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Sample records for eclipsing binaries blue

  1. Eclipsing Binary Update, No. 2.

    NASA Astrophysics Data System (ADS)

    Williams, D. B.

    1996-01-01

    Contents: 1. Wrong again! The elusive period of DHK 41. 2. Stars observed and not observed. 3. Eclipsing binary chart information. 4. Eclipsing binary news and notes. 5. A note on SS Arietis. 6. Featured star: TX Ursae Majoris.

  2. Record-Breaking Eclipsing Binary

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-05-01

    A new record holder exists for the longest-period eclipsing binary star system: TYC-2505-672-1. This intriguing system contains a primary star that is eclipsed by its companion once every 69 years with each eclipse 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 binary star system consists of an M-type red giant star that undergoes a ~3.45-year-long, near-total eclipse with a period of ~69.1 years. This period is more than double that of the previous longest-period eclipsing binary!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 eclipses 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 eclipses. (The blue KELT observations during the eclipse 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 eclipse 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

  3. Double Eclipsing Binary Fitting

    NASA Astrophysics Data System (ADS)

    Cagas, P.; Pejcha, O.

    2012-06-01

    The parameters of the mutual orbit of eclipsing binaries that are physically connected can be obtained by precision timing of minima over time through light travel time effect, apsidal motion or orbital precession. This, however, requires joint analysis of data from different sources obtained through various techniques and with insufficiently quantified uncertainties. In particular, photometric uncertainties are often underestimated, which yields too small uncertainties in minima timings if determined through analysis of a χ2 surface. The task is even more difficult for double eclipsing binaries, especially those with periods close to a resonance such as CzeV344, where minima get often blended with each other. This code solves the double binary parameters simultaneously and then uses these parameters to determine minima timings (or more specifically O-C values) for individual datasets. In both cases, the uncertainties (or more precisely confidence intervals) are determined through bootstrap resampling of the original data. This procedure to a large extent alleviates the common problem with underestimated photometric uncertainties and provides a check on possible degeneracies in the parameters and the stability of the results. While there are shortcomings to this method as well when compared to Markov Chain Monte Carlo methods, the ease of the implementation of bootstrapping is a significant advantage.

  4. Blue stragglers as remnants of stellar mergers - The discovery of short-period eclipsing binaries in the globular cluster NGC 5466

    SciTech Connect

    Mateo, M.; Harris, H.C.; Nemec, J.; Olszewski, E.W. Naval Observatory, Flagstaff, AZ British Columbia Univ., Vancouver Steward Observatory, Tucson, AZ )

    1990-08-01

    Results are reported from a search for short-period variables among blue stragglers in the central region of NGC 5466, based on analysis of 248 B and V CCD images obtained with the U.S. Naval Observatory 1-m, Palomar Observatory 1.5-m, and Steward Observatory 2.3-m telescopes during 1987-1989. The data are presented in extensive tables and graphs and characterized in detail. Nine variable blue stragglers are identified, of which three are eclipsing binaries with periods 0.298-0.511 d (two contact binaries of W UMa type and one detached or semidetached binary) and six are pulsating SX Phe stars. Theoretical models indicate that all of the noneclipsing blue stragglers could be merged close binaries, although other formation mechanisms cannot be completely ruled out. 111 refs.

  5. Spectroscopic Orbits for Kepler FOV Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Matson, Rachel A.; Gies, Douglas R.; Williams, Stephen J.; Guo, Zhao

    2013-02-01

    We are currently involved in a four year program of precise eclipsing binary photometry with the NASA Kepler Observatory. Our goal is to search for variations in minimum light timing for intermediate mass eclipsing binaries. Such periodic variations will reveal the reflex motion caused by any distant, low mass object that orbits the close binary. it Kepler's unprecedented accuracy and continuous observations provide a unique opportunity to detect the low mass companions that are predicted to result from the angular momentum of the natal cloud. The goal of this proposal is to obtain blue spectra of short period (0.9-6d) eclipsing binaries, derive radial velocities, and produce a double-lined spectroscopic orbit (as well as estimates of the stellar effective temperatures, gravities, and metallicities). Combined with the it Kepler light curve, we will determine very accurate masses and radii for the members of the close binary, which will yield the mass-inclination product M_3 sin i for any companions detected by light travel time or other effects. An extended sample of eclipsing binaries with longer periods (up to 50d) is now being investigated to test whether the presence of a tertiary companion declines with increasing period. We propose to obtain a single spectrum at quadrature for the brightest 48 stars in this expanded sample to characterize the effective temperatures and total mass contained in these systems.

  6. PHOEBE: PHysics Of Eclipsing BinariEs

    NASA Astrophysics Data System (ADS)

    Prsa, Andrej; Matijevic, Gal; Latkovic, Olivera; Vilardell, Francesc; Wils, Patrick

    2011-06-01

    PHOEBE (PHysics Of Eclipsing BinariEs) is a modeling package for eclipsing binary 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 eclipsing binaries 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.

  7. Eclipsing binaries - selection of targets

    NASA Astrophysics Data System (ADS)

    Zasche, P.

    2017-04-01

    Are the ground-based observations still needed in the era of robotic all-sky surveys? There were highlighted several fields in the eclipsing binary research, where also the amateur photometry would be very fruitful with also a few suitable systems where the monitoring is needed also using the smaller telescopes.

  8. Close Binaries, Triples, and Eclipses

    NASA Astrophysics Data System (ADS)

    Sanborn, Jason; Zavala, R. T.

    2013-01-01

    Observations of the variable radio source b Per (HR1324) are part of an ongoing survey of close binary systems using the Navy Precision Optical Interferometer. Historical observations of b Per include sparse photometric and spectroscopic observations dating back to 1923, clearly showing this object to be a non-eclipsing, single-lined ellipsoidal variable. This is where the story for b Per stopped until recent inclusion of optical interferometric data which led to the detection of a third, long-period component. As the interferometric observations continue to build up so to is the understanding of this binary system, with the modeled orbital parameters pointing to an edge-on orientation that may allow for the detection of an eclipse by the long-period component. These types of eclipse events are quite rare for long-period binaries due to the nearly edge-on orientation required for their detection, leaving open the opportunity for more traditional methods of observation to add to the body of knowledge concerning this understudied system. Here we present the latest observational data of the b Per system along with an introduction to the best fit orbital parameters governing the eclipsing nature of this complex triple-system.

  9. KEPLER ECLIPSING BINARIES WITH STELLAR COMPANIONS

    SciTech Connect

    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

    2015-12-15

    Many short-period binary stars have distant orbiting companions that have played a role in driving the binary components into close separation. Indirect detection of a tertiary star is possible by measuring apparent changes in eclipse times of eclipsing binaries as the binary orbits the common center of mass. Here we present an analysis of the eclipse timings of 41 eclipsing binaries observed throughout the NASA Kepler mission of long duration and precise photometry. This subset of binaries is characterized by relatively deep and frequent eclipses 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 eclipsing binaries 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 binaries for further evidence of the presence of third stars.

  10. ROTATIONAL DOPPLER BEAMING IN ECLIPSING BINARIES

    SciTech Connect

    Groot, Paul J.

    2012-01-20

    In eclipsing binaries the stellar rotation of the two components will cause a rotational Doppler beaming during eclipse ingress and egress when only part of the eclipsed component is covered. For eclipsing binaries 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 binary, a massive O-star binary and a transiting exoplanet case, similar to WASP-33b. Inclusion of the rotational Doppler beaming in eclipsing 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.

  11. Coevality in Young Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Simon, M.; Toraskar, Jayashree

    2017-06-01

    The ages of the components in very short period pre-main-sequence (PMS) binaries are essential to an understanding of their formation. We considered a sample of seven PMS eclipsing binaries (EBs) with ages 1-6.3 MY and component masses 0.2-1.4 {M}⊙ . The very high precision with which their masses and radii have been measured and the capability provided by the Modules for Experiments in Stellar Astrophysics to calculate their evolutionary tracks at exactly the measured masses allows the determination of age differences of the components independent of their luminosities and effective temperatures. We found that the components of five EBs, ASAS J052821+0338.5, Parenago 1802, JW 380, CoRoT 223992193, and UScoCTIO 5, formed within 0.3 MY of each other. The parameters for the components of V1174 Ori imply an implausible large age difference of 2.7 MY and should be reconsidered. The seventh EB in our sample, RX J0529.4+0041 fell outside the applicability of our analysis.

  12. Recent Minima of 171 Eclipsing Binary Stars

    NASA Astrophysics Data System (ADS)

    Samolyk, G.

    2015-12-01

    This paper continues the publication of times of minima for 171 eclipsing binary 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.

  13. The Kepler Mission and Eclipsing Binaries

    DTIC Science & Technology

    2006-01-01

    Opportunities to Participate, 2005, in A Decade of Extrasolar Planets around Normal Stars (ed. M. Livio), Cambridge: Cambridge University Press, in...smaller planets in the habitable zone of solar-like stars. In the process, many eclipsing binaries (EB) will also be detected and light curves pro- duced...determine the component masses and thereby separate eclipses caused by stellar companions from transits caused by planets . The result will be a rich

  14. Periodicity of Eclipsing Binary Star GK Cepheus

    NASA Astrophysics Data System (ADS)

    2001-10-01

    Eclipsing Binary stars are stars in which there is some mass exchange taking place between two main bodies. This mass exchange produces a change in the magnitude or “brightness” of the star. The star known as GK Cephius has been listed as an eclipsing binary in number of publications, journal articles, and data tables. If the light curve is examined carefully, it exhibits some behavior that is not typical of simple eclipsing binary stars. A study of this light curve is underway to examine the possibility of another gravitational influence being at work in the region of this star. In this paper we will report on the predictions concerning an additional candidate that may be influencing the light curves of the GK Cephius system.

  15. Survey of Candidate Pulsating Eclipsing Binaries - I

    NASA Astrophysics Data System (ADS)

    Dvorak, S.

    2009-08-01

    Initial results from a photometric survey of stars selected from the list of eclipsing binaries that may contain a pulsating component by Soydugan et al. (2006) are reported. A minimum of two nights of CCD observations with V and/or B filters of each of the 35 stars from this list was collected. Of the 35 stars stud- ied, a pulsating component was detected in three of the systems. Pulsations were also serendiptiously detected in the eclipsing binary RR Leporis, which is not on the candidate list.

  16. New Eclipsing Contact Binary System in Auriga

    NASA Astrophysics Data System (ADS)

    Austin, S. J.; Robertson, J. W.; Justice, C.; Campbell, R. T.; Hoskins, J.

    2004-05-01

    We present data on a newly discovered eclipsing binary system. The serendipitous discovery of this variable star was made by J.W. Robertson analyzing inhomogeneous ensemble photometry of stars in the field of the cataclysmic variable FS Aurigae from Indiana University RoboScope data. We obtained differential time-series BVR photometry during 2003 of this field variable using an ensemble of telescopes including the university observatories at ATU, UCA and joint ventures with amateur observatories in the state of Arkansas (Whispering Pines Observatory and Nubbin Ridge Observatory). The orbital period of this eclipsing system is 0.2508 days. The B-V light curve indicates colors of 1.2 around quadrature, to nearly 1.4 at primary eclipse. Binary star light curve models that best fit the BVR differential photometry suggest that the system is a contact binary overfilling the inner Roche Lobe by 12%, a primary component with a temperature of 4350K, a secondary component with a temperature of 3500K, a mass ratio of 0.37, and an inclination of 83 degrees. We present BVR light curves, an ephemeris, and best fit model parameters for the physical characteristics of this new eclipsing binary system.

  17. The Galactic Distribution of Contact Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Castelaz, Michael W.; Dorn, Leah; Breitfeld, Abby; Mies, Regan; Avery, Tess

    2017-01-01

    The number of eclipsing contact binaries in different galactic latitudes and longitudes show peak distributions in the number per square degree in two latitudinal zones (-30 degrees to -25 degrees and +25 degrees to +30 degrees) and large fluctuations in longitude (Huang and Wade 1966, ApJ, 143, 146). Semi-detached or detached binaries are largely concentrated in the galactic plane as shown by Paczynski et al. (MNRAS, 368, 1311), different from the distribution of contact eclipsing binaries. The differences in distributions of different types of eclipsing binaries may be related to either distances or interstellar reddening. We will present a method to calculate photometric distances of W Urase Majoris systems (W UMa; used as a proxy for contact binaries) from 2MASS J and K magnitudes and interstellar reddening models (Schlafly and Finkbeiner 2011, ApJ. 737, 103). We compare the distances to those calculated from the period-luminosity-color relationship described by Rucinski (2004, NewAR, 48, 703). The W UMa systems are taken from the General Catalog of Variable Stars.

  18. Observations of the eclipsing binary b Persei

    NASA Astrophysics Data System (ADS)

    Templeton, Matthew R.

    2015-01-01

    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 eclipse 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 eclipse 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 binary. The potential for multiple eclipses exists. The close binary has a 1.5 day orbital period, and the eclipsing C component requires about 4 days to pass across the close binary pair. The primary eclipse depth is 0.15 magnitude. Photometry to 0.02 or 0.03 mags would be fine to detect this eclipse. Eclipse prediction date (JD 2457033.79 = 2015 01 11 UT, ~+/- 1 day) is based on one orbital period from the 2013 eclipse." More information is available at PI's b Persei eclipse 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.

  19. KEPLER ECLIPSING BINARY STARS. II. 2165 ECLIPSING BINARIES IN THE SECOND DATA RELEASE

    SciTech Connect

    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.

    2011-11-15

    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 eclipsing binary 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 eclipsing binary. A number of interesting objects are identified. We present several exemplary cases: four eclipsing binaries that exhibit extra (tertiary) eclipse events; and eight systems that show clear eclipse 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 eclipsing binary 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.

  20. Eclipsing Binary B-Star Mass Determinations

    NASA Astrophysics Data System (ADS)

    Townsend, Amanda; Eikenberry, Stephen S.

    2016-01-01

    B-stars in binary 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 binary star pairs in NGC2004 in the Large Magellanic Cloud, five of which are both eclipsing and spectroscopic binaries with archival data from VLT-Giraffe and photometric data from MACHO. By using the Wilson eclipsing binary code (e.g., Wilson, 1971), we can determine preliminary stellar masses of the binary 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 binaries, for improved mass measurements of neutron stars and black holes and better constraints on their origin/formation.

  1. Apsidal motion in eclipsing binary GG Orionis

    NASA Astrophysics Data System (ADS)

    Yilan, E.; Bulut, I.

    2016-03-01

    The study of apsidal motion in binary 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 eclipsing binary 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.

  2. Kepler Eclipsing Binary Stars. VIII. Identification of False Positive Eclipsing Binaries and Re-extraction of New Light Curves

    NASA Astrophysics Data System (ADS)

    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

    2016-04-01

    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 Eclipsing Binary Catalog contains information including but not limited to ephemerides, stellar parameters, and analytical approximation fits for every known eclipsing binary system in the Kepler FOV. Using target pixel level data collected from Kepler in conjunction with the Kepler Eclipsing Binary Catalog, we identify false positives among eclipsing binaries, i.e., targets that are not eclipsing binaries themselves, but are instead contaminated by eclipsing binary sources nearby on the sky and show eclipsing binary 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 binary 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 eclipse depth, and the flux eclipse depth. We present 289 new eclipsing binaries 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.

  3. Phenomenological modelling of eclipsing binary stars

    NASA Astrophysics Data System (ADS)

    Andronov, I. L.; Tkachenko, M. G.; Chinarova, L. L.

    2016-03-01

    We review the method NAV ("New Algol Variable") first introduced in (2012Ap.....55..536A) which uses the locally-dependent shapes of eclipses in an addition to the trigonometric polynomial of the second order (which typically describes the "out-of-eclipse" part of the light curve with effects of reflection, ellipticity and O'Connell). Eclipsing binary stars are believed to show distinct eclipses only if belonging to the EA (Algol) type. With a decreasing eclipse width, the statistically optimal value of the trigonometric polynomial s(2003ASPC..292..391A) drastically increases from ~2 for elliptic (EL) variables without eclipses, ~6-8 for EW and up to ~30-50 for some EA with narrow eclipses. 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 eclipses. 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

  4. Light curve analysis of southern eclipsing binary EM Car

    NASA Astrophysics Data System (ADS)

    Ćiçek, C.; Bulut, I.; Bulut, A.

    2017-02-01

    In this study, ASAS light curve of the eclipsing binary EM Car (Sp = O8V, P = 3.4 days) has been analyzed using the Wilson-Devinney method. The light curve analyses have found that EM Car is a detached eclipsing binary system with small eccentric orbit

  5. A Photometric Study of the Eclipsing Binary Star BN Ari

    NASA Astrophysics Data System (ADS)

    Michaels, E. J.

    2015-12-01

    Presented are a set of multi-band light curves, synthetic light curve solutions, and period study for the eclipsing binary star BN Ari. The orbital period was found to be decreasing the past 8 years (~8,200 orbits). The observed light curves were analyzed with the Wilson-Devinney program. The resulting synthetic light curve solution showed the system to be a contact eclipsing binary with total eclipses.

  6. Studies of Long Period Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Ratajczak, M.; Hełminiak, K. G.; Konacki, M.

    2015-07-01

    The survey of long period eclipsing binaries from the All Sky Automated Survey (ASAS) catalog aims at searching for and characterizing subgiants and red giants in double-lined detached binary 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.

  7. Kepler eclipsing binary stars. IV. Precise eclipse times for close binaries and identification of candidate three-body systems

    SciTech Connect

    Conroy, Kyle E.; Stassun, Keivan G.; Prša, Andrej; Orosz, Jerome A.; Welsh, William F.; Fabrycky, Daniel C.

    2014-02-01

    We present a catalog of precise eclipse times and analysis of third-body signals among 1279 close binaries in the latest Kepler Eclipsing Binary Catalog. For these short-period binaries, 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 eclipse timings. We present a method to measure precise eclipse times in the presence of distorted light curves, such as in contact and near-contact binaries which exhibit continuously changing light levels in and out of eclipse. 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 eclipse timing variations of longer period binaries with flat out-of-eclipse regions. Together, these two papers provide comprehensive eclipse timings for all binaries in the Kepler Eclipsing Binary Catalog, as an ongoing resource freely accessible online to the community.

  8. Light Curve Modeling of Eclipsing Binary Stars

    NASA Astrophysics Data System (ADS)

    Milone, E. F.

    In the two decades since the development of the first eclipsing-binary modeling code, new analytic techniques and the availability of powerful, sometimes dedicated computing facilities have made possible vastly improved determinations of fundamental and even transient stellar parameters. The scale of these developments, of course, raises questions about modeling tools, techniques, and philosophies, such as: Who will maintain and upgrade the codes? Will the codes be open to improvement by outsiders, and if so, how? And, indeed, what should be the goals of a modeling program? Such questions had not been aired for a long time and, for this reason alone, deserved to be discussed in as general a forum as the community provides. This volume contains material presented by Commission 42 (Close Binary Stars) during the International Astronomical Union's XXI General Assembly in Argentina, July 1991, and during IAU Colloquium 151, Cordoba, Argentina, August 1991. The techniques discussed include simulations of stellar bright and dark spots, streams, partial and complete stellar disks, prominences, and other features characterizing active stars; modeling of polarization parameters; models that use radial velocities as well as line profile simulations to model velocity field variation across stellar disks; the weighted effects of brightness asymmetries; and models for translucent eclipsing agents such as stellar winds.

  9. Eclipsing binary stars with a δ Scuti component

    NASA Astrophysics Data System (ADS)

    Kahraman Aliçavuş, F.; Soydugan, E.; Smalley, B.; Kubát, J.

    2017-09-01

    Eclipsing binaries with a δ Sct component are powerful tools to derive the fundamental parameters and probe the internal structure of stars. In this study, spectral analysis of six primary δ Sct components in eclipsing binaries has been performed. Values of Teff, v sin i, and metallicity for the stars have been derived from medium-resolution spectroscopy. Additionally, a revised list of δ Sct stars in eclipsing binaries is presented. In this list, we have only given the δ Sct stars in eclipsing binaries to show the effects of the secondary components and tidal-locking on the pulsations of primary δ Sct components. The stellar pulsation, atmospheric and fundamental parameters (e.g. mass, radius) of 92 δ Sct stars in eclipsing binaries have been gathered. Comparison of the properties of single and eclipsing binary member δ Sct stars has been made. We find that single δ Sct stars pulsate in longer periods and with higher amplitudes than the primary δ Sct components in eclipsing binaries. The v sin i of δ Sct components is found to be significantly lower than that of single δ Sct stars. Relationships between the pulsation periods, amplitudes and stellar parameters in our list have been examined. Significant correlations between the pulsation periods and the orbital periods, Teff, log g, radius, mass ratio, v sin i and the filling factor have been found.

  10. The Kepler Mission and Eclipsing Binaries

    NASA Technical Reports Server (NTRS)

    Koch, David; Borucki, William; Lissauer, J.; Basri, Gibor; Brown, Timothy; Caldwell, Douglas; Cochran, William; Jenkins, Jon; Dunham, Edward; Gautier, Nick

    2006-01-01

    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 eclipsing binaries (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 eclipses 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.

  11. The Kepler Mission and Eclipsing Binaries

    NASA Technical Reports Server (NTRS)

    Koch, David; Borucki, William; Lissauer, J.; Basri, Gibor; Brown, Timothy; Caldwell, Douglas; Cochran, William; Jenkins, Jon; Dunham, Edward; Gautier, Nick

    2006-01-01

    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 eclipsing binaries (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 eclipses 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.

  12. The M Dwarf Eclipsing Binary CU Cancri

    NASA Astrophysics Data System (ADS)

    Wilson, R. E.; Pilachowski, C. A.; Terrell, Dirk

    2017-02-01

    Spectral features, radial velocities, elemental abundance estimates, other spectral data, and BVIC light curves are reported for the double-M dwarf eclipsing binary CU Cancri—a good target for a radius check versus the Zero Age Main Sequence (ZAMS) due to the low component masses and corresponding very slow evolutionary expansion. The estimate of [Fe/H] is about 0.4, although continuum placement and other difficulties due to line crowding introduce the usual uncertainties for red dwarfs. Detection of the Li i λ6707 line was attempted, with an estimated upper limit of 50 mÅ. Spectral and photometric indicators of stellar activity are described and illustrated. Other objectives were to measure the stellar radii via simultaneous velocity and light-curve solutions of earlier and new data while also improving the ephemeris by filling gaps in timewise coverage with the new velocities and eclipse data from the new light curves. The radii from our solutions agree within about 2% with those from Ribas, being slightly larger than expected for most estimates of the ZAMS. Some aspects of the red dwarf radius anomaly are briefly discussed. Evolution tracks show only very slight age-related expansion for masses near those in CU Cnc. Such expansion could be significant if CU Cnc were similar in age to the Galaxy, but then its Galactic velocity components should be representative of Population II, and they are not.

  13. Photometric orbits of seven detached eclipsing binaries

    NASA Astrophysics Data System (ADS)

    Popper, D. M.; Etzel, P. B.

    1981-01-01

    Photoelectric light curves of the detached eclipsing binaries V805 Aql, TV Cet, MY Cyg, V478 Cyg, V1143 Cyg, BS Dra, and BK Peg are analyzed. The systems are among those with good spectrographic orbits of both components that are in need of good photometric solutions in order to obtain the absolute properties of the components. The analyses are carried out with a computer program valid for detached systems of spherical or slightly oblate stars in orbits of arbitrary eccentricity. A range of solutions much greater than implied by the internal mean errors of the parameters, is found to give satisfactory fits to the observations. Some of the fits are displayed for a variety of solutions for each system. For the three systems with measurable light variation between eclipses - V478 Cyg, V805 Aql, and MY Cyg - the effect of reflection appears to be substantially less than predicted. Very small, but nonzero, orbital eccentricities are found for four of the systems. The variations of limb darkening with wavelength and with spectral type are found to be in reasonable agreement with predictions from atmospheric theory.

  14. Eclipsing Binary Star Detection Using Kepler

    NASA Astrophysics Data System (ADS)

    Vydra, Ekaterina; Buzasi, Derek L.

    2017-01-01

    Eclipsing binaries (EBs) are laboratories for precision astrophysics, because use of the orbital information of the system allows the determination of the physical parameters of the stars to a much higher degree of precision than is possible for single stars. The Kepler Space Telescope, while designed to hunt for planets, has also been a valuable tool in detecting and characterizing EBs and has already observed over 2200 specimens. Kepler suffered a failure in 2013 that affected its pointing ability, but some ingenious engineering adjustments have allowed it to continue collecting photometric data from new fields of view. Our goals were to develop an algorithm for EB detection using Kepler data, and then with the help of FGCU's K2 Aperture Photometry Pipeline to extend that algorithm to discover new EBs in the K2 fields. Here we report on our progess to date as well as future plans.

  15. B-type stars in eclipsing binaries

    NASA Astrophysics Data System (ADS)

    Ratajczak, Milena; Pigulski, Andrzej

    2016-07-01

    B-type stars in eclipsing binary 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.

  16. MARVELS Radial Velocity Solutions to Seven Kepler Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Heslar, Michael Francis; Thomas, Neil B.; Ge, Jian; Ma, Bo; Herczeg, Alec; Reyes, Alan; SDSS-III MARVELS Team

    2016-01-01

    Eclipsing binaries serve momentous purposes to improve the basis of understanding aspects of stellar astrophysics, such as the accurate calculation of the physical parameters of stars and the enigmatic mass-radius relationship of M and K dwarfs. We report the investigation results of 7 eclipsing binary candidates, initially identified by the Kepler mission, overlapped with the radial velocity observations from the SDSS-III Multi-Object APO Radial-Velocity Exoplanet Large-Area Survey (MARVELS). The RV extractions and spectroscopic solutions of these eclipsing binaries were generated by the University of Florida's 1D data pipeline with a median RV precision of ~60-100 m/s, which was utilized for the DR12 data release. We performed the cross-reference fitting of the MARVELS RV data and the Kepler photometric fluxes obtained from the Kepler Eclipsing Binary Catalog (V2) and modelled the 7 eclipsing binaries in the BinaryMaker3 and PHOEBE programs. This analysis accurately determined the absolute physical and orbital parameters of each binary. Most of the companion stars were determined to have masses of K and M dwarf stars (0.3-0.8 M⊙), and allowed for an investigation into the mass-radius relationship of M and K dwarfs. Among the cases are KIC 9163796, a 122.2 day period "heartbeat star", a recently-discovered class of eccentric binaries known for tidal distortions and pulsations, with a high eccentricity (e~0.75) and KIC 11244501, a 0.29 day period, contact binary with a double-lined spectrum and mass ratio (q~0.45). We also report on the possible reclassification of 2 Kepler eclipsing binary candidates as background eclipsing binaries based on the analysis of the flux measurements, flux ratios of the spectroscopic and photometric solutions, the differences in the FOVs, the image processing of Kepler, and RV and spectral analysis of MARVELS.

  17. CCD Photometry of Five Neglected Eclipsing Binary Stars

    NASA Astrophysics Data System (ADS)

    Cook, Stephen P.

    Differential V-magnitude CCD photometric data are presented for five neglected eclipsing binary stars with shallow eclipses. 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.

  18. Indoor Astronomy: A Model Eclipsing Binary Star System.

    ERIC Educational Resources Information Center

    Bloomer, Raymond H., Jr.

    1979-01-01

    Describes a two-hour physics laboratory experiment modeling the phenomena of eclipsing binary stars developed by the Air Force Academy as part of a week-long laboratory-oriented experience for visiting high school students. (BT)

  19. On the eclipsing binary nature of a nearby ultracool dwarf

    NASA Astrophysics Data System (ADS)

    Gillon, Michael; Jehin, Emmanuel; de Wit, Julien; Demory, Brice-Olivier; Burgasser, Adam; Van Grootel, Valerie; Lederer, Susan; Triaud, Amaury; Delrez, Laetitia; Burdanov, Artem; Queloz, Didier; Magain, Pierre

    2016-02-01

    The eclipsing binary nature of a nearby ultracool dwarf has just been revealed. The aim of this DDT is to investigate this nearby system further through high-precision infrared time-series photometry.

