spectroscopic follow-up of this transiting system with a suite of telescopes and instruments to characterise the properties of each component of the system. Results: We calculated a transit duration of about 2.42 h that occurs every 2.88 days with a slight difference in transit depth and phase between the two components. We estimated a mass ratio of 0.922 ± 0.015 from the semi-amplitudes of the radial velocity curves for each component. We derived masses of 0.091 ± 0.005M⊙ and 0.084 ± 0.004M⊙, radii of 0.388 ± 0.008R⊙ and 0.380 ± 0.008R⊙, luminosities of log (L/L⊙) = -2.020-0.121+0.099 dex and -2.032-0.121+0.099 dex, and effective temperatures of 2901-172+199 K and 2908-172+199 K for the primary and secondary, respectively. Conclusions: We present a complete photometric and radial velocity characterisation of the least massive double-line <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system in the young USco association with two components close to the stellar/substellar limit. This system falls in a gap between the least massive <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in the <span class="hlt">low-mass</span> and substellar regimes at young ages and represents an important addition to constraining evolutionary models at young ages. Based on observations made with telescopes (GTC, WHT) installed in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ASPC..482..119H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ASPC..482..119H"><span id="translatedtitle">Period Studies of 79 Eccentric <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> in the Large Magellanic Cloud</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hong, K.; Kang, Y. W.; Lee, C.-U.</p> <p>2014-08-01</p> <p>We present period studies for seventy-nine <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in the Large Magellanic Cloud. New times of minimum light were derived from the data obtained by the EROS, OGLE-II and OGLE-III surveys. Nineteen stars of the seventy-nine stars show period variation were confirmed. All of the systems were studied by means of an O-C diagram analyses. Nine systems show apsidal motion, six systems show parabola, and four systems show sinusoidal period variations, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AJ....137.2949T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AJ....137.2949T"><span id="translatedtitle">Orbital Solutions and Absolute Elements of the <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> MY Cygni</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tucker, Rebecca S.; Sowell, James R.; Williamon, Richard M.; Coughlin, Jeffrey L.</p> <p>2009-02-01</p> <p>Differential UBV photoelectric photometry for the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> MY Cyg is presented. The Wilson-Devinney program is used to simultaneously solve the three light curves together with previously published radial velocities. A comparison is made with the previous solution found with the Russell-Merrill method. We examine the long-term apsidal motion of this well-detached, slightly eccentric system. We determine absolute dimensions, discuss metallicity/Am-star issues, and estimate the evolutionary status of the stars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008ASPC..392..195F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008ASPC..392..195F"><span id="translatedtitle">FUV Spectroscopy of the sdOB Primary of the <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> System AA Dor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fleig, J.; Rauch, T.; Werner, K.; Kruk, J. W.</p> <p></p> <p>AADor is an <span class="hlt">eclipsing</span>, close, post common-envelope <span class="hlt">binary</span> (PCEB). We present a detailed spectral analysis of its sdOB primary based on observations obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). Due to a strong contamination by interstellar absorption, we had to model both, the stellar spectrum as well as the interstellar line absorption in order to reproduce the FUV observation well and to determine the photospheric parameters precisely.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AAS...22134203R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AAS...22134203R"><span id="translatedtitle">Photometric and Spectroscopic Analysis for the Determination of Physical Parameters of an <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Star System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reid, Piper</p> <p>2013-01-01</p> <p>A <span class="hlt">binary</span> star system is a pair of stars that are bound together by gravity. Most of the stars that we see in the night sky are members of multiple star systems. A system of stars where one star passes in front of the other (as observed from Earth) on a periodic basis is called an <span class="hlt">eclipsing</span> <span class="hlt">binary</span>. <span class="hlt">Eclipsing</span> <span class="hlt">binaries</span> can have very short rotational periods and in all cases these pairs of stars are so far away that they can only be resolved from Earth as a single point of light. The interaction of the two stars serves to produce physical phenomena that can be observed and used to study stellar properties. By careful data collection and analysis is it possible for an amateur astronomer using commercial, low cost equipment (including a home built spectroscope) to gather photometric (brightness versus time) and spectroscopic (brightness versus wavelength) data, analyze the data, and calculate the physical properties of a <span class="hlt">binary</span> star system? Using a CCD camera, tracking mount and telescope photometric data of BB Pegasi was collected and a light curve produced. 57 Cygni was also studied using a spectroscope, tracking mount and telescope to prove that Doppler shift of Hydrogen Balmer absorption lines can be used to determine radial velocity. The orbital period, orbital velocity, radius of each star, separation of the two stars and mass of each star was calculated for the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> BB Pegasi using photometric and spectroscopic data and Kepler’s 3rd Law. These data were then compared to published data. By careful use of consumer grade astronomical equipment it is possible for an amateur astronomer to determine an array of physical parameters of a distant <span class="hlt">binary</span> star system from a suburban setting.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22525454','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22525454"><span id="translatedtitle">COMMON PATTERNS IN THE EVOLUTION BETWEEN THE LUMINOUS NEUTRON STAR <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARY</span> SUBCLASSES</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fridriksson, Joel K.; Homan, Jeroen; Remillard, Ronald A.</p> <p>2015-08-10</p> <p>The X-ray transient XTE J1701–462 was the first source observed to evolve through all known subclasses of low-magnetic-field neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (NS-LMXBs), as a result of large changes in its mass accretion rate. To investigate to what extent similar evolution is seen in other NS-LMXBs we have performed a detailed study of the color–color and hardness–intensity diagrams (CDs and HIDs) of Cyg X-2, Cir X-1, and GX 13+1—three luminous X-ray <span class="hlt">binaries</span>, containing weakly magnetized neutron stars, known to exhibit strong secular changes in their CD/HID tracks. Using the full set of Rossi X-ray Timing Explorer Proportional Counter Array data collected for the sources over the 16 year duration of the mission, we show that Cyg X-2 and Cir X-1 display CD/HID evolution with close similarities to XTE J1701–462. Although GX 13+1 shows behavior that is in some ways unique, it also exhibits similarities to XTE J1701–462, and we conclude that its overall CD/HID properties strongly indicate that it should be classified as a Z source, rather than as an atoll source. We conjecture that the secular evolution of Cyg X-2, Cir X-1, and GX 13+1—illustrated by sequences of CD/HID tracks we construct—arises from changes in the mass accretion rate. Our results strengthen previous suggestions that within single sources Cyg-like Z source behavior takes place at higher luminosities and mass accretion rates than Sco-like Z behavior, and lend support to the notion that the mass accretion rate is the primary physical parameter distinguishing the various NS-LMXB subclasses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000MNRAS.318..599B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000MNRAS.318..599B&link_type=ABSTRACT"><span id="translatedtitle">Simultaneous radio and X-ray observations of Galactic Centre <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berendsen, Stephan G. H.; Fender, Robert; Kuulkers, Erik; Heise, J.; van der Klis, M.</p> <p>2000-10-01</p> <p>We have performed simultaneous X-ray and radio observations of 13 Galactic Centre <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> in 1998 April using the Wide Field Cameras on board BeppoSAX and the Australia Telescope Compact Array, the latter simultaneously at 4.8 and 8.64GHz. We detect two Z sources, GX 17+2 and GX 5-1, and the unusual `hybrid' source GX 13+1. Upper limits, which are significantly deeper than previous non-detections, are placed on the radio emission from two more Z sources and seven atoll sources. Hardness-intensity diagrams constructed from the Wide Field Camera data reveal GX 17+2 and GX 5-1 to have been on the lower part of the horizontal branch and/or the upper part of the normal branch at the time of the observations, and the two non-detected Z sources, GX 340+0 and GX 349+2, to have been on the lower part of the normal branch. This is consistent with the previous empirically determined relation between radio and X-ray emission from Z sources, in which radio emission is strongest on the horizontal branch and weakest on the flaring branch. For the first time we have information on the X-ray state of atoll sources, which are clearly radio-quiet relative to the Z sources, during periods of observed radio upper limits. We place limits on the linear polarization from the three detected sources, and use accurate radio astrometry of GX 17+2 to confirm that it is probably not associated with the optical star NP Ser. Additionally we place strong upper limits on the radio emission from the X-ray <span class="hlt">binary</span> 2S 0921-630, disagreeing with suggestions that it is a Z-source viewed edge-on.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...809...52F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...809...52F"><span id="translatedtitle">Common Patterns in the Evolution between the Luminous Neutron Star <span class="hlt">Low-Mass</span> X-ray <span class="hlt">Binary</span> Subclasses</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fridriksson, Joel K.; Homan, Jeroen; Remillard, Ronald A.</p> <p>2015-08-01</p> <p>The X-ray transient XTE J1701-462 was the first source observed to evolve through all known subclasses of low-magnetic-field neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (NS-LMXBs), as a result of large changes in its mass accretion rate. To investigate to what extent similar evolution is seen in other NS-LMXBs we have performed a detailed study of the color-color and hardness-intensity diagrams (CDs and HIDs) of Cyg X-2, Cir X-1, and GX 13+1—three luminous X-ray <span class="hlt">binaries</span>, containing weakly magnetized neutron stars, known to exhibit strong secular changes in their CD/HID tracks. Using the full set of Rossi X-ray Timing Explorer Proportional Counter Array data collected for the sources over the 16 year duration of the mission, we show that Cyg X-2 and Cir X-1 display CD/HID evolution with close similarities to XTE J1701-462. Although GX 13+1 shows behavior that is in some ways unique, it also exhibits similarities to XTE J1701-462, and we conclude that its overall CD/HID properties strongly indicate that it should be classified as a Z source, rather than as an atoll source. We conjecture that the secular evolution of Cyg X-2, Cir X-1, and GX 13+1—illustrated by sequences of CD/HID tracks we construct—arises from changes in the mass accretion rate. Our results strengthen previous suggestions that within single sources Cyg-like Z source behavior takes place at higher luminosities and mass accretion rates than Sco-like Z behavior, and lend support to the notion that the mass accretion rate is the primary physical parameter distinguishing the various NS-LMXB subclasses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22039179','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22039179"><span id="translatedtitle">A COMPARISON OF BROAD IRON EMISSION LINES IN ARCHIVAL DATA OF NEUTRON STAR <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARIES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cackett, Edward M.; Miller, Jon M.; Reis, Rubens C.; Fabian, Andrew C.; Barret, Didier</p> <p>2012-08-10</p> <p>Relativistic X-ray disklines have been found in multiple neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span>, in close analogy with black holes across the mass scale. These lines have tremendous diagnostic power and have been used to constrain stellar radii and magnetic fields, often finding values that are consistent with independent timing techniques. Here, we compare CCD-based data from Suzaku with Fe K line profiles from archival data taken with gas-based spectrometers. In general, we find good consistency between the gas-based line profiles from EXOSAT, BeppoSAX, and RXTE and the CCD data from Suzaku, demonstrating that the broad profiles seen are intrinsic to the line and not broad due to instrumental issues. However, we do find that when fitting with a Gaussian line profile, the width of the Gaussian can depend on the continuum model in instruments with low spectral resolution, though when the different models fit equally well the line widths generally agree. We also demonstrate that three BeppoSAX observations show evidence for asymmetric lines, with a relativistic diskline model providing a significantly better fit than a Gaussian. We test this by using the posterior predictive p-value method, and bootstrapping of the spectra to show that such deviations from a Gaussian are unlikely to be observed by chance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010084309','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010084309"><span id="translatedtitle">The Discovery of a Second Luminous <span class="hlt">Low</span> <span class="hlt">Mass</span> X-Ray <span class="hlt">Binary</span> System in the Globular Cluster M15</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>White, Nicholas E.; Angelini, Lorella</p> <p>2001-01-01</p> <p>Using the Chandra X-ray Observatory we have discovered a second bright X-ray source in the globular cluster M15 that is 2.7" to the west of AC211, the previously known <span class="hlt">low</span> <span class="hlt">mass</span> X-ray <span class="hlt">binary</span> (LMXB) in this system. Prior to the 0.5" imaging capability of Chandra this second source could not have been resolved from AC211. The luminosity and spectrum of this new source, which we call M15-X2, are consistent with it also being a LMXB system. This is the first time that two LMXBs have been seen to be simultaneously active in a globular cluster. The new source, M15-X2, is coincident with a 18th U magnitude very blue star. The discovery of a second LMXB in M15 clears up a long standing puzzle where the X-ray and optical properties of AC211 appear consistent with the central source being hidden behind an accretion disk corona, and yet also showed a luminous X-ray burst suggesting the neutron star is directly visible. This discovery suggests instead that the X-ray burst did not come from AC211, but rather from the newly discovered X-ray source. We discuss the implications of this discovery for X-ray observations of globular clusters in nearby galaxies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Ap%26SS.361..333H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Ap%26SS.361..333H"><span id="translatedtitle">Analytical model of strange star in <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> KS 1731-260</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hossein, Sk. Monowar; Farhad, Nur; Molla, Sajahan; Kalam, Mehedi</p> <p>2016-10-01</p> <p>In this article using Mehra (Aust. Math. Soc. 6:153, 1966) metric, we propose a model for the strange star in <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> (LMXB) KS 1731-260 (Özel et al., Astrophys. J. 748:5, 2012) which describes interior space-time of the star. We study the strange star's interior and exterior physical properties. We calculate central density (ρ0), surface density (ρb), central pressure (p 0), surface redshift (Z s) and probable radius of the above mentioned strange star, which is very much consistent with the reported data. The special feature of this article is that the radius of the star is 12.31 km where pressure becomes zero and mass comes out as 2.09521 M_{⊙}, whereas maximum mass comes out as 2.09996 M _{⊙} with radius 12.53 km. Therefore, our model suggests that there may be a gaseous atmosphere over a range of 0.22 km outside of the stellar structure which justify the claim of Ho and Heinke (Nature 462:71, 2009).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21452752','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21452752"><span id="translatedtitle">CONTINUED COOLING OF THE CRUST IN THE NEUTRON STAR <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARY</span> KS 1731-260</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cackett, Edward M.; Miller, Jon M.; Brown, Edward F.; Cumming, Andrew; Degenaar, Nathalie; Wijnands, Rudy</p> <p>2010-10-20</p> <p>Some neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> have very long outbursts (lasting several years) which can generate a significant amount of heat in the neutron star crust. After the system has returned to quiescence, the crust then thermally relaxes. This provides a rare opportunity to study the thermal properties of neutron star crusts, putting constraints on the thermal conductivity and hence the structure and composition of the crust. KS 1731-260 is one of only four systems where this crustal cooling has been observed. Here, we present a new Chandra observation of this source approximately eight years after the end of the last outburst and four years since the last observation. We find that the source has continued to cool, with the cooling curve displaying a simple power-law decay. This suggests that the crust has not fully thermally relaxed yet and may continue to cool further. A simple power-law decay is in contrast to theoretical cooling models of the crust, which predict that the crust should now have cooled to the same temperature as the neutron star core.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.456.4001W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.456.4001W"><span id="translatedtitle">Constraining the properties of neutron star crusts with the transient <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> Aql X-1</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Waterhouse, A. C.; Degenaar, N.; Wijnands, R.; Brown, E. F.; Miller, J. M.; Altamirano, D.; Linares, M.</p> <p>2016-03-01</p> <p>Aql X-1 is a prolific transient neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> that exhibits an accretion outburst approximately once every year. Whether the thermal X-rays detected in intervening quiescent episodes are the result of cooling of the neutron star or due to continued low-level accretion remains unclear. In this work, we use Swift data obtained after the long and bright 2011 and 2013 outbursts, as well as the short and faint 2015 outburst, to investigate the hypothesis that cooling of the accretion-heated neutron star crust dominates the quiescent thermal emission in Aql X-1. We demonstrate that the X-ray light curves and measured neutron star surface temperatures are consistent with the expectations of the crust cooling paradigm. By using a thermal evolution code, we find that ≃1.2-3.2 MeV nucleon-1 of shallow heat release describes the observational data well, depending on the assumed mass-accretion rate and temperature of the stellar core. We find no evidence for varying strengths of this shallow heating after different outbursts, but this could be due to limitations of the data. We argue that monitoring Aql X-1 for up to ≃1 yr after future outbursts can be a powerful tool to break model degeneracies and solve open questions about the magnitude, depth, and origin of shallow heating in neutron star crusts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E.753G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E.753G"><span id="translatedtitle">Athena's Constraints on the Dense Matter Equation of State from Quiescent <span class="hlt">Low</span> <span class="hlt">Mass</span> X-ray <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guillot, Sebastien</p> <p>2016-07-01</p> <p>The study of neutron star quiescent <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (qLMXBs) will address one of the science goals of the Athena X-ray observatory. The study of the soft X-ray thermal emission from the neutron star surface in qLMXBs is a crucial tool to place constrains on the dense matter equation of state and understand the interior structure of neutron stars. I will briefly review this method, its strengths and current weaknesses and limitations, as well as the current constraints on the equation of state from qLMXBs. The superior sensitivity of Athena will permit the acquisition of unprecedentedly high signal-to-noise spectra from these sources. It has been demonstrated that a single qLMXB, even with a high signal-to-noise spectrum, will not place useful constraints on the dense matter equation of state. However, a combination of qLMXB spectra has shown great promises of obtaining tight constraints on the equation of state. I will discuss the expected prospects for observations of qLMXBs and in particular, I will show that very tight constraints on the equation of state can be obtained from the observations of qLMXBs with the Athena X-ray observatory (even with a 10 % uncertainty on the flux calibration).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22365424','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22365424"><span id="translatedtitle">The magnetohydrodynamical model of kilohertz quasi-periodic oscillations in neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (II)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shi, Chang-Sheng; Zhang, Shuang-Nan; Li, Xiang-Dong</p> <p>2014-08-10</p> <p>We study the kilohertz quasi-periodic oscillations (kHz QPOs) in neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs) with a new magnetohydrodynamics (MHD) model, in which the compressed magnetosphere is considered. The previous MHD model is reexamined and the relation between the frequencies of the kHz QPOs and the accretion rate in LMXBs is obtained. Our result agrees with the observations of six sources (4U 0614+09, 4U 1636-53, 4U 1608-52, 4U 1915-15, 4U 1728-34, and XTE 1807-294) with measured spins. In this model, the kHz QPOs originate from the MHD waves in the compressed magnetosphere. The single kHz QPOs and twin kHz QPOs are produced in two different parts of the accretion disk and the boundary is close to the corotation radius. The lower QPO frequency in a frequency-accretion rate diagram is cut off at a low accretion rate and the twin kHz QPOs encounter a top ceiling at a high accretion rate due to the restriction of the innermost stable circular orbit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PASJ...68S..14O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PASJ...68S..14O"><span id="translatedtitle">A Suzaku observation of the <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> GS 1826-238 in the hard state</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ono, Ko; Sakurai, Soki; Zhang, Zhongli; Nakazawa, Kazuhiro; Makishima, Kazuo</p> <p>2016-06-01</p> <p>The neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> GS 1826-238 was observed with Suzaku on 2009 October 21, for a total exposure of 1030 ks. Except for the type I bursts, the source intensity was constant within ˜10%. Combining the Suzaku XIS, HXD-PIN, and HXD-GSO data, burst-removed persistent emission was detected over the 0.8-100 keV range, at an unabsorbed flux of 2.6 × 10-9 erg s-1 cm-2. Although the implied 0.8-100 keV luminosity, 1.5 × 1037 erg s-1 (assuming a distance of 7 kpc), is relatively high, the observed hard spectrum confirms that the source was in the hard state. The spectrum was successfully explained by an emission from a soft standard accretion disk partially Comptonized by a hot electron cloud, and a blackbody emission Comptonized by another hotter electron cloud. These results are compared with those from previous studies, including those on the same source by Thompson et al. (2005, ApJ, 634, 1261) and Cocchi, Farinelli, and Paizis (2011, A&A, 529, A155), as well as that of Aql X-1 in the hard state obtained with Suzaku (Sakurai et al. 2014, PASJ, 66, 10).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22342091','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22342091"><span id="translatedtitle">UBVRI analysis of the totally <span class="hlt">eclipsing</span> extreme mass ratio W UMa <span class="hlt">binary</span>, GSC 3208 1986</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Samec, R. G.; Kring, J. D.; Robb, Russell; Van Hamme, W.; Faulkner, D. R.</p> <p>2015-03-01</p> <p>GSC 3208 1986 is an NSVS and TYCHO <span class="hlt">binary</span>, first observed from 1999 to 2000. It is a W UMa <span class="hlt">binary</span> with a period of 0.405 days. The present observations were taken in 2012 September and are of high precision, averaging a standard deviation of better than 5 mmag. The amplitude of the light curve is very nearly 0.5 mag yet it undergoes total <span class="hlt">eclipses</span>. Dominion Astrophysical Observatory spectra give an F3V type (T∼6900 K) for the system, the earliest of the extreme mass ratio W UMa <span class="hlt">binaries</span>. The linear period determination of 0.4045672 days was calculated with the two sets of epochs available. An early NSVS light curve reveals that the period has been smoothly decreasing over its past 12,000 orbits. The <span class="hlt">binary</span> may be undergoing sinusoidal oscillations due to the presence of a third body, possibly with a period of 23±3 years. The high inclination of 85° results in a long duration secondary total <span class="hlt">eclipse</span>, lasting some 49.5 minutes. Findings indicate that GSC 3208 1986 is an immaculate extreme mass ratio, q(m{sub 2}/m{sub 1}) = 0.24, A-type W UMa <span class="hlt">binary</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22342226','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22342226"><span id="translatedtitle">WW Geminorum: An early B-type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> evolving into the contact phase</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yang, Y.-G.; Dai, H.-F.; Yin, X.-G.; Yang, Y. E-mail: yangyg@chnu.edu.cn</p> <p>2014-11-01</p> <p>WW Gem is a B-type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> with a period of 1.2378 days. The CCD photometry of this <span class="hlt">binary</span> was performed in 2013 December using the 85 cm telescope at the Xinglong Stations of the National Astronomical Observatories of China. Using the updated W-D program, the photometric model was deduced from the VRI light curves. The results imply that WW Gem is a near-contact <span class="hlt">eclipsing</span> <span class="hlt">binary</span> whose primary component almost fills its Roche lobe. The photometric mass ratio is q {sub ph} = 0.48(± 0.05). All collected times of minimum light, including two new ones, were used for the period studies. The orbital period changes of WW Gem could be described by an upward parabola, possibly overlaid by a light-time orbit with a period of P {sub mod} = 7.41(± 0.04) yr and a semi-amplitude of A = 0.0079 days(± 0.0005 days), respectively. This kind of cyclic oscillation may be attributed to the light-travel time effect via the third body. The long-term period increases at a rate of dP/dt = +3.47(±0.04) × 10{sup –8} day yr{sup –1}, which may be explained by the conserved mass transfer from the less massive component to the more massive one. With mass transfer, the massive <span class="hlt">binary</span> WW Gem may be evolving into a contact <span class="hlt">binary</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AAS...21915341R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AAS...21915341R"><span id="translatedtitle">Light Curve Solutions of <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> in the Large Magellanic Cloud</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rawls, Meredith L.; Rao, M. S.</p> <p>2012-01-01</p> <p>We present model light curves for nine <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars in the Large Magellanic Cloud (LMC). These systems are detached <span class="hlt">binaries</span> with nearly circular orbits, and were pseudorandomly selected from three of 21 LMC regions in the Optical Gravitational Lensing Experiment II (OGLE-II) survey. We make use of light curves, orbital periods, and <span class="hlt">binary</span> classification as reported in Wyrzykowski et al. (2003). We present light curve solutions created with the software PHysics Of <span class="hlt">Eclipsing</span> <span class="hlt">BinariEs</span> (PHOEBE, Prsa & Zwitter 2005). Each solution has the best-fit mass ratio q, system inclination i, component temperatures T1 and T2, and modified Kopal potentials Ω1 and Ω2. PHOEBE employs a Nelder & Mead's Simplex fitting method that adjusts all the input parameters to find the best fit to the light curve. Many of the light curves have significant scatter, which can lead to multiple degenerate best-fit solutions, and we discuss what can be done in the future to refine our results, derive global stellar parameters, and place these nine systems in a larger context. We acknowledge the support of the International Research Experience for Students (IRES) program, which is sponsored by the NSF and administered by NSO/GONG.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AAS...22315510O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AAS...22315510O"><span id="translatedtitle">Light Curve Analyses of the Short Period, Totally <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> V449 & V463 And</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Okimoto, Jensen; Schwartz, W. H.; Sanders, S. J.; Bradstreet, D. H.</p> <p>2014-01-01</p> <p>As part of our ongoing research on short period <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> which do not have published precision light curves and/or analyses, we placed V449 & V463 And on our observing schedule for the fall of 2013. V449 And (GSC 3281-2158; Mis V1190) was reported by Kazarovet (2005) to be a short period (0.33853 day) overcontact system ranging from V = 12.2 - 12.9 mag. We have obtained more than 1300 total observations in V and Rc. Preliminary light curve analysis reveals a W-type overcontact system with the primary <span class="hlt">eclipse</span> being total and a temperature difference between the stars of ~300 K. The light curves themselves are fairly symmetrical (not typical for these types of systems) except for a more rapid rise in the ascending branch after secondary <span class="hlt">eclipse</span> than symmetry would predict. This seems quite peculiar, as most W-UMa light curves exhibit asymmetries primarily between maxima (the O’Connell effect). Detailed modeling including hot and/or cool spots will be presented, as well as a period study based upon the limited timings available. V463 And (GSC 2764-1417; NSV 14514) was discovered by Khruslov and reported in IBVS 5699 (2006) to be a short period (0.406095 day) system ranging from V = 12.15 - 13.05 mag. Our thoroughly covered V and Rc light curves show that the secondary <span class="hlt">eclipse</span> is total. Subsequent analysis indicates the system is most likely a near-contact <span class="hlt">binary</span> with a temperature difference of ~1200 K between the components. The light curves also demonstrate very significant asymmetries, especially near secondary <span class="hlt">eclipse</span>. The O’Connell effect is 0.08 mag in Rc between the two maxima and the first maxima is significantly asymmetrically shaped. Modeling results including spot analysis and a period study will be presented in this poster.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010CoAst.161...55S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010CoAst.161...55S"><span id="translatedtitle">A new <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system with a pulsating component detected by CoRoT</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sokolovsky, K.; Maceroni, C.; Hareter, M.; Damiani, C.; Balaguer-Núñez, L.; Ribas, I.</p> <p>2010-06-01</p> <p>We report the discovery of CoRoT 102980178 (α = 06h 50m12.10s , δ = -02°41' 21.8'', J2000) an Algol-type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system with a pulsating component (oEA). It was identified using a publicly available 55 day long monochromatic lightcurve from the CoRoT initial run dataset (exoplanet field). Eleven consecutive 1.26m deep total primary and the equal number of 0.25m deep secondary <span class="hlt">eclipses</span> (at phase 0.50) were observed. The following light elements for the primary <span class="hlt">eclipse</span> were derived: HJDMinI = 2454139.0680 + 5.0548d × E. The lightcurve modeling leads to a semidetached configuration with the photometric mass ratio q = 0.2 and orbital inclination i = 85°. The out-of-<span class="hlt">eclipse</span> lightcurve shows ellipsoidal variability and positive O'Connell effect as well as clear 0.01m pulsations with the dominating frequency of 2.75 c/d. The pulsations disappear during the primary <span class="hlt">eclipses</span>, which indicates the primary (more massive) component to be the pulsating star. Careful frequency analysis reveals the second independent pulsation frequency of 0.21 c/d and numerous combinations of these frequencies with the <span class="hlt">binary</span> orbital frequency and its harmonics. On the basis of the CoRoT lightcurve and ground based multicolor photometry, we favor classification of the pulsating component as a γ Doradus type variable, however, classification as an SPB star cannot be excluded.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PASP..128g4201K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PASP..128g4201K&link_type=ABSTRACT"><span id="translatedtitle">Spectroscopic Survey of <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> with a Low-cost Echelle Spectrograph: Scientific Commissioning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kozłowski, S. K.; Konacki, M.; Sybilski, P.; Ratajczak, M.; Pawłaszek, R. K.; Hełminiak, K. G.</p> <p>2016-07-01</p> <p>We present scientific results obtained with a recently commissioned échelle spectrograph on the 0.5 m Solaris-1 telescope in the South African Astronomical Observatory. BACHES is a low-cost slit échelle spectrograph that has a resolution of 21,000 at 5500 Å. The described setup is fully remotely operated and partly automated. Custom hardware components have been designed to allow both spectroscopic and photometric observations. The setup is controlled via dedicated software. The throughput of the system allows us to obtain spectra with an average signal-to-noise ratio of 22 at 6375 Å for a 30 minute exposure of a V = 10 mag target. The stability of the instrument is influenced mainly by the ambient temperature changes. We have obtained radial velocity (RV) rms values for a bright (V = 5.9 mag) spectroscopic <span class="hlt">binary</span> as good as 0.59 and 1.34 km s‑1 for a V = 10.2 mag <span class="hlt">eclipsing</span> <span class="hlt">binary</span>. RV measurements have been combined with available photometric light curves. We present models of six <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems, and for previously known targets, we compare our results with those available in the literature. Masses of <span class="hlt">binary</span> components have been determined with 3% errors for some targets. We confront our results with benchmark values based on measurements from the HARPS and UCLES spectrographs on 4 m class telescopes and find very good agreement. The described setup is very efficient and well suited for a spectroscopic survey. We can now spectroscopically characterize about 300 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars per year up to 10.2 mag assuming typical weather conditions at SAAO without a single observing trip.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PASP..128g4201K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PASP..128g4201K"><span id="translatedtitle">Spectroscopic Survey of <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> with a Low-cost Echelle Spectrograph: Scientific Commissioning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kozłowski, S. K.; Konacki, M.; Sybilski, P.; Ratajczak, M.; Pawłaszek, R. K.; Hełminiak, K. G.</p> <p>2016-07-01</p> <p>We present scientific results obtained with a recently commissioned échelle spectrograph on the 0.5 m Solaris-1 telescope in the South African Astronomical Observatory. BACHES is a low-cost slit échelle spectrograph that has a resolution of 21,000 at 5500 Å. The described setup is fully remotely operated and partly automated. Custom hardware components have been designed to allow both spectroscopic and photometric observations. The setup is controlled via dedicated software. The throughput of the system allows us to obtain spectra with an average signal-to-noise ratio of 22 at 6375 Å for a 30 minute exposure of a V = 10 mag target. The stability of the instrument is influenced mainly by the ambient temperature changes. We have obtained radial velocity (RV) rms values for a bright (V = 5.9 mag) spectroscopic <span class="hlt">binary</span> as good as 0.59 and 1.34 km s-1 for a V = 10.2 mag <span class="hlt">eclipsing</span> <span class="hlt">binary</span>. RV measurements have been combined with available photometric light curves. We present models of six <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems, and for previously known targets, we compare our results with those available in the literature. Masses of <span class="hlt">binary</span> components have been determined with 3% errors for some targets. We confront our results with benchmark values based on measurements from the HARPS and UCLES spectrographs on 4 m class telescopes and find very good agreement. The described setup is very efficient and well suited for a spectroscopic survey. We can now spectroscopically characterize about 300 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars per year up to 10.2 mag assuming typical weather conditions at SAAO without a single observing trip.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010069989','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010069989"><span id="translatedtitle">ASCA Observation of MS 1603.6+2600 (=UW Coronae Borealis): A Dipping <span class="hlt">Low-Mass</span> X-ray <span class="hlt">Binary</span> in the Outer Halo?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mukai, Koji; Smale, Alan; Stahle, Caroline K.; Schlegel, Eric M.; Wijnands, Rudy; White, Nicholas E. (Technical Monitor)</p> <p>2001-01-01</p> <p>MS 1603.6+2600 is a high-latitude X-ray <span class="hlt">binary</span> with a 111 min orbital period, thought to be either an unusual cataclysmic variable or an unusual <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span>. In an ASCA observation in 1997 August, we find a burst whose light curve suggests a Type 1 (thermonuclear flash) origin. We also find an orbital X-ray modulation in MS 1603.6+2600, which is likely to be periodic dips, presumably due to azimuthal structure in the accretion disk. Both are consistent with this system being a normal <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> harboring a neutron star, but at a great distance. We tentatively suggest that MS 1603.6+2600 is located in the outer halo of the Milky Way, perhaps associated with the globular cluster Palomar 14, 11 deg away from MS 1603.6+2600 on the sky at an estimated distance of 73.8 kpc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21300566','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21300566"><span id="translatedtitle">CIRCUMSTELLAR ENVIRONMENT AND EFFECTIVE TEMPERATURE OF THE YOUNG SUBSTELLAR <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> 2MASS J05352184-0546085</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mohanty, Subhanjoy; Stassun, Keivan G.; Mathieu, Robert D.</p> <p>2009-05-20</p> <p>We present new Spitzer IRAC/PU/MIPS photometry from 3.6 to 24 {mu}m, and new Gemini GMOS photometry at 0.48 {mu}m, of the young brown dwarf <span class="hlt">eclipsing</span> <span class="hlt">binary</span> 2MASS J05352184-0546085, located in the Orion Nebula Cluster. No excess disk emission is detected. The measured fluxes at {lambda} {<=} 8 {mu}m are within 1{sigma} ({approx}<0.1 mJy) of a bare photosphere, and the 3{sigma} upper limit at 16 {mu}m is a mere 0.04 mJy above the bare photospheric level. Together with the known properties of the system, this implies the absence of optically thick disks around the individual components. It also implies that if any circumbinary disk is present, it must either be optically thin and extremely tenuous (10{sup -10} M {sub sun}) if it extends in to within {approx}0.1 AU of the <span class="hlt">binary</span> (the approximate tidal truncation radius), or it must be optically thick with a large inner hole, >0.6-10 AU in radius depending on degree of flaring. The consequence in all cases is that disk accretion is likely to be negligible or absent. This supports the recent proposal that the strong H{alpha} emission in the primary (more massive) brown dwarf results from chromospheric activity, and thereby bolsters the hypothesis that the surprising T {sub eff} inversion observed between the components is due to strong magnetic fields on the primary. Our data also set constraints on the T {sub eff} of the components independent of spectral type, and thereby on models of the aforementioned magnetic field effects. We discuss the consequences for the derived fundamental properties of young brown dwarfs and very <span class="hlt">low</span> <span class="hlt">mass</span> stars in general. Specifically, if very active isolated young brown dwarfs and very <span class="hlt">low</span> <span class="hlt">mass</span> stars suffer the same activity/field related effects as the 2M0535-05 primary, the <span class="hlt">low-mass</span> stellar/substellar initial mass function currently derived from standard evolutionary tracks may be substantially in error.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22167236','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22167236"><span id="translatedtitle">AN X-RAY AND OPTICAL LIGHT CURVE MODEL OF THE <span class="hlt">ECLIPSING</span> SYMBIOTIC <span class="hlt">BINARY</span> SMC3</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kato, Mariko; Hachisu, Izumi; Mikolajewska, Joanna</p> <p>2013-01-20</p> <p>Some <span class="hlt">binary</span> evolution scenarios for Type Ia supernovae (SNe Ia) include long-period <span class="hlt">binaries</span> that evolve to symbiotic supersoft X-ray sources in their late stage of evolution. However, symbiotic stars with steady hydrogen burning on the white dwarf's (WD) surface are very rare, and the X-ray characteristics are not well known. SMC3 is one such rare example and a key object for understanding the evolution of symbiotic stars to SNe Ia. SMC3 is an <span class="hlt">eclipsing</span> symbiotic <span class="hlt">binary</span>, consisting of a massive WD and red giant (RG), with an orbital period of 4.5 years in the Small Magellanic Cloud. The long-term V light curve variations are reproduced as orbital variations in the irradiated RG, whose atmosphere fills its Roche lobe, thus supporting the idea that the RG supplies matter to the WD at rates high enough to maintain steady hydrogen burning on the WD. We also present an <span class="hlt">eclipse</span> model in which an X-ray-emitting region around the WD is almost totally occulted by the RG swelling over the Roche lobe on the trailing side, although it is always partly obscured by a long spiral tail of neutral hydrogen surrounding the <span class="hlt">binary</span> in the orbital plane.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1989AJ.....98.1800M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1989AJ.....98.1800M&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Eclipsing</span> <span class="hlt">binary</span> stars as tests of gravity theories - The apsidal motion of AS Camelopardalis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maloney, Frank P.; Guinan, Edward F.; Boyd, Patricia T.</p> <p>1989-11-01</p> <p>AS Camelopardalis is an 8th-magnitude <span class="hlt">eclipsing</span> <span class="hlt">binary</span> that consists of two main-sequence (B8 V and a B9.5 V) components in an eccentric orbit (e = 0.17) with an orbital period of 3.43 days. Like the eccentric <span class="hlt">eclipsing</span> system DI Herculis, and a few other systems, AS Cam is an important test case for studying relativistic apsidal motion. In these systems, the theoretical general relativistic apsidal motion is comparable to that expected from classical effects arising from tidal and rotational deformation of the stellar components. Accurate determinations of the orbital and stellar properties of AS Cam have been made by Hilditch (1972) and Khalliulin and Kozyreva (1983) that permit the theoretical relativistic and classical contributions to the apsidal motion to be determined reasonably well. All the published timings of primary and secondary minima have been gathered and supplemented with <span class="hlt">eclipse</span> timings from 1899 to 1920 obtained from the Harvard plate collection. Least-squares solutions of the <span class="hlt">eclipse</span> timings extending over an 80 yr interval yield a smaller than expected apsidal motion, in agreement with that found by Khalliulin and Kozyreva from a smaller set of data. The observed apsidal motion for AS Cam is about one-third that expected from the combined relativistic and classical effects. Thus, AS Cam joins DI Her in having an observed apsidal motion significantly less than that predicted from theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900027201&hterms=self+determination+theory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dself%2Bdetermination%2Btheory','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900027201&hterms=self+determination+theory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dself%2Bdetermination%2Btheory"><span id="translatedtitle"><span class="hlt">Eclipsing</span> <span class="hlt">binary</span> stars as tests of gravity theories - The apsidal motion of AS Camelopardalis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Maloney, Frank P.; Guinan, Edward F.; Boyd, Patricia T.