  20. On the eclipsing binary nature of a nearby ultracool dwarf

    NASA Astrophysics Data System (ADS)

    Gillon, Michael; de Wit, Julien; Jehin, Emmanuel; Burdanov, Artem; Van Grootel, valerie. vangrootel@ulg. ac. be; Delrez, Laetitia; Magain, Pierre; Burgasser, Adam; Demory, Brice-Olivier; Triaud, Amaury; Queloz, Didier; Lederer, Sue

    2016-01-01

    The eclipsing binary nature of a nearby ultracool dwarf has just been revealed. The aim of this DDT is to investigate this nearby system further through high-precision infrared time-series photometry.

  1. CCD Times of Minima of Selected Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Zejda, Miloslav

    2004-12-01

    682 CCD minima observations of 259 eclipsing binaries made mainly by author are presented. The observed stars were chosen mainly from catalogue BRKA of observing programme of BRNO-Variable Star Section of CAS.

  2. Properties OF M31. V. 298 eclipsing binaries from PAndromeda

    SciTech Connect

    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.

    2014-12-10

    The goal of this work is to conduct a photometric study of eclipsing binaries in M31. We apply a modified box-fitting algorithm to search for eclipsing binary 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 Eclipsing Binary Light curve fitter (DEBiL) by Devor. We will follow up the detached eclipsing binaries spectroscopically and determine the distance to M31.

  3. How I Learned to Stop Worrying and Love Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Moe, Maxwell Cassady

    Relatively massive B-type stars with closely orbiting stellar companions can evolve to produce Type Ia supernovae, X-ray binaries, millisecond pulsars, mergers of neutron stars, gamma ray bursts, and sources of gravitational waves. However, the formation mechanism, intrinsic frequency, and evolutionary processes of B-type binaries are poorly understood. As of 2012, the binary statistics of massive stars had not been measured at low metallicities, extreme mass ratios, or intermediate orbital periods. This thesis utilizes large data sets of eclipsing binaries to measure the physical properties of B-type binaries in these previously unexplored portions of the parameter space. The updated binary statistics provide invaluable insight into the formation of massive stars and binaries as well as reliable initial conditions for population synthesis studies of binary star evolution. We first compare the properties of B-type eclipsing binaries in our Milky Way Galaxy and the nearby Magellanic Cloud Galaxies. We model the eclipsing binary light curves and perform detailed Monte Carlo simulations to recover the intrinsic properties and distributions of the close binary population. We find the frequency, period distribution, and mass-ratio distribution of close B-type binaries do not significantly depend on metallicity or environment. These results indicate the formation of massive binaries are relatively insensitive to their chemical abundances or immediate surroundings. Second, we search for low-mass eclipsing companions to massive B-type stars in the Large Magellanic Cloud Galaxy. In addition to finding such extreme mass-ratio binaries, we serendipitously discover a new class of eclipsing binaries. Each system comprises a massive B-type star that is fully formed and a nascent low-mass companion that is still contracting toward its normal phase of evolution. The large low-mass secondaries discernibly reflect much of the light they intercept from the hot B-type stars, thereby

  4. Pro-Am Collaborations on Eclipsing Binary Star Problems

    NASA Astrophysics Data System (ADS)

    Terrell, D.

    2004-05-01

    I discuss the fruits of a decade of amateur-professional collaboration on eclipsing binary stars. Our team consists of a mix of visual, photoelectric and CCD observers that use the strengths of each observing approach to study newly discovered and neglected eclipsing binary systems. We have active programs on time of minimum measurements and high-precision photometry that results in detailed analysis of the binaries to find fundamental parameters such as masses and radii. We have also discovered and/or characterized several unusal binaries that have had an influence on stellar evolution theory.

  5. APSIDAL MOTION IN ECCENTRIC ECLIPSING BINARY WW CAMELOPARDALIS

    SciTech Connect

    Wolf, M.; Kotkova, L.; Kocian, R.; Dreveny, R.; Hanzl, D.

    2010-03-15

    WW Camelopardalis is a relatively bright eclipsing binary system with a slightly eccentric orbit. A dozen of its new eclipse times were measured as part of our long-term observational project of eccentric eclipsing binaries. Based on a new solution of the current O - C diagram, we found for the first time an apsidal motion in good agreement with theory. Its period is about 370 {+-} 50 years. The determined internal structure constant is close to the theoretically expected value. The relativistic effect is significant, being about 13% of the total apsidal motion rate.

  6. Eclipsing Binaries from the Kepler Mission

    NASA Technical Reports Server (NTRS)

    Koch, David; Borucki, William; Lissauer, J.; Basri, Gibor; Brown, Timothy; Caldwell, Douglas; Cochran, William; Jenkins, Jon; Dunham, Edward; Gautier, Nick

    2005-01-01

    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 eclipsing binaries (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.

  7. MML 53 - The Brightest Pre-Main-Sequence Eclipsing Binary

    NASA Astrophysics Data System (ADS)

    Stempels, H. C.; Hebb, L.

    2011-12-01

    MML 53 is a newly discovered and bright (V=10.8m) pre-main-sequence eclipsing binary located in the 15-22 Myr old Upper-Centaur-Lupus (UCL) star forming region, with component masses of ˜1.02 M⊙ and ˜0.88 M⊙. This system is the first low-mass pre-main-sequence eclipsing binary discovered outside the ˜10 Myr old Orion star-forming region, and samples a slightly older age. A closer examination of MML 53 reveals that this is a three-component system, where the primary and secondary form a close eclipsing binary. Here we present preliminary results from our recent high-resolution spectroscopic study of this object, including estimates of the individual component masses, radii and temperatures. In addition we find indications that the tertiary in MML 53 interacts gravitationally with the eclipsing components.

  8. Fundamental parameters of four massive eclipsing binaries in Westerlund 1

    NASA Astrophysics Data System (ADS)

    Koumpia, E.; Bonanos, A. Z.

    2012-11-01

    Context. Only a small number of high mass stars (>30 M⊙) have fundamental parameters (i.e. masses and radii) measured with high enough accuracy from eclipsing binaries to constrain formation and evolutionary models of massive stars. Aims: This work aims to increase this limited sample, by studying the four massive eclipsing binary candidates discovered by Bonanos in the young massive cluster Westerlund 1. Methods: We present new follow-up echelle spectroscopy of these binaries and models of their light and radial velocity curves. Results: We obtain fundamental parameters for the eight component stars, finding masses that span a range of 10-40 M⊙, and contributing accurate fundamental parameters for one additional very massive star, the 33 M⊙ component of W13. WR77o is found to have a ~40 M⊙ companion, which provides a second dynamical constraint on the mass of the progenitor of the magnetar known in the cluster. We also use W13 to estimate the first, direct, eclipsing binary distance to Westerlund 1 and therefore the magnetar and find it to be at 3.7 ± 0.6 kpc. Conclusions: Our results confirm previous evidence for a high mass for the progenitor of the magnetar. In addition, the availability of eclipsing binaries with accurate parameters opens the way for direct, independent, high precision eclipsing binary distance measurements to Westerlund 1.

  9. What we learn from eclipsing binaries in the ultraviolet

    NASA Technical Reports Server (NTRS)

    Guinan, Edward F.

    1990-01-01

    Recent results on stars and stellar physics from IUE (International Ultraviolet Explorer) observations of eclipsing binaries are discussed. Several case studies are presented, including V 444 Cyg, Aur stars, V 471 Tau and AR Lac. Topics include stellar winds and mass loss, stellar atmospheres, stellar dynamos, and surface activity. Studies of binary star dynamics and evolution are discussed. The progress made with IUE in understanding the complex dynamical and evolutionary processes taking place in W UMa-type binaries and Algol systems is highlighted. The initial results of intensive studies of the W UMa star VW Cep and three representative Algol-type binaries (in different stages of evolution) focused on gas flows and accretion, are included. The future prospects of eclipsing binary research are explored. Remaining problems are surveyed and the next challenges are presented. The roles that eclipsing binaries could play in studies of stellar evolution, cluster dynamics, galactic structure, mass luminosity relations for extra galactic systems, cosmology, and even possible detection of extra solar system planets using eclipsing binaries are discussed.

  10. PERIOD ERROR ESTIMATION FOR THE KEPLER ECLIPSING BINARY CATALOG

    SciTech Connect

    Mighell, Kenneth J.; Plavchan, Peter

    2013-06-15

    The Kepler Eclipsing Binary Catalog (KEBC) describes 2165 eclipsing binaries 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 eclipsing binaries 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 eclipsing binary 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 eclipsing binary systems in the KEBC were measured using the NASA Exoplanet Archive Periodogram Service and compared to period errors estimated using the PEC algorithm.

  11. A DEEPLY ECLIPSING DETACHED DOUBLE HELIUM WHITE DWARF BINARY

    SciTech Connect

    Parsons, S. G.; Marsh, T. R.; Gaensicke, B. T.; Drake, A. J.; Koester, D.

    2011-07-10

    Using Liverpool Telescope+RISE photometry we identify the 2.78 hr period binary star CSS 41177 as a detached eclipsing double white dwarf binary with a 21,100 K primary star and a 10,500 K secondary star. This makes CSS 41177 only the second known eclipsing double white dwarf binary after NLTT 11748. The 2 minute long primary eclipse is 40% deep and the secondary eclipse 10% deep. From Gemini+GMOS spectroscopy, we measure the radial velocities of both components of the binary 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 eclipsing, double-lined spectroscopic binary, 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.

  12. How eclipse time variations, eclipse duration variations, and radial velocities can reveal S-type planets in close eclipsing binaries

    NASA Astrophysics Data System (ADS)

    Oshagh, M.; Heller, R.; Dreizler, S.

    2016-12-01

    While about a dozen transiting planets have been found in wide orbits around an inner, close stellar binary (so-called "P-type planets"), no planet has yet been detected orbiting only one star (a so-called "S-type planet") in an eclipsing binary. This is despite a large number of eclipsing binary systems discovered with the Kepler telescope. Here we propose a new detection method for these S-type planets, which uses a correlation between the stellar radial velocities (RVs), eclipse timing variations (ETVs), and eclipse duration variations (EDVs). We test the capability of this technique by simulating a realistic benchmark system and demonstrate its detectability with existing high-accuracy RV and photometry instruments. We illustrate that, with a small number of RV observations, the RV-ETV diagrams allows us to distinguish between prograde and retrograde planetary orbits and also the planetary mass can be estimated if the stellar cross-correlation functions can be disentangled. We also identify a new (though minimal) contribution of S-type planets to the Rossiter-McLaughlin effect in eclipsing stellar binaries. We finally explore possible detection of exomoons around transiting luminous giant planets and find that the precision required to detect moons in the RV curves of their host planets is of the order of cm s-1 and therefore not accessible with current instruments.

  13. How eclipse time variations, eclipse duration variations, and radial velocities can reveal S-type planets in close eclipsing binaries

    NASA Astrophysics Data System (ADS)

    Oshagh, M.; Heller, R.; Dreizler, S.

    2017-04-01

    While about a dozen transiting planets have been found in wide orbits around an inner, close stellar binary (so-called P-type planets), no planet has yet been detected orbiting only one star (a so-called S-type planet) in an eclipsing binary. This is despite a large number of eclipsing binary systems discovered with the Kepler telescope. Here we propose a new detection method for these S-type planets, which uses a correlation between the stellar radial velocities (RVs), eclipse timing variations (ETVs) and eclipse duration variations (EDVs). We test the capability of this technique by simulating a realistic benchmark system and demonstrate its detectability with existing high-accuracy RV and photometry instruments. We illustrate that with a small number of RV observations, the RV-ETV diagrams allows us to distinguish between prograde and retrograde planetary orbits and also the planetary mass can be estimated if the stellar cross-correlation functions can be disentangled. We also identify a new (though minimal) contribution of S-type planets to the Rossiter-McLaughlin effect in eclipsing stellar binaries. We finally explore possible detection of exomoons around transiting luminous giant planets and find that the precision required to detect moons in the RV curves of their host planets is of the order of cm s-1 and therefore not accessible with current instruments.

  14. The Eclipsing Binary On-Line Atlas (EBOLA)

    NASA Astrophysics Data System (ADS)

    Bradstreet, D. H.; Steelman, D. P.; Sanders, S. J.; Hargis, J. R.

    2004-05-01

    In conjunction with the upcoming release of \\it Binary Maker 3.0, an extensive on-line database of eclipsing binaries is being made available. The purposes of the atlas are: \\begin {enumerate} Allow quick and easy access to information on published eclipsing binaries. 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 eclipsing binaries to accelerate the process of understanding analysis techniques and current work in the field. \\end {enumerate} The database will eventually consist of all published eclipsing binaries with light curve solutions. The following information and data will be supplied whenever available for each binary: original light curves in all bandpasses, original radial velocity observations, light curve parameters, RA and Dec, V-magnitudes, spectral types, color indices, periods, binary 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 Binary 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 binaries with specific characteristics. The website has more than 150 systems already uploaded. The URL for the site is http://ebola.eastern.edu/.

  15. A Long Period Eclipsing Binary Project - Five Years of Observations at ESO

    NASA Astrophysics Data System (ADS)

    Ahlin, P.; Sundman, A.

    1982-06-01

    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 eclipsing binaries formed by a cool supergiant K star and a very much smaller and holter mainsequence (more or less normal) B star. Out of eclipse the B star dominates the blue spectral region, but a pure K-type spectrum is found in eclipse. The drastic spectral changes lor HO 161387 can be seen in Fig 1c and 1d. Periods for these binaries 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 eclipsed 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 eclipse. Besides Aurigae itsell only the stars 31 and 32 Cygni have been studied in greater detail.

  16. MM Herculis - An eclipsing binary of the RS CVn

    NASA Technical Reports Server (NTRS)

    Sowell, J. R.; Hall, D. S.; Henry, G. W.; Burke, E. W., Jr.; Milone, E. F.

    1983-01-01

    V, B and U differential photoelectric photometry has been obtained for the RS Canum Venaticorum-class eclipsing binary star MM Her, with the light outside the eclipse being Fourier-analyzed to study wave migration and amplitude. These, together with the mean light level of the system, have been monitored from 1976 through 1980. Observations within the eclipse have revealed eclipses to be partial, rather than total as previously thought. The geometric elements of the presently rectified light curve are forced on the pre-1980 light curves and found to be compatible. With these elements, and previously obtained double line radial velocity curves, new absolute dimensions of 1.18 solar masses and 1.58 solar radii are calculated for the hotter star and 1.27 solar masses and 2.83 solar radii for the cooler star. The plotting of color indices on the color-color curve indicates G2V and K2IV spectral types.

  17. Photoelectric Photometry of the Eclipsing Binary V505-MONOCEROTIS

    NASA Astrophysics Data System (ADS)

    Chochol, D.; Bakos, G. A.; Bartolini, C.; Guarnieri, A.; Dapergolas, A.; Szabados, L.

    Photoelectric U, B, V observations of the eclipsing binary V 505 Mon, performed at the observatories in Skalnate Pleso, Budapest, Bologna and Waterloo in the years 1972-1984 are presented. The following ephemeris has been derived, using all these data: prim.min. Indications of ongoing mass transfer in a semidetached binary configuration are presented. The possible causes of the observed short-term changes of brightness are discussed.

  18. A model of V356 Sagittarii. [eclipsing binary star

    NASA Technical Reports Server (NTRS)

    Wilson, R. E.; Caldwell, C. N.

    1978-01-01

    It is pointed out that V356 Sgr is an abnormal member of the Algol class of binaries. According to Popper (1955), the primary component is of spectral type B3V and is rotating rapidly, while the secondary is of type A2II and is rotating at least approximately in synchronism with the orbital motion. The system is either semidetached or quite near to being semidetached. The main anomalies are related to the ratio of eclipse depths, the very small reflection effect of the light curves, differences between the duration of the primary and the secondary eclipse, and the unusual characteristics of the primary eclipse. It is concluded that the lack of agreement between theory and observation can be due only to an important attribute of the binary which has not yet been incorporated into the theory. The peculiarities can most reasonably be explained in terms of a geometrically and optically thick disk which surrounds the primary component.

  19. A New Orbit for the Eclipsing Binary V577 Oph

    NASA Astrophysics Data System (ADS)

    Jeffery, Elizabeth J.; Barnes, Thomas G., III; Skillen, Ian; Montemayor, Thomas J.

    2017-09-01

    Pulsating stars in eclipsing binary systems are unique objects for providing constraints on stellar models. To fully leverage the information available from the binary system, full orbital radial velocity curves must be obtained. We report 23 radial velocities for components of the eclipsing binary V577 Oph, whose primary star is a δ Sct variable. The velocities cover a nearly complete orbit and a time base of 20 years. We computed orbital elements for the binary and compared them to the ephemeris computed by Creevey et al. The comparison shows marginally different results. In particular, a change in the systemic velocity by ‑2 km s‑1 is suggested by our results. We compare this systemic velocity difference to that expected due to reflex motion of the binary in response to the third body in the system. The systemic velocity difference is consistent with reflex motion, given our mass determination for the eclipsing binary and the orbital parameters determined by Volkov & Volkova for the three-body orbit. We see no evidence for the third body in our spectra, but we do see strong interstellar Na D lines that are consistent in strength with the direction and expected distance of V577 Oph.

  20. The Masses and Radii of the Eclipsing Binary zeta Aurigae

    NASA Astrophysics Data System (ADS)

    Bennett, Philip D.; Harper, Graham M.; Brown, Alexander; Hummel, Christian A.

    1996-11-01

    We present a full determination of the fundamental stellar and orbital parameters of the eclipsing binary ζ Aurigae (K4 Ib + BS V) using recent observations with the Hubble Space Telescope Goddard High Resolution Spectrograph (GHRS) and the Mark III long-baseline optical interferometer. The information obtained from spectroscopic and interferometric measurements is complementary, and the combination permits a complete determination of the stellar masses, the absolute semimajor axis of the orbit, and the distance. A complete solution requires that both components be visible spectroscopically, and this has always been difficult for the ζ Aur systems. The ζ Aur K star primary presents no difficulty, and accurate radial velocities are readily obtainable in the optical. However, the B star secondary is more problematic. Ground-based radial velocity measurements are hampered by the difficulty of working with the composite spectrum in the blue-violet region, the small number of suitable lines in the generally featureless optical spectrum of the B star, and the great width of the few available lines (the Balmer lines of hydrogen and a few weak He I lines) due to rapid rotation. We avoid the worst of these problems by using GHRS observations in the ultraviolet, where the K star flux is negligible and the intrinsic B star spectrum is more distinctive, and obtain the most accurate determination of the B star radial velocity amplitude to date. We also analyze published photometry of previous eclipses and near-eclipse phases of ζ Aur in order to obtain eclipse durations, which fix the length of the eclipse chord and therefore determine the orbit inclination. The long-baseline interferometry (LBI) yields, in conjunction with the spectroscopic solution, the distance to the system and thus the absolute stellar radius of the resolved K supergiant primary star, ζ Aur A. The secondary is not resolved by LBI, but its angular (and absolute) radius is found by fitting the model

  1. Kepler Eclipsing Binary Stars. VII. The Catalog of Eclipsing Binaries Found in the Entire Kepler Data Set

    NASA Astrophysics Data System (ADS)

    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

    2016-03-01

    The primary Kepler Mission provided nearly continuous monitoring of ∼200,000 objects with unprecedented photometric precision. We present the final catalog of eclipsing binary 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 eclipse timing variations have been computed for each system. We identify several classes of systems including those that exhibit tertiary eclipse events, systems that show clear evidence of additional bodies, heartbeat systems, systems with changing eclipse depths, and systems exhibiting only one eclipse 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 eclipsing and ellipsoidal binary 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.

  2. Eclipsing Binaries From the CSTAR Project at Dome A, Antarctica

    NASA Astrophysics Data System (ADS)

    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

    2015-04-01

    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. Eclipsing binaries are removed by visual inspection, frequency spectrum analysis, and a locally linear embedding technique. We identify 53 eclipsing binaries in the field of view of CSTAR, containing 24 detached binaries, 8 semi-detached binaries, 18 contact binaries, and 3 ellipsoidal variables. To derive the parameters of these binaries, we use the Eclipsing Binaries via Artificial Intelligence method. The primary and secondary eclipse 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.

  3. Eclipsing Binary Science through the Monocle of Kepler

    NASA Astrophysics Data System (ADS)

    Prsa, Andrej; Eclipsing Binary Working Group

    2013-07-01

    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. Eclipsing binary 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 binaries; the ~10-ppm precision and the ~105-square degree field of view yield a sample of ~2500 eclipsing 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 eclipsing binaries, 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 eclipse timing variations. I will emphasize the pioneering efforts to detect and analyze stellar and substellar tertiaries orbiting binary 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

  4. Surface imaging of eclipsing binary stars. 1: Techniques

    NASA Astrophysics Data System (ADS)

    Vincent, A.; Piskunov, N. E.; Tuominen, I.

    1993-11-01

    Surface (Doppler) imaging techniques for mapping the temperature distribution of a single star are generalized to the case of an eclipsing spectroscopic binary. In this paper we study three main questions, crucial for further application of the techniques. We found that the method described in this paper can be successfully used for imaging eclipsing binary systems. The resulting map is more sensitive to the errors in the parameters of the system than is the case of a single star. Characteristic distortions of the map can be used as indicators for fine tuning of some of the parameters. We also found that a good phase coverage of the observations is most important for reducing the artificial equatorial symmetry, typical for the line profile inversion when used for high inclination binary systems.

  5. Photometric study of the pulsating, eclipsing binary OO DRA

    SciTech Connect

    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.

    2014-12-01

    We present a comprehensive photometric study of the pulsating, eclipsing binary 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 binary 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 eclipsing 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 binary system is finally given.

  6. KEPLER ECLIPSING BINARY STARS. III. CLASSIFICATION OF KEPLER ECLIPSING BINARY LIGHT CURVES WITH LOCALLY LINEAR EMBEDDING

    SciTech Connect

    Matijevic, Gal; Prsa, Andrej; Orosz, Jerome A.; Welsh, William F.; Bloemen, Steven; Barclay, Thomas E-mail: andrej.prsa@villanova.edu

    2012-05-15

    We present an automated classification of 2165 Kepler eclipsing binary (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.

  7. Searching Planets Around Some Selected Eclipsing Close Binary Stars Systems

    NASA Astrophysics Data System (ADS)

    Nasiroglu, Ilham; Slowikowska, Agnieszka; Krzeszowski, Krzysztof; Zejmo, M. Michal; Er, Hüseyin; Goździewski, Krzysztof; Zola, Stanislaw; Koziel-Wierzbowska, Dorota; Debski, Bartholomew; Ogloza, Waldemar; Drozdz, Marek

    2016-07-01

    We present updated O-C diagrams of selected short period eclipsing binaries 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 eclipsing binary NSVS 14256825. We collected more than 50 new eclipses for this system that together with the literature data gives more than 120 eclipse 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 binary systems: HU Aqr and V470 Cam.

  8. Solar-Type Eclipsing Binary Systems with Impacting Gas Streams

    NASA Astrophysics Data System (ADS)

    Samec, Ronald G.; Hube, Doug; Faulkner, Danny R.; van Hamme, W.

    2002-08-01

    Our quest is the recovery of near contact solar type eclipsing binaries with evidence for stream impacts. Their existence will provide strong support of dynamic mass transfer leading to coalescence into a state of contact. This will lend strong support to the theoretical scenarios of 1) angular momentum loss(AML)via magnetic breaking scenario and 2)Thermal Relaxation Oscillations (TRO)or oscillations between a near­contact and shallow contact modes. We hypothesize that many F to early K spectral type binaries formerly classified as ''thermally decoupled'' contact binaries and other binaries with large differences in eclipse depths formerly classified as contact binaries in the 0.33 to 0.5d period range will reveal evidence for stream impacts when they are subjected to precision UBVRI multi­band photometry, since these fall in the pre­contact period range for F to K dwarf binaries. Modern light curve synthesis techniques will be used to simultaneously model the multi­band light curves. Impact spots will be adjusted numerically along with the stellar atmosphere parameters. Spectroscopic work will follow to verify stream activity and to obtain fundamental physical characteristics. Our larger goal is to understand close binary evolution in general. This study could supply an important piece to the puzzle. We now have found four candidates, CN And, BE Cep, ZZ Eri and V343 Cen giving us an encouraging 40 percent recovery thus far.

  9. NIP of Stars: early results and new eclipsing binaries

    NASA Astrophysics Data System (ADS)

    Jaque Arancibia, M.; Barba, R.; Morrell, N.; Roman Lopes, A.; Torres Robledo, S.; Gunthardt, G.; Soto, M.; Ferrero, G.; Arias, J. I.; Gamen, R.; Fernadez Lajus, E.

    2014-10-01

    We have performed a near-infrared photometric monitoring of 39 galactic young star clusters and star-forming regions, known as NIP of Stars, between the years 2009-2011, using the Swope telescope at Las Campanas Observatory (Chile) and the RetroCam camera, in H- and Y-bands. This monitoring program is complementary to the Vista Variables in the Via Láctea (VVV), as the brightest sources observed in NIP of Stars are saturated in VVV. The aim of this campaign is to perform a census of photometric variability of such clusters and star-forming regions, with the main goal of discovering massive eclipsing binary stars. In this work, we present a preliminary analysis of this photometric monitoring program with the discovery of tens of candidates for variable stars, among them candidates for massive eclipsing binaries. We included also to the analysis of variability, a small set of images obtained in the Ks with the VISTA telescope in the framework of VVV survey (Minniti et al. 2010). In special, we announce the infrared discovering of four massive eclipsing binaries in the massive young cluster NGC 3603. The stars have been classified spectroscopically as O-type stars, and one of them, MTT 58, has a rare star with a spectral type of O2 If*/WN6, as one of its components. We present a preliminary analysis of the light-curves of these binaries.

  10. Physics Of Eclipsing Binaries. II. Toward the Increased Model Fidelity

    NASA Astrophysics Data System (ADS)

    Prša, A.; Conroy, K. E.; Horvat, M.; Pablo, H.; Kochoska, A.; Bloemen, S.; Giammarco, J.; Hambleton, K. M.; Degroote, P.

    2016-12-01

    The precision of photometric and spectroscopic observations has been systematically improved in the last decade, mostly thanks to space-borne photometric missions and ground-based spectrographs dedicated to finding exoplanets. The field of eclipsing binary stars strongly benefited from this development. Eclipsing binaries serve as critical tools for determining fundamental stellar properties (masses, radii, temperatures, and luminosities), yet the models are not capable of reproducing observed data well, either because of the missing physics or because of insufficient precision. This led to a predicament where radiative and dynamical effects, insofar buried in noise, started showing up routinely in the data, but were not accounted for in the models. PHOEBE (PHysics Of Eclipsing BinariEs; http://phoebe-project.org) is an open source modeling code for computing theoretical light and radial velocity curves that addresses both problems by incorporating missing physics and by increasing the computational fidelity. In particular, we discuss triangulation as a superior surface discretization algorithm, meshing of rotating single stars, light travel time effects, advanced phase computation, volume conservation in eccentric orbits, and improved computation of local intensity across the stellar surfaces that includes the photon-weighted mode, the enhanced limb darkening treatment, the better reflection treatment, and Doppler boosting. Here we present the concepts on which PHOEBE is built and proofs of concept that demonstrate the increased model fidelity.

  11. Gaia eclipsing binary and multiple systems. A study of detectability and classification of eclipsing binaries with Gaia

    NASA Astrophysics Data System (ADS)

    Kochoska, A.; Mowlavi, N.; Prša, A.; Lecoeur-Taïbi, I.; Holl, B.; Rimoldini, L.; Süveges, M.; Eyer, L.