</p> <p>1989-01-01</p> <p>AS Camelopardalis is an 8th-magnitude <span class="hlt">eclipsing</span> <span class="hlt">binary</span> that consists of two main-sequence (B8 V and a B9.5 V) components in an eccentric orbit (e = 0.17) with an orbital period of 3.43 days. Like the eccentric <span class="hlt">eclipsing</span> system DI Herculis, and a few other systems, AS Cam is an important test case for studying relativistic apsidal motion. In these systems, the theoretical general relativistic apsidal motion is comparable to that expected from classical effects arising from tidal and rotational deformation of the stellar components. Accurate determinations of the orbital and stellar properties of AS Cam have been made by Hilditch (1972) and Khalliulin and Kozyreva (1983) that permit the theoretical relativistic and classical contributions to the apsidal motion to be determined reasonably well. All the published timings of primary and secondary minima have been gathered and supplemented with <span class="hlt">eclipse</span> timings from 1899 to 1920 obtained from the Harvard plate collection. Least-squares solutions of the <span class="hlt">eclipse</span> timings extending over an 80 yr interval yield a smaller than expected apsidal motion, in agreement with that found by Khalliulin and Kozyreva from a smaller set of data. The observed apsidal motion for AS Cam is about one-third that expected from the combined relativistic and classical effects. Thus, AS Cam joins DI Her in having an observed apsidal motion significantly less than that predicted from theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21389288','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21389288"><span id="translatedtitle">ABSOLUTE DIMENSIONS OF THE G7+K7 <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> STAR IM VIRGINIS: DISCREPANCIES WITH STELLAR EVOLUTION MODELS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Morales, Juan Carlos; Marschall, Laurence A.; Brehm, William</p> <p>2009-12-10</p> <p>We report extensive spectroscopic and differential photometric BVRI observations of the active, detached, 1.309-day double-lined <span class="hlt">eclipsing</span> <span class="hlt">binary</span> IM Vir, composed of a G7-type primary and a K7 secondary. With these observations, we derive accurate absolute masses and radii of M {sub 1} = 0.981 +- 0.012 M {sub sun}, M {sub 2} = 0.6644 +- 0.0048 M {sub sun}, R {sub 1} = 1.061 +- 0.016 R {sub sun}, and R {sub 2} = 0.681 +- 0.013 R {sub sun} for the primary and secondary, with relative errors under 2%. The effective temperatures are 5570 +- 100 K and 4250 +- 130 K, respectively. The significant difference in mass makes this a favorable case for comparison with stellar evolution theory. We find that both stars are larger than the models predict, by 3.7% for the primary and 7.5% for the secondary, as well as cooler than expected, by 100 K and 150 K, respectively. These discrepancies are in line with previously reported differences in <span class="hlt">low-mass</span> stars, and are believed to be caused by chromospheric activity, which is not accounted for in current models. The effect is not confined to <span class="hlt">low-mass</span> stars: the rapidly rotating primary of IM Vir joins the growing list of objects of near-solar mass (but still with convective envelopes) that show similar anomalies. The comparison with the models suggests an age of 2.4 Gyr for the system, and a metallicity of [Fe/H] approx-0.3 that is consistent with other indications, but requires confirmation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22047790','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22047790"><span id="translatedtitle">THE SDSS-HET SURVEY OF KEPLER <span class="hlt">ECLIPSING</span> <span class="hlt">BINARIES</span>: SPECTROSCOPIC DYNAMICAL MASSES OF THE KEPLER-16 CIRCUMBINARY PLANET HOSTS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bender, Chad F.; Mahadevan, Suvrath; Deshpande, Rohit; Wright, Jason T.; Roy, Arpita; Terrien, Ryan C.; Sigurdsson, Steinn; Ramsey, Lawrence W.; Schneider, Donald P.; Fleming, Scott W.</p> <p>2012-06-01</p> <p>We have used high-resolution spectroscopy to observe the Kepler-16 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> as a double-lined system and measure precise radial velocities for both stellar components. These velocities yield a dynamical mass ratio of q = 0.2994 {+-} 0.0031. When combined with the inclination, i 90.{sup 0}3401{sup +0.0016}{sub -0.0019}, measured from the Kepler photometric data by Doyle et al. (D11), we derive dynamical masses for the Kepler-16 components of M{sub A} = 0.654 {+-} 0.017 M{sub Sun} and M{sub B} = 0.1959 {+-} 0.0031 M{sub Sun }, a precision of 2.5% and 1.5%, respectively. Our results confirm at the {approx}2% level the mass-ratio derived by D11 with their photometric-dynamical model (PDM), q = 0.2937 {+-} 0.0006. These are among the most precise spectroscopic dynamical masses ever measured for <span class="hlt">low-mass</span> stars and provide an important direct test of the results from the PDM technique.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21452774','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21452774"><span id="translatedtitle">ACCURATE MASSES FOR THE PRIMARY AND SECONDARY IN THE <span class="hlt">ECLIPSING</span> WHITE DWARF <span class="hlt">BINARY</span> NLTT 11748</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kilic, Mukremin; Brown, Warren R.; Kenyon, S. J.; Allende Prieto, Carlos; Agueeros, M. A.; Camilo, Fernando</p> <p>2010-10-01</p> <p>We measure the radial velocity curve of the <span class="hlt">eclipsing</span> detached white dwarf <span class="hlt">binary</span> NLTT 11748. The primary exhibits velocity variations with a semi-amplitude of 273 km s{sup -1} and an orbital period of 5.641 hr. We do not detect any spectral features from the secondary star or any spectral changes during the secondary <span class="hlt">eclipse</span>. We use our composite spectrum to constrain the temperature and surface gravity of the primary to be T {sub eff} = 8690 {+-} 140 K and log g = 6.54 {+-} 0.05, which correspond to a mass of 0.18 M {sub sun}. For an inclination angle of 89.{sup 0}9 derived from the <span class="hlt">eclipse</span> modeling, the mass function requires a 0.76 M {sub sun} companion. The merger time for the system is 7.2 Gyr. However, due to the extreme mass ratio of 0.24, the <span class="hlt">binary</span> will most likely create an AM CVn system instead of a merger.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23467166','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23467166"><span id="translatedtitle">An <span class="hlt">eclipsing-binary</span> distance to the Large Magellanic Cloud accurate to two per cent.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pietrzyński, G; Graczyk, D; Gieren, W; Thompson, I B; Pilecki, B; Udalski, A; Soszyński, I; Kozłowski, S; Konorski, P; Suchomska, K; Bono, G; Moroni, P G Prada; Villanova, S; Nardetto, N; Bresolin, F; Kudritzki, R P; Storm, J; Gallenne, A; Smolec, R; Minniti, D; Kubiak, M; Szymański, M K; Poleski, R; Wyrzykowski, L; Ulaczyk, K; Pietrukowicz, P; Górski, M; Karczmarek, P</p> <p>2013-03-01</p> <p>In the era of precision cosmology, it is essential to determine the Hubble constant to an accuracy of three per cent or better. At present, its uncertainty is dominated by the uncertainty in the distance to the Large Magellanic Cloud (LMC), which, being our second-closest galaxy, serves as the best anchor point for the cosmic distance scale. Observations of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> offer a unique opportunity to measure stellar parameters and distances precisely and accurately. The <span class="hlt">eclipsing-binary</span> method was previously applied to the LMC, but the accuracy of the distance results was lessened by the need to model the bright, early-type systems used in those studies. Here we report determinations of the distances to eight long-period, late-type <span class="hlt">eclipsing</span> systems in the LMC, composed of cool, giant stars. For these systems, we can accurately measure both the linear and the angular sizes of their components and avoid the most important problems related to the hot, early-type systems. The LMC distance that we derive from these systems (49.97 ± 0.19 (statistical) ± 1.11 (systematic) kiloparsecs) is accurate to 2.2 per cent and provides a firm base for a 3-per-cent determination of the Hubble constant, with prospects for improvement to 2 per cent in the future. PMID:23467166</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009yCat.120540001W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009yCat.120540001W"><span id="translatedtitle">VizieR Online Data Catalog: OGLE II SMC <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> (Wyrzykowski+, 2004)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wyrzykowski, L.; Udalski, A.; Kubiak, M.; Szymanski, M. K.; Zebrun, K.; Soszinski, I.; Wozniak, P. R.; Pietrzynski, G.; Szewczyk, O.</p> <p>2009-03-01</p> <p>We present new version of the OGLE-II catalog of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars detected in the Small Magellanic Cloud, based on Difference Image Analysis catalog of variable stars in the Magellanic Clouds containing data collected from 1997 to 2000. We found 1351 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars in the central 2.4 square degree area of the SMC. 455 stars are newly discovered objects, not found in the previous release of the catalog. The <span class="hlt">eclipsing</span> objects were selected with the automatic search algorithm based on the artificial neural network. The full catalog with individual photometry is accessible from the OGLE INTERNET archive, at ftp://sirius.astrouw.edu.pl/ogle/ogle2/var_stars/smc/ecl . Regular observations of the SMC fields started on June 26, 1997 and covered about 2.4 square degrees of central parts of the SMC. Reductions of the photometric data collected up to the end of May 2000 were performed with the Difference Image Analysis (DIA) package. (1 data file).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014A%26A...567A...2D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014A%26A...567A...2D"><span id="translatedtitle">Luminosity function of <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> in the globular cluster system of NGC 1399</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>D'Ago, G.; Paolillo, M.; Fabbiano, G.; Puzia, T. H.; Maccarone, T. J.; Kundu, A.; Goudfrooij, P.; Zepf, S. E.</p> <p>2014-07-01</p> <p>Aims: We present a study of the faint end of the X-ray luminosity function (XLF) of <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs) in the Globular Cluster (GC) system of the cD galaxy NGC 1399. Methods: We performed a stacking experiment on 618 X-ray undetected GCs, in order to verify the presence of faint LMXBs and to constrain the faint-end slope of the GC-LMXBs XLF below the individual detection threshold of 8 × 1037 erg s-1 in the 0.5 - 8 keV band. Results: We obtain a significant X-ray detection for the whole GC sample, as well as for the red and blue GC subpopulations, corresponding to an average luminosity per GC ⟨ LX ⟩ GC of (3.6 ± 1.0) × 1036 erg s-1, (6.9 ± 2.1) × 1036 erg s-1, and (1.7 ± 0.9) × 1036 erg s-1, respectively, for all GCs, red GCs, and blue GCs. If LMXBs in red and blue GCs have the same average intrinsic luminosity, we derive a red/blue ratio ≃3 of GCs hosting LMXBs (2.5 ± 1.0 or 4.1 ± 2.5 depending on the surveyed region); alternatively, assuming the fractions observed for brighter sources, we measure an average X-ray luminosity of LX = (4.3 ± 1.3) × 1037 erg s-1 and LX = (3.4 ± 1.7) × 1037 erg s-1 per red and blue GC-LMXBs, respectively. In the assumption that the XLF follows a power-law distribution, we find that a low-luminosity break is required at LX ≤ 8 × 1037 erg s-1 both in the whole, as well as in the color-selected (red and blue) subsamples. Given the bright-end slopes measured above the X-ray completeness limit, this result is significant at >3σ level. Our best estimates for the faint-end slope are βL = -1.39/-1.38/-1.36 for all/red/blue GC-LMXBs. We also find evidence that the luminosity function becomes steeper at luminosities LX ≳ 3 × 1039 erg s-1, as observed in old ellipticals. Conclusions: If most GCs host a single X-ray <span class="hlt">binary</span>, we conclude that in NGC 1399 the XLF flattens at low luminosities as observed in other nearer galaxies, and we discuss some consequences of this flattening on LMXBs formation scenarios.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22130961','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22130961"><span id="translatedtitle">UPPER BOUNDS ON r-MODE AMPLITUDES FROM OBSERVATIONS OF <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARY</span> NEUTRON STARS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mahmoodifar, Simin; Strohmayer, Tod</p> <p>2013-08-20</p> <p>We present upper limits on the amplitude of r-mode oscillations and gravitational-radiation-induced spin-down rates in <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> neutron stars, under the assumption that the quiescent neutron star luminosity is powered by dissipation from a steady-state r-mode. For masses <2 M{sub Sun} we find dimensionless r-mode amplitudes in the range from about 1 Multiplication-Sign 10{sup -8} to 1.5 Multiplication-Sign 10{sup -6}. For the accreting millisecond X-ray pulsar sources with known quiescent spin-down rates, these limits suggest that {approx}< 1% of the observed rate can be due to an unstable r-mode. Interestingly, the source with the highest amplitude limit, NGC 6440, could have an r-mode spin-down rate comparable to the observed, quiescent rate for SAX J1808-3658. Thus, quiescent spin-down measurements for this source would be particularly interesting. For all sources considered here, our amplitude limits suggest that gravitational wave signals are likely too weak for detection with Advanced LIGO. Our highest mass model (2.21 M{sub Sun }) can support enhanced, direct Urca neutrino emission in the core and thus can have higher r-mode amplitudes. Indeed, the inferred r-mode spin-down rates at these higher amplitudes are inconsistent with the observed spin-down rates for some of the sources, such as IGR J00291+5934 and XTE J1751-305. In the absence of other significant sources of internal heat, these results could be used to place an upper limit on the masses of these sources if they were made of hadronic matter, or alternatively it could be used to probe the existence of exotic matter in them if their masses were known.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010108266','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010108266"><span id="translatedtitle">The Discovery of a Second Luminous <span class="hlt">Low</span> <span class="hlt">Mass</span> X-ray <span class="hlt">Binary</span> in the Globular Cluster M15</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>White, Nicholas E.; Angelini, Lorella</p> <p>2001-01-01</p> <p>We report an observation by the Chandra X-ray Observatory of 4U2127+119, the X-ray source identified with the globular cluster M15. The Chandra observation reveals that 4U2127+119 is in fact two bright sources, separated by 2.7". One source is associated with AC21 1, the previously identified optical counterpart to 4U2127+119, a <span class="hlt">low</span> <span class="hlt">mass</span> X-ray <span class="hlt">binary</span> (LMXB). The second source, M15-X2, is coincident with a 19th U magnitude blue star that is 3.3" from the cluster core. The Chandra count rate of M15-X2 is 2.5 times higher than that of AC211. Prior to the 0.5" imaging capability of Chandra the presence of two so closely separated bright sources would not have been resolved, The optical counterpart, X-ray luminosity and spectrum of M15-X2 are consistent with it also being an LMXB system. This is the first time that two LMXBS have been seen to be simultaneously active in a globular cluster. The discovery of a second active LMXB in M15 solves a long standing puzzle where the properties of AC211 appear consistent with it being dominated by an extended accretion disk corona, and yet 4U2127+119 also shows luminous X-ray bursts requiring that the neutron star be directly visible. The resolution of 4U2127+119 into two sources suggests that the X-ray bursts did not come from AC211, but rather from M15X2. We discuss the implications of this discovery for understanding the origin and evolution of LMXBs in GCs as well as X-ray observations of globular clusters in nearby galaxies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...830..122J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...830..122J"><span id="translatedtitle">Timing Observations of PSR J1023+0038 During a <span class="hlt">Low-mass</span> X-Ray <span class="hlt">Binary</span> State</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jaodand, Amruta; Archibald, Anne M.; Hessels, Jason W. T.; Bogdanov, Slavko; D’Angelo, Caroline R.; Patruno, Alessandro; Bassa, Cees; Deller, Adam T.</p> <p>2016-10-01</p> <p>Transitional millisecond pulsars (tMSPs) switch, on roughly multi-year timescales, between rotation-powered radio millisecond pulsar (RMSP) and accretion-powered <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> (LMXB) states. The tMSPs have raised several questions related to the nature of accretion flow in their LMXB state and the mechanism that causes the state switch. The discovery of coherent X-ray pulsations from PSR J1023+0038 (while in the LMXB state) provides us with the first opportunity to perform timing observations and to compare the neutron star’s spin variation during this state to the measured spin-down in the RMSP state. Whereas the X-ray pulsations in the LMXB state likely indicate that some material is accreting onto the neutron star’s magnetic polar caps, radio continuum observations indicate the presence of an outflow. The fraction of the inflowing material being ejected is not clear, but it may be much larger than that reaching the neutron star’s surface. Timing observations can measure the total torque on the neutron star. We have phase-connected nine XMM-Newton observations of PSR J1023+0038 over the last 2.5 years of the LMXB state to establish a precise measurement of spin evolution. We find that the average spin-down rate as an LMXB is 26.8 ± 0.4% faster than the rate (‑2.39 × 10‑15 Hz s‑1) determined during the RMSP state. This shows that negative angular momentum contributions (dipolar magnetic braking, and outflow) exceed positive ones (accreted material), and suggests that the pulsar wind continues to operate at a largely unmodified level. We discuss implications of this tight observational constraint in the context of possible accretion models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140005665','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140005665"><span id="translatedtitle">Upper Bounds on r-Mode Amplitudes from Observations of <span class="hlt">Low-Mass</span> X-Ray <span class="hlt">Binary</span> Neutron Stars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mahmoodifar, Simin; Strohmayer, Tod</p> <p>2013-01-01</p> <p>We present upper limits on the amplitude of r-mode oscillations and gravitational-radiation-induced spin-down rates in <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> neutron stars, under the assumption that the quiescent neutron star luminosity is powered by dissipation from a steady-state r-mode. For masses <2M solar mass we find dimensionless r-mode amplitudes in the range from about 1×10(exp-8) to 1.5×10(exp-6). For the accreting millisecond X-ray pulsar sources with known quiescent spin-down rates, these limits suggest that approx. less than 1% of the observed rate can be due to an unstable r-mode. Interestingly, the source with the highest amplitude limit, NGC 6440, could have an r-mode spin-down rate comparable to the observed, quiescent rate for SAX J1808-3658. Thus, quiescent spin-down measurements for this source would be particularly interesting. For all sources considered here, our amplitude limits suggest that gravitational wave signals are likely too weak for detection with Advanced LIGO. Our highest mass model (2.21M solar mass) can support enhanced, direct Urca neutrino emission in the core and thus can have higher r-mode amplitudes. Indeed, the inferred r-mode spin-down rates at these higher amplitudes are inconsistent with the observed spin-down rates for some of the sources, such as IGR J00291+5934 and XTE J1751-305. In the absence of other significant sources of internal heat, these results could be used to place an upper limit on the masses of these sources if they were made of hadronic matter, or alternatively it could be used to probe the existence of exotic matter in them if their masses were known.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020022184&hterms=puzzles&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dpuzzles','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020022184&hterms=puzzles&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dpuzzles"><span id="translatedtitle">The Discovery of a Second Luminous <span class="hlt">Low-Mass</span> X-Ray <span class="hlt">Binary</span> in the Globular Cluster M15</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>White, Nicholas E.; Angelini, Lorella</p> <p>2001-01-01</p> <p>We report an observation by the Chandra X-Ray Observatory of 4U 2127+119, the X-ray source identified with the globular cluster M15. The Chandra observation reveals that 4U 2127+119 is in fact two bright sources, separated by 2.7 arcsec. One source is associated with AC 211, the previously identified optical counterpart to 4U 2127+119, a <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> (LMXB). The second source, M15 X-2, is coincident with a 19th U magnitude blue star that is 3.3 arcsec from the cluster core. The Chandra count rate of M15 X-2 is 2.5 times higher than that of AC 211. Prior to the 0.5 arcsec imaging capability of Chandra, the presence of two so closely separated bright sources would not have been resolved. The optical counterpart, X-ray luminosity, and spectrum of M15 X-2 are consistent with it also being an LMXB system. This is the first time that two LMXBs have been seen to be simultaneously active in a globular cluster. The discovery of a second active LMXB in M15 solves a long-standing puzzle where the properties of AC 211 appear consistent with it being dominated by an extended accretion disk corona, and yet 4U 2127+119 also shows luminous X-ray bursts requiring that the neutron star be directly visible. The resolution of 4U 2127+119 into two sources suggests that the X-ray bursts did not come from AC 211 but rather from M15 X-2. We discuss the implications of this discovery for understanding the origin and evolution of LMXBs in globular clusters as well as X-ray observations of globular clusters in nearby galaxies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008ApJ...687..542P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008ApJ...687..542P"><span id="translatedtitle">Artificial Intelligence Approach to the Determination of Physical Properties of <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span>. I. The EBAI Project</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prša, A.; Guinan, E. F.; Devinney, E. J.; DeGeorge, M.; Bradstreet, D. H.; Giammarco, J. M.; Alcock, C. R.; Engle, S. G.</p> <p>2008-11-01</p> <p>Achieving maximum scientific results from the overwhelming volume of astronomical data to be acquired over the next few decades demands novel, fully automatic methods of data analysis. Here we concentrate on <span class="hlt">eclipsing</span> <span class="hlt">binary</span> (EB) stars, a prime source of astrophysical information, of which only some hundreds have been rigorously analyzed, but whose numbers will reach millions in a decade. We describe the artificial neural network (ANN) approach which is able to surmount the human bottleneck and permit EB-based scientific yield to keep pace with future data rates. The ANN, following training on a sample of 33,235 model light curves, outputs a set of approximate model parameters [T2/T1, (R1 + R2)/a, esin ω , ecos ω , and sin i] for each input light curve data set. The obtained parameters can then be readily passed to sophisticated modeling engines. We also describe a novel method polyfit for preprocessing observational light curves before inputting their data to the ANN and present the results and analysis of testing the approach on synthetic data and on real data including 50 <span class="hlt">binaries</span> from the Catalog and Atlas of <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> (CALEB) database and 2580 light curves from OGLE survey data. The success rate, defined by less than a 10% error in the network output parameter values, is approximately 90% for the OGLE sample and close to 100% for the CALEB sample—sufficient for a reliable statistical analysis. The code is made available to the public. Our approach is applicable to EB light curves of all classes; this first paper in the <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> via artificial intelligence (EBAI) series focuses on detached EBs, which is the class most challenging for this approach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013ApJ...767...82G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ApJ...767...82G"><span id="translatedtitle">Red Giants in <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> and Multiple-star Systems: Modeling and Asteroseismic Analysis of 70 Candidates from Kepler Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gaulme, P.; McKeever, J.; Rawls, M. L.; Jackiewicz, J.; Mosser, B.; Guzik, J. A.</p> <p>2013-04-01</p> <p>Red giant stars are proving to be an incredible source of information for testing models of stellar evolution, as asteroseismology has opened up a window into their interiors. Such insights are a direct result of the unprecedented data from space missions CoRoT and Kepler as well as recent theoretical advances. <span class="hlt">Eclipsing</span> <span class="hlt">binaries</span> are also fundamental astrophysical objects, and when coupled with asteroseismology, <span class="hlt">binaries</span> provide two independent methods to obtain masses and radii and exciting opportunities to develop highly constrained stellar models. The possibility of discovering pulsating red giants in <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems is therefore an important goal that could potentially offer very robust characterization of these systems. Until recently, only one case has been discovered with Kepler. We cross-correlate the detected red giant and <span class="hlt">eclipsing-binary</span> catalogs from Kepler data to find possible candidate systems. Light-curve modeling and mean properties measured from asteroseismology are combined to yield specific measurements of periods, masses, radii, temperatures, <span class="hlt">eclipse</span> timing variations, core rotation rates, and red giant evolutionary state. After using three different techniques to eliminate false positives, out of the 70 systems common to the red giant and <span class="hlt">eclipsing-binary</span> catalogs we find 13 strong candidates (12 previously unknown) to be <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>, one to be a non-<span class="hlt">eclipsing</span> <span class="hlt">binary</span> with tidally induced oscillations, and 10 more to be hierarchical triple systems, all of which include a pulsating red giant. The systems span a range of orbital eccentricities, periods, and spectral types F, G, K, and M for the companion of the red giant. One case even suggests an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> composed of two red giant stars and another of a red giant with a δ-Scuti star. The discovery of multiple pulsating red giants in <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> provides an exciting test bed for precise astrophysical modeling, and follow-up spectroscopic observations of many of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22167397','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22167397"><span id="translatedtitle">RED GIANTS IN <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> AND MULTIPLE-STAR SYSTEMS: MODELING AND ASTEROSEISMIC ANALYSIS OF 70 CANDIDATES FROM KEPLER DATA</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gaulme, P.; McKeever, J.; Rawls, M. L.; Jackiewicz, J.; Mosser, B.; Guzik, J. A.</p> <p>2013-04-10</p> <p>Red giant stars are proving to be an incredible source of information for testing models of stellar evolution, as asteroseismology has opened up a window into their interiors. Such insights are a direct result of the unprecedented data from space missions CoRoT and Kepler as well as recent theoretical advances. <span class="hlt">Eclipsing</span> <span class="hlt">binaries</span> are also fundamental astrophysical objects, and when coupled with asteroseismology, <span class="hlt">binaries</span> provide two independent methods to obtain masses and radii and exciting opportunities to develop highly constrained stellar models. The possibility of discovering pulsating red giants in <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems is therefore an important goal that could potentially offer very robust characterization of these systems. Until recently, only one case has been discovered with Kepler. We cross-correlate the detected red giant and <span class="hlt">eclipsing-binary</span> catalogs from Kepler data to find possible candidate systems. Light-curve modeling and mean properties measured from asteroseismology are combined to yield specific measurements of periods, masses, radii, temperatures, <span class="hlt">eclipse</span> timing variations, core rotation rates, and red giant evolutionary state. After using three different techniques to eliminate false positives, out of the 70 systems common to the red giant and <span class="hlt">eclipsing-binary</span> catalogs we find 13 strong candidates (12 previously unknown) to be <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>, one to be a non-<span class="hlt">eclipsing</span> <span class="hlt">binary</span> with tidally induced oscillations, and 10 more to be hierarchical triple systems, all of which include a pulsating red giant. The systems span a range of orbital eccentricities, periods, and spectral types F, G, K, and M for the companion of the red giant. One case even suggests an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> composed of two red giant stars and another of a red giant with a {delta}-Scuti star. The discovery of multiple pulsating red giants in <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> provides an exciting test bed for precise astrophysical modeling, and follow-up spectroscopic observations of many</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E2116Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E2116Y"><span id="translatedtitle">Orbital period variation study of massive Beta-Lyrae <span class="hlt">eclipsing</span> <span class="hlt">binary</span> IU Auriga</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yilan, Erkan; Bulut, İbrahim</p> <p>2016-07-01</p> <p>The system IU Aur is a semi-detached close <span class="hlt">binary</span> system with an orbital period of 1.81 days, containing a massive star. The O-C diagram of this <span class="hlt">binary</span> was analyzed with the least-squares method by using all available times of minima. We have found a periodic change of orbital period of IU Aur. This change has been explained by the gravitational effects of a third companion on the binay star. The orbit Parameters of the third body have been derived from the analysis of the O-C curve. The analysis indicates that the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> revolves around a third-body with a mass of about M_{3}>10M_{⊙} in a highly eccentric orbit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850060943&hterms=relativity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Drelativity','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850060943&hterms=relativity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Drelativity"><span id="translatedtitle">The apsidal motion of the eccentric <span class="hlt">eclipsing</span> <span class="hlt">binary</span> DI Herculis - An apparent discrepancy with general relativity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Guinan, E. F.; Maloney, F. P.</p> <p>1985-01-01</p> <p>The apsidal motion of the eccentric <span class="hlt">eclipsing</span> <span class="hlt">binary</span> DI Herculis (HD 175227) is determined from an analysis of the available observations and <span class="hlt">eclipse</span> timings from 1959 to 1984. Least squares solutions to the primary and secondary minima extending over an 84-yr interval yielded a small advance of periastron omega dot of 0.65 deg/100 yr + or - 0.18/100 yr. The observed advance of the periastron is about one seventh of the theoretical value of 4.27 deg/100 yr that is expected from the combined relativistic and classical effects. The discrepancy is about -3.62 deg/100 yr, or a magnitude of about 20 sigma. Classical mechanisms which explain the discrepancy are discussed, together with the possibility that there may be problems with general relativity itself.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4812010R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4812010R"><span id="translatedtitle">Observations of Mutual <span class="hlt">Eclipses</span> by the <span class="hlt">Binary</span> Kuiper Belt Object Manwe-Thorondor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rabinowitz, David L.; Benecchi, Susan D.; Grundy, William M.; Thirouin, Audrey; Verbiscer, Anne J.</p> <p>2016-10-01</p> <p>The <span class="hlt">binary</span> Kuiper Belt Object (385446) Manwe-Thorondor (aka 2003 QW111) is currently undergoing mutual events whereby the two ~100-km bodies alternately <span class="hlt">eclipse</span> and occult each other as seen from Earth [1]. Such events are extremely rare among KBOs (Pluto-Charon and Sila-Nunam being notable exceptions). For Manwe-Thorondor, the events occur over ~0.5-d periods 4 to 5 times per year until the end of 2019. Here we report the results of observations to be made with the Soar 4m telescope at Cerro Pachon, Chile on 2016 Aug 25 and 26 UT, covering one of the deepest predicted <span class="hlt">eclipses</span>. We use these observations to constrain the rotational variability of the two bodies, determine their physical properties (size, shape, albedo, density), and set limits on the presence of any prominent surface features.[1] Grundy, W. et al. 2012, Icarus, 220, 74</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AAS...21341012B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AAS...21341012B"><span id="translatedtitle">Light Curves and Analyses of the <span class="hlt">Eclipsing</span> Overcontact <span class="hlt">Binaries</span> V1033 Her and V1044 Her</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bradstreet, David H.; Sanders, S. J.; Wiley, T. B.; Plumberg, C. J.; Grau, D. M.</p> <p>2009-01-01</p> <p>New precision V & Rc light curves of the <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> V1033 Her and V1044 Her have been obtained using the 41-cm telescope at the Eastern University Observatory equipped with an SBIG ST-10XME CCD. V1033 Her (GSC 2066:1210, P = 0.2981 days, m = 11.2) has only one published unfiltered light curve (Blattler and Diethelm 2001a) with significant scatter in the data. The system was observed on seven nights from 15 Jun - 26 Jul 2006, accumulating approximately 800 observations in both V and Rc. The light curves show distinctly that the system is totally <span class="hlt">eclipsing</span> and preliminary analysis indicates that that <span class="hlt">binary</span> is W-type (the larger, more massive star is the cooler component), has a mass ratio of 0.30, small temperature difference between the stars of 300 K, and a fillout of 0.20. V1044 Her (GSC 3073:837, P = 0.2406 days, m = 12.5) is a partially <span class="hlt">eclipsing</span> overcontact system of very short period and relatively deep <span class="hlt">eclipses</span> of 0.6 mag in Rc. The previously published unfiltered light curve given by Blattler and Diethelm (2001b) had too much scatter for reliable analysis. V1044 Her was observed on eleven nights from 5 Jun - 10 Jul 2005, accumulating more than 800 observations in both V and Rc. Preliminary light curve models indicate a W-type system with a small temperature difference between the stars of 200 K, inclination greater than 80 degrees and an indication of the presence of starspots. The complete light curve analyses as well as a period study of all published times of minimum light will be presented for both systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AN....337..793B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AN....337..793B"><span id="translatedtitle">Testing asteroseismic scaling relations using <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in star clusters and the field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brogaard, K.; Jessen-Hansen, J.; Handberg, R.; Arentoft, T.; Frandsen, S.; Grundahl, F.; Bruntt, H.; Sandquist, E. L.; Miglio, A.; Beck, P. G.; Thygesen, A. O.; Kjærgaard, K. L.; Haugaard, N. A.</p> <p>2016-09-01</p> <p>The accuracy of stellar masses and radii determined from asteroseismology is not known! We examine this issue for giant stars by comparing classical measurements of detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems (dEBs) with asteroseismic measurements from the Kepler mission. For star clusters, we extrapolate measurements of dEBs in the turn-off region to the red giant branch and the red clump where we investigate the giants as an ensemble. For the field stars, we measure dEBs with an oscillating giant component. These measurements allow a comparison of masses and radii calculated from a classical <span class="hlt">eclipsing</span> <span class="hlt">binary</span> analysis to those calculated from asteroseismic scaling relations and/or other asteroseismic methods. Our first results indicate small but significant systematic differences between the classical and asteroseismic measurements. In this contribution we show our latest results and summarize the current status and future plans. We also stress the importance of realizing that for giant stars mass cannot always be translated to age, since an unknown fraction of these evolved through a blue straggler phase with mass transfer in a <span class="hlt">binary</span> system. Rough estimates of how many such stars to expect are given based on our findings in the open clusters NGC 6819 and NGC 6791.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010AIPC.1263..197P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010AIPC.1263..197P&link_type=ABSTRACT"><span id="translatedtitle">Physical Properties and Evolution of the <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> System XZ Canis Minoris</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poochaum, R.; Komonjinda, S.; Soonthornthum, B.; Rattanasoon, S.</p> <p>2010-07-01</p> <p>This research aims to study the <span class="hlt">eclipse</span> <span class="hlt">binary</span> system so that its physical properties and evolution can be determined and used as an example to teach high school astronomy. The study of an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system XZ Canis Minoris (XZ CMi) was done at Sirindhorn Observatory, Chiang Mai University using a 0.5-meter reflecting telescope with CCD photometric system (2184×1417 pixel) in B V and R bands of UVB System. The data obtained were used to construct the light curve for each wavelength band and to compute the times of its light minima. New elements were derived using observations with linear to all available minima. As a result, linear ephemeris is HDJmin I = .578 808 948+/-0.000 000 121+2450 515.321 26+/-0.001 07 E, and the new orbital period of XZ CMi is 0.578 808 948+/-0.000 000 121 day. The values obtained were used with the previously published times of minima to get O-C curve of XZ CMi. The result revealed that the orbital period of XZ CMi is continuously decreased at a rate of 0.007 31+/-0.000 57 sec/year. This result indicates that the <span class="hlt">binary</span> stars are moving closer continuously. From the O-C residuals, there is significant change to indicate the existence of the third body or magnetic activity cycle on the star. However, further analysis of the physical properties of XZ CMi is required.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000A%26A...356..665R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000A%26A...356..665R&link_type=ABSTRACT"><span id="translatedtitle">NLTE spectral analysis of the sdOB primary of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system LB 3459 (AA Dor)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rauch, T.</p> <p>2000-04-01</p> <p>We present a spectral analysis of the sdOB primary star of the <span class="hlt">binary</span> system LB 3459 based on high-resolution high-S/N optical and UV spectra. The metal abundances are determined by means of state-of-the-art NLTE model atmospheres. We determined Teffw42 and log gw{5.2} within very small error limits. The He (1/125 solar), C (1/265), N (1/33), O (1/12), and Si (1/5) abundances appear strongly depleted while that of Fe and Ni are roughly solar and Mg is strongly enriched by a factor of 6. The spectroscopic distance to LB 3459 is d = 396 pc. The mass of the primary component of LB 3459 is 0.330 M_sun derived from comparisons with theoretical models for sdO stars in the log T_eff - \\log g plane. The mass of the secondary is then 0.066 M_sun derived from the mass function. There remains some disagreement between the radius derived from log g and the above mass, and that derived from analysis of the radial-velocity curve and the <span class="hlt">eclipse</span> curves. LB 3459 is a close <span class="hlt">binary</span> system which had experienced a common envelope (CE) phase during its evolution. It fits in the ``<span class="hlt">low</span> <span class="hlt">mass</span> case B'' scenario of Iben & Livio (1993) and the secondary is a brown dwarf. The spectroscopically determined rotational velocity of the primary is v_rot = 34 ± 10 km* sec-1. Thus even bound rotation (v_rot = 45.7 km* sec-1) cannot be ruled out. Based on observations collected at the European Southern Observatory, La Silla, Chile (proposals 55.D-0319, 56.C-0165) and on data retrieved from the International Ultraviolet Explorer (IUE) Final Archive.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ASPC..496..258S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ASPC..496..258S"><span id="translatedtitle">First Spectroscopic Solutions of Two Southern <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span>: HO Tel and QY Tel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sürgit, D.; Erdem, A.; Engelbrecht, C. A.; van Heerden, P.; Manick, R.</p> <p>2015-07-01</p> <p>We present preliminary results from the analysis of spectroscopic observations of two southern <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars, HO Tel and QY Tel. The grating spectra of these two systems were obtained at the Sutherland Station of the South African Astronomical Observatory in 2013. Radial velocities of the components were determined by the Fourier disentangling technique. Keplerian radial velocity models of HO Tel and QY Tel give their mass ratio as 0.921±0.005 and 1.089±0.007, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJS..226...21C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJS..226...21C"><span id="translatedtitle">A Catalog of <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> and Variable Stars Observed with ASTEP 400 from Dome C, Antarctica</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chapellier, E.; Mékarnia, D.; Abe, L.; Guillot, T.; Agabi, K.; Rivet, J.-P.; Schmider, F.-X.; Crouzet, N.; Aristidi, E.</p> <p>2016-10-01</p> <p>We used the large photometric database of the ASTEP program, whose primary goal was to detect exoplanets in the southern hemisphere from Antarctica, to search for <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> (EcBs) and variable stars. 673 EcBs and 1166 variable stars were detected, including 31 previously known stars. The resulting online catalogs give the identification, the classification, the period, and the depth or semi-amplitude of each star. Data and light curves for each object are available at http://astep-vo.oca.eu.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AAS...22840105M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AAS...22840105M"><span id="translatedtitle">Finding False Positives Planet Candidates Due To Background <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> in K2</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mullally, Fergal; Thompson, Susan E.; Coughlin, Jeffrey; DAVE Team</p> <p>2016-06-01</p> <p>We adapt the difference image centroid approach, used for finding background <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>, to vet K2 planet candidates. Difference image centroids were used with great success to vet planet candidates in the original Kepler mission, where the source of a transit could be identified by subtracting images of out-of-transit cadences from in-transit cadences. To account for K2's roll pattern, we reconstruct out-of-transit images from cadences that are nearby in both time and spacecraft roll angle. We describe the method and discuss some K2 planet candidates which this method suggests are false positives.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1984A%26AS...55..403B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1984A%26AS...55..403B"><span id="translatedtitle">Analysis of the U-B-V photoelectric light curves of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> GT CEP</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bartolini, C.; Bonifazi, A.; Milano, L.</p> <p>1984-03-01</p> <p>The authors analyse the UBV light curves of GT Cep with different methods of solution. Some difficulties arise from the peculiar morphology of the light curves. The authors discuss the set of results and finally adopt the solution they derived by the Wilson and Devinney direct method. The system results to be a semi-detached one and this fact partly justifies the observed peculiarities. Given their results, the authors question the physical reliability of different models representing the light curves of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015adap.prop...14L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015adap.prop...14L"><span id="translatedtitle">A First Robust Measurement of the Aging of Field <span class="hlt">Low</span> <span class="hlt">Mass</span> X-ray <span class="hlt">Binary</span> Populations from Hubble and Chandra</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lehmer, Bret</p> <p></p> <p>Our understanding of X-ray <span class="hlt">binary</span> (XRB) formation and evolution have been revolutionized by HST and Chandra by allowing us to study in detail XRBs in extragalactic environments. Theoretically, XRB formation is sensitive to parent stellar population properties like metallicity and stellar age. These dependencies not only make XRBs promising populations for aiding in the measurement of galaxy properties themselves, but also have important astrophysical implications. For example, due to the relatively young stellar ages and primordial metallicities in the early Universe (z > 3), it is predicted that XRBs were more luminous than today and played a significant role in the heating of the intergalactic medium. Unlocking the potential of XRBs as useful probes of galaxy properties and understanding in detail their evolutionary pathways critically requires empirical constraints using well-studied galaxies that span a variety of evolutionary stages. In this ADAP, we will use the combined power of archival observations from Hubble and Chandra data of 16 nearby early-type galaxies to study how <span class="hlt">low-mass</span> XRBs (LMXBs) populations evolve with age. LMXBs are critically important since they are the most numerous XRBs in the MW and are expected to dominate the normal galaxy Xray emissivity of the Universe out to z ~ 2. Understanding separately LMXBs that form via dynamical interactions (e.g., in globular clusters; GCs) versus those that form in-situ in galactic fields is an important poorly constrained area of XRB astrophysics. We are guided by the following key questions: 1. How does the shape and normalization of the field LMXB X-ray luminosity function (XLF) evolve as parent stellar populations age? Using theoretical population synthesis models, what can we learn about the evolution of contributions from various LMXB donor stars (e.g., red-giant, main-sequence, and white dwarf donors)? 2. Is there any evidence that globular cluster (GC) LMXBs seeded field LMXB populations through</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21448866','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21448866"><span id="translatedtitle">DISCOVERY OF A SECOND TRANSIENT <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARY</span> IN THE GLOBULAR CLUSTER NGC 6440</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Heinke, C. O.; Budac, S. A.; Altamirano, D.; Linares, M.; Wijnands, R.; Cohn, H. N.; Lugger, P. M.; Servillat, M.; Grindlay, J. E.; Strohmayer, T. E.; Markwardt, C. B.; Swank, J. H.; Bailyn, C.</p> <p>2010-05-01</p> <p>We have discovered a new transient <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span>, NGC 6440 X-2, with Chandra/ACIS, RXTE/PCA, and Swift/XRT observations of the globular cluster NGC 6440. The discovery outburst (2009 July 28-31) peaked at L{sub X} {approx} 1.5 x 10{sup 36} erg s{sup -1} and lasted for <4 days above L{sub X} = 10{sup 35} erg s{sup -1}. Four other outbursts (2009 May 29-June 4, August 29-September 1, October 1-3, and October 28-31) have been observed with RXTE/PCA (identifying millisecond pulsations) and Swift/XRT (confirming a positional association with NGC 6440 X-2), with similar peak luminosities and decay times. Optical and infrared imaging did not detect a clear counterpart, with best limits of V>21, B>22 in quiescence from archival Hubble Space Telescope imaging, g'>22 during the August outburst from Gemini-South GMOS imaging, and J {approx_gt} 18.5 and K {approx_gt} 17 during the July outburst from CTIO 4 m ISPI imaging. Archival Chandra X-ray images of the core do not detect the quiescent counterpart (L{sub X} < (1-2) x 10{sup 31} erg s{sup -1}) and place a bolometric luminosity limit of L{sub NS} < 6 x 10{sup 31} erg s{sup -1} (one of the lowest measured) for a hydrogen atmosphere neutron star. A short Chandra observation 10 days into quiescence found two photons at NGC 6440 X-2's position, suggesting enhanced quiescent emission at L{sub X} {approx} 6 x 10{sup 31} erg s{sup -1}. NGC 6440 X-2 currently shows the shortest recurrence time ({approx}31 days) of any known X-ray transient, although regular outbursts were not visible in the bulge scans before early 2009. Fast, low-luminosity transients like NGC 6440 X-2 may be easily missed by current X-ray monitoring.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015CQGra..32w5007C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015CQGra..32w5007C"><span id="translatedtitle">Parameter estimation using a complete signal and inspiral templates for <span class="hlt">low-mass</span> <span class="hlt">binary</span> black holes with Advanced LIGO sensitivity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cho, Hee-Suk</p> <p>2015-12-01</p> <p>We study the validity of inspiral templates in gravitational wave data analysis with Advanced LIGO sensitivity for <span class="hlt">low</span> <span class="hlt">mass</span> <span class="hlt">binary</span> black holes with total masses of M≤slant 30{M}⊙ . We mainly focus on the nonspinning system. As our complete inspiral-merger-ringdown waveform model ({I}{M}{R} ), we assume the phenomenological model, ‘PhenomA’, and define our inspiral template model ({{I}}{{merg}}) by taking the inspiral part into account from {I}{M}{R} up to the merger frequency ({f}{{merg}}). We first calculate the true statistical uncertainties using {I}{M}{R} signals and {I}{M}{R} templates. Next, using {I}{M}{R} signals and {{I}}{{merg}} templates, we calculate fitting factors and systematic biases, and compare the biases with the true statistical uncertainties. We find that the valid criteria of the bank of {{I}}{{merg}} templates are obtained as {M}{{crit}}˜ 24{M}⊙ for detection (if M\\gt {M}{{crit}}, the fitting factor is smaller than 0.97), and {M}{{crit}}˜ 26{M}⊙ for parameter estimation (if M\\gt {M}{{crit}}, the systematic bias is larger than the true statistical uncertainty where the signal-to-noise ratio is 20), respectively. In order to see the dependence on the cutoff frequency of the inspiral waveforms, we define another inspiral model {{I}}{{isco}} which is terminated at the innermost-stable-circular-orbit frequency ({f}{{isco}}\\lt {f}{{merg}}). We find that the valid criteria of the bank of {{I}}{{isco}} templates are obtained as {M}{{crit}}˜ 15{M}⊙ and ˜ 17{M}⊙ for detection and parameter estimation, respectively. We investigate the statistical uncertainties for the inspiral template models considering various signal-to-noise ratios, and compare those to the true statistical uncertainties. We also consider the aligned-spinning system with fixed mass ratio ({m}1/{m}2=3) and spin (χ =0.5) by employing the recent phenomenological model, ‘PhenomC’. In this case, we find that the true statistical uncertainties can be much larger</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991PhDT........73H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991PhDT........73H"><span id="translatedtitle">A Spectroscopic Analysis of Extended Matter in <span class="hlt">Eclipsing</span> RS CVN <span class="hlt">Binaries</span>.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hall, Jeffrey Clifton</p> <p>1991-02-01</p> <p>I have conducted a survey of a number of <span class="hlt">eclipsing</span> RS CVn <span class="hlt">binaries</span> to search for the presence of extended matter associated with the component stars. Previous evidence indicates that this extended matter is more like solar quiescent prominences than other structures such as plage; as such, it is most identifiable when viewed off the stellar limb. In <span class="hlt">eclipsing</span> systems, the matter can be seen indirectly as it obscures a portion of the <span class="hlt">eclipsed</span> star's limb. My survey has identified some systems in which this is the case. Parameterization of the physical extent of the extended matter is a geometrical problem wherein the amount of obscuration caused by the prominence depends on its size and orientation as well as its optical depth in the line of interest. I have done this using a Simplex algorithm which I have developed and specifically tailored to the problem at hand. I classify the extended components I have seen and discuss their effect on the spectral profiles. Other spectral diagnostics provide clues as to their origin, and I discuss this in the context of the present "solar analogy" paradigm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016aspk.conf...60V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016aspk.conf...60V"><span id="translatedtitle">A possible third component in the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system HS 2231+2441</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vidmachenko, A. P.; Romanyuk, Ya. O.; Shliahetskaya, Ya. O.</p> <p>2016-05-01</p> <p>We used a differential photometry method in which we compared the flow of program star and standard one. Observations of the 21 nights in the period from July 26 to December 2, 2015 are used for processing. The accuracy of determining for each measurement is in the range 0,003...0,009 m for different nights. On the basis of obtained data were created corresponding light curves. Next, we calculate the time difference between the centers of transits. Its time dependence showed the presence of a possible periodic change in the deflection of the middle transit time from the calculated average value. This may indicate the presence of a third object in the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system. It has been found that the periodic variation of the orbital period can be explained by the gravitational influence of a third companion on the central <span class="hlt">binary</span> system with an orbital period of about 97±10 d.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006Ap%26SS.304...29B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006Ap%26SS.304...29B"><span id="translatedtitle">Updated UBV Light-Curve and Period Analysis of <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> HS Herculis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bozkurt, Zeynep; Değirmenci, Ömer Lütfi</p> <p>2006-08-01</p> <p>UBV light-curves of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> HS Herculis, obtained in 2002 2003 observational seasons, were analysed with Wilson-Devinney computer code. New absolute dimensions of the system were calculated using the results of the light-curve analysis. Period variation of the system was also investigated. Several new times of minima have been secured for this problematic system. An apsidal motion with a period of 80.7 years was confirmed and a third body in a pretty eccentric orbit (e 3 = 0.90 ± 0.08) with a period of 85.4 years was found. The corresponding internal structure constants of the <span class="hlt">binary</span> system, log k 2, and the mass of the third body were derived.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006Ap%26SS.tmp..250B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006Ap%26SS.tmp..250B"><span id="translatedtitle">Updated UBV Light-Curve and Period Analysis of <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> HS Herculis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bozkurt, Zeynep; Değirmenci, Ömer Lütfi</p> <p>2006-08-01</p> <p>UBV light-curves of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> HS Herculis, which obtained in 2002--2003 observational seasons, were analysed with Wilson-Devinney computer code. New absolute dimensions of the system were calculated using the results of the light-curve analysis. Period variation of the system also investigated. Several new times of minima have been secured for this problematic system. An apsidal motion with the period of 80.7 years was confirmed and a third body in an pretty eccentric orbit (e 3 = 0.90 ± 0.08) with a period of 85.4 years was found. The corresponding internal structure constants of the <span class="hlt">binary</span> system, log k 2, and mass of third body were derived.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996AAS...188.6008G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996AAS...188.6008G&link_type=ABSTRACT"><span id="translatedtitle">Multiband Photometry of Southern Very Short Period <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span>. I. V676 Centauri</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gray, J. D.; Samec, R. G.; Woissol, S. L.</p> <p>1996-05-01</p> <p>In this paper, we extend our study of solar-type <span class="hlt">binaries</span> near the the low period limit to include Southern hemisphere systems. Observations are being taken at Cerro Tololo Inter-American Observatory, Chile. Here, we report B,V,R,I observations of V676 Centauri. Our three nights of data were taken in May of 1991 with a dry ice cooled Ga-As photometer attached to the 1.0-m reflector. Two new primary and two secondary epochs of minimum light were determined from the observations, and more than 100 minima were collected from the literature. Our period study spans some 35 years. The light curves show a rather large difference in <span class="hlt">eclipse</span> depths for a W UMa <span class="hlt">binary</span>. An O'Connell effect lends evidence of spot activity in this very short period ( 0.291 d) system. A preliminary photometric analysis of the light curves is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006Ap%26SS.304..347P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006Ap%26SS.304..347P"><span id="translatedtitle">Disentangling Effective Temperatures of Individual <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Components by Means of Color-Index Constraining</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prša, A.; Zwitter, T.</p> <p>2006-08-01</p> <p><span class="hlt">Eclipsing</span> <span class="hlt">binary</span> stars are gratifying objects because of their unique geometrical properties upon which all important physical parameters such as masses, radii, temperatures, luminosities and distance may be obtained in absolute scale. This poses strict demand on the model to be free of systematic effects that would influence the results later used for calibrations, catalogs and evolution theory. We present an objective scheme of obtaining individual temperatures of both <span class="hlt">binary</span> system components by means of color-index constraining, with the only requirement that the observational data-set is acquired in a standard photometric system. We show that for a modest case of two similar main-sequence components the erroneous approach of assuming the temperature of the primary star from the color index yields temperatures which are systematically wrong by ˜ 100K.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6577863','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6577863"><span id="translatedtitle">Analysis of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> ST Carinae using the SIMPLEX algorithm</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Walker, R.L.; Chambliss, C.R. Kutztown Univ., PA )</p> <p>1990-07-01</p> <p>This work presents the analyses of two UBV data sets for the Algol <span class="hlt">binary</span> ST Carinae, presenting a homogeneous study of all the data. The light-curve parameters for the system are derived using the Wilson-Devinney model (1917), with the SIMPLEX algorithm as an optimization procedure, and a mass ratio of q=0.54 is obtained. The primary has colors consistent with a B9.5 V primary, and the solution indicates that the secondary is an F subgiant (Te=6200 K) that fills its Roche lobe. The application of Kepler's law (using the observed period and the mass ratio determined in this investigation) indicates that the absolute dimensions for the components are normal for their respective classes. A description of SIMPLEX is given, and its advantages for the solution of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> parameters are discussed. 19 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AAS...20915114H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AAS...20915114H"><span id="translatedtitle">Light Curve Analysis for W UMa-Type <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Star Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Henderson, Scott; Peach, N.; Olsen, T.</p> <p>2006-12-01</p> <p>We report results from summer 2006 in an ongoing study of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars. Our investigations have focused on the measurement and interpretation of light curves for W UMa-type systems 44i Boötis and VW Cephei. These contact <span class="hlt">binaries</span> have component stars of spectral type G, and revolve with periods of 6.43 and 6.67 hours. Dome automation and scripting capabilities introduced this summer have significantly reduced experimental uncertainties in our data. In support of previous findings we continue to observe an increase in the orbital period of 44i Boo at a rate of 10.4 µs/epoch or 14.2 ms/yr. Residuals computed after incorporating the increasing period suggest an underlying sinusoidal oscillation with a 61.5 year period and amplitude of 648 seconds. AAPT Member Thomas Olsen is sponsoring the lead presenter, SPS Member Scott Henderson, and the co-presenter, SPS Member Nick Peach.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997IAUJD..13E...2G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997IAUJD..13E...2G"><span id="translatedtitle">Photometric Searches for Planets: Evidence of a Transit <span class="hlt">Eclipse</span> by a Jupiter-size Planet Orbiting the <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> CM Draconis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guinan, E. F.; McCook, G. P.; Wright, S.; Bradstreet, D. H.</p> <p></p> <p>We report the possible photometric detection of a planetary transit <span class="hlt">eclipse</span> for the dM4 + dM4 (P = 1.268d) <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star CM Dra. CM Dra was selected as a target for a planetary transit search because its orbital plane is seen almost exactly edge-on and its component stars radii are small relative to the Sun. Photoelectric photometry has been conducted from Mt. Hopkins since 1995 using the Four College Consortium 0.8m APT. On 01 June 1996 UT, during the 3.5hr observing interval from 04:15 to 07:45 UT, CM Dra was fainter by 0.08 mag in the I-band. We modelled the light variation as a planetary transit <span class="hlt">eclipse</span> of the dM star whose limb-darkening (x = 0.45) is from the light curve of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span>. Good fits of the data were obtained for a planet with a diameter = 0.94 +/- 0.04Dj and having an orbital period of about P = 2.2 +/- 0.4 yrs. This putative orbital period is close to the elapsed time interval of 2.01 yrs between the transit event reported here (IAUC No. 6423) and that reported by Martin and Deeg (IAUC No. 6425). Observations of additional photometric transits are needed to confirm the presence of a planet in the CM Dra system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JAVSO..41..182M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JAVSO..41..182M"><span id="translatedtitle">Discovery of Pulsating Components in the Southern <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Systems AW Velorum, HM Puppis, and TT Horologii</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moriarty, D. J. W.; Bohlsen, T.; Heathcote, B.; Richards, T.; Streamer, M.</p> <p>2013-09-01</p> <p><span class="hlt">Eclipsing</span> <span class="hlt">binary</span> stars with pulsating components are especially valuable for studies of stellar evolution. We have discovered that three <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars in the southern sky have a pulsating component with oscillations similar to those of delta Scuti stars. The systems are: AW Velorum, HM Puppis, and TT Horologii. Their spectral types were determined as A7 for AW Vel and HM Pup and F0-F2 for TT Hor. The dominant pulsation frequencies are 15-38 cycles per day with amplitudes of 10-60 millimagnitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.460.4220L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.460.4220L"><span id="translatedtitle">KIC 6220497: a new Algol-type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> with multiperiodic pulsations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Jae Woo; Hong, Kyeongsoo; Kim, Seung-Lee; Koo, Jae-Rim</p> <p>2016-08-01</p> <p>We present both binarity and pulsation of KIC 6220497 from the Kepler observations. The light curve synthesis shows that the <span class="hlt">eclipsing</span> system is a semidetached Algol with parameters of q = 0.243 ± 0.001, i = 77.3 ± 0.3 deg, and ΔT = 3372 ± 58 K, in which the detached primary component fills its Roche lobe by ˜87 per cent. A multiple frequency analysis of the <span class="hlt">eclipse</span>-subtracted light residuals reveals 33 frequencies in the range of 0.75-20.22 d-1 with amplitudes between 0.27 and 4.56 mmag. Among these, four are pulsation frequencies in fundamental (f1, f5) and p (f2, f7) modes, and six are orbital frequency (f8, f31) and its harmonics (f6, f11, f20, f24), which can be attributed to tidally excited modes. For the pulsation frequencies, the pulsation constants of 0.16-0.33 d and the period ratios of Ppul/Porb = 0.042-0.089 indicate that the primary component is a δ Sct pulsating star and, thus, KIC 6220497 is an oscillating <span class="hlt">eclipsing</span> Algol (oEA) star. The dominant pulsation period of 0.117 4051 ± 0.000 0004 d is significantly longer than that expected from empirical relations that link the pulsation period with the orbital period. The surface gravity of log g1 = 3.78 ± 0.03 is clearly smaller than those of the other oEA stars with similar orbital periods. The pulsation period and the surface gravity of the pulsating primary demonstrate that KIC 6220497 would be the more evolved <span class="hlt">eclipsing</span> <span class="hlt">binary</span>, compared with normal oEA stars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930007563','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930007563"><span id="translatedtitle">The atmospheric structures of the companion stars of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> x ray sources</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Clark, George W.</p> <p>1992-01-01</p> <p>This investigation was aimed at determining structural features of the atmospheres of the massive early-type companion stars of <span class="hlt">eclipse</span> x-ray pulsars by measurement of the attenuation of the x-ray spectrum during <span class="hlt">eclipse</span> transitions and in deep <span class="hlt">eclipse</span>. Several extended visits were made to ISAS in Japan by G. Clark and his graduate student, Jonathan Woo to coordinate the Ginga observations and preliminary data reduction, and to work with the Japanese host scientist, Fumiaki Nagase, in the interpretation of the data. At MIT extensive developments were made in software systems for data interpretation. In particular, a Monte Carlo code was developed for a 3-D simulation of the propagation of x-rays from the neutron star through the ionized atmosphere of the companion. With this code it was possible to determine the spectrum of Compton-scattered x-rays in deep <span class="hlt">eclipse</span> and to subtract that component from the observed spectra, thereby isolating the software component that is attributable in large measure to x-rays that have been scattered by interstellar grains. This research has culminated in the submission of paper to the Astrophysical Journal on the determination of properties of the atmosphere of QV Nor, the BOI companion of 4U 1538-52, and the properties of interstellar dust grains along the line of sight from the source. The latter results were an unanticipated byproduct of the investigation. Data from Ginga observations of the Magellanic <span class="hlt">binaries</span> SMC X-1 and LMC X-4 are currently under investigation as the PhD thesis project of Jonathan Woo who anticipated completion in the spring of 1993.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ysc..conf...21V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ysc..conf...21V"><span id="translatedtitle">On a possible additional component in an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system HS 2231 + 2441</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vidmachenko, A. P.; Romanyuk, Ya. O.; Shliahetskaya, Ya. O.</p> <p>2016-05-01</p> <p>Timing method based on the registration period of variations of a periodic process, associated with the star. The study of stellar <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system for a long time allows a series of several transits, depending on the orbital period of the satellite smaller. We present a photometric study of system of the type HW Vir HS 2231 + 2441. Photometric data processing was performed using C-MuniWin Version 1.2.30 program. The accuracy of values for each observation point is in the range 0,003...0,009m for different nights. The calculated ephemeris determined from the light curve by fitting of arc of minimums to the nuclei of primary and secondary <span class="hlt">eclipses</span>. The amplitude of the periodic changes of minimums moments that arise from the orbital motion of a close pair of stars around the barycenter of the triple system, is less than 0.0008 days (1.15 minutes). It was found that the periodic variation of the orbital period can be explained by the gravitational influence of a third companion on the central <span class="hlt">binary</span> system with an orbital period of about 97±10d. Periodogram analysis of the observational data series indicate also on the periodicity with values of 48±5d and 195±15d, but with substantially less reliably</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...594A.100B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...594A.100B"><span id="translatedtitle">New planetary and <span class="hlt">eclipsing</span> <span class="hlt">binary</span> candidates from campaigns 1-6 of the K2 mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barros, S. C. C.; Demangeon, O.; Deleuil, M.</p> <p>2016-10-01</p> <p>Context. With only two functional reaction wheels, Kepler cannot maintain stable pointing at its original target field and has entered a new mode of observation called K2. Aims: We describe a new pipeline to reduce K2 pixel files into light curves that are later searched for transit like features. Methods: Our method is based on many years of experience in planet hunting for the CoRoT mission. Owing to the unstable pointing, K2 light curves present systematics that are correlated with the target position in the charge coupled device (CCD). Therefore, our pipeline also includes a decorrelation of this systematic noise. Our pipeline is optimised for bright stars for which spectroscopic follow-up is possible. We achieve a maximum precision on 6 hours of 6 ppm. The decorrelated light curves are searched for transits with an adapted version of the CoRoT alarm pipeline. Results: We present 172 planetary candidates and 327 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> candidates from campaigns 1, 2, 3, 4, 5, and 6 of K2. Both the planetary candidates and <span class="hlt">eclipsing</span> <span class="hlt">binary</span> candidates lists are made public to promote follow-up studies. The light curves will also be available to the community. Full Tables A.1 and A.2 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/594/A100</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22126767','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22126767"><span id="translatedtitle">ANALYSIS OF SPIN-ORBIT MISALIGNMENT IN THE <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> DI HERCULIS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Philippov, Alexander A.; Rafikov, Roman R.</p> <p>2013-05-10</p> <p>The <span class="hlt">eclipsing</span> <span class="hlt">binary</span> DI Herculis (DI Her) is known to exhibit anomalously slow apsidal precession below the rate predicted by general relativity. Recent measurements of the Rossiter-McLaughlin effect indicate that stellar spins in DI Her are almost orthogonal to the orbital angular momentum, which explains the anomalous precession in agreement with the earlier theoretical suggestion by Shakura. However, these measurements yield only projections of the spin-orbit angles onto the sky plane, leaving the spin projection onto our line of sight unconstrained. Here we describe a method for determining the full three-dimensional spin orientation of the <span class="hlt">binary</span> components relying on the use of the gravity-darkening effect, which is significant for the rapidly rotating stars in DI Her. Gravity darkening gives rise to a nonuniform brightness distribution over the stellar surface, the pattern of which depends on the stellar spin orientation. Using archival photometric data obtained during multiple <span class="hlt">eclipses</span> over several decades, we are able to constrain the unknown spin angles in DI Her with this method, finding that the spin axes of both stars lie close to the plane of the sky. Our procedure fully accounts for the precession of stellar spins over the long time span of observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22520065','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22520065"><span id="translatedtitle">APSIDAL MOTION AND A LIGHT CURVE SOLUTION FOR 13 LMC ECCENTRIC <span class="hlt">ECLIPSING</span> <span class="hlt">BINARIES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zasche, P.; Wolf, M.; Vraštil, J.; Pilarcik, L.</p> <p>2015-12-15</p> <p>New CCD observations for 13 eccentric <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> from the Large Magellanic Cloud were carried out using the Danish 1.54 m telescope located at the La Silla Observatory in Chile. These systems were observed for their times of minimum and 56 new minima were obtained. These are needed for accurate determination of the apsidal motion. Besides that, in total 436 times of minimum were derived from the photometric databases OGLE and MACHO. The O – C diagrams of minimum timings for these B-type <span class="hlt">binaries</span> were analyzed and the parameters of the apsidal motion were computed. The light curves of these systems were fitted using the program PHOEBE, giving the light curve parameters. We derived for the first time relatively short periods of the apsidal motion ranging from 21 to 107 years. The system OGLE-LMC-ECL-07902 was also analyzed using the spectra and radial velocities, resulting in masses of 6.8 and 4.4 M{sub ⊙} for the <span class="hlt">eclipsing</span> components. For one system (OGLE-LMC-ECL-20112), the third-body hypothesis was also used to describe the residuals after subtraction of the apsidal motion, resulting in a period of about 22 years. For several systems an additional third light was also detected, which makes these systems suspect for triplicity.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.460.3873B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.460.3873B"><span id="translatedtitle">Long-term <span class="hlt">eclipse</span> timing of white dwarf <span class="hlt">binaries</span>: an observational hint of a magnetic mechanism at work</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bours, M. C. P.; Marsh, T. R.; Parsons, S. G.; Dhillon, V. S.; Ashley, R. P.; Bento, J. P.; Breedt, E.; Butterley, T.; Caceres, C.; Chote, P.; Copperwheat, C. M.; Hardy, L. K.; Hermes, J. J.; Irawati, P.; Kerry, P.; Kilkenny, D.; Littlefair, S. P.; McAllister, M. J.; Rattanasoon, S.; Sahman, D. I.; Vučković, M.; Wilson, R. W.</p> <p>2016-08-01</p> <p>We present a long-term programme for timing the <span class="hlt">eclipses</span> of white dwarfs in close <span class="hlt">binaries</span> to measure apparent and/or real variations in their orbital periods. Our programme includes 67 close <span class="hlt">binaries</span>, both detached and semi-detached and with M-dwarfs, K-dwarfs, brown dwarfs or white dwarfs secondaries. In total, we have observed more than 650 white dwarf <span class="hlt">eclipses</span>. We use this sample to search for orbital period variations and aim to identify the underlying cause of these variations. We find that the probability of observing orbital period variations increases significantly with the observational baseline. In particular, all <span class="hlt">binaries</span> with baselines exceeding 10 yr, with secondaries of spectral type K2 - M5.5, show variations in the <span class="hlt">eclipse</span> arrival times that in most cases amount to several minutes. In addition, among those with baselines shorter than 10 yr, <span class="hlt">binaries</span> with late spectral type (>M6), brown dwarf or white dwarf secondaries appear to show no orbital period variations. This is in agreement with the so-called Applegate mechanism, which proposes that magnetic cycles in the secondary stars can drive variability in the <span class="hlt">binary</span> orbits. We also present new <span class="hlt">eclipse</span> times of NN Ser, which are still compatible with the previously published circumbinary planetary system model, although only with the addition of a quadratic term to the ephemeris. Finally, we conclude that we are limited by the relatively short observational baseline for many of the <span class="hlt">binaries</span> in the <span class="hlt">eclipse</span> timing programme, and therefore cannot yet draw robust conclusions about the cause of orbital period variations in evolved, white dwarf <span class="hlt">binaries</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010MNRAS.408.2149R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010MNRAS.408.2149R&link_type=ABSTRACT"><span id="translatedtitle">δ Sct-type pulsations in <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems: Y Cam</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rodríguez, E.; García, J. M.; Costa, V.; Lampens, P.; van Cauteren, P.; Mkrtichian, D. E.; Olson, E. C.; Amado, P. J.; Daszyńska-Daszkiewicz, J.; Turcu, V.; Kim, S.-L.; Zhou, A. Y.; López-González, M. J.; Rolland, A.; Díaz-Fraile, D.; Wood, M. A.; Hintz, E.; Pop, A.; Moldovan, D.; Etzel, P. B.; Casanova, V.; Sota, A.; Aceituno, F. J.; Lee, D.-J.</p> <p>2010-11-01</p> <p>We present the results of a three-continent multisite photometric campaign carried out on the Algol-type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system Y Cam, in which the primary component is a multiperiodic δ Sct-type pulsator. The observations consist of 86 nights and more than 450 h of useful data collected mainly during the Northern winter 2002-2003. This means that this is the most extensive time series for such kind of systems obtained so far. These observations were collected mostly in the Johnson V filter, but they also include, for the first time, nearly complete <span class="hlt">binary</span> light curves in simultaneous Strömgren uvby filters together with a few Crawford Hβ data obtained around the orbital phase of the first quadrature. A detailed photometric analysis is presented for both binarity and pulsation. The results indicate a semidetached system with the secondary filling its Roche lobe. No significant contribution from a third body is found. The residuals from the computed <span class="hlt">binary</span> solution were then used to investigate the pulsational content of the primary component. The frequency analysis of the out-of-primary-<span class="hlt">eclipse</span> data leads to a set of eight significant and independent pulsational peaks in a well-defined region of the frequency domain. This means that this is the largest set of excited modes discovered so far in the pulsating component of such kind of systems. The possibility of aliasing problems during the present run or short-term time-scale amplitude variations in some of them was investigated with null results. Indeed the results indicate that f1 and f3 form a frequency doublet with a beat period of Pbeat = 17.065 d. Our results confirm the frequencies already detected by earlier authors and show the presence of some additional significant peaks. The observed amplitudes during the present run are also consistent with those derived from older data sets. We perform a preliminary mode identification for most of the frequencies on the basis of the collected multicolour photometry</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22365343','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22365343"><span id="translatedtitle">Measuring tides and <span class="hlt">binary</span> parameters from gravitational wave data and <span class="hlt">eclipsing</span> timings of detached white dwarf <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shah, Sweta; Nelemans, Gijs</p> <p>2014-08-20</p> <p>The discovery of the most compact detached white dwarf (WD) <span class="hlt">binary</span> SDSS J065133.33+284423.3 has been discussed in terms of probing the tidal effects in WDs. This system is also a verification source for the space-based gravitational wave (GW) detector, eLISA, or the evolved Laser Interferometer Space Antenna, which will observe short-period compact Galactic <span class="hlt">binaries</span> with P {sub orb} ≲ 5 hr. We address the prospects of performing tidal studies using eLISA <span class="hlt">binaries</span> by showing the fractional uncertainties in the orbital decay rate, f-dot , and the rate of that decay, f{sup ¨} expected from both the GW and electromagnetic (EM) data for some of the high-f <span class="hlt">binaries</span>. We find that f-dot and f{sup ¨} can be measured using GW data only for the most massive WD <span class="hlt">binaries</span> observed at high frequencies. From timing the <span class="hlt">eclipses</span> for ∼10 yr, we find that f-dot can be known to ∼0.1% for J0651. We find that from GW data alone, measuring the effects of tides in <span class="hlt">binaries</span> is (almost) impossible. We also investigate the improvement in the knowledge of the <span class="hlt">binary</span> parameters by combining the GW amplitude and inclination with EM data with and without f-dot . In our previous work, we found that EM data on distance constrained the 2σ uncertainty in chirp mass to 15%-25% whereas adding f-dot reduces it to 0.11%. EM data on f-dot also constrain the 2σ uncertainty in distance to 35%-19%. EM data on primary mass constrain the secondary mass m {sub 2} to factors of two to ∼40% whereas adding f-dot reduces this to 25%. Finally, using single-line spectroscopic data constrains 2σ uncertainties in both the m {sub 2}, d to factors of two to ∼40%. Adding EM data on f-dot reduces these 2σ uncertainties to ≤25% and 6%-19%, respectively. Thus we find that EM measurements of f-dot and radial velocity are valuable in constraining eLISA <span class="hlt">binary</span> parameters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013RAA....13.1052F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013RAA....13.1052F"><span id="translatedtitle">Discovery of four W UMa type <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in the field of open cluster ASCC 5</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fang, Xiang-Song; Gu, Sheng-Hong; Zhang, Li-Yun; Pi, Qing-Feng</p> <p>2013-09-01</p> <p>We carried out time-series photometric observations in the Rc-band of the young, poorly studied open cluster ASCC 5 during November and December, 2012, to search for magnetically active stars, and discovered four <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars in this field. In order to characterize these four newly discovered <span class="hlt">binaries</span>, we derived their orbital periods by their times of light minimum, estimated their effective temperatures based on their (J — H) colors and analyzed their light curves using the Wilson-Devinney light curve modeling technique. Our analyses reveal that all of them are contact <span class="hlt">binaries</span> with short orbital periods of less than 0.5 d, with spectral types from late-F to mid-K. Among them, one is a typical A subtype contact <span class="hlt">binary</span> with a mass ratio around 0.5 and a period of 0.44 d, and one is an H subtype contact <span class="hlt">binary</span> with a high mass ratio around 0.9 and a short period of about 0.27 d. The other two systems show low amplitudes of light variation (ARc <=0.11m) their actual photometric mass ratios could not be determined by the light curve modelings, probably due to their attributes of being partially <span class="hlt">eclipsing</span> stars. A preliminary analysis for these two systems indicates that both of them are likely to be W subtype contact <span class="hlt">binaries</span> with low orbital inclinations. In addition, both of these two low amplitude variables show asymmetric distorted light curves (e.g., O'Connell effect of ΔRc ≃0.02m) during the observing runs, suggesting the presence of starspots on these two systems. More interestingly, the one showing a large case of the O'Connell effect presented a remarkable variation in the shape of the light curve on a time scale of one day, indicating that this star is in a very active state. Therefore, these two stars need spectroscopic observations to precisely determine their parameters, as well as further photometric observations to understand the properties of their magnetic activity, e.g., the evolution of starspots.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AJ....151...66B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AJ....151...66B"><span id="translatedtitle">Determining the Age of the Kepler Open Cluster NGC 6819 With a New Triple System and Other <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Stars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brewer, Lauren N.; Sandquist, Eric L.; Mathieu, Robert D.; Milliman, Katelyn; Geller, Aaron M.; Jeffries, Mark W., Jr.; Orosz, Jerome A.; Brogaard, Karsten; Platais, Imants; Bruntt, Hans; Grundahl, Frank; Stello, Dennis; Frandsen, Søren</p> <p>2016-03-01</p> <p>As part of our study of the old (˜2.5 Gyr) open cluster NGC 6819 in the Kepler field, we present photometric (Kepler and ground-based BVRCIC) and spectroscopic observations of the detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> WOCS 24009 (Auner 665; KIC 5023948) with a short orbital period of 3.6 days. WOCS 24009 is a triple-lined system, and we verify that the brightest star is physically orbiting the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> using radial velocities and <span class="hlt">eclipse</span> timing variations. The <span class="hlt">eclipsing</span> <span class="hlt">binary</span> components have masses MB = 1.090 ± 0.010 M⊙ and MC = 1.075 ± 0.013 M⊙, and radii RB = 1.099 ± 0.006 ± 0.005 R⊙ and RC = 1.069 ± 0.006 ± 0.013 R⊙. The bright non-<span class="hlt">eclipsing</span> star resides at the cluster turnoff, and ultimately its mass will directly constrain the turnoff mass: our preliminary determination is MA = 1.251 ± 0.057 M⊙. A careful examination of the light curves indicates that the fainter star in the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> undergoes a very brief period of total <span class="hlt">eclipse</span>, which enables us to precisely decompose the light of the three stars and place them in the color-magnitude diagram (CMD). We also present improved analysis of two previously discussed detached <span class="hlt">eclipsing</span> stars in NGC 6819 (WOCS 40007 and WOCS 23009) en route to a combined determination of the cluster’s distance modulus (m - M)V = 12.38 ± 0.04. Because this paper significantly increases the number of measured stars in the cluster, we can better constrain the age of the CMD to be 2.21 ± 0.10 ± 0.20 Gyr. Additionally, using all measured <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star masses and radii, we constrain the age to 2.38 ± 0.05 ± 0.22 Gyr. The quoted uncertainties are estimates of measurement and systematic uncertainties (due to model physics differences and metal content), respectively. This is paper 57 of the WIYN Open Cluster Study (WOCS).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015A%26A...575A.101D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015A%26A...575A.101D"><span id="translatedtitle">V342 Andromedae B is an eccentric-orbit <span class="hlt">eclipsing</span> <span class="hlt">binary</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dimitrov, W.; Kamiński, K.; Lehmann, H.; Ligęza, P.; Fagas, M.; Bagińska, P.; Kwiatkowski, T.; Bąkowska, K.; Kowalczyk, A.; Polińska, M.; Bartczak, P.; Przybyszewska, A.; Kruszewski, A.; Kurzawa, K.; Schwarzenberg-Czerny, A.