    2017-06-01

    Context. In the new era of large-scale astronomical surveys, automated methods of analysis and classification of bulk data are a fundamental tool for fast and efficient production of deliverables. This becomes ever more important as we enter the Gaia era. Aims: We investigate the potential detectability of eclipsing binaries with Gaia using a data set of all Kepler eclipsing binaries sampled with Gaia cadence and folded with the Kepler period. The performance of fitting methods is evaluated in comparison to real Kepler data parameters and a classification scheme is proposed for the potentially detectable sources based on the geometry of the light curve fits. Methods: The polynomial chain (polyfit) and two-Gaussian models are used for light curve fitting of the data set. Classification is performed with a combination of the t-distributed stochastic neighbor embedding (t-SNE) and density-based spatial clustering of applications with noise (DBSCAN) algorithms. Results: We find that 68% of the Kepler Eclipsing Binary Catalog sources are potentially detectable by Gaia when folded with the Kepler period; we propose a classification scheme of the detectable sources based on the morphological type indicative of the light curve with subclasses that reflect the properties of the fitted model (presence and visibility of eclipses, their width, depth, etc.).

  12. Orbital Circularization of Hot and Cool Kepler Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Van Eylen, Vincent; Winn, Joshua N.; Albrecht, Simon

    2016-06-01

    The rate of tidal circularization is predicted to be faster for relatively cool stars with convective outer layers, compared to hotter stars with radiative outer layers. Observing this effect is challenging because it requires large and well-characterized samples that include both hot and cool stars. Here we seek evidence of the predicted dependence of circularization upon stellar type, using a sample of 945 eclipsing binaries observed by Kepler. This sample complements earlier studies of this effect, which employed smaller samples of better-characterized stars. For each Kepler binary we measure e cos ω based on the relative timing of the primary and secondary eclipses. We examine the distribution of e cos ω as a function of period for binaries composed of hot stars, cool stars, and mixtures of the two types. At the shortest periods, hot-hot binaries are most likely to be eccentric; for periods shorter than four days, significant eccentricities occur frequently for hot-hot binaries, but not for hot-cool or cool-cool binaries. This is in qualitative agreement with theoretical expectations based on the slower dissipation rates of hot stars. However, the interpretation of our results is complicated by the largely unknown ages and evolutionary states of the stars in our sample.

  13. A quintuple star system containing two eclipsing binaries

    NASA Astrophysics Data System (ADS)

    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.

    2016-10-01

    We present a quintuple star system that contains two eclipsing binaries. 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 eclipsing binaries 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' binary is circular with a 5.1-d period, while the `B' binary is eccentric with a 13.1-d period. The γ velocities of the A and B binaries 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' binary (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.

  14. Fundamental Parameters of Four Massive Eclipsing Binaries in Westerlund 1

    NASA Astrophysics Data System (ADS)

    Koumpia, E.; Bonanos, A. Z.

    2012-04-01

    We present fundamental parameters of four massive eclipsing binaries 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.

  15. Fundamental Parameters of Four Massive Eclipsing Binaries in Westerlund 1

    NASA Astrophysics Data System (ADS)

    Bonanos, A.; Koumpia, E.

    2012-01-01

    We present fundamental parameters of four massive eclipsing binaries 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.

  16. Searching Kepler Variable Stars with the Eclipsing Binary Factory Pipeline

    NASA Astrophysics Data System (ADS)

    Parvizi, Mahmoud; Paegert, M.

    2014-01-01

    Repositories of large survey data, such as the Mikulski Archive for Space Telescopes, provide an ideally sized sample from which to identify astrophysically interesting eclipsing binary 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 Eclipsing Binary 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 Eclipsing Binary 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.

  17. Tidally Induced Pulsations in Kepler Eclipsing Binary KIC 3230227

    NASA Astrophysics Data System (ADS)

    Guo, Zhao; Gies, Douglas R.; Fuller, Jim

    2017-01-01

    KIC 3230227 is a short period (P ≈ 7.0 days) eclipsing binary with a very eccentric orbit (e = 0.6). From combined analysis of radial velocities and Kepler light curves, this system is found to be composed of two A-type stars, with masses of M1 = 1.84 ± 0.18 M⊙, M2 = 1.73 ± 0.17 M⊙ and radii of R1 = 2.01 ± 0.09 R⊙, R2 = 1.68 ± 0.08 R⊙ for the primary and secondary, respectively. In addition to an eclipse, the binary light curve shows a brightening and dimming near periastron, making this a somewhat rare eclipsing heartbeat star system. After removing the binary light curve model, more than 10 pulsational frequencies are present in the Fourier spectrum of the residuals, and most of them are integer multiples of the orbital frequency. These pulsations are tidally driven, and both the amplitudes and phases are in agreement with predictions from linear tidal theory for l = 2, m = ‑2 prograde modes.

  18. Fundamental Parameters of Kepler Eclipsing Binaries. I. KIC 5738698

    NASA Astrophysics Data System (ADS)

    Matson, Rachel A.; Gies, Douglas R.; Guo, Zhao; Orosz, Jerome A.

    2016-06-01

    Eclipsing binaries 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 eclipsing binary 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 binary synthesis code Eclipsing 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.

  19. Stripped red giant cores in eclipsing binary star systems

    NASA Astrophysics Data System (ADS)

    Maxted, P. F. L.; Heber, U.; Smalley, B.; Marsh, T. R.

    2013-02-01

    Red giant stars can be stripped of their outer layers by stellar collisions or mass transfer in binary star systems such as low mass X-ray binaries. If the star is stripped on or before its first ascent of the red giant branch it will eventually become a very low mass white dwarf composed almost entirely of helium. Very low mass white dwarfs are well known in binary milli-second pulsars and many have recently been found in surveys such as the Sloan Digital Sky Survey, but the precursor phase during which the remnant evolves to higher effective temperature at nearly constant luminosity has rarely been observed. The cooling timescale for very low mass white dwarfs is very uncertain because they are thought to be born with thick hydrogen envelopes which can sustain weak but stable p-p shell burning, but unstable phases of CNO burning (shell flashes) can remove this hydrogen envelope. The predicted number of shell flashes (if any) is dependent on the mass and composition of the star and other details of the models used. In this talk I present new observations of a bright eclipsing binary star recently discovered in the WASP archive in which a stripped red giant is eclipsed by an A-type dwarf star. These observations were used to derive precise masses and radii for both stars and have be used to test the formation scenario outlined above. In addition, I present the main characteristics of 17 new eclipsing binary stars that are also likely to contain the precursors of very low mass white dwarfs.

  20. Determination of Individual Temperatures and Luminosities in Eclipsing Binary Star Systems.

    DTIC Science & Technology

    1983-06-20

    REPORT 1NO. W DETERMINATION OF INDIVIDUAL TEMPERATURES AND LUMINOSITIES IN ECLIPSING BINARY STAR SYSTEMS UNITED STATES NAVAL ACADEMY ANNAPOLIS, MARYLAND...U.S.N.A. - Trident Scholar project report; no. 122 (1983) DETERMINATION OF INDIVIDUAL TEMPERATURES AND LUMINOSITIES IN ECLIPSING BINARY STAR SYSTEMS A...the temperatures and luminosities of the individual components of eclipsing binary star systems. -’r. Richard L. Walker of the U.S. Naval Observatory

  1. KEPLER ECLIPSING BINARY STARS. I. CATALOG AND PRINCIPAL CHARACTERIZATION OF 1879 ECLIPSING BINARIES IN THE FIRST DATA RELEASE

    SciTech Connect

    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

    2011-03-15

    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 eclipsing binary 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 binaries). We present statistics based on the determined periods and measure the average occurrence rate of eclipsing binaries to be {approx}1.2% across the Kepler field. We further discuss the distribution of binaries 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 eclipsing binary stars.

  2. Physical parameters of neglected southern eclipsing binary IL Lib

    NASA Astrophysics Data System (ADS)

    Özkardeş, B.

    2017-07-01

    This paper presents results from the combined analysis of light curve (from the All Sky Automated Survey) and radial velocity curves (from Nordström et al., 1997) of the eclipsing binary IL Lib. The final solution describes the system as a detached binary. Absolute parameters of this southern detached binary were calculated as follows: M1 = 1.49 ± 0.12 M⊙, M2 = 1.31 ± 0.14 M⊙, R1 = 1.52 ± 0.23 R⊙, R2 = 1.52 ± 0.23 R⊙, L1 = 4.99 ± 2.07 L⊙ and L2 = 3.65 ± 1.55 L⊙. The distance to IL Lib was computed as 103 ± 20 pc using the distance modulus with corrections for interstellar extinction. The positions of the components of IL Lib in the HR diagram are also discussed.

  3. An Update to the Kepler Eclipsing Binary Catalog: the use of Pixel Time Series to Identify Blended Eclipsing Binary Systems

    NASA Astrophysics Data System (ADS)

    Rucker, Michael; Batalha, N. M.; Prsa, A.; Bryson, S. T.; Doyle, L. R.; Slawson, R. W.; Welsh, W. F.; Orosz, J. A.

    2011-01-01

    The Kepler telescope is providing a nearly seamless stream of photometric data of approximately 150,000 stars with unprecedented precision. The Kepler Eclipsing Binary (EB) catalog (based on the first 43 days of data; arXiv:1006.2815) is being continuously augmented as more data are collected and EBs are detected at longer periods. The catalog is expected to contain a small fraction of blends - cases where the eclipse signature is from a nearby source in the photometric aperture. In constructing the original catalog, obvious blends were identified and removed and/or reassigned to the appropriate point source. We build upon this work by performing pixel-level tests similar to those used to identify false positives amongst the Kepler exoplanet candidates. We summarize these tests here and provide examples that illustrate the types of blend scenarios that we have identified. Where appropriate and possible, we modified Kepler's target list with the newly found Kepler star identification numbers. The changes reported here will affect the target lists which will go into effect on December 23, 2010 (start of Quarter 8). An updated version of the Kepler Eclipsing Binary catalog is available online at NASA's Multimission Archive at STSci (MAST) website (http://archive.stsci.edu/kepler).

  4. Kepler eclipsing binary stars - VI. Identification of eclipsing binaries in the K2 Campaign 0 data set

    NASA Astrophysics Data System (ADS)

    LaCourse, Daryll M.; Jek, Kian J.; Jacobs, Thomas L.; Winarski, Troy; Boyajian, Tabetha S.; Rappaport, Saul A.; Sanchis-Ojeda, Roberto; Conroy, Kyle E.; Nelson, Lorne; Barclay, Tom; Fischer, Debra A.; Schmitt, Joseph R.; Wang, Ji; Stassun, Keivan G.; Pepper, Joshua; Coughlin, Jeffrey L.; Shporer, Avi; Prša, Andrej

    2015-10-01

    The original Kepler mission observed and characterized over 2400 eclipsing binaries (EBs) in addition to its prolific exoplanet detections. Despite the mechanical malfunction and subsequent non-recovery of two reaction wheels used to stabilize the instrument, the Kepler satellite continues collecting data in its repurposed K2 mission surveying a series of fields along the ecliptic plane. Here, we present an analysis of the first full baseline K2 data release: the Campaign 0 data set. In the 7761 light curves we have identified a total of 207 EBs. Of these, 97 are new discoveries that were not previously identified. Our pixel-level analysis of these objects has also resulted in identification of several false positives (observed targets contaminated by neighbouring EBs), as well as the serendipitous discovery of two short-period exoplanet candidates. We provide catalogue cross-matched source identifications, orbital periods, morphologies and ephemerides for these eclipsing systems. We also describe the incorporation of the K2 sample into the Kepler Eclipsing Binary Catalog,§ present spectroscopic follow-up observations for a limited selection of nine systems and discuss prospects for upcoming K2 campaigns.

  5. Fundamental Parameters of 4 Massive Eclipsing Binaries in Westerlund 1

    NASA Astrophysics Data System (ADS)

    Bonanos, Alceste Z.; Koumpia, E.

    2011-05-01

    We present fundamental parameters of 4 massive eclipsing binaries 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.

  6. KIC11560447: An Active Eclipsing Binary From the Kepler Field

    NASA Astrophysics Data System (ADS)

    Ozavci, Ibrahim; Hussain, Gaitee; Yılmaz, Mesut; O'Neal, Douglas; osman Selam, Selim; Şenavcı, Hakan Volkan

    2016-07-01

    We performed spectroscopic and photometric analysis of the detached eclipsing binary 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.

  7. Phenomenological Modelling of a Group of Eclipsing Binary Stars

    NASA Astrophysics Data System (ADS)

    Andronov, Ivan L.; Tkachenko, Mariia G.; Chinarova, Lidia L.

    2016-03-01

    Phenomenological modeling of variable stars allows determination of a set of the parameters, which are needed for classification in the "General Catalogue of Variable Stars" and similar catalogs. We apply a recent method NAV ("New Algol Variable") to eclipsing binary stars of different types. Although all periodic functions may be represented as Fourier series with an infinite number of coefficients, this is impossible for a finite number of the observations. Thus one may use a restricted Fourier series, i.e. a trigonometric polynomial (TP) of order s either for fitting the light curve, or to make a periodogram analysis. However, the number of parameters needed drastically increases with decreasing width of minimum. In the NAV algorithm, the special shape of minimum is used, so the number of parameters is limited to 10 (if the period and initial epoch are fixed) or 12 (not fixed). We illustrate the NAV method by application to a recently discovered Algol-type eclipsing variable 2MASS J11080308-6145589 (in the field of previously known variable star RS Car) and compare results to that obtained using the TP fits. For this system, the statistically optimal number of parameters is 44, but the fit is still worse than that of the NAV fit. Application to the system GSC 3692-00624 argues that the NAV fit is better than the TP one even for the case of EW-type stars with much wider eclipses. Model parameters are listed.

  8. Timing of Eclipses of Binary Stars from the ASAS Catalog

    NASA Astrophysics Data System (ADS)

    Kozlowski, S. K.; Konacki, M.; Sybilski, P.

    2011-09-01

    Light was thought of as something infinite and transcendent till 1676 when Olaus Roemer carried out precise measurements of the times of eclipses of Jovian moons. Roemer's scrupulous observations led him to a qualitative conclusion that light travels at a finite speed, at the same time providing scientists with the basics of the Light-Time Effect (LTE). LTE is observed whenever the distance between the observer and any kind of periodic event changes in time. The usual cause of this distance change is the reflex motion about the system's barycenter due to the gravitational influence of one or more additional bodies. We present results of the analysis of 5032 eclipsing contact and detached binaries from the All Sky Automated Survey (ASAS) catalogue for variations in the times of eclipses. We use an approach known from the radio pulsar timing where a template radio pulse of a pulsar is used as a reference to measure the times of arrivals of the collected pulses. Most of the variations we detect in O--Cs correspond to a linear period change, but three show evidence of more than one complete LTE-orbit. For these objects we present preliminary orbital solutions. Our results demonstrate that the timing analysis employed in radio pulsar timing can be effectively used to study large data sets from photometric surveys. This is the prelude to the analysis of data gathered by the Solaris Project which aims at the search for circumbinary planets.

  9. Short Period Eclipsing Binaries In The Field Of The Young Cluster NGC 2362

    NASA Astrophysics Data System (ADS)

    Hamilton, Catrina; Brinckerhoff, Matthew; Richey-Yowell, Tyler; James, David; Cargile, Phillip

    2016-08-01

    In a study of rotation periods in the young (t 5 Myr) cluster NGC 2362 (Hamilton et al. 2009), several new eclipsing systems were discovered. In this poster, we present photometric observations of these systems and separate them into likely eclipsing binaries and interesting puzzles. The binaries are most likely field stars and are not a part of the cluster.

  10. VizieR Online Data Catalog: Bolometric fluxes of eclipsing binaries in Tycho-2 (Stassun+, 2016)

    NASA Astrophysics Data System (ADS)

    Stassun, K. G.; Torres, G.

    2017-03-01

    We present fits to the broadband photometric Spectral Energy Distributions (SEDs) of 158 eclipsing binaries in the Tycho-2 catalog. The complete list of 158 eclipsing binaries is given in Table1, sorted by Tycho number. The results of the SED fitting procedure are summarized in Table2. (3 data files).

  11. A1540-53, an eclipsing X-ray binary pulsator

    NASA Technical Reports Server (NTRS)

    Becker, R. H.; Swank, J. H.; Boldt, E. A.; Holt, S. S.; Pravdo, S. H.; Saba, J. R.; Serlemitsos, P. J.

    1977-01-01

    An eclipsing X-ray binary pulsator consistent with the location of A1540-53 was observed. The source pulse period was 528.93 plus or minus 0.10 seconds. The binary nature is confirmed by a Doppler curve for the pulsation period. The eclipse angle of 30.5 deg plus or minus 3 deg and the 4 h transition to and from eclipse suggest an early type, giant or supergiant, primary star.

  12. A Photometric Study of Three Eclipsing Binary Stars (Poster abstract)

    NASA Astrophysics Data System (ADS)

    Ryan, A.

    2016-12-01

    (Abstract only) As part of a program to study eclipsing binary stars that exhibit the O'Connell Effect (OCE) we are observing a selection of binary stars in a long term study. The OCE is a difference in maximum light across the ligthcurve possibly cause by starspots. We observed for 7 nights at McDonald Observatory using the 30-inch telescope in July 2015, and used the same telescope remotely for a total of 20 additional nights in August, October, December, and January. We will present lightcurves for three stars from this study, characterize the OCE for these stars, and present our model results for the physical parameters of the star making up each of these systems.

  13. Period Variations in Three Eclipsing Binaries in Vulpecula

    NASA Astrophysics Data System (ADS)

    Hanna, M. A.

    2015-07-01

    We investigate the period variations for three eclipsing binaries showing strong evidence of period changes, by means of the O-C residual diagram. Two of them, BK Vul and KN Vul, are W UMa-type contact binaries, while the third, V467 Vul, is a β Lyr semi-detached system. All three exhibit period changes dP/dt (decreases) over the long term, which are usually interpreted as being due to mass transfer from the primary to the secondary component, or mass loss from L2. The period variability of KN Vul also shows a sine-like variation superimposed on the parabolic behavior, which may be interpreted in terms of either magnetic activity or the light time effect.

  14. Inferred Eccentricity and Period Distributions of Kepler Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Prsa, Andrej; Matijevic, G.

    2014-01-01

    Determining the underlying eccentricity and orbital period distributions from an observed sample of eclipsing binary stars is not a trivial task. Shen and Turner (2008) have shown that the commonly used maximum likelihood estimators are biased to larger eccentricities and they do not describe the underlying distribution correctly; orbital periods suffer from a similar bias. Hogg, Myers and Bovy (2010) proposed a hierarchical probabilistic method for inferring the true eccentricity distribution of exoplanet orbits that uses the likelihood functions for individual star eccentricities. The authors show that proper inference outperforms the simple histogramming of the best-fit eccentricity values. We apply this method to the complete sample of eclipsing binary stars observed by the Kepler mission (Prsa et al. 2011) to derive the unbiased underlying eccentricity and orbital period distributions. These distributions can be used for the studies of multiple star formation, dynamical evolution, and they can serve as a drop-in replacement to prior, ad-hoc distributions used in the exoplanet field for determining false positive occurrence rates.

  15. MASS CONSTRAINTS FROM ECLIPSE TIMING IN DOUBLE WHITE DWARF BINARIES

    SciTech Connect

    Kaplan, David L.

    2010-07-10

    I demonstrate that an effect similar to the Roemer delay, familiar from timing radio pulsars, should be detectable in the first eclipsing double white dwarf (WD) binary, NLTT 11748. By measuring the difference of the time between the secondary and primary eclipses 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 binaries 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.

  16. Absolute Dimensions of the Eccentric Eclipsing Binary V541 Cygni

    NASA Astrophysics Data System (ADS)

    Torres, Guillermo; McGruder, Chima D.; Siverd, Robert J.; Rodriguez, Joseph E.; Pepper, Joshua; Stevens, Daniel J.; Stassun, Keivan G.; Lund, Michael B.; James, David

    2017-02-01

    We report new spectroscopic and photometric observations of the main-sequence, detached, eccentric, double-lined eclipsing binary V541 Cyg (P = 15.34 days, e = 0.468). Using these observations together with existing measurements, we determine the component masses and radii to better than 1% precision: {M}1={2.335}-0.013+0.017 {M}ȯ , {M}2={2.260}-0.013+0.016 {M}ȯ , {R}1={1.859}-0.009+0.012 {R}ȯ , and {R}2={1.808}-0.013+0.015 {R}ȯ . The nearly identical B9.5 stars have estimated effective temperatures of 10650 ± 200 K and 10350 ± 200 K. A comparison of these properties with current stellar evolution models shows excellent agreement at an age of about 190 Myr and [Fe/H] ≈ ‑0.18. Both components are found to be rotating at the pseudo-synchronous rate. The system displays a slow periastron advance that is dominated by general relativity (GR), and has previously been claimed to be slower than predicted by theory. Our new measurement, \\dot{ω }={0.859}-0.017+0.042 deg century‑1, has an 88% contribution from GR and agrees with the expected rate within the uncertainties. We also clarify the use of the gravity darkening coefficients in the light-curve fitting Eclipsing Binary Orbit Program (EBOP), a version of which we use here.

  17. Early-type Eclipsing Binaries with Intermediate Orbital Periods

    NASA Astrophysics Data System (ADS)

    Moe, Maxwell; Di Stefano, Rosanne

    2015-09-01

    We analyze 221 eclipsing binaries (EBs) in the Large Magellanic Cloud with B-type main-sequence (MS) primaries (M1 ≈ 4-14 {M}⊙ ) and orbital periods P = 20-50 days that were photometrically monitored by the Optical Gravitational Lensing Experiment. We utilize our three-stage automated pipeline to (1) classify all 221 EBs, (2) fit physical models to the light curves of 130 detached well-defined EBs from which unique parameters can be determined, and (3) recover the intrinsic binary statistics by correcting for selection effects. We uncover two statistically significant trends with age. First, younger EBs tend to reside in dustier environments with larger photometric extinctions, an empirical relation that can be implemented when modeling stellar populations. Second, younger EBs generally have large eccentricities. This demonstrates that massive binaries at moderate orbital periods are born with a Maxwellian “thermal” orbital velocity distribution, which indicates they formed via dynamical interactions. In addition, the age-eccentricity anticorrelation provides a direct constraint for tidal evolution in highly eccentric binaries containing hot MS stars with radiative envelopes. The intrinsic fraction of B-type MS stars with stellar companions q = M2/M1 > 0.2 and orbital periods P = 20-50 days is (7 ± 2)%. We find early-type binaries at P = 20-50 days are weighted significantly toward small mass ratios q ≈ 0.2-0.3, which is different than the results from previous observations of closer binaries with P < 20 days. This indicates that early-type binaries at slightly wider orbital separations have experienced substantially less competitive accretion and coevolution during their formation in the circumbinary disk.

  18. Eclipsing Binaries in the 21st Century—Opportunities for Amateur Astronomers

    NASA Astrophysics Data System (ADS)

    Guinan, E. F.; Engle, S. G.; Devinney, E. J.

    2012-06-01

    Eclipsing binaries play major roles in modern astrophysical research. These stars provide fundamental data on the masses, radii, ages, atmospheres, and interiors of stars as well as serving as test beds for stellar structure and evolution models. The study of eclipsing binaries also returns vital information about the formation and evolution of close binaries themselves. Studying the changes in their periods from the observations of eclipse timings provides insights into evolution of close binaries, mass exchange and loss, apsidal motion for eccentric systems, as well as the discovery of the low mass (unseen) third bodies. Moreover eclipsing binaries in clusters and other galaxies can provide accurate distances to the star clusters and galaxies in which they reside. More recently observations of eclipsing exoplanet-star systems (that is, transiting exoplanets) when coupled with spectroscopy are yielding fundamental information about the frequency and the physical properties of planets orbiting other stars. For the reasons discussed above, observations of eclipsing binary systems have been popular for AAVSO observers and many papers have been published (see Williams et al. 2012, JAAVSO, 40, No. 1). A recent example is the highly successful AAVSO’s Citizen Sky Project focused on the enigmatic long-period eclipsing binary ɛ Aur. Building on the success of the AAVSO during the last century, this paper explores the present and future prospects for research in eclipsing binaries. We focus on what can be done by AAVSO members and other amateur astronomers in the study of eclipsing binaries. Several examples of observing strategies and interesting (and scientifically valuable) projects are discussed as well as future prospects. As discussed, there are many opportunities for AAVSO members to contribute to study of eclipsing binary stars and an increasing variety of objects to observe.

  19. VX Her: Eclipsing Binary System or Single Variable Star

    NASA Astrophysics Data System (ADS)

    Perry, Kathleen; Castelaz, Michael; Henson, Gary; Boghozian, Andrew

    2015-01-01

    VX Her is a pulsating variable star with a period of .4556504 days. It is believed to be part of an eclipsing binary system (Fitch et al. 1966). This hypothesis originated from Fitch seeing VX Her's minimum point on its light curve reaching a 0.7 magnitude fainter than normal and remaining that way for nearly two hours. If VX Her were indeed a binary system, I would expect to see similar results with a fainter minimum and a broader, more horizontal dip. Having reduced and analyzed images from the Southeastern Association for Research in Astronomy Observatory in Chile and Kitt Peak, as well as images from a 0.15m reflector at East Tennessee State University, I found that VX Her has the standard light curve of the prototype variable star, RR Lyrae. Using photometry, I found no differing features in its light curve to suggest that it is indeed a binary system. However, more observations are needed in case VX Her is a wide binary.

  20. The first eclipsing binary catalogue from the MOA-II data base

    NASA Astrophysics Data System (ADS)

    Li, M. C. A.; Rattenbury, N. J.; Bond, I. A.; Sumi, T.; Bennett, D. P.; Koshimoto, N.; Abe, F.; Asakura, Y.; Barry, R.; Bhattacharya, A.; Donachie, M.; Evans, P.; Freeman, M.; Fukui, A.; Hirao, Y.; Itow, Y.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Nagakane, M.; Ohnishi, K.; Saito, To.; Sharan, A.; Sullivan, D. J.; Suzuki, D.; Tristram, P. J.; Yonehara, A.

    2017-09-01

    We present the first catalogue of eclipsing binaries in two MOA (Microlensing Observations in Astrophysics) fields towards the Galactic bulge, in which over 8000 candidates, mostly contact and semidetached binaries of periods <1 d, were identified. In this paper, the light curves of a small number of interesting candidates, including eccentric binaries, binaries with noteworthy phase modulations and eclipsing RS Canum Venaticorum type stars, are shown as examples. In addition, we identified three triple object candidates by detecting the light-travel-time effect in their eclipse time variation curves.

  1. Red Giants in Eclipsing Binaries as a Benchmark for Asteroseismology

    NASA Astrophysics Data System (ADS)

    Rawls, Meredith L.

    2016-04-01

    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 eclipsing binaries. Binarity allows us to directly measure stellar properties independently of asteroseismology. In this dissertation, we study a subset of eight red giant eclipsing binaries 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 binary. 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 binaries 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 binaries offer an

  2. Discovery of the Partially Eclipsing White Dwarf Binary SDSS J143547.87+373338.5

    NASA Astrophysics Data System (ADS)

    Steinfadt, Justin D. R.; Bildsten, Lars; Howell, Steve B.