</p> <p>2015-03-01</p> <p>We present a photometric and spectroscopic study of the visual <span class="hlt">binary</span> V342 Andromedae. Visual components of the system have angular separations of 3 arcseconds. We obtained two spectroscopic data sets. An examination of both the A and B component spectra reveals that the B component is a spectroscopic <span class="hlt">binary</span> with an eccentric orbit. The orbital period, taken from the Hipparcos Catalog, agrees with the orbital period of the B component measured spectroscopically. We also collected a new set of photometric measurements. The argument of periastron is close to 270° and the orbit eccentricity is not seen in our photometric data. About five years after the first spectroscopic observations, a new set of spectroscopic data was obtained. We analysed the apsidal motion, but we did not find any significant changes in the orbital orientation. A Wilson-Devinney model was calculated based on the photometric and the radial velocity curves. The result shows two very similar stars with masses M1 = 1.27 ± 0.01 M⊙, M2 = 1.28 ± 0.01 M⊙, respectively. The radii are R1 = 1.21 ± 0.01 R⊙, R2 = 1.25 ± 0.01 R⊙, respectively. Radial velocity measurements of component A, the most luminous star in the system, reveal no significant periodic variations. We calculated the time of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> orbit's circularization, which is about two orders of magnitude shorter than the estimated age of the system. The discrepancies in the age estimation can be explained by the Kozai effect induced by the visual component A. The atmospheric parameters and the chemical abundances for the <span class="hlt">eclipsing</span> pair, as well as the LSD profiles for both visual components, were calculated from two high-resolution, well-exposed spectra obtained on the 2-m class telescope. Based on spectroscopy obtained at the David Dunlap Observatory, University of Toronto, Canada, Poznań Spectroscopic Telescope 1, Poland and Thüringer Landessternwarte, Tautenburg, Germany.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AAS...21347712K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AAS...21347712K"><span id="translatedtitle">The Search for <span class="hlt">Low</span> <span class="hlt">Mass</span> Compact <span class="hlt">Binary</span> Inspirals in the First Year of S5 LIGO Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Keppel, Drew; LIGO Scientific Collaboration</p> <p>2009-01-01</p> <p>We report on the search for gravitational waves from coalescing compact <span class="hlt">binary</span> systems with total mass from 2-35 solar masses in the LIGO Fifth Science run (S5) first calendar year data. We describe the pipeline employed by the LSC to search for such waveforms in LIGO data, how we suppress false signals originating from instrumental noise, how we evaluate the search efficiency for systems which may include spinning component objects, and how we establish confidence in likely detection candidates. Finally, we describe Bayesian coalescence rate calculations as a function of mass of the <span class="hlt">binary</span> system and for several canonical mass systems including mass distributions representing <span class="hlt">binary</span> neutron stars, <span class="hlt">binary</span> black holes, and black hole neutron star <span class="hlt">binaries</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014MNRAS.443..432M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014MNRAS.443..432M"><span id="translatedtitle"><span class="hlt">Eclipsing</span> <span class="hlt">binary</span> stars in the Large Magellanic Cloud: results from the EROS-2, OGLE and VMC surveys</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Muraveva, T.; Clementini, G.; Maceroni, C.; Evans, C. J.; Moretti, M. I.; Cioni, M.-R. L.; Marquette, J. B.; Ripepi, V.; de Grijs, R.; Groenewegen, M. A. T.; Piatti, A. E.; van Loon, J. Th.</p> <p>2014-09-01</p> <p>We present a catalogue of 1768 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars (EBs) detected in the Large Magellanic Cloud (LMC) by the second generation of the EROS survey (hereinafter EROS-2); 493 of them are new discoveries located in outer regions (out of the central bar) of the LMC. These sources were originally included in a list of candidate classical Cepheids (CCs) extracted from the EROS-2 catalogue on the basis of the period (0.89 < PEROS < 15.85 d) versus luminosity [13.39 < <BEROS> < 17.82 mag] diagram. After visual inspection of the light curves we reclassified them as <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>. They have blue colours (BEROS - REROS < 0.2 mag) hence we classed them as hot <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> (HEBs) containing hot massive components: main sequence (MS) stars or blue giants. We present Ks-band light curves for 999 <span class="hlt">binaries</span> from our sample that have a counterpart in the VISTA near-infrared ESO public survey of the Magellanic Clouds system (VMC). We provide spectral classifications of 13 HEBs with existing spectroscopy. We divided our sample into contact-like <span class="hlt">binaries</span> and detached/semi-detached systems based on both visual inspection and the parameters of the Fourier decomposition of the light curves and analysed the period-luminosity (PL) relations of the contact-like systems using the REROS and Ks magnitudes at maximum light. The contact-like <span class="hlt">binaries</span> in our sample do not follow PL relations. We analysed the sample of contact <span class="hlt">binaries</span> from the OGLE III catalogue and confirmed that PLI and PL_{K_s} sequences are defined only by <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> containing a red giant component.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015MNRAS.448.1945H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015MNRAS.448.1945H&link_type=ABSTRACT"><span id="translatedtitle">Orbital and physical parameters of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> from the ASAS catalogue - VIII. The totally <span class="hlt">eclipsing</span> double-giant system HD 187669</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hełminiak, K. G.; Graczyk, D.; Konacki, M.; Pilecki, B.; Ratajczak, M.; Pietrzyński, G.; Sybilski, P.; Villanova, S.; Gieren, W.; Pojmański, G.; Konorski, P.; Suchomska, K.; Reichart, D. E.; Ivarsen, K. M.; Haislip, J. B.; LaCluyze, A. P.</p> <p>2015-04-01</p> <p>We present the first full orbital and physical analysis of HD 187669, recognized by the All-Sky Automated Survey (ASAS) as the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> ASAS J195222-3233.7. We combined multi-band photometry from the ASAS and SuperWASP public archives and 0.41-m PROMPT robotic telescopes with our high-precision radial velocities from the HARPS spectrograph. Two different approaches were used for the analysis: (1) fitting to all data simultaneously with the WD code and (2) analysing each light curve (with JKTEBOP) and radial velocities separately and combining the partial results at the end. This system also shows a total primary (deeper) <span class="hlt">eclipse</span>, lasting for about 6 d. A spectrum obtained during this <span class="hlt">eclipse</span> was used to perform atmospheric analysis with the MOOG and SME codes to constrain the physical parameters of the secondary. We found that ASAS J195222-3233.7 is a double-lined spectroscopic <span class="hlt">binary</span> composed of two evolved, late-type giants, with masses of M1 = 1.504 ± 0.004 and M2 = 1.505 ± 0.004 M⊙, and radii of R1 = 11.33 ± 0.28 and R2 = 22.62 ± 0.50 R⊙. It is slightly less metal abundant than the Sun, and has a P = 88.39 d orbit. Its properties are well reproduced by a 2.38-Gyr isochrone, and thanks to the metallicity estimation from the totality spectrum and high precision of the masses, it was possible to constrain the age down to 0.1 Gyr. It is the first so evolved Galactic <span class="hlt">eclipsing</span> <span class="hlt">binary</span> measured with such good accuracy, and as such it is a unique benchmark for studying the late stages of stellar evolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014OEJV..165....1H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014OEJV..165....1H&link_type=ABSTRACT"><span id="translatedtitle">Erratum: "B.R.N.O. Contributions #38 Times of minima of <span class="hlt">eclipsing</span> <span class="hlt">binary</span>" (OEJV #160, [2013])</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Honková, K.; Juryšek, J.; Lehký, M.; Šmelcer, L.; Trnka, J.; Mašek, M.; Urbaník, M.; Auer, R.; Vrašták, M.; Kučáková, H.; Ruocco, N.; Magris, M.; Polák, J.; Brát, L.; Audejean, M.; Banfi, M.; Moudrá, M.; Lomoz, F.; Přibík, V.; Dřevěný, R.; Scaggiante, F.; Kocián, R.; Cagaš, P.; Poddaný, S.; Zíbar, M.; Jacobsen, J.; Marek, P.; Colazo, C.; Zardin, D.; Sobotka, P.; Starzomski, J.; Hladík, B.; Vincenzi, M.; Skarka, M.; Walter, F.; Chapman, A.; Díaz, N. D.; Aceti, P.; Singh, P.; Kalista, L.; Kamenec, M.; Zejda, M.; Marchi, F.; Bílek, R.; Guzzo, P.; Corfini, G.; Onderková, K.; Hečko, A.; Mina, F.; Vítek, M.; Barsa, R.; Quinones, C.; Taormina, M.; Melia, R.; Schneiter, M.; Scavuzzo, A.; Marcionni, N.; Ehrenberger, R.; Tapia, L.; Fasseta, G.; Suarez, N.; Scaggiante, D.; Artusi, E.; Garcia, R.; Grnja, J.; Fišer, A.; Hynek, T.; Vilášek, M.; Rozehnal, J.; Kalisch, T.; Lang, K.; Gorková, S.; Novysedlák, R.; Salvaggio, F.; Smyčka, T.; Spurný, M.; Wikander, T.; Mravik, J.; Šuchań, J.; Čaloud, J.</p> <p>2014-08-01</p> <p>Due to an errors in calculated heliocentric corrections, there are 404 wrong HJD minima timings (with larger Difference than Min error; see header of the Table) in "B.R.N.O. Contributions #38 Times of minima of <span class="hlt">eclipsing</span> <span class="hlt">binary</span>" paper. The correct minima timings are presented hereafter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999ARep...43..521G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999ARep...43..521G"><span id="translatedtitle">Empirical L-M, R-M, and M-Teff relations for main-sequence stars: Components of close <span class="hlt">binary</span> systems and <span class="hlt">low-mass</span> stars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gorda, S. Yu.; Svechnikov, M. A.</p> <p>1999-08-01</p> <p>A new catalog of photometric, geometric, and absolute elements of 112 detached main-sequence <span class="hlt">eclipsing</span> variables with known photometric and spectroscopic orbital elements has been combined with speckle-interferometry data for <span class="hlt">low-mass</span> stars to yield new mass-luminosity, mass-radius, and mass-spectrum relations: M_bol = 4.46 - 9.52 - (lg M > -0.4), M_bol = 6.18 - 5.91 lg M (lg M <= -0.4); lg R = 0.096 + 0.652 lg M (lg M > 0.14), lg R = 0.10 + 1.03 lg M (lg M <= 0.14); lg M = - 5.60 + 1.504 lg T_eff (lg T_eff > 3.6), and lg M = - 29.4 + 8.2 lg T_eff (lg T_eff <= 3.6). In most cases, the component masses and radii used are accurate to 2-3 and 2-4%, respectively; the errors for <span class="hlt">low-mass</span> stars are larger by factors of 3-4. The coefficients in the relations were derived using linear least squares fitting with corrections for noise in the independent variable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22140108','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22140108"><span id="translatedtitle">ON THE FORMATION OF THE PECULIAR <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARY</span> IGR J17480-2446 IN TERZAN 5</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jiang Long; Li Xiangdong</p> <p>2013-07-20</p> <p>IGR J17480-2446 is an accreting X-ray pulsar in a <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> harbored in the Galactic globular cluster Terzan 5. Compared with other accreting millisecond pulsars, IGR J17480-2446 is peculiar for its low spin frequency (11 Hz), which suggests that it might be a mildly recycled neutron star at the very early phase of mass transfer. However, this model seems to be in contrast with the low field strength deduced from the kilo-Hertz quasi-periodic oscillations observed in IGR J17480-2446. Here, we suggest an alternative interpretation, assuming that the current <span class="hlt">binary</span> system was formed during an exchange encounter either between a <span class="hlt">binary</span> (which contains a recycled neutron star) and the current donor, or between a <span class="hlt">binary</span> and an isolated, recycled neutron star. In the resulting <span class="hlt">binary</span>, the spin axis of the neutron star could be parallel or anti-parallel with the orbital axis. In the latter case, the abnormally low frequency of IGR J17480-2446 may result from the spin-down to spin-up evolution of the neutron star. We also briefly discuss the possible observational implications of the pulsar in this scenario.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6440652','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6440652"><span id="translatedtitle">Discovery of soft X-ray emission from V471 Tauri and UU Sagittae: two highly evolved, <span class="hlt">low-mass</span> <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Van Buren, D.; Charles, P.A.; Mason, K.O.</p> <p>1980-12-01</p> <p>We report here the discovery of soft X-ray emission from two highly evolved <span class="hlt">low-mass</span> <span class="hlt">binaries</span> using the HEAO 1 A-2 experiment. V471 Tau is a 5 x 10/sup 30/ ergs s/sup -1/ source in the Hyades with a white dwarf and K V star as components. UU Sge is a planetary nebula nucleus containing an sd0-B star and a K V-M V companion with a soft X-ray luminosity of approx.10/sup 32/ ergs s/sup -1/.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007ChJAA...7..258Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007ChJAA...7..258Y"><span id="translatedtitle">TZ Lyrae: an Algol-type <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> with Mass Transfer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Yuan-Gui; Yin, Xin-Guo</p> <p>2007-04-01</p> <p>We present a detailed investigation of the Algol-type <span class="hlt">binary</span> TZ Lyrae, based on 55 light minimum timings spanning 90 years. It is found that the orbital period shows a long-term increase with a cyclic variation superimposed. The rate of the secular increase is dP/dt=+7.18× 10^{-8} d yr^{-1}, indicating that a mass transfer from the less massive component to the more massive one at a rate of dm=+2.21×10^{-8} M_⊙ yr^{-1}. The cyclic component, with a period of P_{3}=45.5 yr and an amplitude of A=0.0040°, may be interpreted as either the light-time effect in the presence of a third body or magnetic activity cycles in the components. Using the latest version Wilson-Devinney code, a revised photometric solution was deduced from B and V observations. The results show that TZ Lyr is an Algol-type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> with a mass ratio of q=0.297(±0.003). The semidetached configuration with a lobe-filling secondary suggests a mass transfer from the secondary to the primary, which is in agreement with the long-term period increase of the <span class="hlt">binary</span> system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...831...48B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...831...48B"><span id="translatedtitle">The Detached <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> KV 29 and the Age of the Open Cluster M11</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bavarsad, Ernest A.; Sandquist, Eric L.; Shetrone, Matthew D.; Orosz, Jerome A.</p> <p>2016-11-01</p> <p>We present an extensive set of photometry and radial velocities for the detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> KV 29 in the intermediate-aged open cluster M11 (NGC 6705). Spectroscopy shows that the system is double lined, and all available evidence (proper motion, photometry, and position on the color–magnitude diagram) indicates that it is a member of the cluster. We find the period of the <span class="hlt">binary</span> to be 4.64276 ± 0.00001 days. We find masses {3.604}-0.011+0.002{M}ȯ and {1.837}-0.006+0.001{M}ȯ and radii {5.392}-0.035+0.018{R}ȯ and {1.656}-0.044+0.007{R}ȯ for the primary and secondary stars, respectively. Because the primary star in the <span class="hlt">binary</span> is rapidly evolving and is brighter than the cluster turnoff in a color–magnitude diagram, the measurement of its mass leads to a strong constraint on the cluster age. We find the age of M11 to be {222}-3+2+/- 15 Myr, where the quoted uncertainties come from statistical errors in the calculated masses and radii, and systematic uncertainties due to the ambiguity of the metallicity of the open cluster and variations within the isochrone models concerning heavy elements and convective overshooting.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21301276','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21301276"><span id="translatedtitle">LONG-TERM PHOTOMETRIC BEHAVIOR OF THE <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> GW CEPHEI</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lee, Jae Woo; Youn, Jae-Hyuck; Han, Wonyong; Lee, Chung-Uk; Kim, Seung-Lee; Kim, Ho-Il; Park, Jang-Ho; Koch, Robert H. E-mail: jhyoon@kasi.re.kr E-mail: leecu@kasi.re.kr E-mail: hikim@kasi.re.kr E-mail: rhkoch@earthlink.net</p> <p>2010-03-15</p> <p>New CCD photometry over four successive years from 2005 is presented for the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> GW Cep, together with reasonable explanations for the light and period variations. All historical light curves, obtained over a 30 yr interval, display striking light changes, and are best modeled by the simultaneous existence of a cool spot and a hot spot on the more massive cool component star. The facts that the system is magnetically active and that the hot spot has consistently existed on the inner hemisphere of the star indicate that the two spots are formed by (1) magnetic dynamo-related activity on the cool star and (2) mass transfer from the primary to the secondary component. Based on 38 light-curve timings from the Wilson-Devinney code and all other minimum epochs, a period study of GW Cep reveals that the orbital period has experienced a sinusoidal variation with a period and semi-amplitude of 32.6 yr and 0.009 days, respectively. In principle, these may be produced either by a light-travel-time effect due to a third body or by an active magnetic cycle of at least one component star. Because we failed to find any connection between luminosity variability and the period change, that change most likely arises from the existence of an unseen third companion star with a minimum mass of 0.22 M {sub sun} gravitationally bound to the <span class="hlt">eclipsing</span> pair.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AJ....139..898L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AJ....139..898L"><span id="translatedtitle">Long-Term Photometric Behavior of the <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> GW Cephei</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Jae Woo; Youn, Jae-Hyuck; Han, Wonyong; Lee, Chung-Uk; Kim, Seung-Lee; Kim, Ho-Il; Park, Jang-Ho; Koch, Robert H.</p> <p>2010-03-01</p> <p>New CCD photometry over four successive years from 2005 is presented for the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> GW Cep, together with reasonable explanations for the light and period variations. All historical light curves, obtained over a 30 yr interval, display striking light changes, and are best modeled by the simultaneous existence of a cool spot and a hot spot on the more massive cool component star. The facts that the system is magnetically active and that the hot spot has consistently existed on the inner hemisphere of the star indicate that the two spots are formed by (1) magnetic dynamo-related activity on the cool star and (2) mass transfer from the primary to the secondary component. Based on 38 light-curve timings from the Wilson-Devinney code and all other minimum epochs, a period study of GW Cep reveals that the orbital period has experienced a sinusoidal variation with a period and semi-amplitude of 32.6 yr and 0.009 days, respectively. In principle, these may be produced either by a light-travel-time effect due to a third body or by an active magnetic cycle of at least one component star. Because we failed to find any connection between luminosity variability and the period change, that change most likely arises from the existence of an unseen third companion star with a minimum mass of 0.22 M sun gravitationally bound to the <span class="hlt">eclipsing</span> pair.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AJ....147..151H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AJ....147..151H"><span id="translatedtitle">Short Apsidal Period of Three Eccentric <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> Discovered in the Large Magellanic Cloud</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hong, Kyeongsoo; Lee, Chung-Uk; Kim, Seung-Lee; Kang, Young-Woon</p> <p>2014-06-01</p> <p>We present new elements of apsidal motion in three eccentric <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> located in the Large Magellanic Cloud. The apsidal motions of the systems were analyzed using both light curves and <span class="hlt">eclipse</span> timings. The OGLE-III data obtained during the long period of 8 yr (2002-2009) allowed us to determine the apsidal motion period from their analyses. The existence of third light in all selected systems was investigated by light curve analysis. The O - C diagrams of EROS 1018, EROS 1041, and EROS 1054 were analyzed using the 30, 44, and 26 new times of minimum light, respectively, determined from full light curves constructed from EROS, MACHO, OGLE-II, OGLE-III, and our own observations. This enabled a detailed study of the apsidal motion in these systems for the first time. All of the systems have a significant apsidal motion below 100 yr. In particular, EROS 1018 shows a very fast apsidal period of 19.9 ± 2.2 yr in a detached system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22340222','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22340222"><span id="translatedtitle">Short apsidal period of three eccentric <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> discovered in the Large Magellanic Cloud</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hong, Kyeongsoo; Lee, Chung-Uk; Kim, Seung-Lee; Kang, Young-Woon</p> <p>2014-06-01</p> <p>We present new elements of apsidal motion in three eccentric <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> located in the Large Magellanic Cloud. The apsidal motions of the systems were analyzed using both light curves and <span class="hlt">eclipse</span> timings. The OGLE-III data obtained during the long period of 8 yr (2002-2009) allowed us to determine the apsidal motion period from their analyses. The existence of third light in all selected systems was investigated by light curve analysis. The O – C diagrams of EROS 1018, EROS 1041, and EROS 1054 were analyzed using the 30, 44, and 26 new times of minimum light, respectively, determined from full light curves constructed from EROS, MACHO, OGLE-II, OGLE-III, and our own observations. This enabled a detailed study of the apsidal motion in these systems for the first time. All of the systems have a significant apsidal motion below 100 yr. In particular, EROS 1018 shows a very fast apsidal period of 19.9 ± 2.2 yr in a detached system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...586A..35G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...586A..35G"><span id="translatedtitle">The Araucaria Project: High-precision orbital parallax and masses of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> TZ Fornacis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gallenne, A.; Pietrzyński, G.; Graczyk, D.; Konorski, P.; Kervella, P.; Mérand, A.; Gieren, W.; Anderson, R. I.; Villanova, S.</p> <p>2016-02-01</p> <p>Context. Independent distance estimates are particularly useful to check the precision of other distance indicators, while accurate and precise masses are necessary to constrain evolution models. Aims: The goal is to measure the masses and distance of the detached <span class="hlt">eclipsing-binary</span> TZ For with a precision level lower than 1% using a fully geometrical and empirical method. Methods: We obtained the first interferometric observations of TZ For with the VLTI/PIONIER combiner, which we combined with new and precise radial velocity measurements to derive its three-dimensional orbit, masses, and distance. Results: The system is well resolved by PIONIER at each observing epoch, which allowed a combined fit with eleven astrometric positions. Our derived values are in a good agreement with previous work, but with an improved precision. We measured the mass of both components to be M1 = 2.057 ± 0.001 M⊙ and M2 = 1.958 ± 0.001 M⊙. The comparison with stellar evolution models gives an age of the system of 1.20 ± 0.10 Gyr. We also derived the distance to the system with a precision level of 1.1%: d = 185.9 ± 1.9 pc. Such precise and accurate geometrical distances to <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> provide a unique opportunity to test the absolute calibration of the surface brightness-colour relation for late-type stars, and will also provide the best opportunity to check on the future Gaia measurements for possible systematic errors. Based on observations made with ESO telescopes at Paranal observatory under program IDs 094.D-0320.The calibrated interferometric data as OIFITS files are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/586/A35</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...818..108R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...818..108R"><span id="translatedtitle">KIC 9246715: The Double Red Giant <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> with Odd Oscillations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rawls, Meredith L.; Gaulme, Patrick; McKeever, Jean; Jackiewicz, Jason; Orosz, Jerome A.; Corsaro, Enrico; Beck, Paul G.; Mosser, Benoît; Latham, David W.; Latham, Christian A.</p> <p>2016-02-01</p> <p>We combine Kepler photometry with ground-based spectra to present a comprehensive dynamical model of the double red giant <span class="hlt">eclipsing</span> <span class="hlt">binary</span> KIC 9246715. While the two stars are very similar in mass ({M}1={2.171}-0.008+0.006 {M}⊙ , {M}2={2.149}-0.008+0.006 {M}⊙ ) and radius ({R}1={8.37}-0.07+0.03 {R}⊙ , {R}2={8.30}-0.03+0.04 {R}⊙ ), an asteroseismic analysis finds one main set of solar-like oscillations with unusually low-amplitude, wide modes. A second set of oscillations from the other star may exist, but this marginal detection is extremely faint. Because the two stars are nearly twins, KIC 9246715 is a difficult target for a precise test of the asteroseismic scaling relations, which yield M = 2.17 ± 0.14 M⊙ and R = 8.26 ± 0.18 R⊙. Both stars are consistent with the inferred asteroseismic properties, but we suspect the main oscillator is Star 2 because it is less active than Star 1. We find evidence for stellar activity and modest tidal forces acting over the 171 day eccentric orbit, which are likely responsible for the essential lack of solar-like oscillations in one star and weak oscillations in the other. Mixed modes indicate the main oscillating star is on the secondary red clump (a core-He-burning star), and stellar evolution modeling supports this with a coeval history for a pair of red clump stars. This system is a useful case study and paves the way for a detailed analysis of more red giants in <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>, an important benchmark for asteroseismology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...808..179D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...808..179D"><span id="translatedtitle">A New sdO+dM <span class="hlt">Binary</span> with Extreme <span class="hlt">Eclipses</span> and Reflection Effect</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Derekas, A.; Németh, P.; Southworth, J.; Borkovits, T.; Sárneczky, K.; Pál, A.; Csák, B.; Garcia-Alvarez, D.; Maxted, P. F. L.; Kiss, L. L.; Vida, K.; Szabó, Gy. M.; Kriskovics, L.</p> <p>2015-08-01</p> <p>We report the discovery of a new totally <span class="hlt">eclipsing</span> <span class="hlt">binary</span> (R.A. = {06}{{h}}{40}{{m}}{29}{{s}}11; decl. = +38°56‧52″2 J = 2000.0; Rmax = 17.2 mag) with an sdO primary and a strongly irradiated red dwarf companion. It has an orbital period of Porb = 0.187284394(11) day and an optical <span class="hlt">eclipse</span> depth in excess of 5 mag. We obtained 2 low-resolution classification spectra with GTC/OSIRIS and 10 medium-resolution spectra with WHT/ISIS to constrain the properties of the <span class="hlt">binary</span> members. The spectra are dominated by H Balmer and He ii absorption lines from the sdO star, and phase-dependent emission lines from the irradiated companion. A combined spectroscopic and light curve analysis implies a hot subdwarf temperature of Teff(spec) = 55,000 ± 3000 K, surface gravity of log g (phot) = 6.2 ± 0.04 (cgs), and a He abundance of {log}(n{He}/n{{H}})=-2.24+/- 0.40. The hot sdO star irradiates the red dwarf companion, heating its substellar point to about 22,500 K. Surface parameters for the companion are difficult to constrain from the currently available data: the most remarkable features are the strong H Balmer and C ii-iii lines in emission. Radial velocity estimates are consistent with the sdO+dM classification. The photometric data do not show any indication of sdO pulsations with amplitudes greater than 7 mmag, and Hα-filter images do not provide evidence for the presence of a planetary nebula associated with the sdO star.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AJ....151...77K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AJ....151...77K"><span id="translatedtitle">Time-series Spectroscopy of the Pulsating <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> XX Cephei</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koo, Jae-Rim; Lee, Jae Woo; Hong, Kyeongsoo; Kim, Seung-Lee; Lee, Chung-Uk</p> <p>2016-03-01</p> <p>Oscillating Algol-type <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> (oEA) are very interesting objects that have three observational features of <span class="hlt">eclipse</span>, pulsation, and mass transfer. Direct measurement of their masses and radii from the double-lined radial velocity data and photometric light curves would be the most essential for understanding their evolutionary process and for performing the asteroseismological study. We present the physical properties of the oEA star XX Cep from high-resolution time-series spectroscopic data. The effective temperature of the primary star was determined to be 7946 ± 240 K by comparing the observed spectra and the Kurucz models. We detected the absorption lines of the secondary star, which had never been detected in previous studies, and obtained the radial velocities for both components. With the published BVRI light curves, we determined the absolute parameters for the <span class="hlt">binary</span> via Wilson-Devinney modeling. The masses and radii are {M}1=2.49+/- 0.06 {M}⊙ , {M}2=0.38+/- 0.01 {M}⊙ , {R}1=2.27+/- 0.02 {R}⊙ , and {R}2=2.43+/- 0.02 {R}⊙ , respectively. The primary star is about 45% more massive and 60% larger than the zero-age main sequence stars with the same effective temperature. It is probably because XX Cep has experienced a very different evolutionary process due to mass transfer, contrasting with the normal main sequence stars. The primary star is located inside the theoretical instability strip of δ Sct-type stars on the HR diagram. We demonstrated that XX Cep is an oEA star, consisting of a δ Sct-type pulsating primary component and an evolved secondary companion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012IAUS..282..271P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012IAUS..282..271P"><span id="translatedtitle">Advances in Modeling <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Stars in the Era of Large All-Sky Surveys with EBAI and PHOEBE</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prša, A.; Guinan, E. F.; Devinney, E. J.; Degroote, P.; Bloemen, S.; Matijevič, G.</p> <p>2012-04-01</p> <p>With the launch of NASA's Kepler mission, stellar astrophysics in general, and the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star field in particular, has witnessed a surge in data quality, interpretation possibilities, and the ability to confront theoretical predictions with observations. The unprecedented data accuracy and an essentially uninterrupted observing mode of over 2000 <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> is revolutionizing the field. Amidst all this excitement, we came to realize that our best models to describe the physical and geometric properties of <span class="hlt">binaries</span> are not good enough. Systematic errors are evident in a large range of <span class="hlt">binary</span> light curves, and the residuals are anything but Gaussian. This is crucial because it limits us in the precision of the attained parameters. Since <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars are prime targets for determining the fundamental properties of stars, including their ages and distances, the penalty for this loss of accuracy affects other areas of astrophysics as well. Here, we propose to substantially revamp our current models by applying the lessons learned while reducing, modeling, and analyzing Kepler data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AAS...22534528G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AAS...22534528G"><span id="translatedtitle">Combining Fits of The Optical Photometry and X-ray Spectra of the <span class="hlt">Low</span> <span class="hlt">Mass</span> X-ray <span class="hlt">Binary</span> V1408 Aquilae.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gomez, Sebastian; Mason, Paul A.; Robinson, Edward L.</p> <p>2015-01-01</p> <p>V1408 Aquilae is a <span class="hlt">binary</span> system with a black hole primary accreting matter from a <span class="hlt">low</span> <span class="hlt">mass</span> secondary. We observed the system at the McDonald Observatory and collected 126 hours of high speed optical photometry on the source. We modeled the optical light curve using the XRbinary light curve synthesis software. The best fits to the optical light curve seem to suggest that the primary is a <span class="hlt">low</span> <span class="hlt">mass</span> black hole, however we cannot exclude some high mass solutions. Our models slightly favor a 3 solar mass primary at an inclination of about 13 degrees. In order to further constrain these parameters, and verify their validity we compared the fits of the optical light curve to fits to the X-ray spectra of the source. Using data from the Chandra Transmission Grating Catalog and Archive and the ISIS software analysis package we modeled the spectra of the source with a multi-temperature blackbody for a relativistic accretion disk around a spinning black hole and an additional photon power law component. The fits to the optical lightcurve and X-ray spectra are in agreement, from this we conclude that the case for V1408 Aql to be at a low inclination and harbor a <span class="hlt">low</span> <span class="hlt">mass</span> black hole is plausible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011A%26A...528L..16G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011A%26A...528L..16G"><span id="translatedtitle"><span class="hlt">Binaries</span> discovered by the SPY survey. VI. Discovery of a <span class="hlt">low</span> <span class="hlt">mass</span> companion to the hot subluminous planetary nebula central star EGB 5 - a recently ejected common envelope?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geier, S.; Napiwotzki, R.; Heber, U.; Nelemans, G.</p> <p>2011-04-01</p> <p>Hot subdwarf B stars (sdBs) in close <span class="hlt">binary</span> systems are assumed to be formed via common envelope ejection. According to theoretical models, the amount of energy and angular momentum deposited in the common envelope scales with the mass of the companion. That <span class="hlt">low</span> <span class="hlt">mass</span> companions near or below the core hydrogen-burning limit are able to trigger the ejection of this envelope is well known. The currently known systems have very short periods ≃0.1-0.3 d. Here we report the discovery of a <span class="hlt">low</span> <span class="hlt">mass</span> companion (M2 > 0.14 M⊙) orbiting the sdB star and central star of a planetary nebula EGB 5 with an orbital period of 16.5 d at a minimum separation of 23 R⊙. Its long period is only just consistent with the energy balance prescription of the common envelope. The marked difference between the short and long period systems will provide strong constraints on the common envelope phase, in particular if the masses of the sdB stars can be measured accurately. Due to selection effects, the fraction of sdBs with <span class="hlt">low</span> <span class="hlt">mass</span> companions and similar or longer periods may be quite high. <span class="hlt">Low</span> <span class="hlt">mass</span> stellar and substellar companions may therefore play a significant role for the still unclear formation of hot subdwarf stars. Furthermore, the nebula around EGB 5 may be the remnant of the ejected common envelope making this <span class="hlt">binary</span> a unique system to study this short und poorly understood phase of <span class="hlt">binary</span> evolution. Based on observations at the Paranal Observatory of the European Southern Observatory for programmes No. 167.H-0407(A) and 71.D-0383(A). Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC). Some of the data used in this work were obtained at the William Herschel Telescope (WHT) operated by the Isaac Newton Group of Telescopes (ING).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009ApJ...692...73H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009ApJ...692...73H"><span id="translatedtitle">A Variable Near-Infrared Counterpart to the Neutron-Star <span class="hlt">Low-Mass</span> X-Ray <span class="hlt">Binary</span> 4U 1705 - 440</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Homan, Jeroen; Kaplan, David L.; van den Berg, Maureen; Young, Andrew J.</p> <p>2009-02-01</p> <p>We report the discovery of a near-infrared (NIR) counterpart to the persistent neutron-star <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> 4U 1705 - 440, at a location consistent with its recently determined Chandra X-ray position. The NIR source is highly variable, with Ks -band magnitudes varying between 15.2 and 17.3 and additional J- and H-band observations revealing color variations. A comparison with contemporaneous X-ray monitoring observations shows that the NIR brightness correlates well with X-ray flux and X-ray spectral state. We also find possible indications of a change in the slope of the NIR/X-ray flux relation among different X-ray states. We discuss and test various proposed mechanisms for the NIR emission from neutron-star <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> and conclude that the NIR emission in 4U 1705 - 440 is most likely dominated by X-ray heating of the outer accretion disk and the secondary star. This paper includes data gathered with the 6.5 m Magellan Baade Telescope, located at Las Campanas Observatory, Chile, and the 4 m Blanco Telescope, located at CTIO, Chile.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.461...79D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.461...79D"><span id="translatedtitle">Phase lags of quasi-periodic oscillations across source states in the <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> 4U 1636-53</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Avellar, Marcio G. B.; Méndez, Mariano; Altamirano, Diego; Sanna, Andrea; Zhang, Guobao</p> <p>2016-09-01</p> <p>While there are many dynamical mechanisms and models that try to explain the origin and phenomenology of the quasi-periodic oscillations (QPOs) seen in the X-ray light curves of <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span>, few of them address how the radiative processes occurring in these extreme environments give rise to the rich set of variability features actually observed in these light curves. A step towards this end comes from the study of the energy and frequency dependence of the phase lags of these QPOs. Here we used a methodology that allowed us to study, for the first time, the dependence of the phase lags of all QPOs in the range of 1-1300 Hz detected in the <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> 4U 1636-53 upon energy and frequency as the source changes its states as it moves through the colour-colour diagram. Our results suggest that within the context of models of up-scattering Comptonization, the phase lags dependences upon frequency and energy can be used to extract size scales and physical conditions of the medium that produces the lags.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930006640','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930006640"><span id="translatedtitle">Ultraviolet observations of close-<span class="hlt">binary</span> and pulsating nuclei of planetary nebulae; Winds and shells around <span class="hlt">low-mass</span> supergiants; The close-<span class="hlt">binary</span> nucleus of the planetary nebula HFG-1; A search for <span class="hlt">binary</span> nuclei of planetary nebulae; UV monitoring of irregularly variable planetary nuclei; and The pulsating nucleus of the planetary nebula Lo 4</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bond, Howard E.</p> <p>1992-01-01</p> <p>A brief summary of the research highlights is presented. The topics covered include the following: <span class="hlt">binary</span> nuclei of planetary nebulae; other variable planetary nuclei; <span class="hlt">low-mass</span> supergiants; and other IUE-related research.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NewA...48...42W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NewA...48...42W"><span id="translatedtitle">The first orbital parameters and period variation of the short-period <span class="hlt">eclipsing</span> <span class="hlt">binary</span> AQ Boo</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Shuai; Zhang, Liyun; Pi, Qingfeng; Han, Xianming L.; Zhang, Xiliang; Lu, Hongpeng; Wang, Daimei; Li, TongAn</p> <p>2016-10-01</p> <p>We obtained the first VRI CCD light curves of the short-period contact <span class="hlt">eclipsing</span> <span class="hlt">binary</span> AQ Boo, which was observed on March 22 and April 19 in 2014 at Xinglong station of National Astronomical Observatories, and on January 20, 21 and February 28 in 2015 at Kunming station of Yunnan Observatories of Chinese Academy of Sciences, China. Using our six newly obtained minima and the minima that other authors obtained previously, we revised the ephemeris of AQ Boo. By fitting the O-C (observed minus calculated) values of the minima, the orbital period of AQ Boo shows a decreasing tendency P˙ = - 1.47(0.17) ×10-7 days/year. We interpret the phenomenon by mass transfer from the secondary (more massive) component to the primary (less massive) one. By using the updated Wilson & Devinney program, we also derived the photometric orbital parameters of AQ Boo for the first time. We conclude that AQ Boo is a near contact <span class="hlt">binary</span> with a low contact factor of 14.43%, and will become an over-contact system as the mass transfer continues.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1991JApA...12..225V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1991JApA...12..225V"><span id="translatedtitle">SPOT modelling and elements of the RS CVn <span class="hlt">eclipsing</span> <span class="hlt">binary</span> WY CANCRI</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vivekananda Rao, P.; Sarma, M. B. K.; Prakash Rao, B. V. N. S.</p> <p>1991-09-01</p> <p>Light curves of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> WY Cancri obtained during 1973-74, 1976-79, and 1984-86 are analyzed. The curves are found to be affected by distortion waves due to spots on the primary component. Modeling of these distortion waves requires the assumption of three or four spot groups of different temperatures, sizes, and latitudes on the surface of the hotter component. The rotational periods for the spot groups are derived along with latitudes. After removal of the distortion waves from the light curves at different epochs, the curves stay apart a different levels, suggesting a residual variation of 50 yrs or more. Unified clean normal light curves are obtained using suitable correction and the Wilson-Devinney synthetic light curve method, and absolute elements are derived. The radii of these components, whose spectral types are G5 +/- 1 V and K9 +/- 1 VB, are considerably smaller than their respective Roche lobes. Thus WY Cnc can be classified as a detached <span class="hlt">binary</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016RAA....16g...9P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016RAA....16g...9P"><span id="translatedtitle">NSVS 1908107, an EB-type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> in the open cluster NGC 869</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pan, Yang; Luo, Zhi-Quan; Zhang, Xiao-Bin; Deng, Li-Cai; Wang, Kun; Luo, Yang-Ping; Fang, Wei-Jing; Peng, Yin-Jiang; Sun, Jin-Jiang; Liu, Qi-Li; Zhou, Qiang</p> <p>2016-07-01</p> <p>We present a time-series BV CCD photometry for an EB-type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> NSVS 1908107, a member of the young open cluster NGC 869. The photometric solution was obtained by using the 2003 version of the Wilson-Devinney code. It reveals that the system is a semi-detached <span class="hlt">binary</span> with the secondary component filling its Roche lobe. The mass ratio was determined to be 0.059±0.001. With the physical parameters of the cluster, the masses, radii and luminosities of the two components of NSVS 1908107 are estimated to be M 1 = 10.34±2.29 M ⊙, R 1 = 4.65±0.34 R ⊙, L 1 = 8076±371 L ⊙ and M 2 = 0.61±0.13 M ⊙, R 2 = 2.40±0.17 R ⊙, L 2 = 1054±48 L ⊙ respectively. The results show that the secondary component could be a giant or subgiant star with the outer envelope being stripped.