    2008-04-01

    We have discovered a partially eclipsing white dwarf, low-mass M dwarf binary (3.015114 hr orbital period), SDSS J143547.87+373338.5, from 2007 May observations at the WIYN telescope. Here we present blue-band photometry of three eclipses. Eclipse fitting gives main-sequence solutions to the M dwarf companion of MS = 0.15-0.35 M⊙ and RS = 0.17-0.32 R⊙. Analysis of the SDSS spectrum constrains the M dwarf further to be of type M4-M6 with MS = 0.11-0.20 M⊙. Once full radial velocity curves are measured, high-precision determinations of the masses and radii of both components will be easily obtained without any knowledge of stellar structure or evolution. ZZ Ceti pulsations from the white dwarf were not found at our 4 mmag detection limit. The WIYN Observatory is a joint facility of the University of Wisconsin-Madison, Indiana University, Yale University, and the National Optical Astronomy Observatory.

  3. The X-ray eclipse of the LMC binary CAL 87

    NASA Technical Reports Server (NTRS)

    Schmidtke, P. C.; Mcgrath, T. K.; Cowley, A. P.; Frattare, L. M.

    1993-01-01

    ROSAT-PSPC observations of the LMC eclipsing binary CAL 87 show a short-duration, shallow X-ray eclipse which coincides in phase with the primary optical minimum. Characteristics of the eclipse suggest the X-ray emitting region is only partially occulted. Similarities with the eclipse of the accretion-disk corona in X 1822-37 are discussed. However, no temperature variation through eclipse is found for CAL 87. A revised orbital period, combining published data and recent optical photometry, is given.

  4. Properties of an eclipsing double white dwarf binary NLTT 11748

    SciTech Connect

    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.

    2014-01-10

    We present high-quality ULTRACAM photometry of the eclipsing detached double white dwarf binary NLTT 11748. This system consists of a carbon/oxygen white dwarf and an extremely low mass (<0.2 M {sub ☉}) helium-core white dwarf in a 5.6 hr orbit. To date, such extremely low-mass 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 eclipses 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 eclipse 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).

  5. Eclipse timing variations to detect exoplanets in binary star systems

    NASA Astrophysics Data System (ADS)

    Schwarz, Richard; Funk, Barbara; Bazso, Akos; Zechner, Renate

    2016-02-01

    This work is devoted to study the circumstances favorable to detect planets in S- or P-Type orbits in close binary star systems by the help of eclipse timing variations (ETVs). A planet in S-Type motion orbits one of the two stars while a planet in P-Type Motion orbits both stars. One can detect ETV signals with the help of former (CoRoT and Kepler) and future space missions Plato, Tess and Cheops). To determine the probability of the detection of such ETV signals with ground based and space telescopes we investigated the dynamics of close binary star systems (stars separated by 0.5 to 3 AU). Therefore we did numerical simulations by using the full three-body problem as dynamical model. The stability and the ETVs are investigated by computing ETV maps for different masses of the secondary star and the exoplanet (Earth, Neptune and Jupiter mass). In addition we changed the planets eccentricity. We can conclude that many ETV amplitudes are large enough to detect planets in S- or P-Type orbits in binary star systems.

  6. Flare activity on low-mass eclipsing binary GJ 3236*

    NASA Astrophysics Data System (ADS)

    Šmelcer, L.; Wolf, M.; Kučáková, H.; Bílek, F.; Dubovský, P.; Hoňková, K.; Vraštil, J.

    2017-04-01

    We report the discovery of optical flares on the very low-mass red-dwarf eclipsing binary GJ 3236 and the results of our 2014-2016 photometric campaign. In total, this binary was monitored photometrically in all filters for about 900 h, which has revealed a flare rate of about 0.06 flares per hour. The amplitude of its flares is the largest among those detected in the V band (∼1.3 mag), R band (∼0.8 mag), I band (∼0.2 mag) and clear band (∼0.5 mag). The light curves of GJ 3236 were analysed and the statistics of detected flare events are presented. The energy released during individual flares was calculated as up to 2.4 × 1027 J and compared with other known active stars. The cumulative distribution of flare energies appears to follow a broken power law. The flare activity of this binary also plays an important role in the precise determination of its physical parameters and evolutionary status.

  7. Distances to Four Solar Neighborhood Eclipsing Binaries from Absolute Fluxes

    NASA Astrophysics Data System (ADS)

    Wilson, R. E.; Van Hamme, W.

    2009-07-01

    Eclipsing binary (EB)-based distances are estimated for four solar neighborhood EBs by means of the Direct Distance Estimation (DDE) algorithm. Results are part of a project to map the solar neighborhood EBs in three dimensions, independently of parallaxes, and provide statistical comparisons between EB and parallax distances. Apart from judgments on adopted temperature and interstellar extinction, DDE's simultaneous light-velocity solutions are essentially objective and work as well for semidetached (SD) and overcontact binaries as for detached systems. Here, we analyze two detached and two SD binaries, all double lined. RS Chamaeleontis is a pre-main-sequence (MS), detached EB with weak δ Scuti variations. WW Aurigae is detached and uncomplicated, except for having high metallicity. RZ Cassiopeiae is SD and has very clear δ Scuti variations and several peculiarities. R Canis Majoris (R CMa) is an apparently simple but historically problematic SD system, also with weak δ Scuti variations. Discussions include solution rules and strategies, weighting, convergence, and third light problems. So far there is no indication of systematic band dependence among the derived distances, so the adopted band-calibration ratios seem consistent. Agreement of EB-based and parallax distances is typically within the overlapped uncertainties, with minor exceptions. We also suggest an explanation for the long-standing undermassiveness problem of R CMa's hotter component, in terms of a fortuitous combination of low metallicity and evolution slightly beyond the MS.

  8. Absolute dimensions of eclipsing binaries. XI - V 451 Ophiuchi

    NASA Astrophysics Data System (ADS)

    Clausen, J. V.; Gimenez, A.; Scarfe, C.

    1986-10-01

    V451 Oph is a detached eclipsing binary with B9 - A0 main sequence components in a slightly eccentric orbit, and this paper presents accurate absolute dimensions for the system: masses 2.78±0.06 and 2.36±0.05 M_sun;; radii 2.64±0.03 and 2.03±0.05 R_sun;; effective temperatures 10800±800 and 9800±500K. An orbital eccentricity e = 0.0125±0.0015 is obtained and the period of periastron revolution is 180±30 yr. The orbital inclination is 85°.9±0°.5, the relative radii are 0.2155±0.0020 and 0.1655±0.0020, respectively, and secondary eclipse is close to being total. The luminosity ratio between the components is found to be 0.489±0.015 (y), slightly lower than the spectroscopic result 0.60±0.05, which cannot be reproduced from the available photometric information. The components are well-represented by the theoretical evolutionary models by Hejlesen (1980) for an initial chemical composition of (X, Z) = (0.70, 0.02) and a common age of 2×108yr.

  9. CzeV615 - a new eclipsing binary

    NASA Astrophysics Data System (ADS)

    Liska, J.; Liskova, Z.

    2014-12-01

    Discovery of a new eclipsing binary system CzeV615 = BD+09 3111 in the vicinity of an RR Lyrae star, AT Ser, is presented. The variability of the star was detected from CCD measurements with a small telescope. Observations from ASAS-3, NSVS and WISE sky-surveys were used for follow-up analysis. A brightness variation with a period of 1.4869803 d and an amplitude of about 0.1 mag was found. The shapes of light curves in the optical and infrared bands indicate a similar surface temperature for both components. Nevertheless, a period of half the value of the presented period can not be ruled out using the mentioned data.

  10. Five New Low-Mass Eclipsing Binary Systems

    NASA Astrophysics Data System (ADS)

    Coughlin, Jeffrey L.; López-Morales, M.; Shaw, J. S.

    2006-12-01

    We present the discovery of five new low-mass eclipsing binaries with masses between 0.54 and 0.95 M⊙, their photometric light curves, and preliminary models. This is part of a continuing campaign to increase the available data on these interesting systems. Once radial-velocity curves are completed, physical parameters will be determined with an error of less than 2-3%, thus allowing for a rigorous examination of stellar models in the lower-main sequence. Our initial analysis seems to support the current findings that low-mass stars have greater radii than models predict, most likely due to the presence of strong magnetic fields. This work is funded by a partnership between the National Science Foundation (NSF AST-0552798) Research Experiences for Undergraduates (REU) and the Department of Defense (DoD) ASSURE (Awards to Stimulate and Support Undergraduate Research Experiences) programs.

  11. ABSOLUTE PROPERTIES OF THE ECLIPSING BINARY STAR V335 SERPENTIS

    SciTech Connect

    Lacy, Claud H. Sandberg; Fekel, Francis C.; Claret, Antonio E-mail: fekel@evans.tsuniv.edu

    2012-08-15

    V335 Ser is now known to be an eccentric double-lined A1+A3 binary star with fairly deep (0.5 mag) partial eclipses. 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.

  12. ABSOLUTE PROPERTIES OF THE ECLIPSING BINARY STAR HY VIRGINIS

    SciTech Connect

    Sandberg Lacy, Claud H.; Fekel, Francis C. E-mail: fekel@evans.tsuniv.edu

    2011-12-15

    HY Vir is found to be a double-lined F0m+F5 binary star with relatively shallow (0.3 mag) partial eclipses. 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.

  13. Absolute properties of the eclipsing binary star IM Persei

    SciTech Connect

    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

    2015-01-01

    IM Per is a detached A7 eccentric eclipsing binary 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.

  14. The solar-type eclipsing binary system LL Aquarii

    NASA Astrophysics Data System (ADS)

    Southworth, J.

    2013-09-01

    The eclipsing binary LL Aqr consists of two late-type stars in an eccentric orbit with a period of 20.17 d. We use an extensive light curve from the SuperWASP survey augmented by published radial velocities and UBV light curves to measure the physical properties of the system. The primary star has a mass of 1.167 ± 0.009 M⊙ and a radius of 1.305 ± 0.007 R⊙. The secondary star is an analogue of the Sun, with a mass and radius of 1.014 ± 0.006 M⊙ and 0.990 ± 0.008 R⊙ respectively. The system shows no signs of stellar activity: the upper limit on spot-induced rotational modulation is 3 mmag, it is slowly rotating, has not been detected at X-ray wavelengths, and the calcium H and K lines exhibit no emission. Theoretical stellar models provide a good match to its properties for a sub-solar metal abundance of Z = 0.008 and an age of 2.5 Gyr. Most low-mass eclipsing binary systems are found to have radii larger than expected from theoretical predictions, blamed on tidally-enhanced magnetic fields in these short-period systems. The properties of LL Aqr support this scenario: it exhibits negligible tidal effects, shows no signs of magnetic activity, and matches theoretical models well. Full Tables 1 and 7 are 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/557/A119

  15. AN ECLIPSING BLUE STRAGGLER IN THE GLOBULAR CLUSTER {omega} CENTAURI

    SciTech Connect

    Li Kai; Qian Shengbang

    2012-12-01

    {omega} Centauri is the largest globular cluster in the Milky Way and hence contains the largest number of variable stars within a single cluster. The results of photometric solutions are presented for the EA-type binary V239 in this cluster. According to our analysis, V239 is a typical Algol-type binary. We obtain M = 1.20 {+-} 0.10 M{sub Sun }, R = 1.21 {+-} 0.03 R{sub Sun }, and L = 13.68 {+-} 0.63 L{sub Sun} for the primary component. The secondary component has M = 0.07 {+-} 0.02 M{sub Sun }, R = 0.90 {+-} 0.03 R{sub Sun }, and L = 2.17 {+-} 0.14 L{sub Sun }. The binary system is located in the blue straggler region on the color-magnitude diagram of {omega} Centauri and the mass of the primary component exceeds the mass of a turnoff star. Therefore, we think that V239 is a blue straggler and that V239 was formed by mass transfer from the present secondary component to the present primary.

  16. Fundamental Calibrators for Stellar Evolution Models: New Eclipsing Binaries in Young Clusters Identified by K2

    NASA Astrophysics Data System (ADS)

    David, Trevor

    2016-07-01

    Double-lined eclipsing binaries serve as fundamental calibrators for stellar evolution models. Benchmark grade calibrators (with mass and radius uncertainties of 3%) having component masses below 1 solar mass are rare, particularly at pre-main sequence stages. We present the discovery and characterization of new eclipsing binaries in young stellar clusters, all identified by K2. In the 5-10 Myr old Upper Scorpius region, the nearest OB association, we present the lowest mass stellar eclipsing binary to date, with both components close to the hydrogen burning limit. Also in Upper Scorpius, we present evidence for a hierarchical triple with an eclipsing pair of brown dwarfs, only the second eclipsing brown dwarf pair known to date. In the 110-125 Myr old Pleiades cluster, only one eclipsing binary was known prior to the K2 mission. We present three new Pleiades eclipsing binaries, all with system masses less than 1 solar mass. We use these systems to critically assess stellar evolution models at low masses and young ages. K2 data in hand has also revealed new eclipsing and transiting systems in the moderately older (600-800 Myr) Hyades and Praesepe clusters.

  17. Eclipsing binary stars in the era of massive surveys First results and future prospects

    NASA Astrophysics Data System (ADS)

    Papageorgiou, Athanasios; Catelan, Márcio; Ramos, Rodrigo Contreras; Drake, Andrew J.

    2017-09-01

    Our thinking about eclipsing binary stars has undergone a tremendous change in the last decade. Eclipsing binary stars are one of nature's best laboratories for determining the fundamental physical properties of stars and thus for testing the predictions of theoretical models. Some of the largest ongoing variable star surveys include the Catalina Real-time Transient Survey (CRTS) and the VISTA Variables in the Vía Láctea survey (VVV). They both contain a large amount of photometric data and plenty of information about eclipsing binaries that wait to be extracted and exploited. Here we briefly describe our efforts in this direction.

  18. Physical parameters and multiplicity of five southern close eclipsing binaries

    NASA Astrophysics Data System (ADS)

    Szalai, T.; Kiss, L. L.; Mészáros, Sz.; Vinkó, J.; Csizmadia, Sz.

    2007-04-01

    Aims:We detected tertiary components of close binaries from spectroscopy and light curve modelling, investigated the light-travel time effect and the possibility of magnetic activity cycles, measured mass ratios for unstudied systems, and derived absolute parameters. Methods: We carried out new photometric and spectroscopic observations of five bright (< V >< 10.5 mag) close eclipsing binaries, predominantly in the southern skies. We obtained full Johnson BV light curves, which were modelled with the Wilson-Devinney code. Radial velocities were measured with the cross-correlation method using IAU radial velocity standards as spectral templates. Period changes were studied with the O-C method, utilising published epochs of minimum light (XY Leo) and ASAS photometry (VZ Lib). Results: For three objects (DX Tuc, QY Hya, V870 Ara), absolute parameters have been determined for the first time. We spectroscopically detected the tertiary components in XY Leo and VZ Lib and discovered one in QY Hya. For XY Leo we updated the light-time effect parameters and detected a secondary periodicity of about 5100 d in the O-C diagram that may hint at the existence of short-period magnetic cycles. A combination of recent photometric data shows that the orbital period of the tertiary star in VZ Lib is likely to be over 1500 d. QY Hya is a semi-detached X-ray active binary in a triple system with K and M-type components, while V870 Ara is a contact binary with the third smallest spectroscopic mass ratio for a W UMa star to date (q = 0.082 ± 0.030). Being close to the theoretical minimum for contact binaries, this small mass ratio suggests that V870 Ara has the potential of constraining evolutionary scenarios of binary mergers. The inferred distances to these systems are compatible with the Hipparcos parallaxes. Based on observations made at the Siding Spring Observatory, Australia. Light curves and radial velocity data are only available in electronic form at the CDS via anonymous ftp

  19. The first Doppler images of the eclipsing binary SZ Piscium

    NASA Astrophysics Data System (ADS)

    Xiang, Yue; Gu, Shenghong; Cameron, A. Collier; Barnes, J. R.; Zhang, Liyun

    2016-02-01

    We present the first Doppler images of the active eclipsing binary 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 binaries.

  20. Low-mass eclipsing binaries in the WFCAM Transit Survey

    NASA Astrophysics Data System (ADS)

    Cruz, Patricia; Diaz, Marcos; Barrado, David; Birkby, Jayne

    2017-10-01

    The characterization of short-period detached low-mass binaries, by the determination of their physical and orbital parameters, reveal the most precise basic parameters of low-mass stars. Particularly, when photometric and spectroscopic data of eclipsing binaries (EBs) are combined. Recently, 16 new low-mass EBs were discovered by the WFCAM Transit Survey (WTS), however, only three of them were fully characterized. Therefore, new spectroscopic data were already acquired with the objective to characterize five new detached low-mass EBs discovered in the WTS, with short periods between 0.59 and 1.72 days. A preliminary analysis of the radial velocity and light curves was performed, where we have derived orbital separations of 2.88 to 6.69 R ⊙, and considering both components, we have found stellar radii ranging from 0.40 to 0.80 R ⊙, and masses between 0.24 and 0.71 M ⊙. In addition to the determination of the orbital parameters of these systems, the relation between mass, radius and orbital period of these objects can be investigated in order to study the mass-radius relationship and the radius anomaly in the low main-sequence.

  1. EPIC 220204960: A Quadruple Star System Containing Two Strongly Interacting Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Rappaport, S.; Vanderburg, A.; Borkovits, T.; Kalomeni, B.; Halpern, J. P.; Ngo, H.; Mace, G. N.; Fulton, B. J.; Howard, A. W.; Isaacson, H.; Petigura, E. A.; Mawet, D.; Kristiansen, M. H.; Jacobs, T. L.; LaCourse, D.; Bieryla, A.; Forgács-Dajka, E.; Nelson, L.

    2017-05-01

    We present a strongly interacting quadruple system associated with the K2 target EPIC 220204960. The K2 target itself is a Kp = 12.7-mag star at Teff ≃ 6100 K, which we designate as 'B-N' (blue northerly image). The host of the quadruple system, however, is a Kp ≃ 17-mag star with a composite M-star spectrum, which we designate as 'R-S' (red southerly image). With a 3.2-arcsec separation and similar radial velocities and photometric distances, 'B-N' is likely physically associated with 'R-S', making this a quintuple system, but that is incidental to our main claim of a strongly interacting quadruple system in 'R-S'. The two binaries in 'R-S' have orbital periods of 13.27 and 14.41 d, respectively, and each has an inclination angle of ≳89°. From our analysis of radial-velocity (RV) measurements, and of the photometric light curve, we conclude that all four stars are very similar with masses close to 0.4 M⊙. Both of the binaries exhibit significant eclipse-timing variations where those of the primary and secondary eclipses 'diverge' by 0.05 d over the course of the 80-d observations. Via a systematic set of numerical simulations of quadruple systems consisting of two interacting binaries, we conclude that the outer orbital period is very likely to be between 300 and 500 d. If sufficient time is devoted to RV studies of this faint target, the outer orbit should be measurable within a year.

  2. Eclipsing binary stars with extreme light curve asymmetries mined from large astronomical surveys

    NASA Astrophysics Data System (ADS)

    Papageorgiou, Athanasios; Kleftogiannis, Georgios; Christopoulou, Panagiota-Eleftheria

    2017-09-01

    The O'Connell effect is one of the most perplexing challenges in binary studies as it has not been convincingly explained. Furthermore, a simple method to obtain essential parameters for eclipsing binaries exhibiting this effect and to extract information describing the asymmetry in the light curve maxima is needed. 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 eclipses.

  3. A solar twin in the eclipsing binary LL Aquarii

    NASA Astrophysics Data System (ADS)

    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.

    2016-10-01

    Aims: In the course of a project to study eclipsing binary 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 eclipsing binary, 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

  4. VizieR Online Data Catalog: Kepler Mission. VII. Eclipsing binaries in DR3 (Kirk+, 2016)

    NASA Astrophysics Data System (ADS)

    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.

    2016-07-01

    The Kepler Eclipsing Binary Catalog lists the stellar parameters from the Kepler Input Catalog (KIC) augmented by: primary and secondary eclipse depth, eclipse width, separation of eclipse, 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/eclipsing_binaries.html. (10 data files).

  5. Multiwavelength Observations of the Eclipsing Binary NSV 03438 Between January 2013 and March 2016

    NASA Astrophysics Data System (ADS)

    Becker, Carter M.

    2017-06-01

    The eclipsing binary NSV 03438 in Canis Minor consists of two M-type stars having approximate effective temperatures of 3235K (M4V) and 2898K (M6V). The period for a cycle during this study was 1.535 days, essentially unchanged from that reported in 1996. A modification of the bisected chord method provides estimates of mid-eclipse Julian Dates with 95% confidence limits for 22 primary and 29 secondary eclipses. The mean depths of primary and secondary eclipses with filter B are 0.69 and 0.62 magnitude, respectively, and 0.65 and 0.61 magnitude, respectively for filter V. APASS standard stars closely associated with NSV 03438 provide a means of determining the magnitude of NSV 03438. In addition, B - V color indexes and effective temperatures of the binary can be assessed at critical stages throughout the eclipse cycle.

  6. Artificial Intelligence and the Brave New World of Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Devinney, E.; Guinan, E.; Bradstreet, D.; DeGeorge, M.; Giammarco, J.; Alcock, C.; Engle, S.

    2005-12-01

    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 eclipsing binary 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 binaries (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 binary stars will provide tests of current theories (or suggest new theories) regarding binary 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

  7. The MACHO Project LMC variable star inventory. V. Classification and orbits of 611 eclipsing binary stars

    SciTech Connect

    The MACHO Collaboration

    1997-07-01

    We report the characteristics of 611 eclipsing binary stars in the Large Megallanic Cloud found by using the MACHO Project photometry database. The sample is magnitude limited, and extends down the main sequence to about spectral type A0. Many evolved binaries are also included. Each eclipsing binary is classified according to the traditional scheme of the {ital General Catalogue of Variable Stars} (EA and EB), and also according to a new decimal classification scheme defined in this paper. The new scheme is sensitive to the two major sources of variance in eclipsing binary star light curves{emdash}the sum of radii, and the surface-brightness ratio, and allow greater precision in characterizing the light curves. Examples of each type of light curve and their variations are given. Sixty-four of the eclipsing binaries have eccentric, rather than circular, orbits. The ephemeris and principal photometric characteristics of each eclipsing binary are listed in a table. Photometric orbits based on the Nelson{endash}Davis{endash}Etzel model have been fitted to all light curves. These data will be useful for planning future observations of these binaries. Plots of all data and fitted orbits and a table of the fitted orbital parameters are available on the AAS CD-ROM series, Vol. 9, 1997. These data are also available at the MACHO home page (http://wwwmacho.mcmaster.ca/). {copyright} {ital 1997 American Astronomical Society.}

  8. KIC 7385478: An Eclipsing Binary with a γ Doradus Component

    NASA Astrophysics Data System (ADS)

    Özdarcan, Orkun; Dal, Hasan Ali

    2017-04-01

    We present spectroscopic and photometric analysis of the eclipsing binary KIC 7385478. We find that the system is formed by F1V + K4III-IV components. Combining results from analysis of spectroscopic data and Kepler photometry, we calculate masses and radii of the primary and the secondary components as M 1 = 1.71 ± 0.08 M⊙, M 2 = 0.37 ± 0.04 M⊙ and R 1 = 1.59 ± 0.03 R⊙, R 2 = 1.90 ± 0.03 R⊙, respectively. Position of the primary component in HR diagram is in the region of γ Doradus type pulsators and residuals from light curve modelling exhibit additional light variation with a dominant period of 0.5 d. These are clear evidences of the γ Doradus type pulsations on the primary component. We also observe occasional increase in amplitude of the residuals, where the orbital period becomes the most dominant period. These may be attributed to the cool star activity originating from the secondary component.

  9. Absolute properties of the eclipsing binary VV CORVI

    SciTech Connect

    Fekel, Francis C.; Henry, Gregory W.; Sowell, James R. E-mail: gregory.w.henry@gmail.com

    2013-12-01

    We have obtained red-wavelength spectroscopy and Johnson B and V differential photoelectric photometry of the eclipsing binary 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.

  10. Absolute properties of the eclipsing binary star AP Andromedae

    SciTech Connect

    Sandberg Lacy, Claud H.; Torres, Guillermo; Fekel, Francis C.; Muterspaugh, Matthew W. E-mail: gtorres@cfa.harvard.edu E-mail: matthew1@coe.tsuniv.edu

    2014-06-01

    AP And is a well-detached F5 eclipsing binary star for which only a very limited amount of information was available before this publication. We have obtained very extensive measurements of the light curve (19,097 differential V magnitude observations) and a radial velocity curve (83 spectroscopic observations) which allow us to fit orbits and determine the absolute properties of the components very accurately: masses of 1.277 ± 0.004 and 1.251 ± 0.004 M {sub ☉}, radii of 1.233 ± 0.006 and 1.1953 ± 0.005 R {sub ☉}, and temperatures of 6565 ± 150 K and 6495 ± 150 K. The distance to the system is about 400 ± 30 pc. Comparison with the theoretical properties of the stellar evolutionary models of the Yonsei-Yale series of Yi et al. shows good agreement between the observations and the theory at an age of about 500 Myr and a slightly sub-solar metallicity.

  11. Absolute properties of the eclipsing binary star V501 Herculis

    SciTech Connect

    Lacy, Claud H. Sandberg; Fekel, Francis C. E-mail: fekel@evans.tsuniv.edu

    2014-10-01

    V501 Her is a well detached G3 eclipsing binary 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.

  12. The hot subdwarf in the eclipsing binary HD 185510

    NASA Technical Reports Server (NTRS)

    Jeffery, C. S.; Simon, Theodore; Evans, T. L.

    1992-01-01

    High-resolution spectroscopic measurements of radial velocity are employed to characterize the eclipsing binary 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 low-mass white dwarf that has not reached its fully degenerate configuration. The object is theorized to be a low-mass helium main-sequence star or a nascent helium degenerate in a post-Algol system.

  13. Fundamental Parameters of the Eclipsing Binary TU Canis Majoris

    NASA Astrophysics Data System (ADS)

    Garcés L., J.; Mennickent, R. E.; Zharikov, S.

    2017-04-01

    We present a spectroscopic and photometric study of the eclipsing binary TU Canis Majoris aimed to obtain their fundamental stellar parameters and evolutionary stage. Our results indicate that the masses, radii, temperatures, and luminosities for the primary and secondary stars are: {M}1=1.761+/- 0.012 {M}ȯ , {M}2=1.144+/- 0.010 {M}ȯ , {R}1=1.553+/- 0.002 {R}ȯ , {R}2=1.075+/- 0.002 {R}ȯ , {T}1=8014+/- 151 K, {T}2=6060+/- 100 K, {L}1=8.913 +/- 0.695 {L}ȯ , and {L}2=1.396+/- 0.097 {L}ȯ . We estimate an age for the system of τ =2.11+/- 0.24× {10}8 years, and a distance of d = 324.81+/- 12.86 pc. In addition, we note that none of the components has filled their respective Roche lobe and both are on the main sequence.

  14. The hot subdwarf in the eclipsing binary HD 185510

    NASA Technical Reports Server (NTRS)

    Jeffery, C. S.; Simon, Theodore; Evans, T. L.

    1992-01-01

    High-resolution spectroscopic measurements of radial velocity are employed to characterize the eclipsing binary 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 low-mass white dwarf that has not reached its fully degenerate configuration. The object is theorized to be a low-mass helium main-sequence star or a nascent helium degenerate in a post-Algol system.

  15. ABSOLUTE PROPERTIES OF THE ECLIPSING BINARY STAR BF DRACONIS

    SciTech Connect

    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

    2012-06-15

    BF Dra is now known to be an eccentric double-lined F6+F6 binary star with relatively deep (0.7 mag) partial eclipses. 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.

  16. A 12 MINUTE ORBITAL PERIOD DETACHED WHITE DWARF ECLIPSING BINARY

    SciTech Connect

    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

    2011-08-10

    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 eclipses. 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 binary, 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.

  17. Doppler Imaging with FUSE: The Partially Eclipsing Binary VW Cep

    NASA Technical Reports Server (NTRS)

    Sonneborn, George (Technical Monitor); Brickhouse, Nancy

    2003-01-01

    This report covers the FUSE Guest Observer program. This project involves the study of emission line profiles for the partially eclipsing, rapidly rotating binary 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.

  18. Candidates of eclipsing multiples based on extraneous eclipses on binary light curves: KIC 7622486, KIC 7668648, KIC 7670485 and KIC 8938628

    NASA Astrophysics Data System (ADS)

    Zhang, Jia; Qian, Sheng-Bang; He, Jian-Duo

    2017-02-01

    Four candidates of eclipsing multiples, based on new extraneous eclipses found on Kepler binary light curves, are presented and studied. KIC 7622486 is a double eclipsing binary candidate with orbital periods of 2.2799960 d and 40.246503 d. The two binary systems do not eclipse each other in the line of sight, but there is mutual gravitational influence between them which leads to the small but definite eccentricity of 0.0035(0.0022) associated with the short 2.2799960 d period orbit. KIC 7668648 is a hierarchical quadruple system candidate, with two sets of solid 203 ± 5 d period extraneous eclipses and another independent set of extraneous eclipses. A clear and credible extraneous eclipse is found on the binary light curve of KIC 7670485 which makes it a triple system candidate. Two sets of extraneous eclipses with periods of about 390 d and 220 d are found on KIC 8938628 binary curves, which not only confirm the previous conclusion of the 388.5 ± 0.3 triple system, but also indicate new additional objects that make KIC 8938628 a hierarchical quadruple system candidate. The results from these four candidates will contribute to the field of eclipsing multiples.

  19. Discovery of a Stripped Red-giant Core in a Bright Eclipsing Binary Star

    NASA Astrophysics Data System (ADS)

    Maxted, P. F. L.; Anderson, D. R.; Burleigh, M. R.; Collier Cameron, A.; Heber, U.; Gänsicke, B. T.; Geier, S.; Kupfer, T.; Marsh, T. R.; Nelemans, G.; O'Toole, S. J.; Østensen, R. H.; Smalley, B.; West, R. G.; Bloemen, S.

    2012-03-01

    We report the serendipitous discovery from WASP archive photometry of a binary star in which an apparently normal A-type star (J0247-25 A) eclipses a smaller, hotter subdwarf star (J0247-25 B). The kinematics of J0247-25 A show that it is a blue-straggler member of the Galactic thick-disk. We present follow-up photometry and spectroscopy from which we derive approximate values for the mass, radius and luminosity for J0247-25 B assuming that J0247-25 A has the mass appropriate for a normal thick-disk star. We find that the properties of J0247-25 B are well matched by models for a red giant stripped of its outer layers and currently in a shell hydrogen-burning stage. In this scenario, J0247-25 B will go on to become a low mass white dwarf (M ˜ 0.25 M⊙) composed mostly of helium. J0247-25 B can be studied in much greater detail than the handful of pre helium white dwarfs (pre-He-WD) identified to-date. These results have been published by Maxted et al. (2011). We also present a preliminary analysis of more recent observations of J0247-25 with the UVES spectrograph, from which we derive much improved masses for both stars in the binary. We find that both stars are more massive than expected and that J0247-25 A rotates sub-synchronously by a factor of about 2. We also present lightcurves for 5 new eclipsing pre-He-WD subsequently identified from the WASP archive photometry, 4 of which have mass estimates for the subdwarf companion based on a pair of radial velocity measurements.

  20. First photometric study of two southern eclipsing binaries IS Tel and DW Aps

    NASA Astrophysics Data System (ADS)

    Özer, S.; Sürgit, D.; Erdem, A.; Öztürk, O.

    2017-02-01

    The paper presents the first photometric analysis of two southern eclipsing binary stars, IS Tel and DW Aps. Their V light curves from the All Sky Automated Survey were modelled by using Wilson-Devinney method. The final models give these two Algol-like binary stars as having detached configurations. Absolute parameters of the components of the systems were also estimated.

  1. Introducing Adapted Nelder & Mead's Downhill Simplex Method to a Fully Automated Analysis of Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Prsa, A.; Zwitter, T.

    2005-01-01

    Eclipsing binaries are extremely attractive objects because absolute physical parameters (masses, luminosities, radii) of both components may be determined from observations. Since most efforts to extract these parameters were based on dedicated observing programmes, existing modelling code is based on interactivity. Gaia will make a revolutionary advance in shear number of observed eclipsing binaries and new methods for automatic handling must be introduced and thoroughly tested. This paper focuses on Nelder & Mead's downhill simplex method applied to a synthetically created test binary as it will be observed by Gaia.

  2. VizieR Online Data Catalog: Kepler Mission. II. Eclipsing binaries in DR2 (Slawson+, 2011)

    NASA Astrophysics Data System (ADS)

    Slawson, R. W.; Prsa, A.; Welsh, W. F.; Orosz, J. A.; Rucker, M.; Batalha, N.; Doyle, L. R.; Engle, S. G.; Conroy, K.; Coughlin, J.; Gregg, T. A.; Fetherolf, T.; Short, D. R.; Windmiller, G.; Fabrycky, D. C.; Howell, S. B.; Jenkins, J. M.; Uddin, K.; Mullally, F.; Seader, S. E.; Thompson, S. E.; Sanderfer, D. T.; Borucki, W.; Koch, D.

    2013-03-01

    The Kepler Mission (launched in 2009 March) provides nearly continuous monitoring of ~156000 objects with unprecedented photometric precision. Coincident with the first data release, we presented a catalog of 1879 eclipsing binary systems identified within the 115deg2 Kepler field of view (FOV). Here, we provide an updated catalog from paper I (Prsa et al. 2011, Cat. J/AJ/141/83) 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 eclipsing binary. A number of interesting objects are identified. We present several exemplary cases: four eclipsing binaries that exhibit extra (tertiary) eclipse events; and eight systems that show clear eclipse 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 eclipsing binary systems in the Kepler FOV has increased to 2165, 1.4% of the Kepler target stars. (4 data files).

  3. Eclipsing Binary Modeling Advances - Recent and On the Way

    NASA Astrophysics Data System (ADS)

    Wilson, R. E.; van Hamme, W.

    2010-12-01

    Several recent departures from tradition in EB models demonstrate increased capability to extract information from observations. In one area, model light curves in absolute flux are matched to observed absolute flux curves to find distances and their uncertainties in a straightforward, one step process called Direct Distance Estimation (DDE) that works well for all morphological types. Eclipsing binaries (EB's) can yield distances as accurate as the better parallax distances for much more remote objects. Comparisons with Hipparcos parallax distances are illustrated for 10 binaries. Published absolute flux calibrations can be supplemented by inverse application of the DDE algorithm to EB's with accurately known distances, and weak EB and ellipsoidal variable solutions can be strengthened in inverse DDE solutions where distances and extinctions are accurately known. A temperature-distance (T-d) theorem guards against over-determined and under-determined solutions and has been generalized to include interstellar extinction (T-d-A theorem). Dependence of derived distance on calibration accuracy, in the presence of interstellar extinction, is investigated here. Simulations showed fast and reliable convergence while recovering known extinction from synthetic light curves in widely separated bands. Conversion from spectroscopic to mean global temperature is now rigorously computable if the spectroscopic observation time is known. We derive even greater distance to D33 J013346.2+304439.9 in M33 than did Bonanos, which already was greater than 11 previous estimates from various indicators, and discuss possible reasons for the disparity. In another area, pulsation and EB analyses are being unified to exploit the growing lists of EB’s that show pulsations. Our interest is in coherent pulsation/EB models in which stars actually pulsate geometrically and thermally, and in impersonal solutions that yield standard errors. For now we apply only a phenomenological model so as to

  4. THE PHASES DIFFERENTIAL ASTROMETRY DATA ARCHIVE. II. UPDATED BINARY STAR ORBITS AND A LONG PERIOD ECLIPSING BINARY

    SciTech Connect

    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

    2010-12-15

    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 binary 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 binaries-{alpha} Com (HD 114378)-shows that the system is likely to have eclipses, despite its very long period of 26 years. The next eclipse is predicted to be within a week of 2015 January 24.

  5. APOGEE/Kepler Overlap Yields Orbital Solutions for a Variety of Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Clark Cunningham, Joni Marie; Windemuth, Diana; Ali, Aleezah; Rawls, Meredith L.; Jackiewicz, Jason

    2017-01-01

    We present orbital solutions, masses, and radii for a set of eclipsing spectroscopic binaries observed by both Kepler and APOGEE. Kepler’s primary mission is to find earth-like planets, but several of the observed stars are instead eclipsing binaries with a range of properties. The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has observed many of these same systems during its near-infrared spectroscopic survey. In this work, we combine Kepler light curves and radial velocities extracted from APOGEE spectra to yield binary orbital solutions, stellar masses, and stellar radii. We select binaries that have at least three good-quality APOGEE visits, are sufficiently bright, are listed in the Kepler Eclipsing Binary Catalog (Kirk et al. 2016), show both a primary and a secondary eclipse, and have well- or semi-detached light curve morphologies. We identify a total of 50 promising targets, and present results for a subset of these. Once radial velocity solutions for both stars in each system are found, we combine them with Kepler light curves to solve for mass and radius. These inferences are especially rare for longer-period binaries, and will contribute to our knowledge of fundamental stellar parameters and binary star statistics. This work is supported the SDSS Faculty and Student (FAST) initiative.

  6. Apsidal motion of two eclipsing binaries: V796 Cyg and V2783 Ori

    NASA Astrophysics Data System (ADS)

    Bulut, A.; Bulut, I.; ćiçek, C.; Erdem, A.

    2017-02-01

    In this study, the orbital period variations of two eclipsing binary systems showing apsidal motion were studied. Their O - C diagrams were analysed using all reliable eclipse timings and the elements of apsidal motion of two systems were improved. We found periods of apsidal motion of V796 Cyg and V2783 Ori to be 32.7 ± 0.2 years and 415 ± 50 years, respectively.

  7. EL CVn-type binaries - discovery of 17 helium white dwarf precursors in bright eclipsing binary star systems

    NASA Astrophysics Data System (ADS)

    Maxted, P. F. L.; Bloemen, S.; Heber, U.; Geier, S.; Wheatley, P. J.; Marsh, T. R.; Breedt, E.; Sebastian, D.; Faillace, G.; Owen, C.; Pulley, D.; Smith, D.; Kolb, U.; Haswell, C. A.; Southworth, J.; Anderson, D. R.; Smalley, B.; Collier Cameron, A.; Hebb, L.; Simpson, E. K.; West, R. G.; Bochinski, J.; Busuttil, R.; Hadigal, S.

    2014-01-01

    The star 1SWASP J024743.37-251549.2 was recently discovered to be a binary star in which an A-type dwarf star eclipses the remnant of a disrupted red giant star (WASP 0247-25 B). The remnant is in a rarely observed state evolving to higher effective temperatures at nearly constant luminosity prior to becoming a very low mass white dwarf composed almost entirely of helium, i.e. it is a pre-helium white dwarf (pre-He-WD). We have used the photometric database from the Wide Angle Search for Planets (WASP) to find 17 eclipsing binary stars with orbital periods P = 0.7-2.2 d with similar light curves to 1SWASP J024743.37-251549.2. The only star in this group previously identified as a variable star is the brightest one, EL CVn, which we adopt as the prototype for this class of eclipsing binary star. The characteristic light curves of EL CVn-type stars show a total eclipse by an A-type dwarf star of a smaller, hotter star and a secondary eclipse of comparable depth to the primary eclipse. We have used new spectroscopic observations for six of these systems to confirm that the companions to the A-type stars in these binaries have very low masses ({≈ } 0.2{ M_{⊙}}). This includes the companion to EL CVn which was not previously known to be a pre-He-WD. EL CVn-type binary star systems will enable us to study the formation of very low mass white dwarfs in great detail, particularly in those cases where the pre-He-WD star shows non-radial pulsations similar to those recently discovered in WASP0247-25 B.

  8. Did the Ancient Egyptians Record the Period of the Eclipsing Binary Algol—The Raging One?

    NASA Astrophysics Data System (ADS)

    Jetsu, L.; Porceddu, S.; Lyytinen, J.; Kajatkari, P.; Lehtinen, J.; Markkanen, T.; Toivari-Viitala, J.

    2013-08-01

    The eclipses in binary stars give precise information of orbital period changes. Goodricke discovered the 2.867 day period in the eclipses of Algol in the year 1783. The irregular orbital period changes of this longest known eclipsing binary continue to puzzle astronomers. The mass transfer between the two members of this binary 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.

  9. DID THE ANCIENT EGYPTIANS RECORD THE PERIOD OF THE ECLIPSING BINARY ALGOL-THE RAGING ONE?

    SciTech Connect

    Jetsu, L.; Porceddu, S.; Lyytinen, J.; Kajatkari, P.; Lehtinen, J.; Markkanen, T.; Toivari-Viitala, J.

    2013-08-10

    The eclipses in binary stars give precise information of orbital period changes. Goodricke discovered the 2.867 day period in the eclipses of Algol in the year 1783. The irregular orbital period changes of this longest known eclipsing binary continue to puzzle astronomers. The mass transfer between the two members of this binary 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.

  10. Asiago eclipsing binaries program. III. V570 Persei

    NASA Astrophysics Data System (ADS)

    Tomasella, L.; Munari, U.; Cassisi, S.; Siviero, A.; Dallaporta, S.; Sordo, R.; Zwitter, T.

    2008-05-01

    The orbit and physical parameters of the previously unsolved double-lined eclipsing binary V570 Per, discovered by the Hipparcos satellite, were derived using high-resolution Echelle spectroscopy and B, V photoelectric photometry. The metallicity from χ2 analysis of the spectra is [ M/H]=+0.02±0.03, and reddening from interstellar NaI and KI absorption lines is EB-V=0.023±0.007. V570 Per is a well-detached system, with shallow eclipses (due to low orbital inclination) and no sign of chromospheric activity. The two components have masses of 1.449±0.006 and 1.350±0.006~M_⊙ and spectral types F3 and F5, respectively. They are both still within the main sequence band (T_1=6842±25 K, T_2=6562± 25 K from χ2 analysis, R_1=1.523±0.030, R_2=1.388± 0.019 R_⊙ derived by forcing the orbital solution to conform to the spectroscopic light ratio) and are dynamically relaxed to co-rotation with the orbital motion (V_rot,1,2 sin i=40 and 36 (±1) km s-1). The distance to V570 Per obtained from the orbital solution is 123 ±2 pc, in excellent agreement with the revised Hipparcos distance of 123±11 pc. The observed properties of V570 Per components were compared to available families of stellar evolutionary tracks and, in particular, to BaSTI models computed on purpose for exactly the observed masses and varied chemical compositions. This system is interesting since both components have their masses in the range where the efficiency of convective core overshooting has to decrease with the total mass as a consequence of the decreasing size of the convective core during the central H-burning stage. Our numerical simulations show that, in order to match all empirical constraints, a small but not null overshooting is required, with efficiencies of λ_OV=0.14 and 0.11 for the 1.449 and 1.350 M_⊙ components, respectively. This confirms the finding of Paper II on the similar system V505 Per. At the ≈0.8 Gyr age of the system, the element diffusion has reduced the surface

  11. 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.

  12. LBT Discovery of a Yellow Supergiant Eclipsing Binary in the Dwarf Galaxy Holmberg IX

    NASA Astrophysics Data System (ADS)

    Prieto, J. L.; Stanek, K. Z.; Kochanek, C. S.; Weisz, D. R.; Baruffolo, A.; Bechtold, J.; Burwitz, V.; De Santis, C.; Gallozzi, S.; Garnavich, P. M.; Giallongo, E.; Hill, J. M.; Pogge, R. W.; Ragazzoni, R.; Speziali, R.; Thompson, D. J.; Wagner, R. M.

    2008-01-01

    In a variability survey of M81 using the Large Binocular Telescope we have discovered a peculiar eclipsing binary (MV ~ - 7.1) in the field of the dwarf galaxy Holmberg IX. It has a period of 271 days, and the light curve is well fit by an overcontact model in which both stars are overflowing their Roche lobes. It is composed of two yellow supergiants (V - Isimeq 1 mag, Teffsimeq 4800 K), rather than the far more common red or blue supergiants. Such systems must be rare. While we failed to find any similar systems in the literature, we did, however, note a second example. The SMC F0 supergiant R47 is a bright (MV ~ - 7.5) periodic variable whose All Sky Automated Survey (ASAS) light curve is well fit as a contact binary with a 181 day period. We propose that these systems are the progenitors of supernovae like SN 2004et and SN 2006ov, which appeared to have yellow progenitors. The binary interactions (mass transfer, mass loss) limit the size of the supergiant to give it a higher surface temperature than an isolated star at the same core evolutionary stage. We also discuss the possibility of this variable being a long-period Cepheid. Based on data acquired using the Large Binocular Telescope (LBT). The LBT is an international collaboration among institutions in the United States, Italy and Germany. LBT Corporation partners are The University of Arizona on behalf of the Arizona university system; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; The Ohio State University, and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota, and University of Virginia.

  13. EPIC 220204960: A Quadruple Star System Containing Two Strongly Interacting Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Rappaport, S.; Vanderburg, A.; Borkovits, T.; Kalomeni, B.; Halpern, J. P.; Ngo, H.; Mace, G. N.; Fulton, B. J.; Howard, A. W.; Isaacson, H.; Petigura, E. A.; Mawet, D.; Kristiansen, M. H.; Jacobs, T. L.; LaCourse, D.; Bieryla, A.; Forgács-Dajka, E.; Nelson, L.

    2017-01-01

    We present a strongly interacting quadruple system associated with the K2 target EPIC 220204960. The K2 target itself is a Kp = 12.7 magnitude star at Teff ≃ 6100 K which we designate as "B-N" (blue northerly image). The host of the quadruple system, however, is a Kp ≃ 17 magnitude star with a composite M-star spectrum, which we designate as "R-S" (red southerly image). With a 3.2″ separation and similar radial velocities and photometric distances, `B-N' is likely physically associated with `R-S', making this a quintuple system, but that is incidental to our main claim of a strongly interacting quadruple system in `R-S'. The two binaries in `R-S' have orbital periods of 13.27 d and 14.41 d, respectively, and each has an inclination angle of ≳ 89°. From our analysis of radial velocity measurements, and of the photometric lightcurve, we conclude that all four stars are very similar with masses close to 0.4 M⊙. Both of the binaries exhibit significant ETVs where those of the primary and secondary eclipses `diverge' by 0.05 days over the course of the 80-day observations. Via a systematic set of numerical simulations of quadruple systems consisting of two interacting binaries, we conclude that the outer orbital period is very likely to be between 300 and 500 days. If sufficient time is devoted to RV studies of this faint target, the outer orbit should be measurable within a year.

  14. The distance to the Andromeda galaxy from eclipsing binaries

    NASA Astrophysics Data System (ADS)

    Vilardell, F.; Ribas, I.; Jordi, C.; Fitzpatrick, E. L.; Guinan, E. F.

    2010-01-01

    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 eclipsing binaries (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

  15. The Effect of Micro-lensing in Eclipsing Binary-star Systems

    NASA Astrophysics Data System (ADS)

    Hoffman, Kelsey L.; Rowe, J.; Hansen, B.

    2013-04-01

    Using photometric observations from the Kepler Space Telescope of eclipsing binary star systems where one component is a white dwarf we have investigated the strength of the micro-lensing effect. We have examined the stellar binary KOI-81 from the Kepler mission. KOI-81 is composed of a white dwarf and a A-type main-sequence star in a 24 day circular orbit and have found that micro-lensing is detectable. We use our lightcurve models to measure the strength of the micro-lensing signal and refine the radius of the eclipsing white dwarf.

  16. EXPECTED LARGE SYNOPTIC SURVEY TELESCOPE (LSST) YIELD OF ECLIPSING BINARY STARS

    SciTech Connect

    Prsa, Andrej; Pepper, Joshua; Stassun, Keivan G.

    2011-08-15

    In this paper, we estimate the Large Synoptic Survey Telescope (LSST) yield of eclipsing binary 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 eclipsing binary 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 eclipsing binaries' physical and geometric parameters. We find that, out of {approx}24 million eclipsing binaries 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 binaries, a true treasure trove for stellar astrophysics.

  17. Double-lined M dwarf eclipsing binaries from Catalina Sky Survey and LAMOST

    NASA Astrophysics Data System (ADS)

    Lee, Chien-Hsiu; Lin, Chien-Cheng

    2017-02-01

    Eclipsing binaries provide a unique opportunity to determine fundamental stellar properties. In the era of wide-field cameras and all-sky imaging surveys, thousands of eclipsing binaries have been reported through light curve classification, yet their basic properties remain unexplored due to the extensive efforts needed to follow them up spectroscopically. In this paper we investigate three M2-M3 type double-lined eclipsing binaries discovered by cross-matching eclipsing binaries from the Catalina Sky Survey with spectroscopically classified M dwarfs from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope survey data release one and two. Because these three M dwarf binaries are faint, we further acquire radial velocity measurements using GMOS on the Gemini North telescope with R∼ 4000, enabling us to determine the mass and radius of individual stellar components. By jointly fitting the light and radial velocity curves of these systems, we derive the mass and radius of the primary and secondary components of these three systems, in the range between 0.28-0.42M_ȯ and 0.29-0.67R_ȯ, respectively. Future observations with a high resolution spectrograph will help us pin down the uncertainties in their stellar parameters, and render these systems benchmarks to study M dwarfs, providing inputs to improving stellar models in the low mass regime, or establishing an empirical mass-radius relation for M dwarf stars.

  18. The Masses of the B Stars in the High Galactic Latitude Eclipsing Binary IT Librae

    NASA Astrophysics Data System (ADS)

    Martin, John C.

    2003-01-01

    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 eclipsing binary 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.

  19. Data Mining Analysis for Eclipsing Binary TrES-Cyg3-04450

    NASA Astrophysics Data System (ADS)

    Hinzel, D. H.

    2015-12-01

    A data mining algorithm was utilized to analyze Johnson V-band charge-coupled device (CCD) photometric data of an object that were taken during a wide field survey of a region in the constellation Cygnus. That algorithm was the Date Compensated Discrete Fourier Transform (DC DFT) which is part of the AAVSO VSTAR applications software. This analysis clearly indicated that the object under study is a detached eclipsing binary, specifically an EA β Persei-type (Algol) eclipsing system, with an orbital period of 2.0664 days. Neither the type nor period of this eclipsing binary had been characterized up to this point. This object has been given the AAVSO designation TrES-Cyg3-04450 and the AUID 000-BLL-484.

  20. Asiago eclipsing binaries program. II. V505 Persei

    NASA Astrophysics Data System (ADS)

    Tomasella, L.; Munari, U.; Siviero, A.; Cassisi, S.; Dallaporta, S.; Zwitter, T.; Sordo, R.

    2008-03-01

    The orbit and fundamental physical parameters of the double-lined eclipsing binary V505 Per are derived by means of Echelle high-resolution and high S/N spectroscopy, and B, V photometry. In addition, effective temperatures, gravities, rotational velocities, and metallicities of both components are also obtained from atmospheric χ2 analysis, showing an excellent match with the results of the orbital solution. An EB-V ≤ 0.01 mag upper limit to the reddening is derived from intensity analysis of interstellar NaI (5890.0 & 5895.9 Å) and KI (7699.0 Å) lines. The distance to the system computed from orbital parameters (60.6 ± 1 pc) is identical to the newly re-reduced Hipparcos parallax (61.5 ± 1.9 pc). The masses of the two components (M1 = 1.2693±0.0011 and M2 = 1.2514±0.0012 M_⊙) place them in the transition region between convective and radiative stellar cores of the HR diagram, with the more massive of the two already showing the effect of evolution within the main sequence band (T1 = 6512±21 K, T2 = 6462±12 K, R1 = 1.287±0.014, R2 = 1.266±0.013 R_⊙). This makes this system particularly relevant to theoretical stellar models as a test of the overshooting. We compare the firm observational results for V505 Per component stars with the predictions of various libraries of theoretical stellar models (BaSTI, Padova, Granada, Yonsei-Yale, Victoria-Regina), as well as with BaSTI models computed specifically for the masses and chemical abundances of V505 Per. We find that the overshooting at the masses of V505 Per component stars is already pretty low, but not nil, and it is described by efficiencies λ_OV = 0.093 and 0.087 for the 1.27 and 1.25 M_⊙ components, respectively. According to the computed BaSTI models, the age of the system is ~0.9 Gyr, and the element diffusion during this time has reduced the surface metallicity from the initial [M/H]= -0.03 to the current [M/H] = -0.13, in excellent agreement with the observed [M/H] = -0.12±0.03. Based

  1. Search for A-F Spectral type pulsating components in Algol-type eclipsing binary systems

    NASA Astrophysics Data System (ADS)

    Kim, S.-L.; Lee, J. W.; Kwon, S.-G.; Youn, J.-H.; Mkrtichian, D. E.; Kim, C.

    2003-07-01

    We present the results of a systematic search for pulsating components in Algol-type eclipsing binary systems. A total number of 14 eclipsing binaries with A-F spectral type primary components were observed for 22 nights. We confirmed small-amplitude oscillating features of a recently detected pulsator TW Dra, which has a pulsating period of 0.053 day and a semi-amplitude of about 5 mmag in B-passband. We discovered new pulsating components in two eclipsing binaries of RX Hya and AB Per. The primary component of RX Hya is pulsating with a dominant period of 0.052 day and a semi-amplitude of about 7 mmag. AB Per has also a pulsating component with a period of 0.196 day and a semi-amplitude of about 10 mmag in B-passband. We suggest that these two new pulsators are members of the newly introduced group of mass-accreting pulsating stars in semi-detached Algol-type eclipsing binary systems. Table 4 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/405/231

  2. HIDES spectroscopy of bright detached eclipsing binaries from the Kepler field - I. Single-lined objects

    NASA Astrophysics Data System (ADS)

    Hełminiak, K. G.; Ukita, N.; Kambe, E.; Kozłowski, S. K.; Sybilski, P.; Ratajczak, M.; Maehara, H.; Konacki, M.

    2016-09-01

    We present results of our spectroscopic observations of nine detached eclipsing binaries (DEBs), selected from the Kepler Eclipsing Binary 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 binaries, 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 eclipse timing variations (ETVs). For these we obtained parameters of outer orbits, by translating the ETVs to RVs of the centre of mass of the eclipsing binary, 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.

  3. ANALYSIS OF DETACHED ECLIPSING BINARIES NEAR THE TURNOFF OF THE OPEN CLUSTER NGC 7142

    SciTech Connect

    Sandquist, Eric L.; Serio, Andrew W.; Orosz, Jerome; Shetrone, Matthew E-mail: aserio@gemini.edu E-mail: shetrone@astro.as.utexas.edu

    2013-08-01

    We analyze extensive BVR{sub C}I{sub C} photometry and radial velocity measurements for three double-lined deeply eclipsing binary stars in the field of the old open cluster NGC 7142. The short period (P = 1.9096825 days) detached binary V375 Cep is a high probability cluster member, and has a total eclipse 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 binary system has a known age, it is useful for testing the idea that radius inflation can occur in short period binaries for stars with significant convective envelopes due to the inhibition of energy transport by magnetic fields. The brighter star in the binary also produces a precision estimate of the distance modulus, independent of reddening estimates: (m - M){sub V} = 12.86 {+-} 0.07. The other two eclipsing binary 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 binary is within 0. Degree-Sign 5 of edge-on, is in a fairly long-period eccentric binary, and contains two almost indistinguishable stars. The other binary (V1) has a small but nonzero eccentricity (e = 0.038) in spite of having an orbital period under 5 days.

  4. Determination of individual temperatures and luminosities in eclipsing binary star systems

    NASA Astrophysics Data System (ADS)

    Campbell, R. M.