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009MNRAS.395.1649C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009MNRAS.395.1649C"><span id="translatedtitle">Absolute parameters of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> V821 Cas from UBVRI light curves and radial velocities†</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Çakırlı, Ö.; Ibanoǧlu, C.; Bilir, S.; Sipahi, E.</p> <p>2009-05-01</p> <p>We present UBVRI photometric measurements and spectroscopic observations of the double-lined <span class="hlt">eclipsing</span> <span class="hlt">binary</span> V821Cas. The radial velocities were obtained by means of the cross-correlation technique. Simultaneous analyses of the multiband light curves and RVs give the absolute parameters for the stars as: and . An analysis of the O-C residuals yielded an apsidal motion in the <span class="hlt">binary</span> at a rate of , corresponding to an apsidal period of U = 118 +/- 19yr. Subtracting the relativistic contribution, we find that logk2obs = -2.590 which is in agreement with the value predicted by theoretical models. Comparison with current stellar evolution models gives an age of 5.6 × 108yr for the system. Based on observations collected at Catania Astrophysical Observatory (Italy) and TÜBİTAK National Observatory (Antalya, Turkey). Table 1 is only available in electronic form at the CDS via anonymous ftp to http://www.blackwell-syngery.com/doi. ‡ E-mail: omur.cakirli@ege.edu.tr</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001aocd.book.....K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001aocd.book.....K"><span id="translatedtitle">An Atlas of O-C Diagrams of <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Stars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kreiner, Jerzy M.; Kim, Chun-Hwey; Nha, Il-Seong</p> <p></p> <p>The Atlas contains data for 1,138 <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> represented by 91,798 minima timings, collected from the usual international and local journals, observatory publications and unpublished minima. Among this source material there is a considerable representation of amateur astronomers. Some timings were found in the card-index catalogue of the Astronomical Observatory of the Jagiellonian University, Cracow. Stars were included in the Atlas provided that they satisfied 3 criteria: (1) at least 20 minima had been times; (2) these minima spanned at least 2,500 cycles; and (3) the 2,500 cycles represented no fewer than 40 years. Some additional stars not strictly satisfying these criteria were also included if useful information was available. For each star, the Atlas contains the (O-C) diagram calculated by the authors and a table of general information containing: <span class="hlt">binary</span> characteristics; assorted catalogue numbers; the statistics of the collected minima timings; the light elements (light ephemeris); comments and literature references. All of the data and diagrams in the Atlas are also available in electronic form on the Internet at <a href="http://www.as.ap.krakow.pl/o-c">http://www.as.ap.krakow.pl/o- c"</a>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NewA...49...38E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NewA...49...38E"><span id="translatedtitle">Absolute parameters of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in Southern Hemisphere sky - II: QY Tel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Erdem, A.; Sürgit, D.; Engelbrecht, C. A.; van Heerden, H. P.; Manick, R.</p> <p>2016-11-01</p> <p>This paper presents the first analysis of spectroscopic and photometric observations of the neglected southern <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star, QY Tel. Spectroscopic observations were carried out at the South African Astronomical Observatory in 2013. New radial velocity curves from this study and V light curves from the All Sky Automated Survey were solved simultaneously using modern light and radial velocity curve synthesis methods. The final model describes QY Tel as a detached <span class="hlt">binary</span> star where both component stars fill at least half of their Roche limiting lobes. The masses and radii were found to be 1.32 (± 0.06) M⊙, 1.74 (± 0.15) R⊙ and 1.44 (± 0.09) M⊙, 2.70 (± 0.16) R⊙ for the primary and secondary components of the system, respectively. The distance to QY Tel was calculated as 365 (± 40) pc, taking into account interstellar extinction. The evolution case of QY Tel is also examined. Both components of the system are evolved main-sequence stars with an age of approximately 3.2 Gy, when compared to Geneva theoretical evolution models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22525366','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22525366"><span id="translatedtitle">PREDICTING GAIA’S PARALLAX DISTANCE TO THE CYGNUS OB2 ASSOCIATION WITH <span class="hlt">ECLIPSING</span> <span class="hlt">BINARIES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kiminki, Daniel C.; Kobulnicky, Henry A.; Álvarez, Carlos A. Vargas; Alexander, Michael J.; Lundquist, Michael J.</p> <p>2015-10-01</p> <p>The Cygnus OB2 Association is one of the nearest and largest collections of massive stars in the Galaxy. Situated at the heart of the “Cygnus X” complex of star-forming regions and molecular clouds, its distance has proven elusive owing to the ambiguous nature of kinematic distances along this ℓ ≃ 80° sightline and the heavy, patchy extinction. In an effort to refine the three-dimensional geometry of key Cygnus X constituents, we have measured distances to four <span class="hlt">eclipsing</span> double-lined OB-type spectroscopic <span class="hlt">binaries</span> that are probable members of Cyg OB2. We find distances of 1.33 ± 0.17, 1.32 ± 0.07, 1.44 ± 0.18, and 1.32 ± 0.13 kpc toward MT91 372, MT91 696, CPR2002 A36, and Schulte 3, respectively. We adopt a weighted average distance of 1.33 ± 0.06 kpc. This agrees well with spectrophotometric estimates for the Association as a whole and with parallax measurements of protostellar masers in the surrounding interstellar clouds, thereby linking the ongoing star formation in these clouds with Cyg OB2. We also identify Schulte 3C (O9.5V), a 4″ visual companion to the 4.75 day <span class="hlt">binary</span> Schulte 3(A+B), as a previously unrecognized Association member.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22357211','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22357211"><span id="translatedtitle">Surface activity and oscillation amplitudes of red giants in <span class="hlt">eclipsing</span> <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gaulme, P.; Jackiewicz, J.; Appourchaux, T.; Mosser, B.</p> <p>2014-04-10</p> <p>Among the 19 red-giant stars belonging to <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems that have been identified in Kepler data, 15 display solar-like oscillations. We study whether the absence of mode detection in the remaining 4 is an observational bias or possibly evidence of mode damping that originates from tidal interactions. A careful analysis of the corresponding Kepler light curves shows that modes with amplitudes that are usually observed in red giants would have been detected if they were present. We observe that mode depletion is strongly associated with short-period systems, in which stellar radii account for 16%-24% of the semi-major axis, and where red-giant surface activity is detected. We suggest that when the rotational and orbital periods synchronize in close <span class="hlt">binaries</span>, the red-giant component is spun up, so that a dynamo mechanism starts and generates a magnetic field, leading to observable stellar activity. Pressure modes would then be damped as acoustic waves dissipate in these fields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...590A..45L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...590A..45L"><span id="translatedtitle">GU Monocerotis: A high-mass <span class="hlt">eclipsing</span> overcontact <span class="hlt">binary</span> in the young open cluster Dolidze 25</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lorenzo, J.; Negueruela, I.; Vilardell, F.; Simón-Díaz, S.; Pastor, P.; Méndez Majuelos, M.</p> <p>2016-05-01</p> <p>Context. The <span class="hlt">eclipsing</span> <span class="hlt">binary</span> GU Mon is located in the star-forming cluster Dolidze 25, which has the lowest metallicity measured in a Milky Way young cluster. Aims: GU Mon has been identified as a short-period <span class="hlt">eclipsing</span> <span class="hlt">binary</span> with two early B-type components. We set out to derive its orbital and stellar parameters. Methods: We present a comprehensive analysis, including B and V light curves and 11 high-resolution spectra, to verify the orbital period and determine parameters. We used the stellar atmosphere code FASTWIND to obtain stellar parameters and create templates for cross-correlation. We obtained a model to fit the light and radial-velocity curves using the Wilson-Devinney code iteratively and simultaneously. Results: The two components of GU Mon are identical stars of spectral type B1 V with the same mass and temperature. The light curves are typical of an EW-type <span class="hlt">binary</span>. The spectroscopic and photometric analyses agree on a period of 0.896640 ± 0.000007 d. We determine a mass of 9.0 ± 0.6 M⊙ for each component and for temperatures of 28 000 ± 2000 K. Both values are consistent with the spectral type. The two stars are overfilling their respective Roche lobes, sharing a common envelope and, therefore the orbit is synchronised and circularised. Conclusions: The GU Mon system has a fill-out factor above 0.8, containing two dwarf B-type stars on the main sequence. The two stars are in a very advanced stage of interaction, with their extreme physical similarity likely due to the common envelope. The expected evolution of such a system very probably leads to a merger while still on the main sequence. Photometry tables are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/590/A45</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AAS...21915327F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AAS...21915327F"><span id="translatedtitle">UBVRI Observations And Analysis Of The Solar Type, Total <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span>, TYC 3034-299-1</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Faulkner, Danny R.; Blum, N.; Samec, R. G.; Jaso, A.; Smith, P. M.; White, J.; Van Hamme, W.</p> <p>2012-01-01</p> <p>TYC 3034-299-1 (CVn) is a magnetically active, solar type contact <span class="hlt">binary</span> and a ROTSE variable. This system was observed as a part of our continuing student/professional collaborative study of interacting <span class="hlt">binaries</span>. The current UBVRI light curves were taken with the Lowell 0.81-m reflector in Flagstaff on May 10 and May 11, 2010. Four times of minimum light were determined from our observations. They include (with standard errors): HJD I = 2455326.72754±0.00024, 2455327.713303±0.00025, HJD II = 2455326.92427±0.00068, 2455327.91256±0.00060. We also obtained the following timings of minimum light from parabolic fits to the data of Blattler (IBVS number 5699, 2006): HJD I = 2453382.6915, 2453445.4980, 2453502.3800, 2453515.4154, 2453517.3907, HJD II = 2453463.4719, 2453515.607. From these and Nelson's (IBVS numbers 5875 and 5929, 2009) observations, an improved ephemeris was calculated from all the available <span class="hlt">eclipse</span> timings: J.D. Hel Min I = 2455326.9244±0.0005 + 0.39500870 ± 0.00000016 d*E. Our light curve amplitudes are deep for a contact <span class="hlt">binary</span>, ranging from 0.85 magnitude in U to 0.66 in I. Time of totality of 7 minutes was detected in the secondary <span class="hlt">eclipse</span> indicating that this system is a W-type W UMa system (less massive star is hotter). The O'Connell effect ranges from 67 mmag to 36 mmag in U to I, respectively, revealing substantial magnetic activity. A 5-color simultaneous light curve solution was calculated using the Wilson Code. Our model reveals a dark spot region at longitude 58°. The 18% fill-out and the virtually identical temperatures of the two stars show that the system has nearly reached thermal contact. We performed a q-search over the interval from q = 0.3 to 0.8. The mass ratio is 0.46. We wish to thank Lowell Observatory for their allocation of observing time and the American Astronomical Society and the Arizona Space Grant for travel support for this observing run.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013hell.conf....4F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013hell.conf....4F"><span id="translatedtitle">Highlight talk by a young astronomer: The Origin of Black Hole Spin in Galactic <span class="hlt">Low-mass</span> X-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fragos, A.</p> <p>2013-09-01</p> <p>Galactic field <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs), like the ones for which black hole (BH) spinmeasurements are available, are believed to form in situ via the evolution of isolated <span class="hlt">binaries</span>. In the standard formation channel these systems survived a common envelope phase that resulted in a <span class="hlt">binary</span> system with an unevolved <span class="hlt">low</span> <span class="hlt">mass</span> main sequence star orbiting around the core of the massive star in a tight orbit. The massive BH progenitor, before the onset of the common envelope phase, had expanded to of ~1000 solar radii. Up to that moment and at solar metallicity, the expansion of the star and the stellar wind mass loss most probably carried away any significant initial angular momentum that the primary star had. During the common envelope phase itself, while the orbit is shrinking significantly, the short timescale (common envelope is expected to last only up to ~1 thermal timescale) and the break of co-rotation of the <span class="hlt">binary</span> will not allow any significant transfer of angular momentum from the orbit to the core of the primary star. Hence, the remaining helium core of the primary star is not expected to be highly spinning. In the detached orbital evolution that follows until the BH formation, the angular momentum losses due to the strong stellar stellar winds will dominate the evolution of the primary over the weaker, due to the <span class="hlt">low</span> <span class="hlt">mass</span> of the companion, tidal forces which tend to synchronize the spin of the BH progenitor with the orbit. As a consequence, the BHs formed in these systems are expected to have low birth spin. However, the measured spins of BHs in LMXBs cover the whole range of spin parameters (a*) from a* = 0 to almost a* = 1. If the assumptions above are even approximately valid, then this implies that the BH spin in LMXBs is determined by the matter that the BH has accreted during the long stable accretion phase of the system. In order to test the hypothesis that the origin of BH spin in Galactic LMXBs is the accretion of matter onto the BH during the</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...587A..54N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...587A..54N"><span id="translatedtitle">SuperWASP discovery and SALT confirmation of a semi-detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> that contains a δ Scuti star</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Norton, A. J.; Lohr, M. E.; Smalley, B.; Wheatley, P. J.; West, R. G.</p> <p>2016-03-01</p> <p>Aims: We searched the SuperWASP archive for objects that display multiply periodic photometric variations. Methods: Specifically we sought evidence for <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars that display a further non-harmonically related signal in their power spectra. Results: The object 1SWASP J050634.16-353648.4 has been identified as a relatively bright (V ~ 11.5) semi-detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> with a 5.104 d orbital period that displays coherent pulsations with a semi-amplitude of 65 mmag at a frequency of 13.45 d-1. Follow-up radial velocity spectroscopy with the Southern African Large Telescope confirmed the <span class="hlt">binary</span> nature of the system. Using the phoebe code to model the radial velocity curve with the SuperWASP photometry enabled parameters of both stellar components to be determined. This yielded a primary (pulsating) star with a mass of 1.73 ± 0.11 M⊙ and a radius of 2.41 ± 0.06 R⊙, as well as a Roche-lobe filling secondary star with a mass of 0.41 ± 0.03 M⊙ and a radius of 4.21 ± 0.11 R⊙. Conclusions: 1SWASP J050634.16-353648.4 is therefore a bright δ Sct pulsator in a semi-detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> with one of the largest pulsation amplitudes of any such system known. The pulsation constant indicates that the mode is likely a first overtone radial pulsation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005ASPC..334..639P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005ASPC..334..639P"><span id="translatedtitle">A New Computer Code for Analyzing the Light Curves of <span class="hlt">Eclipsing</span> Pre-Cataclysmic <span class="hlt">Binaries</span> (PCBs): Application to UU Sge and V477 Lyr</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pustynski, V.-V.; Pustylnik, I.</p> <p>2005-07-01</p> <p>Using our new package of programs for modelling physical conditions in irradiated photospheres of secondary components of Pre-Cataclysmic <span class="hlt">Binaries</span> (PCBs), we analyze the light curves of two <span class="hlt">eclipsing</span> PCBs: UU Sge and V477 Lyr.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AJ....134.1206K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AJ....134.1206K"><span id="translatedtitle">MOST Photometry and DDO Spectroscopy of the <span class="hlt">Eclipsing</span> (White Dwarf + Red Dwarf) <span class="hlt">Binary</span> V471 Tau</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kamiński, Krzysztof Z.; Ruciński, Slavek M.; Matthews, Jaymie M.; Kuschnig, Rainer; Rowe, Jason F.; Guenther, David B.; Moffat, Anthony F. J.; Sasselov, Dimitar; Walker, Gordon A. H.; Weiss, Werner W.</p> <p>2007-09-01</p> <p>The Hyades K2 V + WD system 471 Tau is a prototype post-common envelope system and a likely cataclysmic <span class="hlt">binary</span> progenitor. We present 10 days of nearly continuous optical photometry by the MOST (Microvariability and Oscillations of Stars) satellite and partly simultaneous optical spectroscopy from DDO (David Dunlap Observatory) of the <span class="hlt">binary</span>. The photometric data indicate that the spot coverage of the K dwarf component was less than observed in the past, suggesting that we monitored the star close to a minimum in its activity cycle. Despite the low spot activity, we still detected seven flarelike events whose estimated energies are among the highest ever observed in V471 Tau and whose times of occurrence do not correlate with the <span class="hlt">binary</span> orbital phase. A detailed O - C analysis of the times of <span class="hlt">eclipse</span> over the last ~35 years reveals timing variations which could be explained in several ways, including perturbations by an as-yet-undetected third body in the system or by a small orbital eccentricity inducing slow apsidal motion. The DDO spectra result in improved determinations of the K dwarf projected rotation velocity, VK sin i = 92 km s-1, and the orbital amplitude, KK = 150.5 km s-1. The spectra also allow us to measure changes in Hα emission strength and radial velocity variations. We measure a larger Hα velocity amplitude than found previously, suggesting that the source of the emission in V471 Tau was less concentrated around the sub-white dwarf point on the K star than had been observed in previous studies. Based on data from the MOST satellite, a Canadian Space Agency mission jointly operated by Dynacon, Inc., the University of Toronto Institute for Aerospace Studies, and the University of British Columbia, with the assistance of the University of Vienna, and on data obtained at the David Dunlap Observatory, University of Toronto.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22364412','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22364412"><span id="translatedtitle">A CHANDRA OBSERVATION OF THE <span class="hlt">ECLIPSING</span> WOLF-RAYET <span class="hlt">BINARY</span> CQ Cep</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Skinner, Stephen L.; Zhekov, Svetozar A.; Güdel, Manuel; Schmutz, Werner E-mail: szhekov@space.bas.bg E-mail: werner.schmutz@pmodwrc.ch</p> <p>2015-02-01</p> <p>The short-period (1.64 d) near-contact <span class="hlt">eclipsing</span> WN6+O9 <span class="hlt">binary</span> system CQ Cep provides an ideal laboratory for testing the predictions of X-ray colliding wind shock theory at close separation where the winds may not have reached terminal speeds before colliding. We present results of a Chandra X-ray observation of CQ Cep spanning ∼1 day during which a simultaneous Chandra optical light curve was acquired. Our primary objective was to compare the observed X-ray properties with colliding wind shock theory, which predicts that the hottest shock plasma (T ≳ 20 MK) will form on or near the line-of-centers between the stars. The X-ray spectrum is strikingly similar to apparently single WN6 stars such as WR 134 and spectral lines reveal plasma over a broad range of temperatures T ∼ 4-40 MK. A deep optical <span class="hlt">eclipse</span> was seen as the O star passed in front of the Wolf-Rayet star and we determine an orbital period P {sub orb} = 1.6412400 d. Somewhat surprisingly, no significant X-ray variability was detected. This implies that the hottest X-ray plasma is not confined to the region between the stars, at odds with the colliding wind picture and suggesting that other X-ray production mechanisms may be at work. Hydrodynamic simulations that account for such effects as radiative cooling and orbital motion will be needed to determine if the new Chandra results can be reconciled with the colliding wind picture.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22039366','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22039366"><span id="translatedtitle">YSOVAR: SIX PRE-MAIN-SEQUENCE <span class="hlt">ECLIPSING</span> <span class="hlt">BINARIES</span> IN THE ORION NEBULA CLUSTER</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Morales-Calderon, M.; Stauffer, J. R.; Rebull, L. M.; Stassun, K. G.; Vrba, F. J.; Prato, L.; Hillenbrand, L. A.; Carpenter, J. M.; Terebey, S.; Angione, J.; Covey, K. R.; Terndrup, D. M.; Gutermuth, R.; Song, I.; Plavchan, P.; Marchis, F.; Garcia, E. V.; Margheim, S.; Luhman, K. L.; Irwin, J. M.</p> <p>2012-07-10</p> <p><span class="hlt">Eclipsing</span> <span class="hlt">binaries</span> (EBs) provide critical laboratories for empirically testing predictions of theoretical models of stellar structure and evolution. Pre-main-sequence (PMS) EBs are particularly valuable, both due to their rarity and the highly dynamic nature of PMS evolution, such that a dense grid of PMS EBs is required to properly calibrate theoretical PMS models. Analyzing multi-epoch, multi-color light curves for {approx}2400 candidate Orion Nebula Cluster (ONC) members from our Warm Spitzer Exploration Science Program YSOVAR, we have identified 12 stars whose light curves show <span class="hlt">eclipse</span> features. Four of these 12 EBs are previously known. Supplementing our light curves with follow-up optical and near-infrared spectroscopy, we establish two of the candidates as likely field EBs lying behind the ONC. We confirm the remaining six candidate systems, however, as newly identified ONC PMS EBs. These systems increase the number of known PMS EBs by over 50% and include the highest mass ({theta}{sup 1} Ori E, for which we provide a complete set of well-determined parameters including component masses of 2.807 and 2.797 M{sub Sun }) and longest-period (ISOY J053505.71-052354.1, P {approx} 20 days) PMS EBs currently known. In two cases ({theta}{sup 1} Ori E and ISOY J053526.88-044730.7), enough photometric and spectroscopic data exist to attempt an orbit solution and derive the system parameters. For the remaining systems, we combine our data with literature information to provide a preliminary characterization sufficient to guide follow-up investigations of these rare, benchmark systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004MNRAS.347.1317R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004MNRAS.347.1317R&link_type=ABSTRACT"><span id="translatedtitle">δ Sct-type pulsations in <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems: RZ Cas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rodríguez, E.; García, J. M.; Mkrtichian, D. E.; Costa, V.; Kim, S.-L.; López-González, M. J.; Hintz, E.; Kusakin, A. V.; Gamarova, A. Y.; Lee, J. W.; Youn, J.-H.; Janiashvili, E. B.; Garrido, R.; Moya, A.; Kang, Y. W.</p> <p>2004-02-01</p> <p>We present the results of a three-continent multisite photometric campaign carried out on the Algol-type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system RZ Cas, in which the primary component has recently been discovered to be a δ Sct-type pulsator. The present observations include, for the first time, complete simultaneous Strömgren uvby light curves together with a few Crawford Hβ data collected around the orbital phase of the first quadrature. The new observations confirm the pulsational behaviour of the primary component. A detailed photometric analysis, based on these observations, is presented for both binarity and pulsation. The results indicate a semidetached system where the secondary fills its Roche lobe. The appearance of the light curves reveals the presence of the mass stream from the secondary component and a hotspot where this stream impacts on the surface of the primary star. There are also some indications of chromospheric activity in the secondary. On the other hand, the pulsational behaviour out-of-primary <span class="hlt">eclipse</span> can be well described with only one frequency at 64.1935 cd-1 similar to the main peak found by Ohshima et al. The existence of multiperiodicity is not confirmed in our data. Concerning the mode identification, our results indicate non-radial pulsation in a high radial order (n= 6), with l= 2, |m|= 1, 2 as the most suitable. However, additional effects must be taken into account in the predictions. Moreover, the pulsation amplitude in the u band is larger than in b and v, which is unusual among the δ Sct-type variables. This can be explained as due to pulsation in a high n value and close to the blue edge of the δ Sct region. On the other hand, the early data of Ohshima et al. have also been analysed and similar results are found concerning the frequency content and pulsational amplitude. Finally, a revision of all the photometric out-of-primary-<span class="hlt">eclipse</span> data sets available in the literature is made together with some additional unpublished data leading to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JAVSO..44...39S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JAVSO..44...39S"><span id="translatedtitle">Analysis of Pulsating Components in the <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Systems LT Herculis, RZ Microscopii, LY Puppis, V632 Scorpii, and V638 Scorpii</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Streamer, M.; Bohlsen, T.; Ogmen, Y.</p> <p>2016-06-01</p> <p><span class="hlt">Eclipsing</span> <span class="hlt">binary</span> stars are especially valuable for studies of stellar evolution. If pulsating components are also present then the stellar interior can be studied using asteroseismology techniques. We present photometric data and the analysis of the delta Scuti pulsations that we have discovered in five <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems. The systems are: LT Herculis, RZ Microscopii, LY Puppis, V632 Scorpii and V638 Scorpii. The dominant pulsation frequencies range between 13 - 29 cycles per day with semi-amplitudes of 4 - 20 millimagnitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22139985','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22139985"><span id="translatedtitle">TESTING THE CORE OVERSHOOT MIXING DESCRIBED BY A TURBULENT CONVECTION MODEL ON THE <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> STAR HY VIR</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhang, Q. S.</p> <p>2012-12-20</p> <p>Helioseismic investigation has suggested applying turbulent convection models (TCMs) to convective overshoot. Using the turbulent velocity in the overshoot region determined by a TCM, one can deal with overshoot mixing as a diffusion process, which leads to incomplete mixing. It has been found that this treatment can improve solar sound speed and Li depletion in open clusters. In order to investigate whether the TCM can be applied to overshoot mixing outside the stellar convective core, new observations of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star HY Vir are adopted to calibrate the overshoot mixing parameter. The main conclusions are as follows: (1) the solar TCM parameters and overshoot mixing parameter are also suitable for the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system HY Vir, (2) the incomplete mixing results in a continuous profile of hydrogen abundance, and (3) the e-folding length of the region, in which the hydrogen abundance changes due to overshoot mixing, increases during stellar evolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ApJ...761..153Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ApJ...761..153Z"><span id="translatedtitle">Testing the Core Overshoot Mixing Described by a Turbulent Convection Model on the <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Star HY VIR</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Q. S.</p> <p>2012-12-01</p> <p>Helioseismic investigation has suggested applying turbulent convection models (TCMs) to convective overshoot. Using the turbulent velocity in the overshoot region determined by a TCM, one can deal with overshoot mixing as a diffusion process, which leads to incomplete mixing. It has been found that this treatment can improve solar sound speed and Li depletion in open clusters. In order to investigate whether the TCM can be applied to overshoot mixing outside the stellar convective core, new observations of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star HY Vir are adopted to calibrate the overshoot mixing parameter. The main conclusions are as follows: (1) the solar TCM parameters and overshoot mixing parameter are also suitable for the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system HY Vir, (2) the incomplete mixing results in a continuous profile of hydrogen abundance, and (3) the e-folding length of the region, in which the hydrogen abundance changes due to overshoot mixing, increases during stellar evolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013A%26A...558A..51Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013A%26A...558A..51Z"><span id="translatedtitle">Apsidal motion and absolute parameters for five LMC eccentric <span class="hlt">eclipsing</span> <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zasche, P.; Wolf, M.</p> <p>2013-10-01</p> <p>Aims: As part of our observational projects at the La Silla Danish 1.54-meter telescope, we aim to measure the precise times of minimum light for eccentric <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> in the Large Magellanic Cloud, needed for accurate determination of apsidal motion. Many new times of minima were derived from the photometric databases OGLE and MACHO. Several new minima were also observed. Five early-type and eccentric-orbit <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>: HV 982 (P = 5.d34, e = 0.15), HV 2274 (5.d73, 0.17), MACHO 78.6097.13 (3.d11, 0.05), MACHO 81.8881.47 (3.d88, 0.22), and MACHO 79.5377.76 (2.d64, 0.06) were studied. Methods: The O-C diagrams of the systems were analysed using all reliable timings found in the literature, and new or improved elements of apsidal motion were obtained. Light and radial velocity curves of MACHO 81.8881.47 and MACHO 79.5377.76 were analysed using the program PHOEBE. Results: We derived for the first time or significantly improved the relatively short periods of apsidal motion of 211 (12), 127 (8), 48 (13), 103 (20), and 42 (19) years, respectively. The internal structure constants, log k2, were found to be -2.37, -2.47, -2.17, -2.02, and -1.86 respectively, under the assumption that the component stars rotate pseudosynchronously. The relativistic effects are weak, up to 6% of the total apsidal motion rate. The masses for MACHO 81.8881.47 resulted in 5.51 (0.21) and 5.40 (0.19) M⊙, while for MACHO 79.5377.76 the masses are 11.26 (0.35) and 11.27 (0.35) M⊙, respectively. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 68.A-0223(A), and on data collected with the Danish 1.54 m telescope at the ESO La Silla Observatory.Appendices are available in electronic form at http://www.aanda.org</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22342284','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22342284"><span id="translatedtitle">The EB factory project. I. A fast, neural-net-based, general purpose light curve classifier optimized for <span class="hlt">eclipsing</span> <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Paegert, Martin; Stassun, Keivan G.; Burger, Dan M.</p> <p>2014-08-01</p> <p>We describe a new neural-net-based light curve classifier and provide it with documentation as a ready-to-use tool for the community. While optimized for identification and classification of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars, the classifier is general purpose, and has been developed for speed in the context of upcoming massive surveys such as the Large Synoptic Survey Telescope. A challenge for classifiers in the context of neural-net training and massive data sets is to minimize the number of parameters required to describe each light curve. We show that a simple and fast geometric representation that encodes the overall light curve shape, together with a chi-square parameter to capture higher-order morphology information results in efficient yet robust light curve classification, especially for <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>. Testing the classifier on the ASAS light curve database, we achieve a retrieval rate of 98% and a false-positive rate of 2% for <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>. We achieve similarly high retrieval rates for most other periodic variable-star classes, including RR Lyrae, Mira, and delta Scuti. However, the classifier currently has difficulty discriminating between different sub-classes of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>, and suffers a relatively low (∼60%) retrieval rate for multi-mode delta Cepheid stars. We find that it is imperative to train the classifier's neural network with exemplars that include the full range of light curve quality to which the classifier will be expected to perform; the classifier performs well on noisy light curves only when trained with noisy exemplars. The classifier source code, ancillary programs, a trained neural net, and a guide for use, are provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AJ....148...31P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AJ....148...31P"><span id="translatedtitle">The EB Factory Project. I. A Fast, Neural-net-based, General Purpose Light Curve Classifier Optimized for <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Paegert, Martin; Stassun, Keivan G.; Burger, Dan M.</p> <p>2014-08-01</p> <p>We describe a new neural-net-based light curve classifier and provide it with documentation as a ready-to-use tool for the community. While optimized for identification and classification of <span class="hlt">eclipsing</span> <span class="hlt">binary</span> stars, the classifier is general purpose, and has been developed for speed in the context of upcoming massive surveys such as the Large Synoptic Survey Telescope. A challenge for classifiers in the context of neural-net training and massive data sets is to minimize the number of parameters required to describe each light curve. We show that a simple and fast geometric representation that encodes the overall light curve shape, together with a chi-square parameter to capture higher-order morphology information results in efficient yet robust light curve classification, especially for <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>. Testing the classifier on the ASAS light curve database, we achieve a retrieval rate of 98% and a false-positive rate of 2% for <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>. We achieve similarly high retrieval rates for most other periodic variable-star classes, including RR Lyrae, Mira, and delta Scuti. However, the classifier currently has difficulty discriminating between different sub-classes of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>, and suffers a relatively low (~60%) retrieval rate for multi-mode delta Cepheid stars. We find that it is imperative to train the classifier's neural network with exemplars that include the full range of light curve quality to which the classifier will be expected to perform; the classifier performs well on noisy light curves only when trained with noisy exemplars. The classifier source code, ancillary programs, a trained neural net, and a guide for use, are provided.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015yCat..35780025M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015yCat..35780025M"><span id="translatedtitle">VizieR Online Data Catalog: Light curves for the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> V1094 Tau (Maxted+, 2015)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maxted, P. F. L.; Hutcheon, R. J.; Torres, G.; Lacy, C. H. S.; Southworth, J.; Smalley, B.; Pavlovski, K.; Marschall, L. A.; Clausen, J. V.</p> <p>2015-04-01</p> <p>Photometric light curves of the detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> V1094 Tau in the Stroemgren u-,v-,b- and y-bands, and in the Johnson V-band. The curves in the Stroemgren bands were obtained with the Stroemgren Automatic Telescope (SAT) at ESO, La Silla. The curves in the V-band were obtained with the NFO telescope in New Mexico and with the URSA telescope at the University of Arkansas. (6 data files).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...825...10T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...825...10T"><span id="translatedtitle">The First <span class="hlt">Low-mass</span> Black Hole X-Ray <span class="hlt">Binary</span> Identified in Quiescence Outside of a Globular Cluster</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tetarenko, B. E.; Bahramian, A.; Arnason, R. M.; Miller-Jones, J. C. A.; Repetto, S.; Heinke, C. O.; Maccarone, T. J.; Chomiuk, L.; Sivakoff, G. R.; Strader, J.; Kirsten, F.; Vlemmings, W.</p> <p>2016-07-01</p> <p>The observed relation between the X-ray and radio properties of low-luminosity accreting black holes (BHs) has enabled the identification of multiple candidate black hole X-ray <span class="hlt">binaries</span> (BHXBs) in globular clusters (GCs). Here, we report an identification of the radio source VLA J213002.08+120904 (aka M15 S2), recently reported in Kirsten et al., as a BHXB candidate. They showed that the parallax of this flat-spectrum variable radio source indicates a {2.2}-0.3+0.5 kpc distance, which identifies it as lying in the foreground of the GC M15. We determine the radio characteristics of this source and place a deep limit on the X-ray luminosity of ˜4 × 1029 erg s-1. Furthermore, we astrometrically identify a faint red stellar counterpart in archival Hubble images with colors consistent with a foreground star; at 2.2 kpc, its inferred mass is 0.1-0.2 M ⊙. We rule out that this object is a pulsar, neutron star X-ray <span class="hlt">binary</span>, cataclysmic variable, or planetary nebula, concluding that VLA J213002.08+120904 is the first accreting BHXB candidate discovered in quiescence outside of a GC. Given the relatively small area over which parallax studies of radio sources have been performed, this discovery suggests a much larger population of quiescent BHXBs in our Galaxy, 2.6 × 104-1.7 × 108 BHXBs at 3σ confidence, than has been previously estimated (˜102-104) through population synthesis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ARep...60..807K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ARep...60..807K"><span id="translatedtitle">Orbital-period variations of the Algol-type <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> RW CrB and AO ser</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khaliullina, A. I.</p> <p>2016-09-01</p> <p>Orbital-period variations of the Algol-type <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> RW CrB and AO Ser are analyzed. It is shown that the period variations of these systems are due mainly to the light-time effect due to the <span class="hlt">eclipsing</span> <span class="hlt">binary</span>'s motion in its long-period orbit. The period variations of RW CrB are reproduced by motion of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> with a period of 55.8 years around a third body with the mass M 3 > 0.36 M⊙. The period variations of AO Ser can be reproduced either solely with the light-time effect, or by a superposition of the light-time effect and a slow secular decrease in the period. In the former case, the period of the long-period orbit is 111.5 years; in the latter case, it is 108 years. Both cases imply the same mass for the third body in the AO Ser system: M 3 > 0.35 M⊙. The residual small-amplitude orbitalperiod variations of the two systems can be due to magnetic cycles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016AAS...22821809C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016AAS...22821809C&link_type=ABSTRACT"><span id="translatedtitle">BVRI Photometric Study of the Totally <span class="hlt">Eclipsing</span> Short Period Solar Type, Near-Contact W UMA <span class="hlt">Binary</span>, NSVS 5066754</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caton, Daniel B.; Samec, Ronald G.; Nyaude, Ropafadzo; Faulkner, Danny R.</p> <p>2016-06-01</p> <p>High precision BVRcIc light curves of NSVS 5066754 were observed on May 17-20, 2014 at Dark Sky Observatory in North Carolina with the 0.81-m reflector of Appalachian State University. It is a solar type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> (T1~5750 K) with a period of only 0.375132 (1) d. In fact, it appeared as one of the shortest period in Shaw’s list of near contact <span class="hlt">binaries</span>. Therefore, we initially believed this to be a pre-contact WUMa <span class="hlt">Binary</span> (PCWB’s). However, the <span class="hlt">Binary</span> Maker fits and our Wilson-Devinney solutions show that the <span class="hlt">binary</span> could have either a semi-detached or a contact <span class="hlt">binary</span> configuration.Five times of minimum light were calculated, for 3 primary and 2 secondary <span class="hlt">eclipses</span> from our present observations: In addition, observations at minima were introduced from archived All Sky Automated Survey Data along with the discovery ephemeris. The following decreasing quadratic ephemeris was determined from all available times of minimum light:JDHelMinI=2456797.63848±0.00047d + 0.3747796± 0. 0000068 X E --0.0000000241± 0.0000000005X E2Our contact solution, with a sum of square residuals = 0.49, gave a mass ratio of 0.50, and a component temperature difference of ~360 K, somewhat large for a contact <span class="hlt">binary</span>. Two substantial cool spots were determined in this solution of 37 deg and 28 deg radius with a t-factor or 0.92 and 0.78 respectively. The fill-out is very shallow, ~6%.The semi-detached solution (mode 4: V1010 Oph configuration, meaning the system is approaching first contact) is of poorer quality with a sum of square residuals = 0.87. It has a mass ratio of 0.63, and a component temperature of ~460 K. The fill-outs are 100% and 97% for the primary and secondary components, respectively. Two spots were determined, one hot (t-factor of 1.16, 14 deg radius, colatitude 101 deg) and one cool spot (t-factor of 0.94, 48 deg radius, colatitude 90 deg). The models in both cases are total <span class="hlt">eclipsing</span> with high inclinations in the 86-89 deg range, and a time of constant light is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150023315','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150023315"><span id="translatedtitle">The X-Ray Luminosity Functions of Field <span class="hlt">Low-Mass</span> X-Ray <span class="hlt">Binaries</span> in Early-Type Galaxies: Evidence for a Stellar Age Dependence</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lehmer, B. D.; Berkeley, M.; Zezas, A.; Alexander, D. M.; Basu-Zych, A.; Bauer, F. E.; Brandt, W. N.; Fragos, T.; Hornschemeier, A. E.; Kalogera, V.; Ptak, A.; Sivakoff, G. R.; Tzanavaris, P.; Yukita, M.