    1983-06-01

    The purpose of this project was to determine the temperatures and luminosities of the individual components of eclipsing binary star systems. The information was gained by UBV photometry of a system at total eclipse and at a time outside eclipse. The light at totality is due entirely to the occulting star, and outside eclipse, both stars contribute fully. A method is derived for subtracting out the light of the occulting star to obtain measurements of the occulted. Systems for which a complete solution (temperature and luminosity of both components) was reached include: TU Camelopardi, TW Draconis, AK Herculis, V566 Ophiuchi, W Ursae Majoris, and AG Virginis. Systems observed only during totality, thus solving only the occulting star, include alpha Corona Borealis and AM Leonis. RS Canes Venatici and TZ Bootes were observed only out of eclipse, and must await further study. Once a solution for a system was obtained, it was presented graphically on a Hertzsprung-Russell diagram, and was examined from the viewpoint of binary evolution.

  5. Thermal inertia of eclipsing binary asteroids: the role of component shape

    NASA Astrophysics Data System (ADS)

    Mueller, Michael; van de Weijgaert, Marlies

    2015-11-01

    Thermal inertia controls the temperature distribution on asteroid surfaces. This is of crucial importance to the Yarkovsky effect and for the planning of spacecraft operations on or near the surface. Additionally, thermal inertia is a sensitive indicator for regolith structure.A uniquely direct way of measuring thermal inertia is through observations of the thermal response to an eclipse in a binary system, when one component shadows the other. This method was pioneered by Mueller et al. (2010), who observed eclipses in (617) Patroclus using Spitzer IRS. Buie et al. (2015) report observations of a stellar occultation by Patroclus. Their estimate for the system's projected size agrees well with the Spitzer result. However, the occultation revealed that the components are much more oblately shaped than was assumed by Mueller et al.This prompted us to study the role of component shape in the analysis of thermal eclipse data. Conceivably, the global shape can have a significant impact on the shape and size of the eclipsed area and therefore on its thermal emission. So far, this has not been studied in a systematic way. Using Patroclus and the existing Spitzer data as our test case, we vary the ellipsoidal component shape and determine the resulting best-fit thermal inertia. This will lead to an updated estimate of Patroclus' thermal inertia, along with a potentially more realistic estimate of its uncertainty. Beyond that, our results will inform ongoing and future thermal studies of other eclipsing binary asteroids.

  6. Initial Estimates on the Performance of the LSST on the Detection of Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Wells, Mark; Prs̆a, Andrej; Jones, Lynne; Yoachim, Peter

    2017-06-01

    In this work, we quantify the performance of the Large Synoptic Survey Telescope (LSST) on the detection of eclipsing binaries. We use Kepler observed binaries to create a large sample of simulated pseudo-LSST binary light curves. From these light curves, we attempt to recover the known binary signal. The success rate of period recovery from the pseudo-LSST light curves is indicative of LSST's expected performance. Using an off-the-shelf analysis of variance routine, we successfully recover 71% of the targets in our sample. We examine how the binary period impacts recovery success and see that for periods longer than 10 days, the chance of successful binary recovery drops below 50%.

  7. An automated search of O'Connell effect for Large Numbers of Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Papageorgiou, A.; Kleftogiannis, G.; Christopoulou, P. E.

    2013-09-01

    The O'Connell effect in eclipsing binary systems (unequally high maxima) has stood for many decades as one of the most perplexing challenges in binary 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 binary 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 eclipses. 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 binaries. 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 eclipsing binaries (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.

  8. A Computational Guide to Physics of Eclipsing Binaries. I. Demonstrations and Perspectives

    NASA Astrophysics Data System (ADS)

    Prša, A.; Zwitter, T.

    2005-07-01

    PHOEBE (PHysics Of Eclipsing BinariEs) is a modeling package for eclipsing binary stars, built on top of the widely used WD program of Wilson & Devinney. This introductory paper gives an overview of the most important scientific extensions (incorporating observational spectra of eclipsing binaries 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 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. The operability of all these extensions is demonstrated on a synthetic main-sequence test binary; applications to real data will be published in follow-up papers. PHOEBE is released under the GNU General Public License, which guarantees it to be free and open to anyone interested in joining in on future development.

  9. Testing Low-Mass Stellar Models: Three New Detached Eclipsing Binaries below 0.75Msun

    NASA Astrophysics Data System (ADS)

    López-Morales, M.; Shaw, J. S.

    2007-06-01

    Full tests of stellar models below 1Msun have been hindered until now by the scarce number of precise measurements of the stars' most fundamental parameters: their masses and radii. With current observational techniques, the required precision to distinguish between different models (errors < 2-3 %) can only be achieved using detached eclipsing binaries where 1) both stars are similar in mass, i.e. q = M1/M2 ˜ 1.0, and 2) each star is a main sequence object below 1Msun. Until 2003 only three such binaries had been found and analyzed in detail. Two new systems were published in 2005 (Creevey et al.; López-Morales & Ribas), almost doubling the previous number of data points. Here we present preliminary results for 3 new low-mass detached eclipsing binaries. These are the first studied systems from our sample of 41 new binaries (Shaw & López-Morales, this proceedings). We also provide an updated comparison between the Mass-Radius and the Mass-Teff relations predicted by the models and the observational data from detached eclipsing binaries.

  10. Eclipsing Binaries through the Double Looking Glass of Kepler and Keck

    NASA Astrophysics Data System (ADS)

    Weiss, Lauren M.; Marcy, G.; Orosz, J.; Welsh, W.; Prša, A.; Richards, J.; Gegenheimer, S.; Bloom, J. S.

    2012-05-01

    The Kepler Space Telescope has detected a panoply of physical effects in binary star systems to unprecedented precision, in particular the relativistic Doppler beaming signature. We present Keck/HIRES radial velocity measurements of four Kepler Input Catalog (KIC) eclipsing binaries. We compute self-consistent solutions to the eclipsing binaries by fitting the light curve and radial velocities simultaneously with the legacy code ELC. We also attempt a novel two-dimensional radial velocity fitting technique to solve for the velocity of the primary and secondary star in each system. Our velocity fitting procedure draws from a library of over 700 Keck/HIRES spectra of stars with known effective temperature, surface gravity, and metallicity to construct a composite spectral template from which we can measure the velocities of both stars. We discuss the orbital dynamics and stellar physics of these four KIC systems, including ellipsoidal variations, relativistic Doppler beaming, spot activity, pulsations, and third-body, low-mass companions of the binary systems. In particular, we note that long-lived spot activity in tidally synchronous binary systems can produce long-lived asymmetries in the light curve before and after the primary eclipse. These asymmetries can masquerade as the relativistic Doppler beaming signature, and we caution beaming enthusiasts to consider spot activity before attributing light curve asymmetries to relativistic beaming.

  11. Eclipsing binary stars in the Large and Small Magellanic Clouds from the MACHO project: The Sample

    SciTech Connect

    Faccioli, L; Alcock, C; Cook, K; Prochter, G; Protopapas, P; Syphers, D

    2007-03-29

    We present a new sample of 4634 eclipsing binary stars in the Large Magellanic Cloud (LMC), expanding on a previous sample of 611 objects and a new sample of 1509 eclipsing binary 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 binary star populations are possible.

  12. Towards a Fundamental Understanding of Short Period Eclipsing Binary Systems Using Kepler Data

    NASA Astrophysics Data System (ADS)

    Prsa, Andrej

    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. Eclipsing binary 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, eclipsing binaries are ideal physical laboratories for studying other physical phenomena, such as asteroseismic properties, chromospheric activity, proximity effects, mass transfer in close binaries, etc. Because of the eclipses, 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 eclipsing binary star astrophysics. This proposal focuses on a carefully selected set of 100 short period eclipsing binary stars. The fundamental goal of the project is to study the intrinsic astrophysical effects typical of short period binaries 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 binaries host low-mass (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

  13. HII 2407: AN ECLIPSING BINARY REVEALED BY K2 OBSERVATIONS OF THE PLEIADES

    SciTech Connect

    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

    2015-11-20

    The star HII 2407 is a member of the relatively young Pleiades star cluster and was previously discovered to be a single-lined spectroscopic binary. It is newly identified here within Kepler/K2 photometric time series data as an eclipsing binary 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 eclipsing binary status.

  14. Doubled-lined eclipsing binary system KIC~2306740 with pulsating component discovered from Kepler space photometry

    NASA Astrophysics Data System (ADS)

    Yakut, Kadri

    2015-08-01

    We present a detailed study of KIC 2306740, an eccentric double-lined eclipsing binary 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 binary system. Duplicity effects are extracted from the light curve in order to estimate pulsation frequencies from the residuals.We modelled the detached binary system assuming non-conservative evolution models with the Cambridge STARS(TWIN) code.

  15. Phenomenological modeling of the light curves of algol-type eclipsing binary stars

    NASA Astrophysics Data System (ADS)

    Andronov, I. L.

    2012-12-01

    We propose a special class of functions for mathematical modeling of periodic signals of a special type with a nonuniform distribution of the arguments. This method has been developed for determining the phenomenological characteristics of light curves required for listing in the "General Catalog of Variable Stars" (GCVS) and other data bases. For eclipsing binary stars with smooth light curves (types EB and EW) a trigonometric polynomial of optimal degree in a complete or symmetric form is recommended. For eclipsing binary systems with relatively narrow minima, approximating the light curves by a class of nonpolynomial spline functions is statistically optimal. A combination of a second order trigonometric polynomial (TP2, which describes "reflection", ellipsoidal" and "spotting" effects) and localized contributions of the minima (parametrized with respect to depth and profile separately for the primary and secondary minima) is used. This approach is characterized by a statistical accuracy of the smoothing curve that is a factor of ~1.5-2 times better than for a trigonometric polynomial of statistically optimal degree, and by the absence of false "waves" in the light curve associated with the Gibbs effect. Besides finding the width of the minimum, which cannot be determined using a trigonometric polynomial approximation, this method can be used to determine its depth with better accuracy, and to separate the effects of the eclipse and the part outside the eclipse. For multicolor observations, the improved accuracy of the smoothing curve for each filter makes it possible to obtain more accurate plots of the variation in the color index. The efficiency of the proposed method increases as the width of the eclipse becomes smaller. This method supplements the trigonometric polynomial approximation. The method, referred to as the NAV (New Algol Variable) method, is illustrated by applying it to the eclipsing binary systems VSX J022427.8-104034=USNO-B1.0 0793-0023471 and

  16. A Time Series of BV photometry and Halpha Emission Fluxes of the Eclipsing Binary VV Cep

    NASA Astrophysics Data System (ADS)

    Pollmann, E.; Vollmann, W.; Bennett, P. D.

    2017-02-01

    VV Cephei (= HR 8383 = HD 208816) is the brightest eclipsing M supergiant binary (M2 Iab + B0-2? V) in the sky, and is a massive binary with one of the longest known orbital periods (7430 days = 20.34 years) of any eclipsing system. With the next eclipse beginning in August 2017, and lasting nearly two years (650 days) from 1st to 4th contact, an extensive observational campaign is planned. This paper focusses on the photometric variability of the system out of eclipse, and presents and photometry and H emission fluxes observed over the period from mid-2008 through late 2016. The and light curves show correlated variability with peak power of 145 days, presumably due to low-amplitude pulsations of the M supergiant. The H emission fluxes show a short-term variability, but the sampling is not sufficient to permit quantitative analysis. However, the H fluxes also appear to show a long-term modulation related to the variable orbital separation of this eccentric binary.

  17. Observations of candidate oscillating eclipsing binaries and two newly discovered pulsating variables

    NASA Astrophysics Data System (ADS)

    Liakos, A.; Niarchos, P.

    2009-03-01

    CCD observations of 24 eclipsing binary 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 eclipsing variables. The Fourier analysis of the observations of each star, the dominant pulsation frequencies and the derived frequency spectra are also presented.

  18. The EBAI Project: Neural Network/Artificial Intelligence Approaches to Solve Automatically Large Numbers of Light Curves of Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Guinan, E. F.; Prša, A.; Devinney, E. J.; Engle, S. G.

    2009-08-01

    Major advances in observing technology promise to greatly increase discovery rates of eclipsing binaries (EBs). For example, missions such as the Large Synoptic Survey Telescope (LSST), the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) and Gaia are expected to yield hundreds of thousands (even millions) of new variable stars and eclipsing binaries. Current personal interactive (and time consuming) methods of determining the physical and orbital parameters of eclipsing binaries from the current practice of analyzing their light curves will be inadequate to keep up with the overwhelming influx of new data. At present, the currently used methods require significant technical skill and experience; it typically takes 2-3 weeks to model a single binary. We are therefore developing an Artificial Intelligence / Neural Network system with the hope of creating a fully automated, high throughput process for gleaning the orbital and physical properties of EB systems from the observations of tens of thousands of eclipsing binaries at a time. The EBAI project -- Eclipsing Binaries with Artificial Intelligence -- aims to provide estimates of principal parameters for thousands of eclipsing binaries in a matter of seconds. Initial tests of the neural network's performance and reliability have been conducted and are presented here.

  19. The dynamical mass of a classical Cepheid variable star in an eclipsing binary system.

    PubMed

    Pietrzyński, G; Thompson, I B; Gieren, W; Graczyk, D; Bono, G; Udalski, A; Soszyński, I; Minniti, D; Pilecki, B

    2010-11-25

    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, low-mass stars with a very different evolutionary history) in a binary 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-eclipsing binaries 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 eclipsing double-lined binary has hitherto been reported. Here we report the discovery of a classical Cepheid in a well detached, double-lined eclipsing binary 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.

  20. THE ANTICORRELATED NATURE OF THE PRIMARY AND SECONDARY ECLIPSE TIMING VARIATIONS FOR THE KEPLER CONTACT BINARIES

    SciTech Connect

    Tran, K.; Rappaport, S.; Levine, A.; Borkovits, T.; Csizmadia, Sz.; Kalomeni, B. E-mail: aml@space.mit.edu E-mail: szilard.csizmadia@dlr.de

    2013-09-01

    We report a study of the eclipse timing variations in contact binary 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 eclipses of some 2000 Kepler binaries. We find {approx}390 short-period binaries 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 eclipse timing variations. We present a detailed analysis and results for 32 of these binaries 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.

  1. USNO-A2.0 1200-1153830 is a binary star with a total eclipse with sharp transitions

    NASA Astrophysics Data System (ADS)

    Roy, Rene; Behrend, Raoul

    2017-02-01

    Based on their photometric observations, R. Roy (Blauvac, France) and R. Behrend (Geneva Observatory) found that USNO-A2.0 1200-1153830 is a binary star for which the lightcurve is characterized by a 0.4mag total eclipse and a rather soft secondary eclipse.

  2. Undergraduate Research to Obtain Preliminary Solutions for New Eclipsing Binary Systems

    NASA Astrophysics Data System (ADS)

    Wetterer, Charles J.; Walker, A. C.; Izzo, D. M.; Bloomer, R. H.

    2009-01-01

    An ongoing research program using the 0.61-m telescope at the US Air Force Academy (AFA) Observatory strives to identify, conduct multi-filter photometry, and obtain preliminary model solutions to new eclipsing binary systems. The new candidate systems currently come from the recent list of over 1800 suspected variable stars in the original CCD/Transit Instrument (CTI-I) survey. The undergraduate students involved in the program are AFA cadets in academic research courses and visiting students from the Appalachian College Association's Consortium for Astronomy Research and Teaching (CART) who conduct observations over the summer at the AFA Observatory and continue collaborative interactions with AFA cadets during the following academic year. The goal is to increase the number of known eclipsing variable star systems and identify interesting systems for follow-up research. This is an ideal small telescope research program in which to involve undergraduate students. Hundreds of potential eclipsing systems remaining to be explored.

  3. WOCS 40007: A DETACHED ECLIPSING BINARY NEAR THE TURNOFF OF THE OPEN CLUSTER NGC 6819

    SciTech Connect

    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

    2013-09-15

    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 eclipsing binary 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 binary components. In addition, we discover a third star orbiting the binary with a period greater than 3000 days using radial velocities and Kepler eclipse timings. Because the stars in the eclipsing binary 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 binary. 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 binary 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 binary.

  4. The eclipsing, double-lined, Of supergiant binary Cygnus OB2-B17

    NASA Astrophysics Data System (ADS)

    Stroud, V. E.; Clark, J. S.; Negueruela, I.; Roche, P.; Norton, A. J.; Vilardell, F.

    2010-02-01

    Context. Massive, eclipsing, double-lined, spectroscopic binaries 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 binaries and γ-ray bursts. Aims: We present a photometric and spectroscopic analysis of the candidate binary system Cyg OB2-B17 to show that it is indeed a massive evolved binary. 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 eclipsing, double-lined, spectroscopic binary 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 binary containing components with similar luminosities, and in turn with the preliminary spectral types and age of the association.

  5. A NEW CLASS OF NASCENT ECLIPSING BINARIES WITH EXTREME MASS RATIOS

    SciTech Connect

    Moe, Maxwell; Stefano, Rosanne Di

    2015-03-10

    Early B-type main-sequence (MS) stars (M {sub 1} ≈ 5-16 M {sub ☉}) with closely orbiting low-mass stellar companions (q = M {sub 2}/M {sub 1} < 0.25) can evolve to produce Type Ia supernovae, low-mass X-ray binaries, and millisecond pulsars. However, the formation mechanism and intrinsic frequency of such close extreme mass-ratio binaries have been debated, especially considering none have hitherto been detected. Utilizing observations of the Large Magellanic Cloud galaxy conducted by the Optical Gravitational Lensing Experiment, we have discovered a new class of eclipsing binaries in which a luminous B-type MS star irradiates a closely orbiting low-mass pre-MS companion that has not yet fully formed. The primordial pre-MS companions have large radii and discernibly reflect much of the light they intercept from the B-type MS primaries (ΔI {sub refl} ≈ 0.02-0.14 mag). For the 18 definitive MS + pre-MS eclipsing binaries in our sample with good model fits to the observed light-curves, we measure short orbital periods P = 3.0-8.5 days, young ages τ ≈ 0.6-8 Myr, and small secondary masses M {sub 2} ≈ 0.8-2.4 M {sub ☉} (q ≈ 0.07-0.36). The majority of these nascent eclipsing binaries are still associated with stellar nurseries, e.g., the system with the deepest eclipse ΔI {sub 1} = 2.8 mag and youngest age τ = 0.6 ± 0.4 Myr is embedded in the bright H II region 30 Doradus. After correcting for selection effects, we find that (2.0 ± 0.6)% of B-type MS stars have companions with short orbital periods P = 3.0-8.5 days and extreme mass ratios q ≈ 0.06-0.25. This is ≈10 times greater than that observed for solar-type MS primaries. We discuss how these new eclipsing binaries provide invaluable insights, diagnostics, and challenges for the formation and evolution of stars, binaries, and H II regions.

  6. A New γ-Ray Loud, Eclipsing Low-mass X-Ray Binary

    NASA Astrophysics Data System (ADS)

    Strader, Jay; Li, Kwan-Lok; Chomiuk, Laura; Heinke, Craig O.; Udalski, Andrzej; Peacock, Mark; Shishkovsky, Laura; Tremou, Evangelia

    2016-11-01

    We report the discovery of an eclipsing low-mass X-ray binary at the center of the 3FGL error ellipse of the unassociated Fermi/Large Area Telescope γ-ray source 3FGL J0427.9-6704. Photometry from OGLE and the SMARTS 1.3 m telescope and spectroscopy from the SOAR telescope have allowed us to classify the system as an eclipsing low-mass X-ray binary (P = 8.8 hr) with a main-sequence donor and a neutron-star accretor. Broad double-peaked H and He emission lines suggest the ongoing presence of an accretion disk. Remarkably, the system shows separate sets of absorption lines associated with the accretion disk and the secondary, and we use their radial velocities to find evidence for a massive (˜1.8-1.9 M ⊙) neutron-star primary. In addition to a total X-ray eclipse with a duration of ˜2200 s observed with NuSTAR, the X-ray light curve also shows properties similar to those observed among known transitional millisecond pulsars: short-term variability, a hard power-law spectrum ({{Γ }}˜ 1.7), and a comparable 0.5-10 keV luminosity (˜ 2.4× {10}33 erg s-1). We find tentative evidence for a partial (˜ 60 % ) γ-ray eclipse at the same phase as the X-ray eclipse, suggesting the γ-ray emission may not be confined to the immediate region of the compact object. The favorable inclination of this binary is promising for future efforts to determine the origin of γ-rays among accreting neutron stars.

  7. AbsParEB and InPeVEB: Software for the Calculation of Absolute and Orbital Period Changes Parameters of Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Liakos, A.

    2015-07-01

    The software ABSPAREB (Absolute Parameters of Eclipsing Binaries) calculates the absolute parameters and their formal errors for three different modes: a) double-lined spectroscopic eclipsing binary, b) single-lined spectroscopic eclipsing binary, and c) for an eclipsing binary for which there is no spectroscopic information. In addition, the positions of the binary's members on the mass-radius and color-magnitude diagrams can be also plotted. INPEVEB (Interpretation of Period Variations of Eclipsing Binaries) calculates the parameters as well as their formal errors for several orbital period modulating mechanisms in eclipsing binaries (i.e., LITE, the Applegate mechanism, mass transfer/loss, apsidal motion, magnetic braking) using from an analysis of their O-C diagrams. Both programs are available online (free of charge) in Graphical User Interface form and were written in PYTHON.

  8. Phenomenological Parameters of the Prototype Eclipsing Binaries Algol, β Lyrae and W UMa

    NASA Astrophysics Data System (ADS)

    Tkachenko, Mariia G.; Andronov, Ivan L.; Chinarova, Lidia L.

    2016-12-01

    The phenomenological parameters of eclipsing binary stars, which are the prototypes of the EA, EB and EW systems are determined using the expert complex of computer programs, which realizes the NAV ("New Algol Variable") algorithm (Andronov 2010, 2012) and its possible modifications are discussed, as well as constrains for estimates of some physical parameters of the systems in a case of photometric observations only, such as the degree of eclipse, ratio of the mean surface brightnesses of the components. The half-duration of the eclipse is 0.0617(7), 0.1092(18) and 0.1015(7) for Algol, β Lyrae and W UMa, respectively. The brightness ratio is 6.8±1.0, 4.9±1.0 and 1.15±0.13. These results show that the eclipses have distinct begin and end not only in EA (as generally assumed), but also in EB and EW - type systems as well. The algorithm may be applied to classification and study of the newly discovered (or poorly studied) eclipsing variables based on own observations or that obtained using photometric surveys.

  9. New Developments in Eclipsing Binary Light Curve Modeling

    NASA Astrophysics Data System (ADS)

    Milone, E. F.; Stagg, C. R.

    1994-03-01

    The light curve modeling of binary 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 binary stars and ensembles containing them. Here we discuss the newer horizons of light curve modeling and the steps being taken toward them.

  10. Orbital Parameters of the Eclipsing Detached Kepler Binaries with Eccentric Orbits

    NASA Astrophysics Data System (ADS)

    Kjurkchieva, Diana; Vasileva, Doroteya; Atanasova, Teodora

    2017-09-01

    We present precise values of the eccentricity and periastron angle of 529 detached, eccentric, eclipsing stars from the Kepler Eclipsing Binary catalog that were determined by modeling their long cadence data. The temperatures and relative radii of their components as well as their mass ratios were calculated based on approximate values of the empirical relations of MS stars. Around one-third of the secondary components were revealed to be very late dwarfs, some of them possible brown dwarf candidates. Most of our targets fall below the envelope P(1 - e 2)3/2 = 5 days. The (e, P) distribution of the known eccentric binaries exhibits a rough trend of increasing eccentricity with the period. The prolonged and continuous Kepler observations allowed us to identify 60 new highly eccentric targets with e > 0.5.

  11. Using Gaussian Processes to Model Noise in Eclipsing Binary Light Curves

    NASA Astrophysics Data System (ADS)

    Prsa, Andrej; Hambleton, Kelly M.

    2017-01-01

    The most precise data we have at hand arguably comes from NASA's Kepler mission, for which there is no good flux calibration available since it was designed to measure relative flux changes down to ~20ppm level. Instrumental artifacts thus abound in the data, and they vary with the module, location on the CCD, target brightness, electronic cross-talk, etc. In addition, Kepler's near-uninterrupted mode of observation reveals astrophysical signals and transient phenomena (i.e. spots, flares, protuberances, pulsations, magnetic field features, etc) that are not accounted for in the models. These "nuisance" signals, along with instrumental artifacts, are considered noise when modeling light curves; this noise is highly correlated and it cannot be considered poissonian or gaussian. Detrending non-white noise from light curve data has been an ongoing challenge in modeling eclipsing binary star and exoplanet transit light curves. Here we present an approach using Gaussian Processes (GP) to model noise as part of the overall likelihood function. The likelihood function consists of the eclipsing binary light curve generator PHOEBE, correlated noise model using GP, and a poissonian (shot) noise attributed to the actual stochastic component of the entire noise model. We consider GP parameters and poissonian noise amplitude as free parameters that are being sampled within the likelihood function, so the end result is the posterior probability not only for eclipsing binary model parameters, but for the noise parameters as well. We show that the posteriors of principal parameters are significantly more robust when noise is modeled rigorously compared to modeling detrended data with an eclipsing binary model alone. This work has been funded by NSF grant #1517460.

  12. VizieR Online Data Catalog: Eclipsing binary parallaxes with Gaia data (Stassun+, 2016)

    NASA Astrophysics Data System (ADS)

    Stassun, K. G.; Torres, G.

    2017-02-01

    We adopted the predicted parallaxes for the 158 eclipsing binaries (EBs) included in the study of Stassun & Torres (2016, arXiv:1609.02579). Of these, 116 had parallaxes available in the Gaia first data release (see I/337). We excluded from our analysis any EBs identified as potentially problematic in Stassun & Torres (2016). This left 111 EBs with good parallaxes from both the EB analysis and from Gaia. (1 data file).

  13. Data Mining the Ogle-II I-band Database for Eclipsing Binary Stars

    NASA Astrophysics Data System (ADS)

    Ciocca, M.

    2013-08-01

    The OGLE I-band database is a searchable database of quality photometric data available to the public. During Phase 2 of the experiment, known as "OGLE-II", I-band observations were made over a period of approximately 1,000 days, resulting in over 1010 measurements of more than 40 million stars. This was accomplished by using a filter with a passband near the standard Cousins Ic. The database of these observations is fully searchable using the mysql database engine, and provides the magnitude measurements and their uncertainties. In this work, a program of data mining the OGLE I-band database was performed, resulting in the discovery of 42 previously unreported eclipsing binaries. Using the software package Peranso (Vanmuster 2011) to analyze the light curves obtained from OGLE-II, the eclipsing types, the epochs and the periods of these eclipsing variables were determined, to one part in 106. A preliminary attempt to model the physical parameters of these binaries was also performed, using the Binary Maker 3 software (Bradstreet and Steelman 2004).

  14. GSC 4232.2850, a new eclipsing binary with elliptical orbit

    NASA Astrophysics Data System (ADS)

    Goranskij, V.; Shugarov, S.; Kroll, P.; Golovin, A.