</p> <p>2014-01-01</p> <p>We present direct constraints on how the formation of <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> (LMXB) populations in galactic fields depends on stellar age. In this pilot study, we utilize Chandra and Hubble Space Telescope (HST) data to detect and characterize the X-ray point source populations of three nearby early-type galaxies: NGC 3115, 3379, and 3384. The luminosity-weighted stellar ages of our sample span approximately equal to 3-10 Gyr. X-ray <span class="hlt">binary</span> population synthesis models predict that the field LMXBs associated with younger stellar populations should be more numerous and luminous per unit stellar mass than older populations due to the evolution of LMXB donor star masses. Crucially, the combination of deep Chandra and HST observations allows us to test directly this prediction by identifying and removing counterparts to X-ray point sources that are unrelated to the field LMXB populations, including LMXBs that are formed dynamically in globular clusters, Galactic stars, and background AGN/galaxies. We find that the "young" early-type galaxy NGC 3384 (approximately equals 2-5 Gyr) has an excess of luminous field LMXBs (L(sub x) approximately greater than (5-10) × 10(exp 37) erg s(exp -1)) per unit K-band luminosity (L(sub K); a proxy for stellar mass) than the "old" early-type galaxies NGC 3115 and 3379 (approximately equals 8-10 Gyr), which results in a factor of 2-3 excess of L(sub X)/L(sub K) for NGC 3384. This result is consistent with the X-ray <span class="hlt">binary</span> population synthesis model predictions; however, our small galaxy sample size does not allow us to draw definitive conclusions on the evolution field LMXBs in general. We discuss how future surveys of larger galaxy samples that combine deep Chandra and HST data could provide a powerful new benchmark for calibrating X-ray <span class="hlt">binary</span> population synthesis models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22356488','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22356488"><span id="translatedtitle">The X-ray luminosity functions of field <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> in early-type galaxies: Evidence for a stellar age dependence</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lehmer, B. D.; Tzanavaris, P.; Yukita, M.; Berkeley, M.; Basu-Zych, A.; Hornschemeier, A. E.; Ptak, A.; Zezas, A.; Alexander, D. M.; Bauer, F. E.; Brandt, W. N.; Fragos, T.; Kalogera, V.; Sivakoff, G. R.</p> <p>2014-07-01</p> <p>We present direct constraints on how the formation of <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> (LMXB) populations in galactic fields depends on stellar age. In this pilot study, we utilize Chandra and Hubble Space Telescope (HST) data to detect and characterize the X-ray point source populations of three nearby early-type galaxies: NGC 3115, 3379, and 3384. The luminosity-weighted stellar ages of our sample span ≈3-10 Gyr. X-ray <span class="hlt">binary</span> population synthesis models predict that the field LMXBs associated with younger stellar populations should be more numerous and luminous per unit stellar mass than older populations due to the evolution of LMXB donor star masses. Crucially, the combination of deep Chandra and HST observations allows us to test directly this prediction by identifying and removing counterparts to X-ray point sources that are unrelated to the field LMXB populations, including LMXBs that are formed dynamically in globular clusters, Galactic stars, and background active galactic nuclei/galaxies. We find that the 'young' early-type galaxy NGC 3384 (≈2-5 Gyr) has an excess of luminous field LMXBs (L {sub X} ≳ (5-10) × 10{sup 37} erg s{sup –1}) per unit K-band luminosity (L{sub K} ; a proxy for stellar mass) than the 'old' early-type galaxies NGC 3115 and 3379 (≈8-10 Gyr), which results in a factor of ≈2-3 excess of L {sub X}/L{sub K} for NGC 3384. This result is consistent with the X-ray <span class="hlt">binary</span> population synthesis model predictions; however, our small galaxy sample size does not allow us to draw definitive conclusions on the evolution field LMXBs in general. We discuss how future surveys of larger galaxy samples that combine deep Chandra and HST data could provide a powerful new benchmark for calibrating X-ray <span class="hlt">binary</span> population synthesis models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21562735','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21562735"><span id="translatedtitle"><span class="hlt">BINARIES</span> DISCOVERED BY THE MUCHFUSS PROJECT: SDSS J08205+0008-AN <span class="hlt">ECLIPSING</span> SUBDWARF B <span class="hlt">BINARY</span> WITH A BROWN DWARF COMPANION</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Geier, S.; Schaffenroth, V.; Drechsel, H.; Heber, U.; Kupfer, T.; Tillich, A.; Oestensen, R. H.; Smolders, K.; Degroote, P.; Maxted, P. F. L.; Barlow, B. N.; Gaensicke, B. T.; Marsh, T. R.; Napiwotzki, R.</p> <p>2011-04-20</p> <p>Hot subdwarf B stars (sdBs) are extreme horizontal branch stars believed to originate from close <span class="hlt">binary</span> evolution. Indeed about half of the known sdB stars are found in close <span class="hlt">binaries</span> with periods ranging from a few hours to a few days. The enormous mass loss required to remove the hydrogen envelope of the red-giant progenitor almost entirely can be explained by common envelope ejection. A rare subclass of these <span class="hlt">binaries</span> are the <span class="hlt">eclipsing</span> HW Vir <span class="hlt">binaries</span> where the sdB is orbited by a dwarf M star. Here, we report the discovery of an HW Vir system in the course of the MUCHFUSS project. A most likely substellar object ({approx_equal}0.068 M{sub sun}) was found to orbit the hot subdwarf J08205+0008 with a period of 0.096 days. Since the <span class="hlt">eclipses</span> are total, the system parameters are very well constrained. J08205+0008 has the lowest unambiguously measured companion mass yet found in a subdwarf B <span class="hlt">binary</span>. This implies that the most likely substellar companion has not only survived the engulfment by the red-giant envelope, but also triggered its ejection and enabled the sdB star to form. The system provides evidence that brown dwarfs may indeed be able to significantly affect late stellar evolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AJ....133.1934A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AJ....133.1934A"><span id="translatedtitle">Late-Type Near-Contact <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> [HH97] FS Aur-79</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Austin, S. J.; Robertson, J. W.; Tycner, C.; Campbell, T.; Honeycutt, R. K.</p> <p>2007-05-01</p> <p>The secondary photometric standard star number 79 for the FS Aur field (Henden & Honeycutt 1997), designated as [HH97] FS Aur-79 (GSC 1874-399), is a short-period (0.2508 days) <span class="hlt">eclipsing</span> <span class="hlt">binary</span> whose light curve is a combination of the β Lyr and BY Dra type variables. High signal-to-noise ratio multicolor photometry was obtained using the US Naval Observatory 1 m telescope. These light curves show asymmetry at quadrature phases (the O'Connell effect), which can be modeled with the presence of starspots. A low-resolution spectrum obtained with the 3.5 m Wisconsin-Indiana-Yale-NOAO telescope at orbital phase 0.76 is consistent with a spectral type of dK7e and dM3e. A radial velocity curve for the primary star was constructed using 24 high-resolution spectra from the 9.2 m Hobby-Eberly Telescope. Spectra show Hα and Hβ in emission confirming chromospheric activity and possibly the presence of circumstellar material. <span class="hlt">Binary</span> star models that simultaneously fit the U, B, V, R, and radial velocity curves are those with a primary star of mass 0.59+/-0.02 Msolar, temperature 4100+/-25 K, and mean radius 0.67 Rsolar, just filling its Roche lobe, and a secondary star of mass 0.31+/-0.09 Msolar, temperature 3425+/-25 K, and mean radius 0.48 Rsolar, just within its Roche lobe. An inclination angle of 83deg+/-2deg with a center-of-mass separation of 1.62 Rsolar is also derived. Starspots, expected for a rotation period of less than 1 day, had to be included in the modeling to fit the O'Connell effect.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22126940','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22126940"><span id="translatedtitle">CHARACTERIZING THE COOL KOIs. V. KOI-256: A MUTUALLY <span class="hlt">ECLIPSING</span> POST-COMMON ENVELOPE <span class="hlt">BINARY</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Muirhead, Philip S.; Shporer, Avi; Becker, Juliette; Swift, Jonathan J.; Hinkley, Sasha; Pineda, J. Sebastian; Bottom, Michael; Baranec, Christoph; Riddle, Reed; Tendulkar, Shriharsh P.; Bui, Khanh; Vanderburg, Andrew; Lloyd, James P.; Fuller, Jim; Zhao, Ming; Howard, Andrew W.; Von Braun, Kaspar; Boyajian, Tabetha S.; Law, Nicholas; Ramaprakash, A. N.; and others</p> <p>2013-04-20</p> <p>We report that Kepler Object of Interest 256 (KOI-256) is a mutually <span class="hlt">eclipsing</span> post-common envelope <span class="hlt">binary</span> (ePCEB), consisting of a cool white dwarf (M{sub *} = 0.592 {+-} 0.089 M{sub Sun }, R{sub *} = 0.01345 {+-} 0.00091 R{sub Sun }, T{sub eff} = 7100 {+-} 700 K) and an active M3 dwarf (M{sub *} = 0.51 {+-} 0.16 M{sub Sun }, R{sub *} = 0.540 {+-} 0.014 R{sub Sun }, T{sub eff} = 3450 {+-} 50 K) with an orbital period of 1.37865 {+-} 0.00001 days. KOI-256 is listed as hosting a transiting planet-candidate by Borucki et al. and Batalha et al.; here we report that the planet-candidate transit signal is in fact the occultation of a white dwarf as it passes behind the M dwarf. We combine publicly-available long- and short-cadence Kepler light curves with ground-based measurements to robustly determine the system parameters. The occultation events are readily apparent in the Kepler light curve, as is spin-orbit synchronization of the M dwarf, and we detect the transit of the white dwarf in front of the M dwarf halfway between the occultation events. The size of the white dwarf with respect to the Einstein ring during transit (R{sub Ein} = 0.00473 {+-} 0.00055 R{sub Sun }) causes the transit depth to be shallower than expected from pure geometry due to gravitational lensing. KOI-256 is an old, long-period ePCEB and serves as a benchmark object for studying the evolution of <span class="hlt">binary</span> star systems as well as white dwarfs themselves, thanks largely to the availability of near-continuous, ultra-precise Kepler photometry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AJ....152....2L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AJ....152....2L"><span id="translatedtitle">Absolute Properties of the Pre-main-sequence <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Star NP Persei</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lacy, Claud H. Sandberg; Fekel, Francis C.; Pavlovski, Krešimir; Torres, Guillermo; Muterspaugh, Matthew W.</p> <p>2016-07-01</p> <p>NP Per is a well-detached, 2.2 day <span class="hlt">eclipsing</span> <span class="hlt">binary</span> whose components are both pre-main-sequence stars that are still contracting toward the main-sequence phase of evolution. We report extensive photometric and spectroscopic observations with which we have determined their properties accurately. Their surface temperatures are quite different: 6420 ± 90 K for the larger F5 primary star and 4540 ± 160 K for the smaller K5e star. Their masses and radii are 1.3207 ± 0.0087 solar masses and 1.372 ± 0.013 solar radii for the primary, and 1.0456 ± 0.0046 solar masses and 1.229 ± 0.013 solar radii for the secondary. The orbital period is variable over long periods of time. A comparison of the observations with current stellar evolution models from MESA indicates that the stars cannot be fit at a single age: the secondary appears significantly younger than the primary. If the stars are assumed to be coeval and to have the age of the primary (17 Myr), then the secondary is larger and cooler than predicted by current models. The Hα spectral line of the secondary component is completely filled by, presumably, chromospheric emission due to a magnetic activity cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...826...69G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...826...69G"><span id="translatedtitle">Kepler <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span> with Delta Scuti/Gamma Doradus Pulsating Components I: KIC 9851944</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guo, Zhao; Gies, Douglas R.; Matson, Rachel A.; García Hernández, Antonio</p> <p>2016-07-01</p> <p>KIC 9851944 is a short-period (P = 2.16 days) <span class="hlt">eclipsing</span> <span class="hlt">binary</span> in the Kepler field of view. By combining the analysis of Kepler photometry and phase-resolved spectra from Kitt Peak National Observatory and Lowell Observatory, we determine the atmospheric and physical parameters of both stars. The two components have very different radii (2.27 R ⊙, 3.19 R ⊙) but close masses (1.76 M ⊙, 1.79 M ⊙) and effective temperatures (7026, 6902 K), indicating different evolutionary stages. The hotter primary is still on the main sequence (MS), while the cooler and larger secondary star has evolved to the post-MS, burning hydrogen in a shell. A comparison with coeval evolutionary models shows that it requires solar metallicity and a higher mass ratio to fit the radii and temperatures of both stars simultaneously. Both components show δ Scuti-type pulsations, which we interpret as p-modes and p and g mixed modes. After a close examination of the evolution of δ Scuti pulsational frequencies, we make a comparison of the observed frequencies with those calculated from MESA/GYRE.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003BASBr..23..106S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003BASBr..23..106S"><span id="translatedtitle">GSC 7672 2238: a new <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system near the delta scuti star AI Vel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Santos-Júnior, J. M.; Pereira, P. C. R.; Cruz, W. S.; Andrade-Pilling, D. P.</p> <p>2003-08-01</p> <p>We report the discovery of a new <span class="hlt">eclipsing</span> <span class="hlt">binary</span> star in the field of the Delta Scuti variable star AI Vel. Initially used as a check star during a monitoring of AI Vel, GSC 7672: 2238 turned out to be variable as soon as we started the project. Time series CCD photometry were performed during 2002 and 2003 using the Meade LX200 (25cm) telescope of Fundação Planetário da Cidade do Rio de Janeiro. The observed times of primary minima provided an orbital period of 0.97188 day. The depth of the primary and secondary minima is about 0m.5 and 0m.2 respectively. The amount of data and the behavior of the light curve led us to interpret this modulation as related to the orbital motion of a short-period Algol. The light curves show discrepances around phases 0.1-0.2, just after the primary minimum. This behavior may be well explained in terms of mass transfer from the lobe-filling secundary star. In addition, we made spectroscopic observation at Perkin-Elmer 1.6m telescope on the Laboratório Nacional de Astrofí sica. The optical spectrum shows clearly the absorption Ha line, typical of short-period Algols with transient or absent disks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NewA...46...47O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NewA...46...47O"><span id="translatedtitle">V421 Pegasi: a detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> with a possible γ Doradus component</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Özdarcan, O.; Çakırlı, Ö.; Akan, C.</p> <p>2016-07-01</p> <p>We present spectroscopic and photometric study of V421 Peg. This <span class="hlt">eclipsing</span> <span class="hlt">binary</span> displays lines from both components that are well separated. This allowed us to classify the primary and secondary component as F(1 ± 0.5) V and F(2 ± 0.5) V, respectively. We use our radial velocity measurements together with Hipparcos and ASAS photometry and apply simultaneous analysis, which yields masses and radii of the primary and secondary components as M1 = 1.594 ± 0.029 M⊙, M2 = 1.356 ± 0.029 M⊙ and R1 = 1.584 ± 0.028 R⊙, R2 = 1.328 ± 0.029 R⊙, respectively. Positions of the components in HR diagram suggest that the primary component is a γ Doradus variable candidate. Spectroscopic and photometric properties of the system indicates reddening value of E(B - V) = 0m.021 which puts the system to the distance of 158 ± 4 pc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003PASP..115...49M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003PASP..115...49M"><span id="translatedtitle">The Masses of the B Stars in the High Galactic Latitude <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> IT Librae</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martin, John C.</p> <p>2003-01-01</p> <p>A number of blue stars that appear to be similar to Population I B stars in the star-forming regions of the Galactic disk are found more than 1 kpc from the Galactic plane. Uncertainties about the true distances and masses of these high-latitude B stars have fueled a debate as to their origin and evolutionary status. The <span class="hlt">eclipsing</span> <span class="hlt">binary</span> IT Lib is composed of two B stars, is approximately 1 kpc above the Galactic plane, and is moving back toward the plane. Observations of the light and velocity curves presented here lead to the conclusion that the B stars in this system are massive young main-sequence stars. While there are several possible explanations, it appears most plausible that the IT Lib system formed in the disk about 30 million years ago and was ejected on a trajectory taking it to its present position. Based on observations made at the 2.1 m Otto Struve Telescope of McDonald Observatory operated by the University of Texas at Austin and also at the 2.1 m telescope at Kitt Peak National Observatory, National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under cooperative agreement with the National Science Foundation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012A%26A...539A.129L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012A%26A...539A.129L"><span id="translatedtitle">A fresh insight into the evolutionary status and third body hypothesis of the <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> AD Andromedae, AL Camelopardalis, and V338 Herculis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liakos, A.; Niarchos, P.; Budding, E.</p> <p>2012-03-01</p> <p>Aims: We aim to derive the absolute parameters of the components of AD And, AL Cam, and V338 Her, interpret their orbital period changes and discuss their evolutionary status. Methods: New and complete multi-filter light curves of the <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> AD And, AL Cam, and V338 Her were obtained and analysed with modern methods. Using all reliably observed times of minimum light, we examined orbital period irregularities using the least squares method. In addition, we acquired new spectroscopic observations during the secondary <span class="hlt">eclipses</span> for AL Cam and V338 Her. Results: For AL Cam and V338 Her, we derive reliable spectral types for their primary stars. Statistical checks of orbital period analysis for all systems are very reassuring in the cases of V338 Her and AD And, although less so for AL Cam. The LIght-Time Effect (LITE) results are checked by inclusion of a third light option in the photometric analyses. Light curve solutions provide the means to calculate the absolute parameters of the components of the systems and reliably estimate their present evolutionary status. Conclusions: AL Cam and V338 Her are confirmed as classical Algols of relatively <span class="hlt">low</span> <span class="hlt">mass</span> in similar configurations. Unlike AL Cam, however, V338 Her is still transferring matter between its components, raising interest in the determinability of the evolutionary histories of Algols. AD And is found to be a detached system in which both close stars are of age ~109 yr and is probably a "non-classical" young triple, at an interesting stage of its dynamical evolution. The spectra and reduced photometric data are available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/539/A129</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ApJ...756..148D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ApJ...756..148D"><span id="translatedtitle">The Quiescent X-Ray Properties of the Accreting Millisecond X-Ray Pulsar and <span class="hlt">Eclipsing</span> <span class="hlt">binary</span> Swift J1749.4-2807</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Degenaar, N.; Patruno, A.; Wijnands, R.</p> <p>2012-09-01</p> <p>Swift J1749.4-2807 is a transient neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> that contains an accreting millisecond X-ray pulsar spinning at 518 Hz. It is the first of its kind that displays X-ray <span class="hlt">eclipses</span>, which holds significant promise to precisely constrain the mass of the neutron star. We report on a ~= 105 ks long XMM-Newton observation performed when Swift J1749.4-2807 was in quiescence. We detect the source at a 0.5-10 keV luminosity of sime1 × 1033(D/6.7 kpc)2 erg s-1. The X-ray light curve displays three <span class="hlt">eclipses</span> that are consistent in orbital phase and duration with the ephemeris derived during outburst. Unlike most quiescent neutron stars, the X-ray spectrum can be adequately described with a simple power law, while a pure-hydrogen atmosphere model does not fit the data. We place an upper limit on the 0.01-100 keV thermal luminosity of the cooling neutron star of <~ 2 × 1033 erg s-1 and constrain its temperature to be <~ 0.1 keV (for an observer at infinity). Timing analysis does not reveal evidence for X-ray pulsations near the known spin frequency of the neutron star or its first overtone with a fractional rms of <~ 34% and <~ 28%, respectively. We discuss the implications of our findings for dynamical mass measurements, the thermal state of the neutron star, and the origin of the quiescent X-ray emission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22092377','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22092377"><span id="translatedtitle">THE QUIESCENT X-RAY PROPERTIES OF THE ACCRETING MILLISECOND X-RAY PULSAR AND <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> SWIFT J1749.4-2807</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Degenaar, N.; Patruno, A.; Wijnands, R.</p> <p>2012-09-10</p> <p>Swift J1749.4-2807 is a transient neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> that contains an accreting millisecond X-ray pulsar spinning at 518 Hz. It is the first of its kind that displays X-ray <span class="hlt">eclipses</span>, which holds significant promise to precisely constrain the mass of the neutron star. We report on a {approx_equal} 105 ks long XMM-Newton observation performed when Swift J1749.4-2807 was in quiescence. We detect the source at a 0.5-10 keV luminosity of {approx_equal}1 Multiplication-Sign 10{sup 33}(D/6.7 kpc){sup 2} erg s{sup -1}. The X-ray light curve displays three <span class="hlt">eclipses</span> that are consistent in orbital phase and duration with the ephemeris derived during outburst. Unlike most quiescent neutron stars, the X-ray spectrum can be adequately described with a simple power law, while a pure-hydrogen atmosphere model does not fit the data. We place an upper limit on the 0.01-100 keV thermal luminosity of the cooling neutron star of {approx}< 2 Multiplication-Sign 10{sup 33} erg s{sup -1} and constrain its temperature to be {approx}< 0.1 keV (for an observer at infinity). Timing analysis does not reveal evidence for X-ray pulsations near the known spin frequency of the neutron star or its first overtone with a fractional rms of {approx}< 34% and {approx}< 28%, respectively. We discuss the implications of our findings for dynamical mass measurements, the thermal state of the neutron star, and the origin of the quiescent X-ray emission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22370246','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22370246"><span id="translatedtitle">The puzzling negative orbit-period derivative of the <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> 4U 1820-30 in NGC 6624</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Peuten, M.; Brockamp, M.; Küpper, A. H. W.; Kroupa, P. E-mail: brockamp@astro.uni-bonn.de E-mail: pavel@astro.uni-bonn.de</p> <p>2014-11-10</p> <p>4U 1820-30 is a <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> near the center of the globular cluster NGC 6624 consisting of, at least, one neutron star and one helium white dwarf. Analyzing 16 yr of data from the Rossi X-ray Timing Explorer (RXTE) allows us to measure its orbital period and its time derivative with unprecedented accuracy to be P = 685.01197 ± 0.00003 s and P-dot / P=−5.3±0.3×10{sup −8} yr{sup −1}. Hence, we confirm that the period derivative is significantly negative at the >17σ level, contrary to theoretical expectations for an isolated X-ray <span class="hlt">binary</span>. We discuss possible scenarios that could explain this discrepancy and conclude that the center of NGC 6624 most likely contains large amounts of nonluminous matter such as dark remnants. We also discuss the possibility of an IMBH inside NGC 6624, or that a dark remnant close to 4U 1820-30 causes the observed shift.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22016231','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22016231"><span id="translatedtitle">A 2.15 hr ORBITAL PERIOD FOR THE <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARY</span> XB 1832-330 IN THE GLOBULAR CLUSTER NGC 6652</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Engel, M. C.; Heinke, C. O.; Sivakoff, G. R.; Elshamouty, K. G.; Edmonds, P. D. E-mail: heinke@ualberta.ca</p> <p>2012-03-10</p> <p>We present a candidate orbital period for the <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> (LMXB) XB 1832-330 in the globular cluster NGC 6652 using a 6.5 hr Gemini South observation of the optical counterpart of the system. Light curves in g' and r' for two LMXBs in the cluster, sources A and B in previous literature, were extracted and analyzed for periodicity using the ISIS image subtraction package. A clear sinusoidal modulation is evident in both of A's curves, of amplitude {approx}0.11 mag in g' and {approx}0.065 mag in r', while B's curves exhibit rapid flickering, of amplitude {approx}1 mag in g' and {approx}0.5 mag in r'. A Lomb-Scargle test revealed a 2.15 hr periodic variation in the magnitude of A with a false alarm probability less than 10{sup -11}, and no significant periodicity in the light curve for B. Though it is possible that saturated stars in the vicinity of our sources partially contaminated our signal, the identification of A's <span class="hlt">binary</span> period is nonetheless robust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010NewA...15..113S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010NewA...15..113S"><span id="translatedtitle"><span class="hlt">Eclipsing</span> and density effects on the spectral behavior of Beta Lyrae <span class="hlt">binary</span> system in the UV</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sanad, M. R.</p> <p>2010-01-01</p> <p>We analyze both long and short high resolution ultraviolet spectrum of Beta Lyrae <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system observed with the International Ultraviolet Explorer (IUE) between 1980 and 1989. The main spectral features are P Cygni profiles originating from different environments of Beta Lyrae. A set of 23 Mg II k&h spectral lines at 2800 Å, originating from the extended envelope [Hack, M., 1980. IAUS, 88, 271H], have been identified and measured to determine their fluxes and widths. We found that there is spectral variability for these physical parameters with phase, similar to that found for the light curve [Kondo, Y., McCluskey, G.E., Jeffery, M.M.S., Ronald, S.P., Carolina, P.S. McCluskey, Joel, A.E., 1994. ApJ, 421, 787], which we attribute to the <span class="hlt">eclipse</span> effects [Ak, H., Chadima, P., Harmanec, P., Demircan, O., Yang, S., Koubský, P., Škoda, P., Šlechta, M., Wolf, M., Božić, H., 2007. A&A, 463, 233], in addition to the changes of density and temperature of the region from which these lines are coming, as a result of the variability of mass loss from the primary star to the secondary [Hoffman, J.L., Nordsieck, K.H., Fox, G.K., 1998. AJ, 115, 1576; Linnell, A.P., Hubeny, I., Harmanec, P., 1998. ApJ, 509, 379]. Also we present a study of Fe II spectral line at 2600 Å, originating from the atmosphere of the primary star [Hack, M., 1980. IAUS, 88, 271H]. We found spectral variability of line fluxes and line widths with phase similar to that found for Mg II k&h lines. Finally we present a study of Si IV spectral line at 1394 Å, originating from the extended envelope [Hack, M., 1980. IAUS, 88, 271H]. A set of 52 Si IV spectral line at 1394 Å have been identified and measured to determine their fluxes and widths. Also we found spectral variability of these physical parameters with phase similar to that found for Mg II k&h and Fe II spectral lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AAS...22125036B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AAS...22125036B"><span id="translatedtitle">A Detached <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> near the Turnoff of the Open Cluster NGC 6819 and Determining Age Using Kepler</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brewer, Lauren; Sandquist, E. L.; Mathieu, R. D.; Milliman, K.; Geller, A. M.; Jeffries, M.; Orosz, J. A.; Brogaard, K. F.; Platais, I.; Bruntt, H.; Grundahl, F.; Stello, D.; Frandsen, S.</p> <p>2013-01-01</p> <p>Measurements of the mass and radius of detached <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> (DEB) can be used to accurately determine the ages of clusters if an <span class="hlt">eclipsing</span> star is evolved enough and sits near the cluster turnoff on the color-magnitude diagram (CMD). Multiple DEBs in a cluster can constrain the age even more tightly, and can also lead to inferences about chemical composition (such as helium abundance). As part of our study of the old 2.5 Gyr) open cluster NGC 6819 in the Kepler field, we present results for the DEB Auner 665 (WOCS 24009) with a short period of 3.6 days. We make use of photometric observations from the Kepler spacecraft and from the 1 m telescope at Mount Laguna Observatory in B, V, Rc, and Ic. Radial velocities were measured as part of a long-term study of the cluster (e.g., Hole et al. 2009) using the WIYN 3.5-meter telescope. A665 is a triple-lined system, and we verify that the brightest star is physically orbiting the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> based on radial velocities and <span class="hlt">eclipse</span> timing variations. The stars that make up the detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> are almost identical in temperature, with <span class="hlt">eclipses</span> that are only clearly distinguishable using Kepler photometry. A new astrometric study of NGC 6819 confirms the cluster membership probability of A665 at a level of P=99%. Ultimately, we will compare the masses and radii obtained with theoretical isochrones and analyze the derived age of NGC 6819, which can also be used to improve stellar theoretical models with better constraints in the mass-radius plane. Our target is to reduce the uncertainty on the cluster age to less than 10% using results from A665 and other known DEBs. The results for this system will also help produce a valuable test of the asteroseismic mass estimates for giant stars in the cluster (Stello et al. 2011). We gratefully acknowledge funding from the National Science Foundation under grant AST-0908536 and NASA under grants NNX11AC76G and NNX12AC88G.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014MNRAS.444.3004D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014MNRAS.444.3004D"><span id="translatedtitle">Unveiling the redback nature of the <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> XSS J1227.0-4859 through optical observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Martino, D.; Casares, J.; Mason, E.; Buckley, D. A. H.; Kotze, M. M.; Bonnet-Bidaud, J.-M.; Mouchet, M.; Coppejans, R.; Gulbis, A. A. S.</p> <p>2014-11-01</p> <p>The peculiar <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> XSS J12270-4859, associated with the Fermi/LAT source 2FGL J1227.7-4853, was in an X-ray, gamma-ray and optical low-luminosity persistent state for about a decade until the end of 2012, when it entered into the dimmest state ever observed. The nature of the compact object has been controversial until the detection of a 1.69 ms radio pulsar early 2014. We present optical spectroscopy and optical/near-IR photometry during the previous brighter and in the recent faint states. We determine the first spectroscopic orbital ephemeris and an accurate orbital period of 6.912 46(5) h. We infer a mid G-type donor star and a distance d = 1.8-2.0 kpc. The donor spectral type changes from G5 V to F5 V between inferior and superior conjunctions, a signature of strong irradiation effects. We infer a <span class="hlt">binary</span> inclination 45° ≲ i ≲ 65° and a highly undermassive donor, M2 ˜ 0.06-0.12 M⊙, for a neutron star mass in the range 1.4-3 M⊙. Thus, this <span class="hlt">binary</span> joins as the seventh member the group of `redbacks'. In the high state, the emission lines reveal the presence of an accretion disc. They tend to vanish at the donor star superior conjunction, where also flares are preferentially observed together with the occurrence of random dips. This behaviour could be related to the propeller mechanism of the neutron star recently proposed to be acting in this system during the high state. In the low state, the emission lines are absent in all orbital phases indicating that accretion has completely switched-off and that XSS J12270-4859 has transited from an accretion-powered to a rotation-powered phase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015RAA....15.1493K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015RAA....15.1493K"><span id="translatedtitle">Light curve solutions of six <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> at the lower limit of periods for W UMa stars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kjurkchieva, Diana P.; Dimitrov, Dinko P.; Ibryamov, Sunay I.</p> <p>2015-09-01</p> <p>Photometric observations are presented in V and I bands of six <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> at the lower limit of the orbital periods for W UMa stars. Three of them are newly discovered <span class="hlt">eclipsing</span> systems. The light curve solutions reveal that all short-period targets are contact or overcontact <span class="hlt">binaries</span> and six new <span class="hlt">binaries</span> are added to the family of short-period systems with estimated parameters. Four <span class="hlt">binaries</span> have components that are equal in size and a mass ratio near 1. The phase variability shown by the V-I colors of all targets may be explained by lower temperatures on their back surfaces than those on their side surfaces. Five systems exhibit the O'Connell effect that can be modeled by cool spots on the side surfaces of their primary components. The light curves of V1067 Her in 2011 and 2012 are fitted by diametrically opposite spots. Applying the criteria for subdivision of W UMa stars to our targets leads to ambiguous results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21260265','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21260265"><span id="translatedtitle">Fundamental Properties of <span class="hlt">Low-Mass</span> Stars and Brown Dwarfs</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Liu, Michael C.; Dupuy, Trent J.; Stassun, Keivan G.; Allard, France; Blake, Cullen H.; Bonnefoy, M.; Cody, Ann Marie; Kraus, Adam; Day-Jones, A. C.; Lopez-Morales, Mercedes</p> <p>2009-02-16</p> <p>Precise measurements of the fundamental properties of <span class="hlt">low-mass</span> stars and brown dwarfs are key to understanding the physics underlying their formation and evolution. While there has been great progress over the last decade in studying the bulk spectrophotometric properties of <span class="hlt">low-mass</span> objects, direct determination of their masses, radii, and temperatures have been very sparse. Thus, theoretical predictions of <span class="hlt">low-mass</span> evolution and ultracool atmospheres remain to be rigorously tested. The situation is alarming given that such models are widely used, from the determination of the <span class="hlt">low-mass</span> end of the initial mass function to the characterization of exoplanets.An increasing number of mass, radius, and age determinations are placing critical constraints on the physics of <span class="hlt">low-mass</span> objects. A wide variety of approaches are being pursued, including <span class="hlt">eclipsing</span> <span class="hlt">binary</span> studies, astrometric-spectroscopic orbital solutions, interferometry, and characterization of benchmark systems. In parallel, many more systems suitable for concerted study are now being found, thanks to new capabilities spanning both the very widest (all-sky surveys) and very narrowest (diffraction-limited adaptive optics) areas of the sky. This Cool Stars 15 splinter session highlighted the current successes and limitations of this rapidly growing area of precision astrophysics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21394458','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21394458"><span id="translatedtitle">SpeX SPECTROSCOPY OF UNRESOLVED VERY <span class="hlt">LOW</span> <span class="hlt">MASS</span> <span class="hlt">BINARIES</span>. I. IDENTIFICATION OF 17 CANDIDATE <span class="hlt">BINARIES</span> STRADDLING THE L DWARF/T DWARF TRANSITION</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Burgasser, Adam J.; Cruz, Kelle L.; Cushing, Michael; Looper, Dagny L.; Gelino, Christopher R.; Kirkpatrick, J. Davy; Faherty, Jacqueline K.; Reid, I. Neill</p> <p>2010-02-20</p> <p>We report the identification of 17 candidate brown dwarf <span class="hlt">binaries</span> whose components straddle the L dwarf/T dwarf transition. These sources were culled from a large near-infrared spectral sample of L and T dwarfs observed with the Infrared Telescope Facility SpeX spectrograph. Candidates were selected on the basis of spectral ratios which segregate known (resolved) L dwarf/T dwarf pairs from presumably single sources. Composite templates, constructed by combining 13,581 pairs of absolute flux-calibrated spectra, are shown to provide statistically superior fits to the spectra of our 17 candidates as compared to single templates. Ten of these candidates appear to have secondary components that are significantly brighter than their primaries over the 1.0-1.3 {mu}m band, indicative of rapid condensate depletion at the L dwarf/T dwarf transition. Our results support prior indications of enhanced multiplicity amongst early-type T dwarfs; 53% +- 7% of the T0-T4 dwarfs in our spectral sample are found to be either resolved or unresolved (candidate) pairs, although this is consistent with an intrinsic (volume complete) brown dwarf <span class="hlt">binary</span> fraction of only 15%. If verified, this sample of spectral <span class="hlt">binaries</span> more than doubles the number of known L dwarf/T dwarf transition pairs, enabling a broader exploration of this poorly understood phase of brown dwarf atmospheric evolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AAS...22710506R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AAS...22710506R"><span id="translatedtitle">What Makes Red Giants Tick? Linking Tidal Forces, Activity, and Solar-Like Oscillations via <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rawls, Meredith L.; Gaulme, Patrick; McKeever, Jean; Jackiewicz, Jason</p> <p>2016-01-01</p> <p>Thanks to advances in asteroseismology, red giants have become astrophysical laboratories for studying stellar evolution and probing the Milky Way. However, not all red giants show solar-like oscillations. It has been proposed that stronger tidal interactions from short-period <span class="hlt">binaries</span> and increased magnetic activity on spotty giants are linked to absent or damped solar-like oscillations, yet each star tells a nuanced story. In this work, we characterize a subset of red giants in <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> observed by Kepler. The <span class="hlt">binaries</span> exhibit a range of orbital periods, solar-like oscillation behavior, and stellar activity. We use orbital solutions together with a suite of modeling tools to combine photometry and spectroscopy in a detailed analysis of tidal synchronization timescales, star spot activity, and stellar evolution histories. These red giants offer an unprecedented opportunity to test stellar physics and are important benchmarks for ensemble asteroseismology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006SASS...25..141S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006SASS...25..141S"><span id="translatedtitle">Analysis of GSC 2475-1587 and GSC 841-277: Two <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> Stars Found During Asteroid Lightcurve Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stephens, R. D.; Warner, B. D.</p> <p>2006-05-01</p> <p>When observing asteroids we select from two to five comparison stars for differential photometry, taking the average value of the comparisons for the single value to be subtracted from the value for the asteroid. As a check, the raw data of each comparison star are plotted as is the difference between any single comparison and the average of the remaining stars in the set. On more than one occasion, we have found that at least one of the comparisons was variable. In two instances, we took time away from our asteroid lightcurve work to determine the period of the two <span class="hlt">binaries</span> and attempted to model the system using David Bradstreet's <span class="hlt">Binary</span> Maker 3. Unfortunately, neither <span class="hlt">binary</span> showed a total <span class="hlt">eclipse</span>. Therefore, our results are not conclusive and present only one of many possibilities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22092114','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22092114"><span id="translatedtitle">HIGH-RESOLUTION SPECTROSCOPY DURING <span class="hlt">ECLIPSE</span> OF THE YOUNG SUBSTELLAR <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> 2MASS 0535-0546. II. SECONDARY SPECTRUM: NO EVIDENCE THAT SPOTS CAUSE THE TEMPERATURE REVERSAL</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mohanty, Subhanjoy; Stassun, Keivan G. E-mail: keivan.stassun@vanderbilt.edu</p> <p>2012-10-10</p> <p>We present high-resolution optical spectra of the young brown dwarf <span class="hlt">eclipsing</span> <span class="hlt">binary</span> 2M0535-05, obtained during <span class="hlt">eclipse</span> of the higher-mass (primary) brown dwarf. Combined with our previous spectrum of the primary alone (Paper I), the new observations yield the spectrum of the secondary alone. We investigate, through a differential analysis of the two <span class="hlt">binary</span> components, whether cool surface spots are responsible for suppressing the temperature of the primary. In Paper I, we found a significant discrepancy between the empirical surface gravity of the primary and that inferred via fine analysis of its spectrum. Here we find precisely the same discrepancy in surface gravity, both qualitatively and quantitatively. While this may again be ascribed to either cool spots or model opacity errors, it implies that cool spots cannot be responsible for preferentially lowering the temperature of the primary: if they were, spot effects on the primary spectrum should be preferentially larger, and they are not. The T{sub eff}'s we infer for the primary and secondary, from the TiO-{epsilon} bands alone, show the same reversal, in the same ratio, as is empirically observed, bolstering the validity of our analysis. In turn, this implies that if suppression of convection by magnetic fields on the primary is the fundamental cause of the T{sub eff} reversal, then it cannot be a local suppression yielding spots mainly on the primary (though both components may be equally spotted), but a global suppression in the interior of the primary. We briefly discuss current theories of how this might work.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21301677','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21301677"><span id="translatedtitle">THE PERIOD VARIATION OF AND A SPOT MODEL FOR THE <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> AR BOOTIS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lee, Jae Woo; Youn, Jae-Hyuck; Lee, Chung-Uk; Kim, Seung-Lee; Koch, Robert H. E-mail: jhyoon@kasi.re.kr E-mail: slkim@kasi.re.kr</p> <p>2009-08-15</p> <p>New CCD photometric observations of the <span class="hlt">eclipsing</span> system AR Boo were obtained from 2006 February to 2008 April. The star's photometric properties are derived from detailed studies of the period variability and of all available light curves. We find that over about 56 yr the orbital period of the system has varied due to a combination of an upward parabola and a sinusoid rather than in a monotonic fashion. Mass transfer from the less massive primary to the more massive secondary component is likely responsible for at least a significant part of the secular period change. The cyclical variation with a period of 7.57 yr and a semi-amplitude of 0.0015 d can be produced either by a light-travel-time effect due to an unseen companion with a scaled mass of M {sub 3}sin i {sub 3} = 0.081 M {sub sun} or by a magnetic period modulation in the secondary star. Historical light curves of AR Boo, as well as our own, display season-to-season light variability, which are best modeled by including both a cool spot and a hot one on the secondary star. We think that the spots express magnetic dynamo-related activity and offer limited support for preferring the magnetic interpretation of the 7.57 yr cycle over the third-body interpretation. Our solutions confirm that AR Boo belongs to the W-subtype contact <span class="hlt">binary</span> class, consisting of a hotter, less massive primary star with a spectral type of G9 and a companion of spectral type K1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014NewA...27...81Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014NewA...27...81Z"><span id="translatedtitle">Magnetic activity and orbital period variation of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> KV Gem</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Liyun; Pi, Qingfeng; Yang, Yuangui; Li, Zhongmu</p> <p>2014-02-01</p> <p>This paper presents new CCD BVRI light curves of a neglected <span class="hlt">eclipsing</span> <span class="hlt">binary</span> KV Gem. Our new light curves were obtained in 2010 and 2011 at the Xinglong station of the National Astronomical Observatories, China. By analyzing all available light minimum times, we derived an update ephemeris and found there existed a cyclic variation overlaying a continuous period decrease. This kind of cyclic variation may probably be attributed to the light-time effect via the presence of an unseen third body or magnetic activity cycle. The long-term period decrease suggests that KV Gem is undergoing a mass transfer from the secondary component to the primary component at a rate of 3.4(0.3)×(10-7 M⊙/year for period decrease and a third body (10.3±0.2 years), and 5.5(0.6)×10-7 M⊙/year for decrease and magnetic cycle (8.8±0.1 years). By analyzing the light curves in 2011, photometric solutions and starspots parameters of the system are obtained using Wilson-Devinney program. Based on the photometric solution in 2011, we still could use the spot model to explain successfully our light curves in 2010 and three published light curves. Comparing the starspot longitudes and factors, KV Gem are variable on a long time scale of about years. For the data of KV Gem, the brightness vary with time around phases 0, 0.25, 0.5, and 0.75, which means that there is a possible photospheric active evolution. More data are needed to monitor to detect stellar cycle of KV Gem. For chromospheric activity of KV Gem, we found strong absorption in the observed Hβ,Hγ, and Ca II H & K spectra, and no obvious emission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AJ....138..478L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AJ....138..478L"><span id="translatedtitle">The Period Variation of and a Spot Model for the <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> AR Bootis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Jae Woo; Youn, Jae-Hyuck; Lee, Chung-Uk; Kim, Seung-Lee; Koch, Robert H.