    2005-04-01

    GSC 4232.2830 (20h 01m 28s.407, +61? 10' 17".18, 2000.0, v=12m.1) was suspected to be an eclipsing binary by VPG in the routine overview of photographical plates taken with 40-cm astrograph of SAI Crimean station. To define orbital elements of the binary, we searched for observations in Sonneberg Observatory plate collection, NSVS database (Wozniak et al., 2004), and carried out visual monitoring with a small telescope equipped with an electronic image tube, an analogue of a night vision device. Later, when we had found a preliminary solution, we carried out accurate CCD photometry to improve the orbital elements. We should note, that the depths of eclipses in the NSVS database do not exceed 0m.2, what contradicts to other observations. We suppose that NSVS measurements concern to integral light of two stars, a variable star, and a nearby brighter star, GSC 4232.2395, due to low resolution of this survey, 72". Using all the available observations we found the single orbital solution with an elliptical orbit and the period of 11,6 day. The center of the secondary minimum occurs at the orbital phase 0.69835 or 8.1 day after the primary minimum. The improved ephemeris derived using accurate CCD observations is following: HJD Min I = 2453278,3185(2) + 11.628188 (5) x E. O-C analysis does not show orbital period variations during the time interval of observations, or any evidence of apsidal motion. The observations show that both eclipses have about equal depth 0m.60, but essentially different duration, 0p.028 (7 h.8) for Min I, and 0 p.0175 (4 h.9) for Min II. The eclipses are partial. CCD photometry gives mean colors U-B = -0 m.06, B-V = 0 m.57, and V-R = 0 m.50 without notable color variations in the eclipse phases. Old Sonneberg photographic observations indicate that the eclipses were shallower in the middle of the past century than in the present time! Such contradictions may suggest that the depth of eclipses varied, as in the well-known system SSLac

  15. WW Geminorum: An early B-type eclipsing binary evolving into the contact phase

    SciTech Connect

    Yang, Y.-G.; Dai, H.-F.; Yin, X.-G.; Yang, Y. E-mail: yangyg@chnu.edu.cn

    2014-11-01

    WW Gem is a B-type eclipsing binary with a period of 1.2378 days. The CCD photometry of this binary 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 eclipsing binary 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 binary WW Gem may be evolving into a contact binary.

  16. Light Curve Solutions of Eclipsing Binaries in the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Rawls, Meredith L.; Rao, M. S.

    2012-01-01

    We present model light curves for nine eclipsing binary stars in the Large Magellanic Cloud (LMC). These systems are detached binaries 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 binary classification as reported in Wyrzykowski et al. (2003). We present light curve solutions created with the software PHysics Of Eclipsing BinariEs (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.

  17. WW Geminorum: An Early B-type Eclipsing Binary Evolving into the Contact Phase

    NASA Astrophysics Data System (ADS)

    Yang, Y.-G.; Yang, Y.; Dai, H.-F.; Yin, X.-G.

    2014-11-01

    WW Gem is a B-type eclipsing binary with a period of 1.2378 days. The CCD photometry of this binary 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 eclipsing binary whose primary component almost fills its Roche lobe. The photometric mass ratio is q 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 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) × 10-8 day yr-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 binary WW Gem may be evolving into a contact binary.

  18. UBVRI analysis of the totally eclipsing extreme mass ratio W UMa binary, GSC 3208 1986

    SciTech Connect

    Samec, R. G.; Kring, J. D.; Robb, Russell; Van Hamme, W.; Faulkner, D. R.

    2015-03-01

    GSC 3208 1986 is an NSVS and TYCHO binary, first observed from 1999 to 2000. It is a W UMa binary 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 eclipses. Dominion Astrophysical Observatory spectra give an F3V type (T∼6900 K) for the system, the earliest of the extreme mass ratio W UMa binaries. 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 binary 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 eclipse, 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 binary.

  19. Accurate Parameters for the Most Massive Stars in the Local Universe: the Brightest Eclipsing Binaries in M33

    NASA Astrophysics Data System (ADS)

    Prieto, José L.; Bonanos, Alceste; Stanek, Krzysztof

    2007-08-01

    Eclipsing binaries are the only systems that provide accurate fundamental parameters of distant stars. Currently, only a handful of accurate measurements of stars with masses between 40-80 Msun have been made. We propose to make accurate measurements of the masses, radii and luminosities of the most massive eclipsing binaries in M33. The results of this study will provide much needed constraints on theories that model the formation and evolution of massive stars and binary systems. Furthermore, it will provide vital statistics on the occurrence of massive binary twins, like the 80+80 solar masses WR 20a system and the 30+30 solar masses detached eclipsing binary in M33.

  20. Photometric Study of Extreme Long Period Eclipsing Binary 31 CYG

    NASA Astrophysics Data System (ADS)

    Jeong, Jang Hae; Lee, Yong-Sam; Kim, Ho-Il

    1991-12-01

    The UBV light curves of an extreme long period binary star 31 Cyg are made with the observations obtained at Yonsei University Observatory for three seasons from 1988 to 1991 and the RI light curves are also made for one season in 1990-1991. The new combined UBV light curves of 31 Cyg are constructed with YOU's and collected data. A preliminary solution of the light curves of 31 Cygis made using Wilson-Devinney codes.

  1. The OB binary HD152219: a detached, double-lined, eclipsing system

    NASA Astrophysics Data System (ADS)

    Sana, H.; Gosset, E.; Rauw, G.

    2006-09-01

    We present the results of an optical spectroscopic campaign on the massive binary 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 eclipsing binary 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).

  2. 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.

  3. Testing low-mass stellar models with M-dwarf eclipsing binaries from SDSS Stripe 82

    NASA Astrophysics Data System (ADS)

    Bhatti, Waqas A.

    Large astronomical surveys such as the Sloan Digital Sky Survey (SDSS) have revolutionized ensemble studies of stellar populations in the Galaxy. Modern and upcoming synoptic surveys extend this concept to the time-domain, by covering large areas of the sky to a faint magnitude limit, and at observing cadences optimized for a large range in variability. In this thesis, we explore methods of efficiently analyzing a large synoptic survey dataset and its application to stellar astronomy, specifically focusing on the discovery and characterization of low-mass star eclipsing binaries. Eclipsing binaries (EBs) provide direct measurements of the absolute masses and radii of the component stars. Recent observations of EBs composed of low-mass stars (< 0.7 M⊙ ) indicate that the measured radii of the component stars are systematically 10-15% larger than those predicted by stellar models. Tidally induced magnetic fields that arise in these close binaries may be responsible for this discrepancy. The small number of fully characterized low-mass EBs, however, makes any hypothesis for this discrepancy difficult to verify. These objects are difficult to detect because of the intrinsic faintness of low-mass stars, in addition to the already low probability of favorable orbital alignment for eclipse observation. Fortunately, both of these problems can be overcome by a large-area and deep time-domain survey. We describe a search for periodic variables carried out using multi-band timeseries photometry from SDSS Stripe 82 focused on identifying a large sample of EBs to help resolve this issue. We outline the construction of our light-curve catalog and the methodology for extracting variable point sources. We discuss the classification of the ˜1100 periodic variables found in these data, and the subsequent discovery of ˜211 EB candidates with securely determined periods. For ˜90 EBs with suitable light-curves, we fit binary models and estimate parameters for the binary components

  4. A Double-line M-dwarf Eclipsing Binary from CSS x SDSS

    NASA Astrophysics Data System (ADS)

    Lee, Chien-Hsiu

    2017-03-01

    Eclipsing binaries offer a unique opportunity to determine basic stellar properties. With the advent of wide-field camera and all-sky time-domain surveys, thousands of eclipsing binaries have been charted via light curve classification, yet their fundamental properties remain unexplored mainly due to the extensive efforts needed for spectroscopic follow-ups. In this paper, we present the discovery of a short-period (P = 0.313 day), double-lined M-dwarf eclipsing binary, CSSJ114804.3+255132/SDSSJ114804.35+255132.6, by cross-matching binary light curves from the Catalina Sky Survey and spectroscopically classified M dwarfs from the Sloan Digital Sky Survey. We obtain follow-up spectra using the Gemini telescope, enabling us to determine the mass, radius, and temperature of the primary and secondary component to be M 1 = 0.47 ± 0.03(statistic) ± 0.03(systematic) M ⊙, M 2 = 0.46 ± 0.03(statistic) ± 0.03(systematic) M ⊙, R 1 = 0.52 ± 0.08(statistic) ± 0.07(systematic) R ⊙, R 2 =0.60 ± 0.08(statistic) ± 0.08(systematic) R ⊙, T 1 = 3560 ± 100 K, and T 2 = 3040 ± 100 K, respectively. The systematic error was estimated using the difference between eccentric and non-eccentric fits. Our analysis also indicates that there is definitively third-light contamination (66%) in the CSS photometry. The secondary star seems inflated, probably due to tidal locking of the close secondary companion, which is common for very short-period binary systems. Future spectroscopic observations with high resolution will narrow down the uncertainties of stellar parameters for both components, rendering this system as a benchmark for studying fundamental properties of M dwarfs.

  5. 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.

  6. KIC 11401845: An Eclipsing Binary with Multiperiodic Pulsations and Light-travel Time

    NASA Astrophysics Data System (ADS)

    Lee, Jae Woo; Hong, Kyeongsoo; Kim, Seung-Lee; Koo, Jae-Rim

    2017-02-01

    We report the {\\text{}}{Kepler} photometry of KIC 11401845 displaying multiperiodic pulsations, superimposed on binary effects. Light-curve synthesis shows that the binary star is a short-period detached system with a very low mass ratio of q = 0.070 and filling factors of F1 = 45% and F2 = 99%. Multiple-frequency analyses were applied to the light residuals after subtracting the synthetic eclipsing curve from the observed data. We detected 23 frequencies with signal-to-noise ratios larger than 4.0, of which the orbital harmonics (f4, f6, f9, f15) in the low-frequency domain may originate from tidally excited modes. For the high frequencies of 13.7–23.8 day‑1, the period ratios and pulsation constants are in the ranges of {P}{pul}/{P}{orb}=0.020{--}0.034 and Q = 0.018–0.031 days, respectively. These values and the position on the Hertzsprung–Russell diagram demonstrate that the primary component is a δ Sct pulsating star. We examined the eclipse timing variation of KIC 11401845 from the pulsation-subtracted data and found a delay of 56 ± 17 s in the arrival times of the secondary eclipses relative to the primary eclipses. A possible explanation of the time shift may be some combination of a light-travel-time delay of about 34 s and a very small eccentricity of e\\cos ω < 0.0002. This result represents the first measurement of the Rømer delay in noncompact binaries.

  7. DISCOVERY OF THE ECLIPSING DETACHED DOUBLE WHITE DWARF BINARY NLTT 11748

    SciTech Connect

    Steinfadt, Justin D. R.; Shporer, Avi; Bildsten, Lars; Kaplan, David L.; Howell, Steve B.

    2010-06-20

    We report the discovery of the first eclipsing detached double white dwarf (WD) binary. In a pulsation search, the low-mass 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 eclipses 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 eclipses 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 binary, the primary eclipse 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 binary's fate once contact is reached.

  8. γ Doradus Pulsations in the Eclipsing Binary Star KIC 6048106

    NASA Astrophysics Data System (ADS)

    Lee, Jae Woo

    2016-12-01

    We present the Kepler photometry of KIC 6048106, which is exhibiting the O’Connell effect and multiperiodic pulsations. Including a starspot on either of the components, light-curve synthesis indicates that this system is a semi-detached Algol with a mass ratio of 0.211, an orbital inclination of 73.°9, and a large temperature difference of 2534 K. To examine in detail both the spot variations and pulsations, we separately analyzed the Kepler time-series data at the interval of an orbital period in an iterative way. The results reveal that the variable asymmetries of the light maxima can be interpreted as the changes with time of a magnetic cool spot on the secondary component. Multiple frequency analyses were performed in the outside-eclipse light residuals after removal of the binarity effects from the observed Kepler data. We detected 30 frequencies with signal to noise amplitude ratios larger than 4.0, of which six (f 2-f 6 and f 10) can be identified as high-order (17 ≤ n ≤ 25) low-degree (ℓ = 2) gravity-mode pulsations that were stable during the observing run of 200 days. In contrast, the other frequencies may be harmonic and combination terms. For the six frequencies, the pulsation periods and pulsation constants are in the ranges of 0.352-0.506 days and 0.232-0.333 days, respectively. These values and the position on the Hertzsprung-Russell diagram demonstrate that the primary star is a γ Dor variable. The evolutionary status and the pulsation nature of KIC 6048106 are discussed.

  9. Secondaries of eclipsing binaries. VI. R Canis Majoris

    SciTech Connect

    Tomkin, J.

    1985-10-01

    High S/N Reticon observations of the Algol system R CMa are described, revealing the Na D lines of the secondary for the first time. The observations and accompanying observations of the primary in the blue provide the secondary velocity curve and a redetermination of the primary velocity curve. The very small mass (0.17 plus or minus 0.02 solar mass) determined for the evolved, Roche-lobe-filling secondary is a consequence of severe mass loss, and it is argued that this star has lost at least 80 percent its original mass. 15 references.

  10. AN X-RAY AND OPTICAL LIGHT CURVE MODEL OF THE ECLIPSING SYMBIOTIC BINARY SMC3

    SciTech Connect

    Kato, Mariko; Hachisu, Izumi; Mikolajewska, Joanna

    2013-01-20

    Some binary evolution scenarios for Type Ia supernovae (SNe Ia) include long-period binaries 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 eclipsing symbiotic binary, 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 eclipse 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 binary in the orbital plane.

  11. The Araucaria Project. The Distance to the Small Magellanic Cloud from Late-type Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Graczyk, Dariusz; Pietrzyński, Grzegorz; Thompson, Ian B.; Gieren, Wolfgang; Pilecki, Bogumił; Konorski, Piotr; Udalski, Andrzej; Soszyński, Igor; Villanova, Sandro; Górski, Marek; Suchomska, Ksenia; Karczmarek, Paulina; Kudritzki, Rolf-Peter; Bresolin, Fabio; Gallenne, Alexandre

    2014-01-01

    We present a distance determination to the Small Magellanic Cloud (SMC) based on an analysis of four detached, long-period, late-type eclipsing binaries discovered by the Optical Gravitational Lensing Experiment (OGLE) survey. The components of the binaries show negligible intrinsic variability. A consistent set of stellar parameters was derived with low statistical and systematic uncertainty. The absolute dimensions of the stars are calculated with a precision of better than 3%. The surface brightness-infrared color relation was used to derive the distance to each binary. The four systems clump around a distance modulus of (m - M) = 18.99 with a dispersion of only 0.05 mag. Combining these results with the distance published by Graczyk et al. for the eclipsing binary OGLE SMC113.3 4007, we obtain a mean distance modulus to the SMC of 18.965 ± 0.025 (stat.) ± 0.048 (syst.) mag. This corresponds to a distance of 62.1 ± 1.9 kpc, where the error includes both uncertainties. Taking into account other recent published determinations of the SMC distance we calculated the distance modulus difference between the SMC and the Large Magellanic Cloud equal to 0.458 ± 0.068 mag. Finally, we advocate μSMC = 18.95 ± 0.07 as a new "canonical" value of the distance modulus to this galaxy.

  12. The Araucaria project. The distance to the small Magellanic Cloud from late-type eclipsing binaries

    SciTech Connect

    Graczyk, Dariusz; Pietrzyński, Grzegorz; Gieren, Wolfgang; Pilecki, Bogumił; Villanova, Sandro; Gallenne, Alexandre; Thompson, Ian B.; Konorski, Piotr; Udalski, Andrzej; Soszyński, Igor; Górski, Marek; Suchomska, Ksenia; Karczmarek, Paulina; Kudritzki, Rolf-Peter; Bresolin, Fabio

    2014-01-01

    We present a distance determination to the Small Magellanic Cloud (SMC) based on an analysis of four detached, long-period, late-type eclipsing binaries discovered by the Optical Gravitational Lensing Experiment (OGLE) survey. The components of the binaries show negligible intrinsic variability. A consistent set of stellar parameters was derived with low statistical and systematic uncertainty. The absolute dimensions of the stars are calculated with a precision of better than 3%. The surface brightness-infrared color relation was used to derive the distance to each binary. The four systems clump around a distance modulus of (m – M) = 18.99 with a dispersion of only 0.05 mag. Combining these results with the distance published by Graczyk et al. for the eclipsing binary OGLE SMC113.3 4007, we obtain a mean distance modulus to the SMC of 18.965 ± 0.025 (stat.) ± 0.048 (syst.) mag. This corresponds to a distance of 62.1 ± 1.9 kpc, where the error includes both uncertainties. Taking into account other recent published determinations of the SMC distance we calculated the distance modulus difference between the SMC and the Large Magellanic Cloud equal to 0.458 ± 0.068 mag. Finally, we advocate μ{sub SMC} = 18.95 ± 0.07 as a new 'canonical' value of the distance modulus to this galaxy.

  13. A period study and revised photometric model for the eclipsing binary ZZ Cyg

    NASA Astrophysics Data System (ADS)

    Yang, Yuangui; Zhang, Liyun; Dai, Haifeng; Li, Huali

    2015-05-01

    We present new photometry of the eclipsing binary ZZ Cyg. From all accumulated eclipsing times, we constructed the (O-C) curve, which can be described by a downward parabola with a possible light-time orbit. The period decrease rate is dP / dt = - 5.73 (± 0.18) dyr-1 . The modulated period, semi-amplitude and eccentricity for the light-time orbit are Pmod = 71.4 (± 1.1)yr , A = 0.0071 (± 0.0005)day and e = 0.420 (± 0.053) , respectively. After removing effects of the magnetic activity, this kind of cyclic oscillation may be attributed to light-time effect via an additional companion. By using the W-D code, the photometric model was updated, which identified that ZZ Cyg is a near-contact binary. We find that a hot spot may occur on the primary that explains the asymmetric light curve. The secular period decrease may possibly cause the fill-out factor of the primary to increase. Finally it will finally fill its Roche lobe. This kind of binary, ZZ Cyg, may evolve into contact binary star.

  14. 3D modelling of accretion disc in eclipsing binary system V1239 Her

    NASA Astrophysics Data System (ADS)

    Lukin, V. V.; Malanchev, K. L.; Shakura, N. I.; Postnov, K. A.; Chechetkin, V. M.; Utrobin, V. P.

    2017-05-01

    We present the results of 3D-hydrodynamical simulations of accretion flow in the eclipsing dwarf nova V1239 Her in quiescence. The model includes the optical star filling its Roche lobe, a gas stream emanating from the inner Lagrangian point of the binary system, and the accretion disc structure. A cold hydrogen gas stream is initially emitted towards a point-like gravitational centre. A stationary accretion disc is formed in about 15 orbital periods after the beginning of accretion. The model takes into account partial ionization of hydrogen and uses realistic cooling function for hydrogen. The light curve of the system is calculated as the volume emission of optically thin layers along the line of sight up to the optical depth τ = 2/3 calculated using Planck-averaged opacities. The calculated eclipse light curves show good agreement with observations, with the changing shape of pre-eclipse and post-eclipse light curves being explained entirely due to ˜50 per cent variations in the mass accretion rate through the gas stream.

  15. Eclipsing binary stars as tests of gravity theories - The apsidal motion of AS Camelopardalis

    NASA Technical Reports Server (NTRS)

    Maloney, Frank P.; Guinan, Edward F.; Boyd, Patricia T.

    1989-01-01

    AS Camelopardalis is an 8th-magnitude eclipsing binary 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 eclipsing 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 eclipse timings from 1899 to 1920 obtained from the Harvard plate collection. Least-squares solutions of the eclipse 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.

  16. VizieR Online Data Catalog: OGLE II SMC eclipsing binaries (Wyrzykowski+, 2004)

    NASA Astrophysics Data System (ADS)

    Wyrzykowski, L.; Udalski, A.; Kubiak, M.; Szymanski, M. K.; Zebrun, K.; Soszinski, I.; Wozniak, P. R.; Pietrzynski, G.; Szewczyk, O.

    2009-03-01

    We present new version of the OGLE-II catalog of eclipsing binary 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 eclipsing binary 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 eclipsing 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).

  17. Substellar companions in low-mass eclipsing binaries. NSVS 01286630, NSVS 02502726, and NSVS 07453183

    NASA Astrophysics Data System (ADS)

    Wolf, M.; Zasche, P.; Kučáková, H.; Vraštil, J.; Hornoch, K.; Šmelcer, L.; Bílek, F.; Pilarčík, L.; Chrastina, M.

    2016-03-01

    Aims: As part of our long-term observational project we aim to measure very precise mid-eclipse times for low-mass eclipsing binaries, which are needed to accurately determine their period changes. Over two hundred new precise times of minimum light recorded with CCD were obtained for three eclipsing binaries with short orbital periods: NSVS 01286630 (P = 0.38°), NSVS 02502726 (0.56°), and NSVS 07453183 (0.37°). Methods: O-C diagrams of studied stars were analysed using all reliable timings, and new parameters of the light-time effect were obtained. Results: We derived for the first time or improved the very short orbital periods of third bodies of between one and seven years for all measured low-mass systems. We calculated that the lowest masses of the third components are between those of red and brown dwarfs. The multiplicity of these systems also plays an important role in the precise determination of their physical parameters. This research is part of an ongoing collaboration between professional astronomers and the Czech Astronomical Society, Variable Star and Exoplanet Section.

  18. High-Resolution Infrared Spectroscopic Observations of the Upper Scorpius Eclipsing Binary EPIC 203868608

    NASA Astrophysics Data System (ADS)

    Johnson, Marshall C.; Mace, Gregory N.; Kim, Hwihyun; Kaplan, Kyle; McLane, Jacob; Sokal, Kimberly R.

    2017-06-01

    EPIC 203868608 is a source in the ~10 Myr old Upper Scorpius OB association. Using K2 photometry and ground-based follow-up observations, David et al. (2016) found that it consists of two brown dwarfs with a tertiary object at a projected separation of ~20 AU; the former objects appear to be a double-lined eclipsing binary with a period of 4.5 days. This is one of only two known eclipsing SB2s where both components are below the hydrogen-burning limit. We present additional follow-up observations of this system from the IGRINS high-resolution near-infrared spectrograph at McDonald Observatory. Our measured radial velocities do not follow the orbital solution presented by David et al. (2016). Instead, our combined IGRINS plus literature radial velocity dataset appears to indicate a period significantly different than that of the eclipsing binary obvious from the K2 light curve. We will discuss possible scenarios to account for the conflicting observations of this system.

  19. A photometric study of the eclipsing binary RX Hercules

    NASA Technical Reports Server (NTRS)

    Jeffreys, K. W.

    1980-01-01

    A new photoelectric light curve of RX Hercules, a binary system with similar components, has been analyzed using Wood's computer model. RX Her, using Popper's spectroscopic mass ratio of q = 0.8472, turned out to be composed of a dimmer AO component and a larger B9.5 component. This detached system, upon analysis of the residuals in secondary minimum, shows some asymmetry during ingress which then disappears just before secondary minimum. The eccentricity e = 0.022 determined in this study is a little larger than previously published values of e = 0.018. In combination with the spectroscopic analysis of Popper, and ubvy data of Olson and Hill and Hilditch new photometric elements for RX Her were found.

  20. RED GIANTS IN ECLIPSING BINARY AND MULTIPLE-STAR SYSTEMS: MODELING AND ASTEROSEISMIC ANALYSIS OF 70 CANDIDATES FROM KEPLER DATA

    SciTech Connect

    Gaulme, P.; McKeever, J.; Rawls, M. L.; Jackiewicz, J.; Mosser, B.; Guzik, J. A.

    2013-04-10

    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. Eclipsing binaries are also fundamental astrophysical objects, and when coupled with asteroseismology, binaries 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 eclipsing binary 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 eclipsing-binary 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, eclipse 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 eclipsing-binary catalogs we find 13 strong candidates (12 previously unknown) to be eclipsing binaries, one to be a non-eclipsing binary 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 eclipsing binary 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 eclipsing binaries provides an exciting test bed for precise astrophysical modeling, and follow-up spectroscopic observations of many

  1. Testing the Asteroseismic Scaling Relations for Red Giants with Eclipsing Binaries Observed by Kepler

    NASA Astrophysics Data System (ADS)

    Gaulme, P.; McKeever, J.; Jackiewicz, J.; Rawls, M. L.; Corsaro, E.; Mosser, B.; Southworth, J.; Mahadevan, S.; Bender, C.; Deshpande, R.

    2016-12-01

    Given the potential of ensemble asteroseismology for understanding fundamental properties of large numbers of stars, it is critical to determine the accuracy of the scaling relations on which these measurements are based. From several powerful validation techniques, all indications so far show that stellar radius estimates from the asteroseismic scaling relations are accurate to within a few percent. Eclipsing binary systems hosting at least one star with detectable solar-like oscillations constitute the ideal test objects for validating asteroseismic radius and mass inferences. By combining radial velocity (RV) measurements and photometric time series of eclipses, it is possible to determine the masses and radii of each component of a double-lined spectroscopic binary. We report the results of a four-year RV survey performed with the échelle spectrometer of the Astrophysical Research Consortium’s 3.5 m telescope and the APOGEE spectrometer at Apache Point Observatory. We compare the masses and radii of 10 red giants (RGs) obtained by combining radial velocities and eclipse photometry with the estimates from the asteroseismic scaling relations. We find that the asteroseismic scaling relations overestimate RG radii by about 5% on average and masses by about 15% for stars at various stages of RG evolution. Systematic overestimation of mass leads to underestimation of stellar age, which can have important implications for ensemble asteroseismology used for Galactic studies. As part of a second objective, where asteroseismology is used for understanding binary systems, we confirm that oscillations of RGs in close binaries can be suppressed enough to be undetectable, a hypothesis that was proposed in a previous work.

  2. Orbital period variation study of massive Beta-Lyrae eclipsing binary IU Auriga

    NASA Astrophysics Data System (ADS)

    Yilan, Erkan; Bulut, İbrahim

    2016-07-01

    The system IU Aur is a semi-detached close binary system with an orbital period of 1.81 days, containing a massive star. The O-C diagram of this binary 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 eclipsing binary revolves around a third-body with a mass of about M_{3}>10M_{⊙} in a highly eccentric orbit.

  3. A study of the EB-type eclipsing binary GR Tauri with mass transfer

    NASA Astrophysics Data System (ADS)

    Gu, Sheng-hong; Chen, Pei-sheng; Choy, Yu-kou; Leung, Kam-cheung; Chung, Wai-keung; Poon, Tak-sun

    2004-08-01

    In this paper, new CCD BV light curves of the EB-type eclipsing binary GR Tau, which were obtained in 1999, are analyzed by means of the Wilson-Devinney program. The photometric solution of this system is obtained, and its absolute parameters are also derived. Our study has demonstrated that GR Tau is a near-contact binary system with an almost-contact semidetached configuration in which the primary fills its Roche lobe, and both components are main-sequence stars. The asymmetric shape of the light curves can be explained by a hot spot on the surface of the secondary, which is created by the mass transfer from the primary to the secondary. GR Tau belongs to the V1010 Oph subclass of near-contact binaries, and is a good example of a system in the broken-contact phase predicted by the TRO theory.

  4. Photometric Analysis and Period Investigation of the EW Type Eclipsing Binary V441 Lac

    NASA Astrophysics Data System (ADS)

    Li, K.; Hu, S.-M.; Guo, D.-F.; Jiang, Y.-G.; Gao, D.-Y.; Chen, X.

    2016-09-01

    Four color light curves of the EW type eclipsing binary V441 Lac were presented and analyzed by the W-D code. It is found that V441 Lac is an extremely low mass ratio ( q = 0.093±0.001) semi-detached binary 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 binary due to mass transfer from the less massive component to the more massive one predicted by the thermal relaxation oscillation theory.

  5. Gaia eclipsing binary and multiple systems. Supervised classification and self-organizing maps

    NASA Astrophysics Data System (ADS)

    Süveges, M.; Barblan, F.; Lecoeur-Taïbi, I.; Prša, A.; Holl, B.; Eyer, L.; Kochoska, A.; Mowlavi, N.; Rimoldini, L.