</p> <p>2009-08-01</p> <p>New CCD photometric observations of the <span class="hlt">eclipsing</span> system AR Boo were obtained from 2006 February to 2008 April. The star's photometric properties are derived from detailed studies of the period variability and of all available light curves. We find that over about 56 yr the orbital period of the system has varied due to a combination of an upward parabola and a sinusoid rather than in a monotonic fashion. Mass transfer from the less massive primary to the more massive secondary component is likely responsible for at least a significant part of the secular period change. The cyclical variation with a period of 7.57 yr and a semi-amplitude of 0.0015 d can be produced either by a light-travel-time effect due to an unseen companion with a scaled mass of M 3sin i 3 = 0.081 M sun or by a magnetic period modulation in the secondary star. Historical light curves of AR Boo, as well as our own, display season-to-season light variability, which are best modeled by including both a cool spot and a hot one on the secondary star. We think that the spots express magnetic dynamo-related activity and offer limited support for preferring the magnetic interpretation of the 7.57 yr cycle over the third-body interpretation. Our solutions confirm that AR Boo belongs to the W-subtype contact <span class="hlt">binary</span> class, consisting of a hotter, less massive primary star with a spectral type of G9 and a companion of spectral type K1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22092206','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22092206"><span id="translatedtitle">THREE NEW <span class="hlt">ECLIPSING</span> WHITE-DWARF-M-DWARF <span class="hlt">BINARIES</span> DISCOVERED IN A SEARCH FOR TRANSITING PLANETS AROUND M-DWARFS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Law, Nicholas M.; Kraus, Adam L.; Street, Rachel; Fulton, Benjamin J.; Shporer, Avi; Lister, Tim; Hillenbrand, Lynne A.; Baranec, Christoph; Bui, Khanh; Davis, Jack T. C.; Dekany, Richard G.; Kulkarni, S. R.; Ofek, Eran O.; Bloom, Joshua S.; Cenko, S. Bradley; Filippenko, Alexei V.; Burse, Mahesh P.; Das, H. K.; Kasliwal, Mansi M.; Nugent, Peter; and others</p> <p>2012-10-01</p> <p>We present three new <span class="hlt">eclipsing</span> white-dwarf/M-dwarf <span class="hlt">binary</span> systems discovered during a search for transiting planets around M-dwarfs. Unlike most known <span class="hlt">eclipsing</span> systems of this type, the optical and infrared emission is dominated by the M-dwarf components, and the systems have optical colors and discovery light curves consistent with being Jupiter-radius transiting planets around early M-dwarfs. We detail the PTF/M-dwarf transiting planet survey, part of the Palomar Transient Factory (PTF). We present a graphics processing unit (GPU)-based box-least-squares search for transits that runs approximately 8 Multiplication-Sign faster than similar algorithms implemented on general purpose systems. For the discovered systems, we decompose low-resolution spectra of the systems into white-dwarf and M-dwarf components, and use radial velocity measurements and cooling models to estimate masses and radii for the white dwarfs. The systems are compact, with periods between 0.35 and 0.45 days and semimajor axes of approximately 2 R{sub Sun} (0.01 AU). The M-dwarfs have masses of approximately 0.35 M{sub Sun }, and the white dwarfs have hydrogen-rich atmospheres with temperatures of around 8000 K and have masses of approximately 0.5 M{sub Sun }. We use the Robo-AO laser guide star adaptive optics system to tentatively identify one of the objects as a triple system. We also use high-cadence photometry to put an upper limit on the white-dwarf radius of 0.025 R{sub Sun} (95% confidence) in one of the systems. Accounting for our detection efficiency and geometric factors, we estimate that 0.08%{sub -0.05%}{sup +0.10%} (90% confidence) of M-dwarfs are in these short-period, post-common-envelope white-dwarf/M-dwarf <span class="hlt">binaries</span> where the optical light is dominated by the M-dwarf. The lack of detections at shorter periods, despite near-100% detection efficiency for such systems, suggests that <span class="hlt">binaries</span> including these relatively low-temperature white dwarfs are preferentially found at</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21300533','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21300533"><span id="translatedtitle">2MASS 22344161+4041387AB: A WIDE, YOUNG, ACCRETING, <span class="hlt">LOW-MASS</span> <span class="hlt">BINARY</span> IN THE LkH{alpha}233 GROUP</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Allers, K. N.; Liu, Michael C.; Cushing, Michael C.; Dupuy, Trent J.; Mathews, Geoffrey S.; Shkolnik, Evgenya; Reid, I. Neill; Cruz, Kelle L.; Vacca, W. D.</p> <p>2009-05-20</p> <p>We report the discovery of a young, 0.''16 <span class="hlt">binary</span>, 2M2234+4041AB, found as the result of a Keck laser guide star adaptive optics imaging survey of young field ultracool dwarfs. Spatially resolved near-infrared photometry and spectroscopy indicate that the luminosity and temperature ratios of the system are near unity. From optical and near-infrared spectroscopy, we determine a composite spectral type of M6 for the system. Gravity-sensitive spectral features in the spectra of 2M2234+4041AB are best matched to those of young objects ({approx}1 Myr old). A comparison of the T {sub eff} and age of 2M2234+4041AB to evolutionary models indicates that the mass of each component is 0.10{sup +0.075} {sub -0.04} M {sub sun}. Emission lines of H{alpha} in the composite optical spectrum of the system and Br{gamma} in spatially resolved near-IR spectra of the two components indicate that the system is actively accreting. Both components of the system have IR excesses, indicating that they both harbor circumstellar disks. Though 2M2234+4041AB was originally identified as a young field dwarf, it lies 1.'5 from the well-studied Herbig Ae/Be star, LkH{alpha}233. The distance to LkH{alpha}233 is typically assumed to be 880 pc. It is unlikely that 2M2234+4041AB could be this distant, as it would then be more luminous than any known Taurus objects of similar spectral type. We re-evaluate the distance to the LkH{alpha}233 group and find a value of 325{sup +72} {sub -50} pc, based on the Hipparcos distance to a nearby B3-type group member (HD 213976). 2M2234+4041AB is the first <span class="hlt">low-mass</span> star to be potentially associated with the LkH{alpha}233 group. At a distance of 325 pc, its projected physical separation is 51 AU, making it one of the growing number of wide, <span class="hlt">low-mass</span> <span class="hlt">binaries</span> found in young star-forming regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006MNRAS.371...67S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006MNRAS.371...67S&link_type=ABSTRACT"><span id="translatedtitle">The OB <span class="hlt">binary</span> HD152219: a detached, double-lined, <span class="hlt">eclipsing</span> system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sana, H.; Gosset, E.; Rauw, G.</p> <p>2006-09-01</p> <p>We present the results of an optical spectroscopic campaign on the massive <span class="hlt">binary</span> HD152219 located near the core of the NGC6231 cluster. Though the primary to secondary optical brightness ratio is probably about 10, we clearly detect the secondary spectral signature and we derive the first reliable SB2 orbital solution for the system. The orbital period is close to 4.2403d and the orbit is slightly eccentric (e = 0.08 +/- 0.01). The system is most probably formed by an O9.5 giant and a B1-2 V-III star. We derive minimal masses of 18.6 +/- 0.3 and 7.3 +/- 0.1Msolar for the primary and secondary, respectively, and we constrain the stellar radius at values about 11 and 5Rsolar. INTEGRAL-Optical Monitoring Camera (OMC) data reveal that HD152219 is the third O-type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> known in NGC6231. In the Hertzsprung-Russell (HR) diagram, the primary component lies on the blue edge of the β Cep-type instability strip and its spectral lines display clear profile variations that are reminiscent of those expected from non-radial pulsations. Finally, we report the analysis of XMM-Newton observations of the system. The X-ray spectrum is relatively soft and is well reproduced by a two-temperature mekal model with kT1 = 0.26keV and kT2 = 0.67keV. The X-ray flux is most probably variable on a time-scale of days. The average X-ray luminosity during our campaign is log(LX) ~ 31.8 (ergs-1), but shows fluctuations of about 10 per cent around this value. Based on observations collected at the European Southern Observatory (La Silla, Chile) and with the XMM-Newton satellite, an ESA science mission with instruments and contributions directly funded by ESA Member States and the USA (NASA); also based on data from the Optical Monitoring Camera (OMC) Archive at LAEFF, processed by ISDC. E-mail: hsana@eso.org ‡ FNRS Research Associate (Belgium).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...808..140C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...808..140C"><span id="translatedtitle">Probing the Masses and Radii of Donor Stars in <span class="hlt">Eclipsing</span> X-Ray <span class="hlt">Binaries</span> with the Swift Burst Alert Telescope</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Coley, Joel B.; Corbet, Robin H. D.; Krimm, Hans A.</p> <p>2015-08-01</p> <p>Physical parameters of both the mass donor and compact object can be constrained in X-ray <span class="hlt">binaries</span> with well-defined <span class="hlt">eclipses</span>, as our survey of wind-fed supergiant X-ray <span class="hlt">binaries</span> IGR J16393-4643, IGR J16418-4532, IGR J16479-4514, IGR J18027-2016, and XTE J1855-026 reveals. Using the orbital period and Kepler’s third law, we express the <span class="hlt">eclipse</span> half-angle in terms of radius, inclination angle, and the sum of the masses. Pulse-timing and radial velocity curves can give masses of both the donor and compact object as in the case of the “double-lined” <span class="hlt">binaries</span> IGR J18027-2016 and XTE J1855-026. The <span class="hlt">eclipse</span> half angles are {15}-2+3, {31.7}-0.8+0.7, 32 ± 2,34 ± 2, and 33.6+/- 0.7 degrees for IGR J16393-4643, IGR J16418-4532, IGR J16479-4514, IGR J18027-2016, and XTE 1855-026, respectively. In wind-fed systems, the primary not exceeding the Roche-lobe size provides an upper limit on system parameters. In IGR J16393-4643, spectral types of B0 V or B0-5 III are found to be consistent with the <span class="hlt">eclipse</span> duration and Roche-lobe, but the previously proposed donor stars in IGR J16418-4532 and IGR J16479-4514 were found to be inconsistent with the Roche-lobe size. Stars with spectral types O7.5 I and earlier are possible. For IGR J18027-2016, the mass and radius of the donor star lie between 18.6-19.4 {M}⊙ and 17.4-19.5 {R}⊙ . We constrain the neutron star mass between 1.37 and 1.43 {M}⊙ .We find the mass and radius of the donor star in XTE J1855-026 to lie between 19.6-20.2 {M}⊙ and 21.5-23.0 {R}⊙ . The neutron star mass was constrained to 1.77-1.82 {M}⊙ . <span class="hlt">Eclipse</span> profiles are asymmetric in IGR J18027-2016 and XTE J1855-026, which we attribute to accretion wakes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011MNRAS.415..235H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011MNRAS.415..235H"><span id="translatedtitle">The bright unidentifiedγ-ray source 1FGL J1227.9-4852: can it be associated with a <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span>?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hill, A. B.; Szostek, A.; Corbel, S.; Camilo, F.; Corbet, R. H. D.; Dubois, R.; Dubus, G.; Edwards, P. G.; Ferrara, E. C.; Kerr, M.; Koerding, E.; Kozieł, D.; Stawarz, Ł.</p> <p>2011-07-01</p> <p>We present an analysis of high energy (HE; 0.1-300 GeV) γ-ray observations of 1FGL J1227.9-4852 with the Fermi Gamma-ray Space Telescope, follow-up radio observations with the Australia Telescope Compact Array, Giant Metrewave Radio Telescope and Parkes radio telescopes of the same field and follow-up optical observations with the ESO VLT. We also examine archival XMM-Newton and INTEGRAL X-ray observations of the region around this source. The γ-ray spectrum of 1FGL J1227.9-4852 is best fitted with an exponentially cut-off power law, reminiscent of the population of pulsars observed by Fermi. A previously unknown, compact radio source within the 99.7 per cent error circle of 1FGL J1227.9-4852 is discovered and has a morphology consistent either with an AGN core/jet structure or with two roughly symmetric lobes of a distant radio galaxy. A single bright X-ray source XSS J12270-4859, a <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span>, also lies within the 1FGL J1227.9-4852 error circle and we report the first detection of radio emission from this source. The potential association of 1FGL J1227.9-4852 with each of these counterparts is discussed. Based upon the available data we find the association of the γ-ray source to the compact double radio source unlikely and suggest that XSS J12270-4859 is a more likely counterpart to the new HE source. We propose that XSS J12270-4859 may be a millisecond <span class="hlt">binary</span> pulsar and draw comparisons with PSR J1023+0038.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012MNRAS.425.1245H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012MNRAS.425.1245H"><span id="translatedtitle">Orbital and physical parameters of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> from the All-Sky Automated Survey catalogue - IV. A 0.61 + 0.45 M⊙ <span class="hlt">binary</span> in a multiple system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hełminiak, K. G.; Konacki, M.; RóŻyczka, M.; KałuŻny, J.; Ratajczak, M.; Borkowski, J.; Sybilski, P.; Muterspaugh, M. W.; Reichart, D. E.; Ivarsen, K. M.; Haislip, J. B.; Crain, J. A.; Foster, A. C.; Nysewander, M. C.; LaCluyze, A. P.</p> <p>2012-09-01</p> <p>We present the orbital and physical parameters of a newly discovered <span class="hlt">low-mass</span> detached <span class="hlt">eclipsing</span> <span class="hlt">binary</span> from the All-Sky Automated Survey (ASAS) data base: ASAS J011328-3821.1 A, which is a member of a visual <span class="hlt">binary</span> system with the secondary component separated by about 1.4 arcsec. The radial velocities have been calculated from the high-resolution spectra obtained with the 1.9-m Radcliffe telescope/Grating Instrument for Radiation Analysis with a Fibre-Fed Echelle (GIRAFFE) spectrograph, the 3.9-m Anglo-Australian Telescope (AAT)/University College London Echelle Spectrograph (UCLES) and the 3.0-m Shane telescope/Hamilton Spectrograph (HamSpec) on the basis of the TODCOR technique and the positions of the Hα emission lines. For the analysis, we have used V- and I-band photometry obtained with the 1.0-m Elizabeth telescope and the 0.41-m Panchromatic Robotic Optical Monitoring and Polarimetry Telescopes (PROMPT), supplemented with the publicly available ASAS light curve of the system. We have found that ASAS J011328-3821.1 A is composed of two late-type dwarfs, which have masses of M1 = 0.612 ± 0.030 M⊙ and M2 = 0.445 ± 0.019 M⊙ and radii of R1 = 0.596 ± 0.020 R⊙ and R2 = 0.445 ± 0.024 R⊙. Both show a substantial level of activity, which manifests in strong Hα and Hβ emission and the presence of cool spots. The influence of the third light on the <span class="hlt">eclipsing</span> pair properties has also been evaluated and the photometric properties of component B have been derived. A comparison with several popular stellar evolution models shows that the system is on its main-sequence evolution stage and that it is probably more metal-rich than the Sun. We have also found several clues to suggest that component B itself is a <span class="hlt">binary</span> composed of two nearly identical ˜0.5-M⊙ stars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...827..134S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...827..134S"><span id="translatedtitle">A NuSTAR Observation of the Reflection Spectrum of the <span class="hlt">Low-mass</span> X-Ray <span class="hlt">Binary</span> 4U 1728-34</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sleator, Clio C.; Tomsick, John A.; King, Ashley L.; Miller, Jon M.; Boggs, Steven E.; Bachetti, Matteo; Barret, Didier; Chenevez, Jérôme; Christensen, Finn E.; Craig, William W.; Hailey, Charles J.; Harrison, Fiona A.; Rahoui, Farid; Stern, Daniel K.; Walton, Dominic J.; Zhang, William W.</p> <p>2016-08-01</p> <p>We report on a simultaneous NuSTAR and Swift observation of the neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> 4U 1728-34. We identified and removed four Type I X-ray bursts during the observation in order to study the persistent emission. The continuum spectrum is hard and described well by a blackbody with kT = 1.5 keV and a cutoff power law with Γ = 1.5, and a cutoff temperature of 25 keV. Residuals between 6 and 8 keV provide strong evidence of a broad Fe Kα line. By modeling the spectrum with a relativistically blurred reflection model, we find an upper limit for the inner disk radius of {R}{{in}}≤slant 2{R}{{ISCO}}. Consequently, we find that R NS ≤ 23 km, assuming M = 1.4 M ⊙ and a = 0.15. We also find an upper limit on the magnetic field of B ≤ 2 × 108 G.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016cosp...41E2187Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E2187Z"><span id="translatedtitle">On the evolutionary status of the donors in the <span class="hlt">low</span> <span class="hlt">mass</span> X-ray <span class="hlt">binary</span> systems containing black holes or neutron stars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ziolkowski, Janusz</p> <p>2016-07-01</p> <p>We consider donors (optical components) in four <span class="hlt">low</span> <span class="hlt">mass</span> X-ray <span class="hlt">binaries</span>: two black hole systems (GRS1915+105/V1387 Aql and GS 2023+338/V404 Cyg) and two neutron star systems (X2127+119 and IGR J17451-3022). In all four cases we found that donors are most likely so called "stripped" giants. Such star consists of a degenerate, nearly isothermal helium core and a more or less depleted hydrogen rich envelope. Both parts are separated by a hydrogen burning shell. The structure of such an object is relatively simple and easy to model. In all four systems we can estimate relatively precisely the radii of the donors (which depend almost exclusively on the orbital periods). In two black hole systems we can additionally estimate their luminosities. Analysing the internal structure of the donors, we found that they could be "stripped" giants in all four systems. The likely masses are ~ 0.28 Msun for V1387 Aql, ~ 0.54 Msun for V404 Cyg, ~ 0.16-0.17 Msun for the companion of X2127+119 and ~ 0.15-0.2 Msun for the companion of IGR J17451-3022. For the last system another possible solution is a MS star of ~ 0.75 Msun.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...821..105C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...821..105C"><span id="translatedtitle">A Test of the Nature of the Fe K Line in the Neutron Star <span class="hlt">Low-mass</span> X-Ray <span class="hlt">Binary</span> Serpens X-1</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chiang, Chia-Ying; Cackett, Edward M.; Miller, Jon M.; Barret, Didier; Fabian, Andy C.; D'Aì, Antonino; Parker, Michael L.; Bhattacharyya, Sudip; Burderi, Luciano; Di Salvo, Tiziana; Egron, Elise; Homan, Jeroen; Iaria, Rosario; Lin, Dacheng; Miller, M. Coleman</p> <p>2016-04-01</p> <p>Broad Fe K emission lines have been widely observed in the X-ray spectra of black hole systems as well as in neutron star systems. The intrinsically narrow Fe K fluorescent line is generally believed to be part of the reflection spectrum originating in an illuminated accretion disk which is broadened by strong relativistic effects. However, the nature of the lines in neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXBs) has been a matter of debate. We therefore obtained the longest, high-resolution X-ray spectrum of a neutron star LMXB to date with a 300 ks Chandra High Energy Transmission Grating Spectrometer (HETGS) observation of Serpens X-1. The observation was taken under the “continuous clocking” mode, and thus was free of photon pile-up effects. We carry out a systematic analysis and find that the blurred reflection model fits the Fe line of Serpens X-1 significantly better than a broad Gaussian component does, implying that the relativistic reflection scenario is much preferred. Chandra HETGS also provides a highest spectral resolution view of the Fe K region and we find no strong evidence for additional narrow lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140006006','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140006006"><span id="translatedtitle">An Fe XXIV Absorption Line in the Persistent Spectrum of the Dipping <span class="hlt">Low-Mass</span> X-Ray <span class="hlt">Binary</span> 1A 1744-361</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip</p> <p>2012-01-01</p> <p>We report on Chandra X-ray Observatory (Chandra) High Energy Transmission Grating spectra of the dipping <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> 1A 1744-361 during its 2008 July outburst. We find that its persistent emission is well modeled by a blackbody (kT approx. 1.0 keV) plus power law (Gamma approx. 1.7) with an absorption edge. In the residuals of the combined spectrum, we find a significant absorption line at 6.961 +/- 0.002 keV, consistent with the Fe xxvi (hydrogen-like Fe) 2-1 transition.We place an upper limit on the velocity of a redshifted flow of nu < 221 km/s. We find an equivalent width for the line of 27+2/-3 eV, from which we determine a column density of (7 +/- 1)×10(exp 17) /sq. cm via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of >103.6 erg cm/s. We discuss what implications the feature has on the system and its geometry. We also present Rossi X-ray Timing Explorer data accumulated during this latest outburst and, via an updated color-color diagram, clearly show that 1A 1744-361 is an "atoll" source</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...831...45C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...831...45C"><span id="translatedtitle">On the Evolution of the Inner Disk Radius with Flux in the Neutron Star <span class="hlt">Low-mass</span> X-Ray <span class="hlt">Binary</span> Serpens X-1</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chiang, Chia-Ying; Morgan, Robert A.; Cackett, Edward M.; Miller, Jon M.; Bhattacharyya, Sudip; Strohmayer, Tod E.</p> <p>2016-11-01</p> <p>We analyze the latest Suzaku observation of the bright neutron star (NS) <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> Serpens X-1 taken in 2013 October and 2014 April. The observation was taken using the burst mode and only suffered mild pile-up effects. A broad iron line is clearly detected in the X-ray spectrum. We test different models and find that the iron line is asymmetric and best interpreted by relativistic reflection. The relativistically broadened iron line is generally believed to originate from the innermost regions of the accretion disk, where strong gravity causes a series of special and general relativistic effects. The iron line profile indicates an inner radius of ∼8 R G, which gives an upper limit on the size of the NS. The asymmetric iron line has been observed in a number of previous observations, which gives several inner radius measurements at different flux states. We find that the inner radius of Serpens X-1 does not evolve significantly over the range of L/L Edd ∼ 0.4–0.6, and the lack of flux dependence of the inner radius implies that the accretion disk may be truncated outside of the innermost stable circular orbit by the boundary layer, rather than the stellar magnetic field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22036967','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22036967"><span id="translatedtitle">AN Fe XXIV ABSORPTION LINE IN THE PERSISTENT SPECTRUM OF THE DIPPING <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARY</span> 1A 1744-361</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip</p> <p>2012-07-01</p> <p>We report on Chandra X-ray Observatory (Chandra) High Energy Transmission Grating spectra of the dipping <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> 1A 1744-361 during its 2008 July outburst. We find that its persistent emission is well modeled by a blackbody (kT {approx} 1.0 keV) plus power law ({Gamma} {approx} 1.7) with an absorption edge. In the residuals of the combined spectrum, we find a significant absorption line at 6.961 {+-} 0.002 keV, consistent with the Fe XXVI (hydrogen-like Fe) 2-1 transition. We place an upper limit on the velocity of a redshifted flow of v < 221 km s{sup -1}. We find an equivalent width for the line of 27{sup +2}{sub -3} eV, from which we determine a column density of (7 {+-} 1) Multiplication-Sign 10{sup 17} cm{sup -2} via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of >10{sup 3.6} erg cm s{sup -1}. We discuss what implications the feature has on the system and its geometry. We also present Rossi X-ray Timing Explorer data accumulated during this latest outburst and, via an updated color-color diagram, clearly show that 1A 1744-361 is an 'atoll' source.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997ApJ...486..955I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997ApJ...486..955I"><span id="translatedtitle">On the Evolution of <span class="hlt">Low-Mass</span> X-Ray <span class="hlt">Binaries</span> under the Influence of a Donor Stellar Wind Induced by X-Rays from the Accretor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Iben, Icko, Jr.; Tutukov, Alexander V.; Fedorova, Alexandra V.</p> <p>1997-09-01</p> <p>In a <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> (LMXB), an intense stellar wind from the mass donor may be a consequence of the absorption of X-rays from the mass-accreting neutron star or black hole, and such a wind could change the evolution of these <span class="hlt">binaries</span> dramatically compared with the evolution of cataclysmic variables (CVs), which are close <span class="hlt">binaries</span> in which the accretor is a white dwarf. An analytical study and numerical models show that, in the closest and brightest LMXBs, a relativistic companion can capture up to ~10% of the mass lost in the induced stellar wind (ISW) from the main-sequence or subgiant donor, and this is enough to keep the X-ray luminosity of a typical LMXB on the level of LX ~ 5000 L⊙ and to accelerate the rotation of an old neutron star with a low magnetic field into the millisecond-period range. A self-sustained ISW may exist even if the donor does not fill its Roche lobe, but the system can be bright (LX > 100 L⊙) only if the radius of the donor is a substantial fraction (>~0.8) of the Roche lobe radius. A lower limit on the Roche lobe filling factor follows from the circumstance that both the rate Ėwind at which work must be done to lift wind matter off the donor and the rate Ėabs at which the donor absorbs X-ray energy are proportional to ṀISW (the ISW mass-loss rate) and from the requirement that Ėwind<Ėabs in order for energy to be conserved. The observed number (~100) of bright LMXBs in our Galaxy can be understood as the product of a relatively short lifetime (a few × 107 yr) and a small theoretical birthrate (~2 × 10-6-8 × 10-6 yr-1), which is comparable to semiempirical estimates of the birthrate of LMXBs and millisecond pulsars (~2 × 10-6 yr-1). The theoretical lifetime is ~10-60 times shorter than when the ISW is not taken into account, and the theoretical birthrate is ~3-6 times smaller, because of the fact that the ISW acts to expand the orbit and reduce the number of systems that can evolve through an X-ray bright stage under</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992JASS....9...30C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992JASS....9...30C"><span id="translatedtitle">The Reflection Effect on the <span class="hlt">Eclipsing</span> <span class="hlt">Binary</span> by the Wilson and Devinney's Model and Russell and Merrill's Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Choea, Seong Hee; Kang, Young Woon</p> <p>1992-06-01</p> <p>The reflection effect on three types of <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> has been analyzed Wilson and Devinney's model and Russell and Merrill's model. The reflection effect was displayed on the theoretical light curves for the various conditions using the Wilson and Devinney's light curve program. Two models were compared after the rectifing the theoretical light curves including the reflection effect with the Russell and Merrill's method. The result shows that two models have an agreement on the reflection effect just in cases of the small difference in temperature and albedo between two stars in the system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21560557','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21560557"><span id="translatedtitle">DISCOVERY OF AN ACCRETING MILLISECOND PULSAR IN THE <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> SYSTEM SWIFT J1749.4-2807</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Altamirano, D.; Cavecchi, Y.; Patruno, A.; Watts, A.; Degenaar, N.; Kalamkar, M.; Van der Klis, M.; Armas Padilla, M.; Kaur, R.; Yang, Y. J.; Wijnands, R.; Linares, M.; Rea, N.; Casella, P.; Soleri, P.</p> <p>2011-01-20</p> <p>We report on the discovery and the timing analysis of the first <span class="hlt">eclipsing</span> accretion-powered millisecond X-ray pulsar (AMXP): SWIFT J1749.4-2807. The neutron star rotates at a frequency of {approx}517.9 Hz and is in a <span class="hlt">binary</span> system with an orbital period of 8.8 hr and a projected semimajor axis of {approx}1.90 lt-s. Assuming a neutron star between 0.8 and 2.2 M{sub sun} and using the mass function of the system and the <span class="hlt">eclipse</span> half-angle, we constrain the mass of the companion and the inclination of the system to be in the {approx}0.46-0.81 M{sub sun} and {approx} 74.{sup 0}4-77.{sup 0}3 range, respectively. To date, this is the tightest constraint on the orbital inclination of any AMXP. As in other AMXPs, the pulse profile shows harmonic content up to the third overtone. However, this is the first AMXP to show a first overtone with rms amplitudes between {approx}6% and {approx}23%, which is the strongest ever seen and which can be more than two times stronger than the fundamental. The fact that SWIFT J1749.4-2807 is an <span class="hlt">eclipsing</span> system that shows uncommonly strong harmonic content suggests that it might be the best source to date to set constraints on neutron star properties including compactness and geometry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007ASPC..370..139B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007ASPC..370..139B&link_type=ABSTRACT"><span id="translatedtitle">Solar and Stellar <span class="hlt">Eclipse</span> Mapping</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Budding, E.</p> <p>2007-05-01</p> <p>The special circumstance of solar <span class="hlt">eclipse</span> affords an opportunity to review its background, particularly in the cultural context of western Anatolia. This links with a current project of çanakkale Onsekiz Mart University. Turning to the more general subject of stellar <span class="hlt">eclipses</span>, topics of particular note concern: choice of fitting functions, disk <span class="hlt">eclipses</span>, spot <span class="hlt">eclipses</span> and the gravity-darkening effect. These topics arise within new era <span class="hlt">eclipsing</span> <span class="hlt">binary</span> studies and are relevant to active researches on remote <span class="hlt">binaries</span> and extrasolar planets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002ApJ...564..260F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002ApJ...564..260F&link_type=ABSTRACT"><span id="translatedtitle">Fundamental Properties and Distances of the Large Magellanic Cloud from <span class="hlt">Eclipsing</span> <span class="hlt">Binaries</span>. II. HV 982</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fitzpatrick, E. L.; Ribas, I.; Guinan, E. F.; DeWarf, L. E.; Maloney, F. P.; Massa, D.</p> <p>2002-01-01</p> <p>We have determined the distance to a second <span class="hlt">eclipsing</span> <span class="hlt">binary</span> (EB) system in the Large Magellanic Cloud, HV 982 (~B1 IV-V+~B1 IV-V). The measurement of the distance-among other properties of the system-is based on optical photometry and spectroscopy and space-based UV/optical spectrophotometry. The analysis combines the ``classical'' EB study of light and radial velocity curves, which yields the stellar masses and radii, with a new analysis of the observed energy distribution, which yields the effective temperature, metallicity, and reddening of the system plus the distance ``attenuation factor,'' essentially (radius/distance)2. Combining the results gives the distance to HV 982, which is 50.2+/-1.2 kpc. This distance determination consists of a detailed study of well-understood objects (B stars) in a well-understood evolutionary phase (core H burning). The results are entirely consistent with-but do not depend on-stellar evolution calculations. There are no ``zero-point'' uncertainties as, for example, with the use of Cepheid variables. Neither is the result subject to sampling biases, as may affect techniques that utilize whole stellar populations, such as red giant branch stars. Moreover, the analysis is insensitive to stellar metallicity (although the metallicity of the stars is explicitly determined), and the effects of interstellar extinction are determined for each object studied. After correcting for the location of HV 982, we find an implied distance to the optical center of the LMC's bar of dLMC=50.7+/-1.2 kpc. This result differs by nearly 5 kpc from our earlier result for the EB HV 2274, which implies a bar distance of 45.9 kpc. These results may either reflect marginally compatible measures of a unique LMC distance or, alternatively, suggest a significant depth to the stellar distribution in the LMC. Some evidence for this latter hypothesis is discussed. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...590A..85Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...590A..85Z"><span id="translatedtitle">The first study of the light-travel time effect in massive LMC <span class="hlt">eclipsing</span> <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zasche, P.; Wolf, M.; Vraštil, J.; Pilarčík, L.; Juryšek, J.</p> <p>2016-05-01</p> <p>Aims: New CCD observations for semidetached and detached <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> from the Large Magellanic Cloud were carried out using the Danish 1.54-m telescope located at the La Silla Observatory in Chile. The selected systems were monitored for their times of minima, which were required to be able to study the period changes taking place in them. In addition, many new times of minima were derived from the photometric surveys OGLE-II, OGLE-III, and MACHO. Methods: The O-C diagrams of minima timings were analysed using the hypothesis of the light-travel time effect, i.e. assuming the orbital motion around a common barycenter with the distant component. Moreover, the light curves of these systems were also analysed using the program PHOEBE, which provided the physical parameters of the stars. Results: For the first time, in this study we derived the relatively short periods of modulation in these systems, which relates to third bodies. The orbital periods resulted from 3.6 to 11.3 yr and the eccentricities were found to be up to 0.64. This is the first time that this kind of analysis for the set of extragalactic sources has been performed. The Wolf-Rayet system OGLE-LMC-ECL-08823 is the most mysterious one, owing to the resultant high mass function. Another system, OGLE-LMC-ECL-19996, was found to contain a third body with a very high mass (M3,min = 26M⊙). One system (OGLE-LMC-ECL-09971) is suspicious because of its eccentricity, and another one (OGLE-LMC-ECL-20162) shows some light curve variability, with a possible flare-like or microlensing-like event. Conclusions: All of these results came only from the photometric observations of the systems and can be considered as a good starting point for future dedicated observations. Based on data collected with the Danish 1.54-m telescope at the ESO La Silla Observatory.Full Table 4 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014NewAR..60....1S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014NewAR..60....1S"><span id="translatedtitle">Empirical tests of pre-main-sequence stellar evolution models with <span class="hlt">eclipsing</span> <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stassun, Keivan G.; Feiden, Gregory A.; Torres, Guillermo</p> <p>2014-06-01</p> <p>We examine the performance of standard pre-main-sequence (PMS) stellar evolution models against the accurately measured properties of a benchmark sample of 26 PMS stars in 13 <span class="hlt">eclipsing</span> <span class="hlt">binary</span> (EB) systems having masses 0.04-4.0 M⊙ and nominal ages ≈1-20 Myr. We provide a definitive compilation of all fundamental properties for the EBs, with a careful and consistent reassessment of observational uncertainties. We also provide a definitive compilation of the various PMS model sets, including physical ingredients and limits of applicability. No set of model isochrones is able to successfully reproduce all of the measured properties of all of the EBs. In the H-R diagram, the masses inferred for the individual stars by the models are accurate to better than 10% at ≳1 M⊙, but below 1 M⊙ they are discrepant by 50-100%. Adjusting the observed radii and temperatures using empirical relations for the effects of magnetic activity helps to resolve the discrepancies in a few cases, but fails as a general solution. We find evidence that the failure of the models to match the data is linked to the triples in the EB sample; at least half of the EBs possess tertiary companions. Excluding the triples, the models reproduce the stellar masses to better than ∼10% in the H-R diagram, down to 0.5 M⊙, below which the current sample is fully contaminated by tertiaries. We consider several mechanisms by which a tertiary might cause changes in the EB properties and thus corrupt the agreement with stellar model predictions. We show that the energies of the tertiary orbits are comparable to that needed to potentially explain the scatter in the EB properties through injection of heat, perhaps involving tidal interaction. It seems from the evidence at hand that this mechanism, however it operates in detail, has more influence on the surface properties of the stars than on their internal structure, as the lithium abundances are broadly in good agreement with model predictions. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21305028','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21305028"><span id="translatedtitle">DISCOVERY OF A RED GIANT WITH SOLAR-LIKE OSCILLATIONS IN AN <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> SYSTEM FROM KEPLER SPACE-BASED PHOTOMETRY</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hekker, S.; Debosscher, J.; De Ridder, J.; Aerts, C.; Van Winckel, H.; Beck, P. G.; Blomme, J.; Huber, D.; Hidas, M. G.; Stello, D.; Bedding, T. R.; Gilliland, R. L.; Christensen-Dalsgaard, J.; Kjeldsen, H.; Brown, T. M.; Borucki, W. J.; Koch, D.; Jenkins, J. M.; Pigulski, A.</p> <p>2010-04-20</p> <p>Oscillating stars in <span class="hlt">binary</span> systems are among the most interesting stellar laboratories, as these can provide information on the stellar parameters and stellar internal structures. Here we present a red giant with solar-like oscillations in an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> observed with the NASA Kepler satellite. We compute stellar parameters of the red giant from spectra and the asteroseismic mass and radius from the oscillations. Although only one <span class="hlt">eclipse</span> has been observed so far, we can already determine that the secondary is a main-sequence F star in an eccentric orbit with a semi-major axis larger than 0.5 AU and orbital period longer than 75 days.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140010267','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140010267"><span id="translatedtitle">The Chandra Delta Ori Large Project: Occultation Measurements of the Shocked Gas tn the Nearest <span class="hlt">Eclipsing</span> O-Star <span class="hlt">Binary</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Corcoran, Michael F.; Nichols, Joy; Naze, Yael; Rauw, Gregor; Pollock, Andrew; Moffat, Anthony; Richardson, Noel; Evans, Nancy; Hamaguchi, Kenji; Oskinova, Lida; Hamann, W. -R.; Gull, Ted; Ignace, Rico; Hole, Tabetha; Iping, Rosina; Walborn, Nolan; Hoffman, Jennifer; Lomax, Jamie; Waldron, Wayne; Owocki, Stan; Maiz-Apellaniz, Jesus; Leutenegger, Maurice; Hole, Tabetha; Gayley, Ken; Russell, Chris</p> <p>2013-01-01</p> <p>Delta Ori is the nearest massive, single-lined <span class="hlt">eclipsing</span> <span class="hlt">binary</span> (O9.5 II + B0.5III). As such it serves as a fundamental calibrator of the mass-radius-luminosity relation in the upper HR diagram. It is also the only <span class="hlt">eclipsing</span> O-type <span class="hlt">binary</span> system which is bright enough to be observable with the CHANDRA gratings in a reasonable exposure. Studies of resolved X-ray line complexes provide tracers of wind mass loss rate and clumpiness; occultation by the X-ray dark companion of the line emitting region can provide direct spatial information on the location of the X-ray emitting gas produced by shocks embedded in the wind of the primary star. We obtained phase-resolved spectra with Chandra in order to determine the level of phase-dependent vs. secular variability in the shocked wind. Along with the Chandra observations we obtained simultaneous photometry from space with the Canadian MOST satellite to help understand the relation between X-ray and photospheric variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ARep...60..517K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ARep...60..517K"><span id="translatedtitle">Variations in the orbital periods of the Algol-type <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> RZ Cas and Z Dra</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khaliullina, A. I.</p> <p>2016-05-01</p> <p>A detailed study of variations of the orbital periods of the Algol-type <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems RZ Cas and Z Dra is presented. The fairly complex variations of the periods of both systems can be represented as a superposition of a secular increase of the period, slow periodic fluctuations, and quasiperiodic oscillations with a small amplitude occurring on timescales of decades. The secular increase of the period can be explained by the steady mass transfer from the less massive to the more massive component with conservation of the total angular momentum. The mass-transfer rate is 5.7 × 10-9 M ⊙/yr for RZ Cas and 3.0×10-8 M ⊙/yr for Z Dra. To explain the long-period cyclic variations of the orbital periods of RZCas and Z Dra, it must be assumed that the <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> move in long-period orbits. RZ Cas moves with a period of 133 yr around a third body withmass M 3 > 0.55 M ⊙, while Z Dra moves with a period of 60 yr around a third body with mass M 3 > 0.7 M ⊙. The residual fluctuations of the periods may be due to a superposition of variations due to magnetic cycles and non-stationary ejections of matter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22340019','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22340019"><span id="translatedtitle">Absolute properties of the <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system AQ Serpentis: A stringent test of convective core overshooting in stellar evolution models</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Torres, Guillermo; Vaz, Luiz Paulo R.; Sandberg Lacy, Claud H.; Claret, Antonio E-mail: lpv@fisica.ufmg.br E-mail: claret@iaa.es</p> <p>2014-02-01</p> <p>We report differential photometric observations and radial-velocity measurements of the detached, 1.69 day period, double-lined <span class="hlt">eclipsing</span> <span class="hlt">binary</span> AQ Ser. Accurate masses and radii for the components are determined to better than 1.8% and 1.1%, respectively, and are M {sub 1} = 1.417 ± 0.021 M {sub ☉}, M {sub 2} = 1.346 ± 0.024 M {sub ☉}, R {sub 1} = 2.451 ± 0.027 R {sub ☉}, and R {sub 2} = 2.281 ± 0.014 R {sub ☉}. The temperatures are 6340 ± 100 K (spectral type F6) and 6430 ± 100 K (F5), respectively. Both stars are considerably evolved, such that predictions from stellar evolution theory are particularly sensitive to the degree of extra mixing above the convective core (overshoot). The component masses are different enough to exclude a location in the H-R diagram past the point of central hydrogen exhaustion, which implies the need for extra mixing. Moreover, we find that current main-sequence models are unable to match the observed properties at a single age even when allowing the unknown metallicity, mixing length parameter, and convective overshooting parameter to vary freely and independently for the two components. The age of the more massive star appears systematically younger. AQ Ser and other similarly evolved <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> showing the same discrepancy highlight an outstanding and largely overlooked problem with the description of overshooting in current stellar theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22342148','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22342148"><span id="translatedtitle">Photometric investigation of the totally <span class="hlt">eclipsing</span> contact <span class="hlt">binary</span> V12 in the intermediate-age open cluster NGC 7789</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Qian, S.-B.; Wang, J.-J.; Liu, L.; Zhou, X.; Essam, A.; Ali, G. B.; Haroon, A.-A.</p> <p>2015-02-01</p> <p>NGC 7789 is an intermediate-age open cluster with an age similar to the mean age of contact <span class="hlt">binary</span> stars. V12 is a bright W UMa-type <span class="hlt">binary</span> star with an orbital period of 0.3917 days. The first complete light curves of V12 in the V, R, and I bands are presented and analyzed with the Wilson–Devinney (W-D) method. The results show that V12 is an intermediate-contact <span class="hlt">binary</span> (f=43.0(±2.2)%) with a mass ratio of 3.848, and it is a W-type contact <span class="hlt">binary</span> where the less massive component is slightly hotter than the more massive one. The asymmetry of the light curves is explained by the presence of a dark spot on the more massive component. The derived orbital inclination (i=83{sub .}{sup ∘}6) indicates that it is a totally <span class="hlt">eclipsing</span> <span class="hlt">binary</span>, which suggests that the determined parameters are reliable. The orbital period may show a long-term increase at a rate of P-dot =+2.48(±0.17)×10{sup −6} days yr{sup −1} that reveals a rapid mass transfer from the less massive component to the more massive one. However, more observations are needed to confirm this conclusion. The presence of an intermediate-contact <span class="hlt">binary</span> in an intermediate-age open cluster may suggest that some contact <span class="hlt">binaries</span> have a very short pre-contact timescale. The presence of a third body and/or stellar collision may help to shorten the pre-contact evolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014MNRAS.438.2105P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014MNRAS.438.2105P"><span id="translatedtitle">A propeller scenario for the gamma-ray emission of <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span>: the case of XSS J12270-4859</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Papitto, A.; Torres, D. F.; Li, Jian</p> <p>2014-03-01</p> <p>XSS J12270-4859 is the only <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> (LMXB) with a proposed persistent gamma-ray counterpart in the Fermi-Large Area Telescope domain, 2FGL 1227.7-4853. Here, we present the results of the analysis of recent INTEGRAL observations, aimed at assessing the long-term variability of the hard X-ray emission, and thus the stability of the accretion state. We confirm that the source behaves as a persistent hard X-ray emitter between 2003 and 2012. We propose that XSS J12270-4859 hosts a neutron star in a propeller state, a state we investigate in detail, developing a theoretical model to reproduce the associated X-ray and gamma-ray properties. This model can be understood as being of a more general nature, representing a viable alternative by which LMXBs can appear as gamma-ray sources. In particular, this may apply to the case of millisecond pulsars performing a transition from a state powered by the rotation of their magnetic field to a state powered by matter infall, such as that recently observed from the transitional pulsar PSR J1023+0038. While the surface magnetic field of a typical neutron star (NS) in an LMXB is lower by more than four orders of magnitude than the much more intense fields of neutron stars accompanying high-mass <span class="hlt">binaries</span>, the radius at which the matter inflow is truncated in an NS-LMXB system is much smaller. The magnetic field at the magnetospheric interface is then orders of magnitude larger at this interface, and as consequence, so is the power to accelerate electrons. We demonstrate that the cooling of the accelerated electron population takes place mainly through synchrotron interaction with the magnetic field permeating the interface, and through inverse Compton losses due to the interaction between the electrons and the synchrotron photons they emit. We found that self-synchrotron Compton processes can explain the high-energy phenomenology of XSS J12270-4859.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PASJ...68...50A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PASJ...68...50A"><span id="translatedtitle">Hard-tail emission in the soft state of <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> and their relation to the neutron star magnetic field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Asai, Kazumi; Mihara, Tatehiro; Mastuoka, Masaru; Sugizaki, Mutsumi</p> <p>2016-08-01</p> <p>Average hard-tail X-ray emission in the soft state of nine bright Atoll <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> containing a neutron star (NS-LMXBs) are investigated by using the light curves of MAXI/GSC (Gas Slit Camera) and Swift/BAT (Burst Alert Telescope). Two sources (4U 1820-30 and 4U 1735-44) exhibit a large hardness ratio (15-50 keV/2-10 keV: HR >0.1), while the other sources distribute at HR ≲ 0.1. In either case, HR does not depend on the 2-10 keV luminosity. Therefore the difference of HR is due to the 15-50 keV luminosity, which is Comptonized emission. The Compton cloud is assumed to be around the neutron star. The size of the Compton cloud would affect the value of HR. Although the magnetic field of an NS-LMXB is weak, we could expect a larger Alfvén radius than the innermost stable circular orbit or the neutron star radius in some sources. In such cases, the accretion inflow is stopped at the Alfvén radius and would create a relatively large Compton cloud. This would result in the observed larger Comptonized emission. By attributing the difference of the size of Compton cloud to the Alfvén radius, we can estimate the magnetic fields of neutron stars. The obtained lower/upper limits are consistent with the previous results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...831...25E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...831...25E"><span id="translatedtitle">A New Correlation with Lower Kilohertz Quasi-periodic Oscillation Frequency in the Ensemble of <span class="hlt">Low-mass</span> X-Ray <span class="hlt">Binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Erkut, M. Hakan; Duran, Şİvan; Çatmabacak, Önder; Çatmabacak, Onur</p> <p>2016-11-01</p> <p>We study the dependence of kilohertz quasi-periodic oscillation (kHz QPO) frequency on accretion-related parameters in the ensemble of neutron-star <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span>. Based on the mass accretion rate, \\dot{M}, and the magnetic field strength, B, on the surface of the neutron star, we find a correlation between the lower kHz QPO frequency and \\dot{M}/{B}2. The correlation holds in the current ensemble of Z and atoll sources and therefore can explain the lack of correlation between the kHz QPO frequency and X-ray luminosity in the same ensemble. The average run of lower kHz QPO frequencies throughout the correlation can be described by a power-law fit to source data. The simple power law, however, cannot describe the frequency distribution in an individual source. The model function fit to frequency data, on the other hand, can account for the observed distribution of lower kHz QPO frequencies in the case of individual sources as well as the ensemble of sources. The model function depends on the basic length scales, such as the magnetospheric radius and the radial width of the boundary region, both of which are expected to vary with \\dot{M} to determine the QPO frequencies. In addition to modifying the length scales, and hence the QPO frequencies, the variation in \\dot{M}, being sufficiently large, may also lead to distinct accretion regimes, which would be characterized by Z and atoll phases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014MNRAS.438.2784C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014MNRAS.438.2784C"><span id="translatedtitle">The nature of the island and banana states in atoll sources and a unified model for <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Church, M. J.; Gibiec, A.; Bałucińska-Church, M.</p> <p>2014-03-01</p> <p>We propose an explanation of the island and banana states and the relation between atoll and Z-track sources, constituting a unified model for <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (LMXB). We find a dramatic transition at a luminosity of 1-2 × 1037 erg s-1 above which the high-energy cut-off ECO of the Comptonized emission in all sources is low at a few keV. There is thermal equilibrium between the neutron star at ˜2 keV and the Comptonizing accretion disc corona (ADC) causing the low ECO in the banana state of atolls and all states of the Z-track sources. Below this luminosity, ECO increases towards 100 keV causing the hardness of the island state. Thermal equilibrium is lost, the ADC becoming much hotter than the neutron star via an additional coronal heating mechanism. This suggests a unified model of LMXB: the banana state is a basic state with the mass accretion rate dot{M} increasing, corresponding to the normal branch of Z-track sources. The island state has high ADC temperature, this state not existing in the Z-sources with luminosities much greater than the critical value. The Z-track sources have an additional flaring branch consistent with unstable nuclear burning on the neutron star at high dot{M}. This burning regime does not exist at low dot{M} so this branch is not seen in atolls (except GX atolls). The horizontal branch in Z-track sources has a strong increase in radiation pressure disrupting the inner disc and launching relativistic jets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22133851','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22133851"><span id="translatedtitle">A CHANGE IN THE QUIESCENT X-RAY SPECTRUM OF THE NEUTRON STAR <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARY</span> MXB 1659-29</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cackett, E. M.; Brown, E. F.; Cumming, A.; Degenaar, N.; Miller, J. M.; Fridriksson, J. K.; Wijnands, R.; Homan, J.</p> <p>2013-09-10</p> <p>The quasi-persistent neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> MXB 1659-29 went into quiescence in 2001, and we have followed its quiescent X-ray evolution since. Observations over the first 4 yr showed a rapid drop in flux and temperature of the neutron star atmosphere, interpreted as cooling of the neutron star crust which had been heated during the 2.5 yr outburst. However, observations taken approximately 1400 and 2400 days into quiescence were consistent with each other, suggesting the crust had reached thermal equilibrium with the core. Here we present a new Chandra observation of MXB 1659-29 taken 11 yr into quiescence and 4 yr since the last Chandra observation. This new observation shows an unexpected factor of {approx}3 drop in count rate and change in spectral shape since the last observation, which cannot be explained simply by continued cooling. Two possible scenarios are that either the neutron star temperature has remained unchanged and there has been an increase in the column density, or, alternatively the neutron star temperature has dropped precipitously and the spectrum is now dominated by a power-law component. The first scenario may be possible given that MXB 1659-29 is a near edge-on system, and an increase in column density could be due to build-up of material in, and a thickening of, a truncated accretion disk during quiescence. But, a large change in disk height may not be plausible if standard accretion disk theory holds during quiescence. Alternatively, the disk may be precessing, leading to a higher column density during this latest observation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090038691','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090038691"><span id="translatedtitle">An Fe XXVI Absorption Line in the Persistent Spectrum of the Dipping <span class="hlt">Low</span> <span class="hlt">Mass</span> X-ray <span class="hlt">Binary</span> 1A 1744-361</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip</p> <p>2009-01-01</p> <p>We report on Chandra X-ray Observatory (CXO) High-Energy Transmission Grating (HETG) spectra of the dipping <span class="hlt">Low</span> <span class="hlt">Mass</span> X-ray <span class="hlt">Binary</span> (LMXB) 1A 1744-361 during its July 2008 outburst. We find that its persistent emission is well modeled by a blackbody (kT approx. 1.0 keV) plus power-law (Gamma approx. 1.7) with an absorption edge at 7.6 keV. In the residuals of the combined spectrum we find a significant absorption line at 6.961+/-0.002 keV, consistent with the Fe XXVI (hydrogen-like Fe) 2 - 1 transition. We place an upper limit on the velocity of a redshifted flow of v < 221 km/s. We find an equivalent width for the line of 27+2/-3 eV, from which we determine a column density of 7+/-1 x 10(exp 17)/sq cm via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of > 10(exp 3.6) erg cm/s. The properties of this line are consistent with those observed in other dipping LMXBs. Using Rossi X-ray Timing Explorer (RXTE) data accumulated during this latest outburst we present an updated color-color diagram which clearly shows that IA 1744-361 is an "atoll" source. Finally, using additional dips found in the RXTE and CXO data we provide an updated orbital period estimate of 52+/-5 minutes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21455022','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21455022"><span id="translatedtitle">XTE J1701-462 AND ITS IMPLICATIONS FOR THE NATURE OF SUBCLASSES IN LOW-MAGNETIC-FIELD NEUTRON STAR <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARIES</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Homan, Jeroen; Fridriksson, Joel K.; Remillard, Ronald A.; Lewin, Walter H. G.; Van der Klis, Michiel; Wijnands, Rudy; Altamirano, Diego; Mendez, Mariano; Lin Dacheng; Casella, Piergiorgio; Belloni, Tomaso M.</p> <p>2010-08-10</p> <p>We report on an analysis of Rossi X-Ray Timing Explorer data of the transient neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> (NS-LMXB) XTE J1701-462, obtained during its 2006-2007 outburst. The X-ray properties of the source changed between those of various types of NS-LMXB subclasses. At high luminosities, the source switched between two types of Z source behavior and at low luminosities we observed a transition from Z source to atoll source behavior. These transitions between subclasses primarily manifest themselves as changes in the shapes of the tracks in X-ray color-color (CD) and hardness-intensity diagrams (HID), but they are accompanied by changes in the kHz quasi-periodic oscillations, broadband variability, burst behavior, and/or X-ray spectra. We find that for most of the outburst the low-energy X-ray flux is a good parameter to track the gradual evolution of the tracks in CD and HID, allowing us to resolve the evolution of the source in greater detail than before and relate the observed properties to other NS-LMXBs. We further find that during the transition from Z to atoll, characteristic behavior known as the atoll upper banana can equivalently be described as the final stage of a weakening Z source flaring branch, thereby blurring the line between the two subclasses. Our findings strongly suggest that the wide variety in behavior observed in NS-LXMBs with different luminosities can be linked through changes in a single variable parameter, namely the mass accretion rate, without the need for additional differences in the neutron star parameters or viewing angle. We briefly discuss the implications of our findings for the spectral changes observed in NS-LMXBs and suggest that, contrary to what is often assumed, the position along the color-color tracks of Z sources is not determined by the instantaneous mass accretion rate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AJ....152...75O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AJ....152...75O"><span id="translatedtitle">A Wide-field Survey for Transiting Hot Jupiters and <span class="hlt">Eclipsing</span> Pre-main-sequence <span class="hlt">Binaries</span> in Young Stellar Associations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oelkers, Ryan J.; Macri, Lucas M.; Marshall, Jennifer L.; DePoy, Darren L.; Lambas, Diego G.; Colazo, Carlos; Stringer, Katelyn</p> <p>2016-09-01</p> <p>The past two decades have seen a significant advancement in the detection, classification, and understanding of exoplanets and <span class="hlt">binaries</span>. This is due, in large part, to the increase in use of small-aperture telescopes (<20 cm) to survey large areas of the sky to milli-mag precision with rapid cadence. The vast majority of the planetary and <span class="hlt">binary</span> systems studied to date consists of main-sequence or evolved objects, leading to a dearth of knowledge of properties at early times (<50 Myr). Only a dozen <span class="hlt">binaries</span> and one candidate transiting Hot Jupiter are known among pre-main-sequence objects, yet these are the systems that can provide the best constraints on stellar formation and planetary migration models. The deficiency in the number of well characterized systems is driven by the inherent and aperiodic variability found in pre-main-sequence objects, which can mask and mimic <span class="hlt">eclipse</span> signals. Hence, a dramatic increase in the number of young systems with high-quality observations is highly desirable to guide further theoretical developments. We have recently completed a photometric survey of three nearby (<150 pc) and young (<50 Myr) moving groups with a small-aperture telescope. While our survey reached the requisite photometric precision, the temporal coverage was insufficient to detect Hot Jupiters. Nevertheless, we discovered 346 pre-main-sequence <span class="hlt">binary</span> candidates, including 74 high-priority objects for further study. This paper includes data taken at The McDonald Observatory of The University of Texas at Austin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19820058444&hterms=Variable+stars&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2528Variable%2Bstars%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820058444&hterms=Variable+stars&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2528Variable%2Bstars%2529"><span id="translatedtitle">The variable He 10830 A line of Algol. [<span class="hlt">eclipsing</span> <span class="hlt">binary</span> star</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zirin, H.; Liggett, M. A.</p> <p>1982-01-01</p> <p>Spectra of several <span class="hlt">eclipses</span> of Algol in the range 10500-11000 A where the line contribution of Algol B is important, are presented. Strong unshifted 10830 (2000 mA) absorption peaks at primary minimum but disappears between phases 0.3 and 0.7. At minimum the line must primarily arise in Algol B, but the presence of 10830 absorption just outside <span class="hlt">eclipse</span>, when the contribution to the total light of Algol B is small, must be due to excitation of He in the atmosphere of the primary by X-ray irradiation from Algol B, a known X-ray source. A Si I line from Algol B is also detected, and the Pa-gamma line sometimes peaks during <span class="hlt">eclipse</span>. Even if some of the 10830 absorption comes from Algol A, Algol B still has the strongest 10830 (3000 mA) yet measured in any star.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850064726&hterms=cv&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dcv','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850064726&hterms=cv&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dcv"><span id="translatedtitle">Analysis of ultraviolet atmospheric <span class="hlt">eclipses</span> in the Wolf-Rayet <span class="hlt">binary</span> CV Serpentis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Eaton, J. A.; Cherepashchuk, A. M.; Khaliullin, Kh. F.</p> <p>1985-01-01</p> <p>While no <span class="hlt">eclipses</span> deeper than 0.04 mag are noted in the present UV spectra, covering one-half of an orbital cycle of CV Ser, in the electron scattering continuum at 2400-3200 A or in fine error sensor observations, marked atmospheric <span class="hlt">eclipses</span> of up to 0.5 mag depth are observed in individual strong lines and over large ranges of the continuum at shorter wavelengths. The flux above the continuum in the C II 1247 A, Si IV 1400 A, and Si IV 1723 lines showed similar phase dependence with emission weakening, as well as with the emission's going into absorption as phase progresses from superior to inferior conjunction of the WC star (primary <span class="hlt">eclipse</span>). These observations show effects very similar to the behavior of WN stars in the UV.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1018354','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1018354"><span id="translatedtitle">The architecture of the hierarchical triple star KOI 928 from <span class="hlt">eclipse</span> timing variations seen in Kepler photometry</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Steffen, J. H.; Quinn, S. N.; Borucki, W. J.; Brugamyer, E.; Bryson, S. T.; Buchhave, L. A.; Cochran, W. D.; Endl, M.; Fabrycky, D C.; Ford, E. B.; Holman, M. J.; Jenkins, J.</p> <p>2011-10-01</p> <p>We present a hierarchical triple star system (KIC 9140402) where a <span class="hlt">low</span> <span class="hlt">mass</span> <span class="hlt">eclipsing</span> <span class="hlt">binary</span> orbits a more massive third star. The orbital period of the <span class="hlt">binary</span> (4.98829 Days) is determined by the <span class="hlt">eclipse</span> times seen in photometry from NASA's Kepler spacecraft. The periodically changing tidal field, due to the eccentric orbit of the <span class="hlt">binary</span> about the tertiary, causes a change in the orbital period of the <span class="hlt">binary</span>. The resulting <span class="hlt">eclipse</span> timing variations provide insight into the dynamics and architecture of this system and allow the inference of the total mass of the <span class="hlt">binary</span> (0.424±0.017M<sub>circle-dot</sub>) and the orbital parameters of the <span class="hlt">binary</span> about the central star.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1018354-architecture-hierarchical-triple-star-koi-from-eclipse-timing-variations-seen-kepler-photometry','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1018354-architecture-hierarchical-triple-star-koi-from-eclipse-timing-variations-seen-kepler-photometry"><span id="translatedtitle">The architecture of the hierarchical triple star KOI 928 from <span class="hlt">eclipse</span> timing variations seen in Kepler photometry</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Steffen, J. H.; Quinn, S. N.; Borucki, W. J.; Brugamyer, E.; Bryson, S. T.; Buchhave, L. A.; Cochran, W. D.; Endl, M.; Fabrycky, D C.; Ford, E. B.; et al</p> <p>2011-10-01</p> <p>We present a hierarchical triple star system (KIC 9140402) where a <span class="hlt">low</span> <span class="hlt">mass</span> <span class="hlt">eclipsing</span> <span class="hlt">binary</span> orbits a more massive third star. The orbital period of the <span class="hlt">binary</span> (4.98829 Days) is determined by the <span class="hlt">eclipse</span> times seen in photometry from NASA's Kepler spacecraft. The periodically changing tidal field, due to the eccentric orbit of the <span class="hlt">binary</span> about the tertiary, causes a change in the orbital period of the <span class="hlt">binary</span>. The resulting <span class="hlt">eclipse</span> timing variations provide insight into the dynamics and architecture of this system and allow the inference of the total mass of the <span class="hlt">binary</span> (0.424±0.017Mcircle-dot) and the orbital parameters ofmore » the <span class="hlt">binary</span> about the central star.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995PASP..107..307P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995PASP..107..307P"><span id="translatedtitle">The Remarkable <span class="hlt">Eclipsing</span> Asynchronous AM Herculis <span class="hlt">Binary</span> RX J19402-1025</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Patterson, Joseph; Skillman, David R.; Thorstensen, John; Hellier, Coel</p> <p>1995-04-01</p> <p>We report on two years of photometric and spectroscopic observation of the recently discovered AM Herculis star RX J19402-1025. A sharp <span class="hlt">eclipse</span> feature is present in the optical and X-ray light curves, repeating with a period of 12116.290 +- 0.003 s. The out-of-<span class="hlt">eclipse</span> optical waveform contains approximately equal contributions from a signal at the same period and another signal at 12150 s. As these signals drift in adn out of phase, the waveform of the light curve changes in a complex but predictable manner. After one entire "super-cycle" of 50 days (the beat period between the shorter periods), the light curve returns to its initial shape. We present long-term ephemerides for each of these periods. It is highly probable that the <span class="hlt">eclipse</span> period is the underlying orbital period, while the magnetic white dwarf rotates with P = 12150 s. The <span class="hlt">eclipses</span> appear to be <span class="hlt">eclipses</span> of the white dwarf by the secondary star. But there is probably also a small obscuring effect from cold gas surrounding the secondary, especially on the orbit-leading side where the stream begins to fall towards the white dwarf. The latter hypothesis can account for several puzzling effects in this star, as well as the tendency among most AM Her stars for the sharp emission-line components to slightly precede the actual motion of the secondary. The presence of <span class="hlt">eclipses</span> in an asynchronous Am Her star provides a marvelous opportunity to study how changes in the orientation of magnetic field lines affect the accretion flows. Repeated polarimetric light curves and high-resolution studies of the emission lines are now critical to exploit this potential. (SECTION: Stars)</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21300537','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21300537"><span id="translatedtitle">THE ARAUCARIA PROJECT. DETERMINATION OF THE LARGE MAGELLANIC CLOUD DISTANCE FROM LATE-TYPE <span class="hlt">ECLIPSING</span> <span class="hlt">BINARY</span> SYSTEMS. I. OGLE-051019.64-685812.3</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pietrzynski, Grzegorz; Graczyk, Dariusz; Gieren, Wolfgang; Szewczyk, Olaf; Kolaczkowski, Zbigniew; Thompson, Ian B.; Udalski, Andrzej; Minniti, Dante; Bresolin, Fabio; Kudritzki, Rolf-Peter E-mail: darek@astro-udec.cl E-mail: szewczyk@astro-udec.cl E-mail: udalski@astrouw.edu.pl E-mail: bresolin@ifa.hawaii.edu</p> <p>2009-05-20</p> <p>We have analyzed the double-lined <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system OGLE-051019.64-685812.3 in the LMC which consists of two G4 giant components with very similar effective temperatures. A detailed analysis of the Optical Gravitational Lensing Experiment I-band light curve of the system, radial velocity curves for both components derived from high-resolution spectra, and near-infrared magnitudes of the <span class="hlt">binary</span> system measured outside the <span class="hlt">eclipses</span> has allowed us to obtain an accurate orbit solution for this <span class="hlt">eclipsing</span> <span class="hlt">binary</span> and its fundamental physical parameters. Using a surface brightness (V - K)-color relation for giant stars we have calculated the distance to the system and obtained a true distance modulus of 18.50 mag, with an estimated total uncertainty of {+-}3%. More similar <span class="hlt">eclipsing</span> <span class="hlt">binary</span> systems in the LMC which we have discovered and for which we are currently obtaining the relevant data will allow us to better check on the systematics of the method and eventually provide a distance determination to the LMC accurate to 1%, much needed for the calibration of the distance scale.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015A%26A...576A..88L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015A%26A...576A..88L"><span id="translatedtitle"><span class="hlt">Eclipsing</span> <span class="hlt">binaries</span> and fast rotators in the Kepler sample. Characterization via radial velocity analysis from Calar Alto</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lillo-Box, J.; Barrado, D.; Mancini, L.; Henning, Th.; Figueira, P.; Ciceri, S.; Santos, N.</p> <p>2015-04-01</p> <p>Context. The Kepler mission has searched for planetary transits in more than two hundred thousand stars by obtaining very accurate photometric data over a long period of time. Among the thousands of detected candidates, the planetary nature of around 15% has been established or validated by different techniques. But additional data are needed to characterize the rest of the candidates and reject other possible configurations. Aims: We started a follow-up program to validate, confirm, and characterize some of the planet candidates. In this paper we present the radial velocity analysis of those that present large variations, which are compatible with being <span class="hlt">eclipsing</span> <span class="hlt">binaries</span>. We also study those showing high rotational velocities, which prevents us from reaching the necessary precision to detect planetary-like objects. Methods: We present new radial velocity results for 13 Kepler objects of interest (KOIs) obtained with the CAFE spectrograph at the Calar Alto Observatory and analyze their high-spatial resolution (lucky) images obtained with AstraLux and the Kepler light curves of some interesting cases. Results: We have found five spectroscopic and <span class="hlt">eclipsing</span> <span class="hlt">binaries</span> (group A). Among them, the case of KOI-3853 is of particular interest. This system is a new example of the so-called heartbeat stars, showing dynamic tidal distortions in the Kepler light curve. We have also detected duration and depth variations of the <span class="hlt">eclipse</span>. We suggest possible scenarios to explain such an effect, including the presence of a third substellar body possibly detected in our radial velocity analysis. We also provide upper mass limits to the transiting companions of six other KOIs with high rotational velocities (group B). This property prevents the radial velocity method from achieving the necessary precision to detect planetary-like masses. Finally, we analyze the large radial velocity variations of two other KOIs, which are incompatible with the presence of planetary-mass objects</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22140109','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22140109"><span id="translatedtitle">MEASUREMENT OF THE RADIUS OF NEUTRON STARS WITH HIGH SIGNAL-TO-NOISE QUIESCENT <span class="hlt">LOW-MASS</span> X-RAY <span class="hlt">BINARIES</span> IN GLOBULAR CLUSTERS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Guillot, Sebastien; Rutledge, Robert E.; Servillat, Mathieu; Webb, Natalie A. E-mail: rutledge@physics.mcgill.ca</p> <p>2013-07-20</p> <p>This paper presents the measurement of the neutron star (NS) radius using the thermal spectra from quiescent <span class="hlt">low-mass</span> X-ray <span class="hlt">binaries</span> (qLMXBs) inside globular clusters (GCs). Recent observations of NSs have presented evidence that cold ultra dense matter-present in the core of NSs-is best described by ''normal matter'' equations of state (EoSs). Such EoSs predict that the radii of NSs, R{sub NS}, are quasi-constant (within measurement errors, of {approx}10%) for astrophysically relevant masses (M{sub NS}>0.5 M{sub Sun }). The present work adopts this theoretical prediction as an assumption, and uses it to constrain a single R{sub NS} value from five qLMXB targets with available high signal-to-noise X-ray spectroscopic data. Employing a Markov chain Monte-Carlo approach, we produce the marginalized posterior distribution for R{sub NS}, constrained to be the same value for all five NSs in the sample. An effort was made to include all quantifiable sources of uncertainty into the uncertainty of the quoted radius measurement. These include the uncertainties in the distances to the GCs, the uncertainties due to the Galactic absorption in the direction of the GCs, and the possibility of a hard power-law spectral component for count excesses at high photon energy, which are observed in some qLMXBs in the Galactic plane. Using conservative assumptions, we found that the radius, common to the five qLMXBs and constant for a wide range of masses, lies in the low range of possible NS radii, R{sub NS}=9.1{sup +1.3}{sub -1.5} km (90%-confidence). Such a value is consistent with low-R{sub NS} equations of state. We compare this result with previous radius measurements of NSs from various analyses of different types of systems. In addition, we compare the spectral analyses of individual qLMXBs to previous works.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013MNRAS.436.2465B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013MNRAS.436.2465B"><span id="translatedtitle">Daily multiwavelength Swift monitoring of the neutron star <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> Cen X-4: evidence for accretion and reprocessing during quiescence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bernardini, F.; Cackett, E. M.; Brown, E. F.; D'Angelo, C.; Degenaar, N.; Miller, J. M.; Reynolds, M.; Wijnands, R.</p> <p>2013-12-01</p> <p>We conducted the first long-term (60 d), multiwavelength (optical, ultraviolet, UV, and X-ray) simultaneous monitoring of Cen X-4 with daily Swift observations from 2012 June to August, with the goal of understanding variability in the <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> Cen X-4 during quiescence. We found Cen X-4 to be highly variable in all energy bands on time-scales from days to months, with the strongest quiescent variability a factor of 22 drop in the X-ray count rate in only 4 d. The X-ray, UV and optical (V band) emission are correlated on time-scales down to less than 110 s. The shape of the correlation is a power law with index γ about 0.2-0.6. The X-ray spectrum is well fitted by a hydrogen neutron star (NS) atmosphere (kT = 59-80 eV) and a power law (with spectral index Γ = 1.4-2.0), with the spectral shape remaining constant as the flux varies. Both components vary in tandem, with each responsible for about 50 per cent of the total X-ray flux, implying that they are physically linked. We conclude that the X-rays are likely generated by matter accreting down to the NS surface. Moreover, based on the short time-scale of the correlation, we also unambiguously demonstrate that the UV emission cannot be due to either thermal emission from the stream impact point, or a standard optically thick, geometrically thin disc. The spectral energy distribution shows a small UV emitting region, too hot to arise from the accretion disc, that we identified as a hotspot on the companion star. Therefore, the UV emission is most likely produced by reprocessing from the companion star, indeed the vertical size of the disc is small and can only reprocess a marginal fraction of the X-ray emission. We also found the accretion disc in quiescence to likely be UV faint, with a minimal contribution to the whole UV flux.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014A%26A...565A..55D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014A%26A...565A..55D"><span id="translatedtitle">CoRoT 105906206: a short-period and totally <span class="hlt">eclipsing</span> <span class="hlt">binary</span> with a δ Scuti type pulsator</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>da Silva, R.; Maceroni, C.; Gandolfi, D.; Lehmann, H.; Hatzes, A. P.</p> <p>2014-05-01</p> <p>Aims: <span class="hlt">Eclipsing</span> <span class="hlt">binary</span> systems with pulsating components allow determination of several physical parameters of the stars, such as mass and radius, that can be used to constrain the modeling of stellar interiors and evolution when combined with the pulsation properties. We present the results of the study of CoRoT 105906206, an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> system with a pulsating component located in the CoRoT LRc02 field. Methods: The analysis of the CoRoT light curve was complemented by high-resolution spectra from the Sandiford at McDonald Observatory and FEROS at ESO spectrographs, which revealed a double-lined spectroscopic <span class="hlt">binary</span>. We used an iterative procedure to separate the pulsation-induced photometric variations from the <span class="hlt">eclipse</span> signals. First, a Fourier analysis was used to identify the significant frequencies and amplitudes due to pulsations. Second, after removing the contribution of the pulsations from the light curve we applied the PIKAIA genetic-algorithm approach to derive the best parameters for describing the system orbital properties. Results: The light curve cleaned for pulsations contains the partial <span class="hlt">eclipse</span> of the primary and the total <span class="hlt">eclipse</span> of the secondary. The system has an orbital period of about 3.694 days and is formed by a primary star with mass M1 = 2.25 ± 0.04 M⊙, radius R1 = 4.24±0.02 R⊙, and effective temperature Teff,1 = 6750 ± 150 K, and a secondary with M2 = 1.29 ± 0.03 M⊙, R2 = 1.34±0.01 R⊙, and Teff,2 = 6152 ± 162 K. The best solution for the parameters was obtained by taking into account the asymmetric modulation observed in the light curve, known as the O'Connell effect, presumably caused by Doppler beaming. The analysis of the Fourier spectrum revealed that the primary component has p-mode pulsations in the range 5-13 d-1, which are typical of δ Scuti type stars. Based on the photometry collected by the CoRoT satellite and on spectroscopy obtained with the Sandiford spectrograph attached at the 2.1-m telescope at Mc</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17943124','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17943124"><span id="translatedtitle">A 15.65-solar-mass black hole in an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> in the nearby spiral galaxy M 33.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Orosz, Jerome A; McClintock, Jeffrey E; Narayan, Ramesh; Bailyn, Charles D; Hartman, Joel D; Macri, Lucas; Liu, Jiefeng; Pietsch, Wolfgang; Remillard, Ronald A; Shporer, Avi; Mazeh, Tsevi</p> <p>2007-10-18</p> <p>Stellar-mass black holes are found in X-ray-emitting <span class="hlt">binary</span> systems, where their mass can be determined from the dynamics of their companion stars. Models of stellar evolution have difficulty producing black holes in close <span class="hlt">binaries</span> with masses more than ten times that of the Sun (>10; ref. 4), which is consistent with the fact that the most massive stellar black holes known so far all have masses within one standard deviation of 10. Here we report a mass of (15.65 +/- 1.45) for the black hole in the recently discovered system M 33 X-7, which is located in the nearby galaxy Messier 33 (M 33) and is the only known black hole that is in an <span class="hlt">eclipsing</span> <span class="hlt">binary</span>. To produce such a massive black hole, the progenitor star must have retained much of its outer envelope until after helium fusion in the core was completed. On the other hand, in order for the black hole to be in its present 3.45-day orbit about its (70.0 +/- 6.9) companion, there must have been a 'common envelope' phase of evolution in which a significant amount of mass was lost from the system. We find that the common envelope phase could not have occurred in M 33 X-7 unless the amount of mass lost from the progenitor during its evolution was an order of magnitude less than what is usually assumed in evolutionary models of massive stars. PMID:17943124</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17943124','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17943124"><span id="translatedtitle">A 15.65-solar-mass black hole in an <span class="hlt">eclipsing</span> <span class="hlt">binary</span> in the nearby spiral galaxy M 33.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Orosz, Jerome A; McClintock, Jeffrey E; Narayan, Ramesh; Bailyn, Charles D; Hartman, Joel D; Macri, Lucas; Liu, Jiefeng; Pietsch, Wolfgang; Remillard, Ronald A; Shporer, Avi; Mazeh, Tsevi</p> <p>2007-10-18</p> <p>Stellar-mass black holes are found in X-ray-emitting <span class="hlt">binary</span> systems, where their mass can be determined from the dynamics of their companion stars. Models of stellar evolution have difficulty producing black holes in close <span class="hlt">binaries</span> with masses more than ten times that of the Sun (>10; ref. 4), which is consistent with the fact that the most massive stellar black holes known so far all have masses within one standard deviation of 10. Here we report a mass of (15.65 +/- 1.45) for the black hole in the recently discovered system M 33 X-7, which is located in the nearby galaxy Messier 33 (M 33) and is the only known black hole that is in an <span class="hlt">eclipsing</span> <span class="hlt">binary</span>. To produce such a massive black hole, the progenitor star must have retained much of its outer envelope until after helium fusion in the core was completed. On the other hand, in order for the black hole to be in its present 3.45-day orbit about its (70.0 +/- 6.9) companion, there must have been a 'common envelope' phase of evolution in which a significant amount of mass was lost from the system. We find that the common envelope phase could not have occurred in M 33 X-7 unless the amount of mass lost from the progenitor during its evolution was an order of magnitude less than what is usually assumed in evolutionary models of massive stars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013A%26A...550A..89D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013A%26A...550A..89D"><span id="translatedtitle">X-ray follow-ups of XSS J12270-4859: a <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> with gamma-ray Fermi-LAT association</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Martino, D.; Belloni, T.; Falanga, M.; Papitto, A.; Motta, S.; Pellizzoni, A.; Evangelista, Y.; Piano, G.; Masetti, N.; Bonnet-Bidaud, J.-M.; Mouchet, M.; Mukai, K.; Possenti, A.</p> <p>2013-02-01</p> <p>Context. XSS J1227.0-4859 is a peculiar, hard X-ray source recently positionally associated to the Fermi-LAT source 1FGL J1227.9-4852/2FGL J1227.7-4853. Multi-wavelength observations have added information on this source, indicating a low-luminosity <span class="hlt">low-mass</span> X-ray <span class="hlt">binary</span> (LMXB), but its nature is still unclear. Aims: To progress in our understanding, we present new X-ray data from a monitoring campaign performed in 2011 with the XMM-Newton, RXTE, and Swift satellites and combine them with new gamma-ray data from the Fermi and AGILE satellites. We complement the study with simultaneous near-UV photometry from XMM-Newton and with previous UV/optical and near-IR data. Methods: We analysed the temporal characteristics in the X-rays, near-UV, and gamma rays and studied the broad-band spectral energy distribution from radio to gamma rays. Results: The X-ray history of XSS J1227 over 7 yr shows a persistent and rather stable low-luminosity (6 × 1033 d1 kpc2 erg s-1) source, with flares and dips being peculiar and permanent characteristics. The associated Fermi-LAT source 2FGL J1227.7-4853 is also stable over an overlapping period of 4.7 yr. Searches for X-ray fast pulsations down to msec give upper limits to pulse fractional amplitudes of 15-25% that do not rule out a fast spinning pulsar. The combined UV/optical/near-IR spectrum reveals a hot component at ~13 kK and a cool one at ~4.6 kK. The latter would suggest a late-type K2-K5 companion star, a distance range of 1.4-3.6 kpc, and an orbital period of 7-9 h. A near-UV variability (≳6 h) also suggests a longer orbital period than previously estimated. Conclusions: The analysis shows that the X-ray and UV/optical/near-IR emissions are more compatible with an accretion-powered compact object than with a rotational powered pulsar. The X-ray to UV bolometric luminosity ratio could be consistent with a <span class="hlt">binary</span> hosting a neutron star, but the uncertainties in the radio data may also allow an LMXB black hole with a compact</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AN....337..640K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AN....337..640K"><span id="translatedtitle">Light-curve solutions of 20 <span class="hlt">eclipsing</span> Kepler <span class="hlt">binaries</span>, most of them with pronounced spot and flare activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">N