    2017-07-01

    Context. Large surveys producing tera- and petabyte-scale databases require machine-learning and knowledge discovery methods to deal with the overwhelming quantity of data and the difficulties of extracting concise, meaningful information with reliable assessment of its uncertainty. This study investigates the potential of a few machine-learning methods for the automated analysis of eclipsing binaries in the data of such surveys. Aims: We aim to aid the extraction of samples of eclipsing binaries from such databases and to provide basic information about the objects. We intend to estimate class labels according to two different, well-known classification systems, one based on the light curve morphology (EA/EB/EW classes) and the other based on the physical characteristics of the binary system (system morphology classes; detached through overcontact systems). Furthermore, we explore low-dimensional surfaces along which the light curves of eclipsing binaries are concentrated, and consider their use in the characterization of the binary systems and in the exploration of biases of the full unknown Gaia data with respect to the training sets. Methods: We have explored the performance of principal component analysis (PCA), linear discriminant analysis (LDA), Random Forest classification and self-organizing maps (SOM) for the above aims. We pre-processed the photometric time series by combining a double Gaussian profile fit and a constrained smoothing spline, in order to de-noise and interpolate the observed light curves. We achieved further denoising, and selected the most important variability elements from the light curves using PCA. Supervised classification was performed using Random Forest and LDA based on the PC decomposition, while SOM gives a continuous 2-dimensional manifold of the light curves arranged by a few important features. We estimated the uncertainty of the supervised methods due to the specific finite training set using ensembles of models constructed

  6. Observations of Mutual Eclipses by the Binary Kuiper Belt Object Manwe-Thorondor

    NASA Astrophysics Data System (ADS)

    Rabinowitz, David L.; Benecchi, Susan D.; Grundy, William M.; Thirouin, Audrey; Verbiscer, Anne J.

    2016-10-01

    The binary Kuiper Belt Object (385446) Manwe-Thorondor (aka 2003 QW111) is currently undergoing mutual events whereby the two ~100-km bodies alternately eclipse 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 eclipses. 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

  7. The apsidal motion of the eccentric eclipsing binary DI Herculis - An apparent discrepancy with general relativity

    NASA Technical Reports Server (NTRS)

    Guinan, E. F.; Maloney, F. P.

    1985-01-01

    The apsidal motion of the eccentric eclipsing binary DI Herculis (HD 175227) is determined from an analysis of the available observations and eclipse 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.

  8. The apsidal motion of the eccentric eclipsing binary DI Herculis - An apparent discrepancy with general relativity

    NASA Technical Reports Server (NTRS)

    Guinan, E. F.; Maloney, F. P.

    1985-01-01

    The apsidal motion of the eccentric eclipsing binary DI Herculis (HD 175227) is determined from an analysis of the available observations and eclipse 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.

  9. The Palomar Transient Factory Orion Project: Eclipsing Binaries and Young Stellar Objects

    NASA Astrophysics Data System (ADS)

    van Eyken, Julian C.; Ciardi, David R.; Rebull, Luisa M.; Stauffer, John R.; Akeson, Rachel L.; Beichman, Charles A.; Boden, Andrew F.; von Braun, Kaspar; Gelino, Dawn M.; Hoard, D. W.; Howell, Steve B.; Kane, Stephen R.; Plavchan, Peter; Ramírez, Solange V.; Bloom, Joshua S.; Cenko, S. Bradley; Kasliwal, Mansi M.; Kulkarni, Shrinivas R.; Law, Nicholas M.; Nugent, Peter E.; Ofek, Eran O.; Poznanski, Dovi; Quimby, Robert M.; Grillmair, Carl J.; Laher, Russ; Levitan, David; Mattingly, Sean; Surace, Jason A.

    2011-08-01

    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 (3fdg5 × 2fdg3) 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 eclipsing binaries and young stellar objects. We find 82 new eclipsing binary 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 low-mass (M-dwarf primary) eclipsing systems in the sample, which include six of the candidate young systems. Forty-five of the binary systems are close (mainly contact) systems, and one of these shows an orbital period among the shortest known for W UMa binaries, at 0.2156509 ± 0.0000071 days, with flat-bottomed primary eclipses, 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 binary system with an inflated low-mass 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 (CVSO 35) and

  10. THE PALOMAR TRANSIENT FACTORY ORION PROJECT: ECLIPSING BINARIES AND YOUNG STELLAR OBJECTS

    SciTech Connect

    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.

    2011-08-15

    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 eclipsing binaries and young stellar objects. We find 82 new eclipsing binary 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 low-mass (M-dwarf primary) eclipsing systems in the sample, which include six of the candidate young systems. Forty-five of the binary systems are close (mainly contact) systems, and one of these shows an orbital period among the shortest known for W UMa binaries, at 0.2156509 {+-} 0.0000071 days, with flat-bottomed primary eclipses, 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 binary system with an inflated low-mass 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

  11. Identification and Follow-Up Observations of Low-Mass Eclipsing Binaries from Kepler

    NASA Astrophysics Data System (ADS)

    Coughlin, Jeffrey; Lopez-Morales, M.; Marzoa, R. I.; Harrison, T.; Ule, N.; Hoffman, D.

    2011-01-01

    An outstanding problem in Astronomy for the past 15+ years has been that the radii of low-mass, (M < 1.0 M⊙), main-sequence stars in eclipsing binary systems are consistently about 15% larger than predicted by theoretical models. The main cause is hypothesized to be rapid rotation due to binary spin-up, as all but one of the currently known systems have P < 3.0 days. We present 100+ new low-mass, main-sequence, double-lined eclipsing binaries (LMMS DDEBs) from both our Kepler Guest Observer Program, as well as the initial Kepler public data release. We identify over 25 new systems with P > 10 days, extending the sample of LMMS DDEBs into this completely heretofore unexplored period range. We present the initial results of our intensive observing campaign to obtain ground-based radial-velocity and multi-color photometry follow-up of these long-period systems, in order to determine precise masses and radii. We thank all the hard-working members of the Kepler team, and acknowledge support from the Kepler Guest Observer Program, the New Mexico Space Grant Consortium, and a NSF Graduate Research Fellowship.

  12. FORMATION OF BLACK WIDOWS AND REDBACKS—TWO DISTINCT POPULATIONS OF ECLIPSING BINARY MILLISECOND PULSARS

    SciTech Connect

    Chen, Hai-Liang; Chen, Xuefei; Han, Zhanwen; Tauris, Thomas M.

    2013-09-20

    Eclipsing binary 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 low-mass X-ray binaries by employing the MESA stellar evolution code. Our results confirm that one can explain the formation of most of these eclipsing binary 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.

  13. Precise analysis of two Kepler detached eclipsing binary stars KIC 3327980 and KIC 10156064

    NASA Astrophysics Data System (ADS)

    Aliçavuş, Fahri; Soydugan, Faruk

    2017-02-01

    Stars are one of the most important objects to understand how the galaxies are formed, shaped and evolved. Hence, the determination of the absolute parameters of stars plays a crucial role. The absolute parameters (e.g. mass and radii) of the detached eclipsing binary stars could be determined with well accuracy. These accurate parameters could be used for understanding of the evolutional status of single stars in detailed. In this study, we carried out light curve solutions of two well-detached binaries KIC 3327980 and KIC 10156064 which were observed by Kepler space telescope. As a result, mass and radii of primary and secondary components were derived as M1 = 1.64M⊙, M2 = 1.42M⊙, R1 = 2.08R⊙, R2 = 1.66R⊙ for KIC 3327980 and M1 = 1.67M⊙, M2 = 1.05M⊙, R1 = 1.92R⊙, R2 = 1.06R⊙ for KIC 10156064. Additionally, the evolutionary status of the components of the systems were discussed and compared with the evolutional status of the other detached eclipsing binaries.

  14. Physical Properties and Evolution of the Eclipsing Binary System XZ Canis Minoris

    NASA Astrophysics Data System (ADS)

    Poochaum, R.; Komonjinda, S.; Soonthornthum, B.; Rattanasoon, S.

    2010-07-01

    This research aims to study the eclipse binary 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 eclipsing binary 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 binary 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.

  15. The Eclipsing Binary Pulsar PSR B1718-19: a Clean RS CVN System?

    NASA Astrophysics Data System (ADS)

    Kaspi, Victoria

    1996-07-01

    We request WFPC2 observations of the eclipsing binary pulsarPSR B1718-19. This slowly-rotating pulsar lies in thedirection of the globular cluster NGC 6342, and defiesstandard binary pulsar formation models in which the pulsar is``spun-up'' via mass accretion. Furthermore, the observedeclipses cannot be explained with standard models. Thispulsar's unusual properties can be explained elegantly if itscompanion is an active, non-degenerate star like thoseobserved in RS CVn systems, but in this case, subject only togravity. Following Keck observations of the field, we proposeHST observations of PSR B1718-19 to detect and studyvariability in the companion, in order to answer the followingquestions. 1- Are the eclipses seen in PSR B1718-19 indeed aresult of RS CVn-type activity in the companion, and what isthe evolutionary history of the binary? 2- Is the activity inRS CVn systems purely a tidal effect? 3- How are mass loss,rotation, and surface activity related in RS CVn stars? 4- IsPSR B1718-19 in NGC 6342?

  16. New Pleiades Eclipsing Binaries and a Hyades Transiting System Identified by K2

    NASA Astrophysics Data System (ADS)

    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

    2016-05-01

    We present the discovery in Kepler’s K2 mission observations and our follow-up radial velocity (RV) observations from Keck/HIRES for four eclipsing binary (EB) star systems in the young benchmark Pleiades and Hyades clusters. Based on our modeling results, we announce two new low mass ({M}{tot}\\lt 0.6 {M}⊙ ) EBs among Pleiades members (HCG 76 and MHO 9) and we report on two previously known Pleiades binaries that are also found to be EB systems (HII 2407 and HD 23642). We measured the masses of the binary 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 low mass eclipsing system (vA 50) that was concurrently discovered and studied by Mann et al. We confirm that the eclipse 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.

  17. Period Discovery and Light Curve Analysis of the Young 25 Ori Association Eclipsing Binary GSC 118-199

    NASA Astrophysics Data System (ADS)

    Bradstreet, David H.; Sanders, S. J.; Regi, A.

    2014-01-01

    GSC 118-199 (5-6432) was discovered to be an eclipsing binary by Van Eyken et al. (2011) in their intensive monitoring of the young (7-25 Myr) 25 Ori association as part of the Palomar Transient Factory (PTF) Orion project. However, because of the brightness of the system (Rc = 12.7 mag), their instruments could only accurately monitor the binary during its deep (0.6 mag in Rc) total eclipse. They did not observe enough eclipses to reliably determine a period and no secondary eclipse was ever detected. GSC 118-199 was observed at Eastern University from Feb 2011 - Mar 2013 in order to discover the period and subsequently analyze the light curve of this presumably very young totally eclipsing system. More than 3500 observations in V and Rc were obtained and several primary and secondary eclipses were secured and an accurate period determined. The secondary eclipse depth was measured to be ~0.1 mag in Rc centered at 0.496P in phase. The ephemeris for the system has been determined to be 2455189.72682(5) + 6.185181(4) E. Preliminary light curve analyses indicate that the system is a detached, totally eclipsing binary, where the larger but less massive component is the cooler star by ~3000 K. The system also exhibits a slightly eccentric 0.02) orbit, a typical indicator of youth in a binary system. This poster will investigate the possible ramifications of the unusual nature of this young system with the hope that additional observations obtained in late 2013 will provide additional weight and clarity to the preliminary solution.

  18. A Catalog of Eclipsing Binaries and Variable Stars Observed with ASTEP 400 from Dome C, Antarctica

    NASA Astrophysics Data System (ADS)

    Chapellier, E.; Mékarnia, D.; Abe, L.; Guillot, T.; Agabi, K.; Rivet, J.-P.; Schmider, F.-X.; Crouzet, N.; Aristidi, E.

    2016-10-01

    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 eclipsing binaries (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.

  19. Light-time effect in two eclipsing binaries: NO Vul and EW Lyr

    NASA Astrophysics Data System (ADS)

    Bulut, A.; Bulut, I.; ćiçek, C.; Erdem, A.

    2017-02-01

    In this study, orbital period variations of two eclipsing binary systems (NO Vul and EW Lyr) were discussed. Possible light time effects due to third bodies in these systems were re-examined. The mass function and orbital period of hypothetical third bodies were calculated to be 0.000627 ± 0.000003 M⊙, 26.17 ± 0.05 years and 0.12682 ± 0.00003 M⊙, 77.23 ± 0.72 years for NO Vul and EW Lyr, respectively.

  20. Investigation of Cyclic O-C Changes in a Sample of Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Jableka, D.; Zola, S.; Riddle, R.; Baranec, C.; Law, N.

    2015-07-01

    In this work we present an analysis of cyclic or pseudo-cyclic O-C behavior in a sample of 29 eclipsing binaries, selected to exhibit large-amplitude changes in O-C. We attempt to explain the period variations by: 1) the light time travel effect due to an unseen third body orbiting a system; 2) a sudden jump in the linear ephemeris caused by either variations in the mass transfer rate or CME ejections. A search for tertiary components was carried out with adaptive optics imaging for six systems exhibiting the highest amplitude in their O-C diagrams.

  1. First Spectroscopic Solutions of Two Southern Eclipsing Binaries: HO Tel and QY Tel

    NASA Astrophysics Data System (ADS)

    Sürgit, D.; Erdem, A.; Engelbrecht, C. A.; van Heerden, P.; Manick, R.

    2015-07-01

    We present preliminary results from the analysis of spectroscopic observations of two southern eclipsing binary 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.

  2. Finding False Positives Planet Candidates Due To Background Eclipsing Binaries in K2

    NASA Astrophysics Data System (ADS)

    Mullally, Fergal; Thompson, Susan E.; Coughlin, Jeffrey; DAVE Team

    2016-06-01

    We adapt the difference image centroid approach, used for finding background eclipsing binaries, 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.

  3. The substellar companion in the eclipsing white dwarf binary SDSS J141126.20+200911.1

    NASA Astrophysics Data System (ADS)

    Littlefair, S. P.; Casewell, S. L.; Parsons, S. G.; Dhillon, V. S.; Marsh, T. R.; Gänsicke, B. T.; Bloemen, S.; Catalan, S.; Irawati, P.; Hardy, L. K.; Mcallister, M.; Bours, M. C. P.; Richichi, Andrea; Burleigh, M. R.; Burningham, B.; Breedt, E.; Kerry, P.

    2014-12-01

    We present high time resolution SDSS-g' and SDSS-z' light curves of the primary eclipse in SDSS J141126.20+200911.1, together with time-resolved X-Shooter spectroscopy and near-infrared (NIR) JHKs photometry. Our observations confirm the substellar nature of the companion, making SDSS J141126.20+200911.1 the first eclipsing white dwarf/brown dwarf binary known. We measure a (white dwarf model dependent) mass and radius for the brown dwarf companion of M2 = 0.050 ± 0.002 M⊙ and R2 = 0.072 ± 0.004 M⊙, respectively. The lack of a robust detection of the companion light in the z'-band eclipse constrains the spectral type of the companion to be later than L5. Comparing the NIR photometry to the expected white dwarf flux reveals a clear Ks-band excess, suggesting a spectral type in the range L7-T1. The radius measurement is consistent with the predictions of evolutionary models, and suggests a system age in excess of 3 Gyr. The low companion mass is inconsistent with the inferred spectral type of L7-T1, instead predicting a spectral type nearer T5. This indicates that irradiation of the companion in SDSS J141126.20+200911.1 could be causing a significant temperature increase, at least on one hemisphere.

  4. The chromospherically active, triple, ellipsoidal, and eclipsing binary HD 6286 = BE Piscium: a laboratory for binary evolution

    NASA Astrophysics Data System (ADS)

    Strassmeier, K. G.; Bartus, J.; Fekel, F. C.; Henry, G. W.

    2008-07-01

    Aims: We present a detailed analysis of the star HD 6286 = BE Psc from 16 years of spectroscopic observations and 18 seasons of photometric ones. The star is an evolved, chromospherically active, eclipsing binary, consisting of a K1 giant plus an F6 dwarf/subgiant in a circular orbit with a period of 35.671 days. A faint, close visual companion of spectral type ≈G0 makes the system triple. The orbital inclination of the eclipsing pair is 81.8deg. Methods: We have obtained simultaneous solutions with our extensive set of radial velocities and BVI light curves that include the star spot variability of the K giant, the ellipticity of the K giant, and the eclipses of the spectroscopic binary system. Results: Our spot solutions suggest persistent polar spots, one in each hemisphere, that are cooler than the surrounding photosphere by 810±150 K over the timespan of our observations. The K giant and the F6 dwarf/subgiant have masses of 1.56 M⊙ and 1.31 M⊙ and mean radii of 12.0 and 1.9 R⊙, respectively. The masses have uncertainties of just ≈1.5%. No irradiation effect was detected. We compared our results to theoretical evolutionary tracks that suggest an age for the system of ≈2.7 Gyr. The modest logarithmic lithium abundance of the primary of 1.30 (upper limit) indicates that the star may have already experienced its first dredge up. The rotation period of the primary is 35.49 ± 0.01 days and appears to be synchronized with the orbital period of the eclipsing pair to within 0.5%. Our data are inconclusive as to whether the secondary is synchronized. Conclusions: Circularization of the orbit has taken place, and we conclude that the rapid increase in the size of the K giant, as it evolved across the Hertzsprung gap and up the base of the giant branch, likely caused the orbit to become circular.

  5. Period Variations of the Eclipsing Binary Systems T LMi and VX Lac

    NASA Astrophysics Data System (ADS)

    Yılmaz, M.; İzci, D. D.; Gümüş, D.; Özavci, İ.; Selam, S. O.

    2015-07-01

    We present a period analysis of the two Algol-type eclipsing binary systems T LMi and VX Lac using all available times of minimum in the literature, as well as new minima obtained at the Ankara University Kreiken Observatory. The period analysis of T LMi suggests mass transfer between the components and also a third body that is dynamically bound to the binary system. The analysis of VX Lac also suggests mass transfer between the components, and the presence of a third and a fourth body under the assumption of a Light-Time Effect. In addition, the periodic variation of VX Lac was examined under the hypothesis of magnetic activity, and the corresponding parameters were derived. We report here the orbital parameters for both systems, along with the ones related to mass transfer, and those for the third and fourth bodies.

  6. Age and Metallicity Estimates for Moderate-Mass Stars in Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Kovaleva, D. A.

    2001-12-01

    We estimate the ages and metallicities for the components of 43 binary systems using a compilation of accurate observational data on eclipsing binaries for which lines of both components are visible in their spectra, together with two independent modern sets of stellar evolution models computed for a wide range of masses and chemical abundances. The uncertainties of the resulting values are computed, and their stability is demonstrated. The ages and metallicity are compared with those derived in other studies using different methods, as well as with independent estimates from photometric observations and observations of clusters. These comparisons con firm the reliability of our age estimates. The resulting metallicities depend significantly on the choice of theoretical model. Comparison with independent estimates favors the estimates based on the evolutionary tracks of the Geneva group.

  7. The unique eclipsing binary system V541 Cygni with relativistic apsidal motion

    NASA Astrophysics Data System (ADS)

    Khaliullin, K. F.

    1985-12-01

    The first photoelectric light curve has been obtained for the binary star V541 Cygni (B8.5 V+B8.7 V, P = 15d.34) discovered by Kulikowski (1948). The light curve exhibits extremely narrow and deep minima of almost equal depth. Photometric elements are determined. Very small relative radii, orbital inclination close to π/2, high eccentricity (e = 0.474), and favorable orientation of the line of apsides with respect to an observer, as well as close similarity of the components, render the V541 Cyg system unique among eclipsing binaries. The apsidal motion in this system has been detected. The observed rotation rate of the line of apsides, ωobs = 0°.090±0°.013 yr-1, agrees within the errors with the prediction by general relativity.

  8. ASAS LIGHT CURVES OF INTERMEDIATE-MASS ECLIPSING BINARY STARS AND THE PARAMETERS OF HI Mon

    SciTech Connect

    Williams, S. J.; Gies, D. R.; Matson, R. A.; Caballero-Nieves, S.; Helsel, J. W. E-mail: gies@chara.gsu.edu E-mail: scaballero@chara.gsu.edu

    2011-07-15

    We present a catalog of 56 candidate intermediate-mass eclipsing binary systems extracted from the third data release of the All Sky Automated Survey. We gather pertinent observational data and derive orbital properties, including ephemerides, for these systems as a prelude to anticipated spectroscopic observations. We find that 37 of the 56, or {approx}66%, of the systems are not identified in the Simbad Astronomical Database as known binaries. As a specific example, we show spectroscopic data obtained for the system HI Mon (B0 V + B0.5 V) observed at key orbital phases based on the computed ephemeris, present a combined spectroscopic and photometric solution for the system, and give stellar parameters for each component.

  9. ASAS Light Curves of Intermediate-mass Eclipsing Binary Stars and the Parameters of HI Mon

    NASA Astrophysics Data System (ADS)

    Williams, S. J.; Gies, D. R.; Helsel, J. W.; Matson, R. A.; Caballero-Nieves, S.

    2011-07-01

    We present a catalog of 56 candidate intermediate-mass eclipsing binary systems extracted from the third data release of the All Sky Automated Survey. We gather pertinent observational data and derive orbital properties, including ephemerides, for these systems as a prelude to anticipated spectroscopic observations. We find that 37 of the 56, or ~66%, of the systems are not identified in the Simbad Astronomical Database as known binaries. As a specific example, we show spectroscopic data obtained for the system HI Mon (B0 V + B0.5 V) observed at key orbital phases based on the computed ephemeris, present a combined spectroscopic and photometric solution for the system, and give stellar parameters for each component.

  10. Multi-band photometric study of the short-period eclipsing binary GR Boo

    NASA Astrophysics Data System (ADS)

    Wang, Daimei; Zhang, Liyun; Han, Xianming L.; Lu, Hongpeng

    2017-05-01

    We present BVRI light curves with complete phase coverage for the short-period (p = 0.377day) eclipsing binary star GR Boo. We carried out the observations using the SARA 90 cm telescope located at Kitt Peak National Observatory. We obtained six new light curve minimum times. By fitting all of the available O-C minimum times, we obtained an updated ephemeris that shows the orbital period of GR Boo is decreasing at a rate of P˙ = - 2.36 ×10-7 days/year. This decrease in its period can be explained by either mass transfer from the more massive component to the less massive one, or angular momentum exchange due to magnetic activities. We also obtained a set of revised orbital parameters using the Wilson & Devinney program. And finally, we concluded that GR Boo is a contact binary with a dark spot.

  11. Binary coalescence from case A evolution: mergers and blue stragglers

    NASA Astrophysics Data System (ADS)

    Chen, Xuefei; Han, Zhanwen

    2008-03-01

    We have constructed some main-sequence mergers from case A binary evolution and we have studied their characteristics using the stellar evolution code written by Eggleton. The values of both total mass and orbital angular momentum are conservative in our binary evolutions. Assuming that the matter from the secondary homogeneously mixes with the envelope of the primary and that no mass is lost from the system during the merger process, we found that some mergers might be on the left of the zero-age main sequence as defined by normal surface composition (i.e. helium content Y = 0.28 with metallicity Z = 0.02 for Population I) on a colour-magnitude diagram because of enhanced surface helium content. The study also shows that the central hydrogen content of the mergers is independent of mass. Our simple models can possibly explain a few blue stragglers observed on the left of zero-age main sequence in some clusters. However, the concentration towards the blue side of the main sequence with decreasing mass, as predicted by Sandquist et al., will not appear in our models. The products with little central hydrogen in our models are probably subgiants when they are formed, as the primaries in the progenitors also have little central hydrogen and will likely leave the main sequence during the merger process. As a consequence, we fit the formula of magnitude Mv and B-V of the mergers when they return to thermal equilibrium with maximum errors 0.29 and 0.037, respectively. Taking the above into account, we performed Monte Carlo simulations to examine our models in an old open cluster NGC 2682 and an intermediate-age cluster NGC 2660. The angular momentum loss (AML) of low-mass binaries is very important in NGC 2682, and its effect can be estimated in a simple way. In NGC 2682, binary mergers from our models cover the region with high luminosity and those from the AML are located in the region with low luminosity, which has a certain width. The blue stragglers from the AML are

  12. RXJ2130.6+4710 - an eclipsing white dwarf-M-dwarf binary star

    NASA Astrophysics Data System (ADS)

    Maxted, P. F. L.; Marsh, T. R.; Morales-Rueda, L.; Barstow, M. A.; Dobbie, P. D.; Schreiber, M. R.; Dhillon, V. S.; Brinkworth, C. S.

    2004-12-01

    We report the detection of eclipses in the close white-dwarf-M-dwarf binary star RXJ2130.6+4710. We present light curves in the B, V and I bands and fast photometry obtained with the three-channel CCD photometer Ultracam of the eclipse in the u', g' and r' bands. The depth of the eclipse varies from 3.0 mag in the u' band to less than 0.1 mag in the I band. The times of mid-eclipse are given by the ephemeris BJD(mid-eclipse) = 2452785.681876(2) + 0.521035625(3) E, where figures in parentheses denote uncertainties in the final digit. We present medium-resolution spectroscopy from which we have measured the spectroscopic orbits of the M dwarf and white dwarf. We estimate that the spectral type of the M dwarf is M3.5Ve or M4Ve, although the data on which this is based are not ideal for spectral classification. We have compared the spectra of the white dwarf with synthetic spectra from pure hydrogen model atmospheres to estimate that the effective temperature of the white dwarf is Teff= 18000 +/- 1000 K. We have used the width of the primary eclipse and duration of totality measured precisely from the Ultracam u' data combined with the amplitude of the ellipsoidal effect in the I band and the semi-amplitudes of the spectroscopic orbits to derive masses and radii for the M dwarf and white dwarf. The M dwarf has a mass of 0.555 +/- 0.023 Msolar and a radius of 0.534 +/- 0.053 Rsolar, which is a typical radius for stars of this mass. The mass of the white dwarf is 0.554 +/- 0.017 Msolar and its radius is 0.0137 +/- 0.0014 Rsolar, which is the radius expected for a carbon-oxygen white dwarf of this mass and effective temperature. The light curves are affected by frequent flares from the M dwarf and the associated dark spots on its surface can be detected from the distortions to the light curves and radial velocities. RXJ2130.6+4710 is a rare example of a pre-cataclysmic variable star that will start mass transfer at a period above the period gap for cataclysmic variables.

  13. Detection of the Second Eclipsing High-Mass X-Ray Binary in M 33

    NASA Astrophysics Data System (ADS)

    Pietsch, Wolfgang; Haberl, Frank; Gaetz, Terrance J.; Hartman, Joel D.; Plucinsky, Paul P.; Tüllmann, Ralph; Williams, Benjamin F.; Shporer, Avi; Mazeh, Tsevi; Pannuti, Thomas G.

    2009-03-01

    Chandra data of the X-ray source [PMH2004] 47 were obtained in the ACIS Survey of M 33 (ChASeM33) in 2006. During one of the observations, the source varied from a high state to a low state and back, in two other observations it varied from a low state to respectively intermediate states. These transitions are interpreted as eclipse ingresses and egresses of a compact object in a high-mass X-ray binary (HMXB) system. The phase of mideclipse is given by HJD 245 3997.476 ± 0.006, the eclipse half angle is 30fdg6 ± 1fdg2. Adding XMM-Newton observations of [PMH2004] 47 in 2001 we determine the binary period to be 1.732479 ± 0.000027 days. This period is also consistent with ROSAT HRI observations of the source in 1994. No short-term periodicity compatible with a rotation period of the compact object is detected. There are indications for a long-term variability similar to that detected for Her X-1. During the high state the spectrum of the source is hard (power-law spectrum with photon index ~0.85) with an unabsorbed luminosity of 2 ×1037 erg s-1 (0.2-4.5 keV). We identify as an optical counterpart a V ~ 21.0 mag star with T eff>19000 K, log(g)>2.5. The Canada-France-Hawaii Telescope optical light curves for this star show an ellipsoidal variation with the same period as the X-ray light curve. The optical light curve together with the X-ray eclipse can be modeled by a compact object with a mass consistent with a neutron star or a black hole in an HMXB. However, the hard power-law X-ray spectrum favors a neutron star as the compact object in this second eclipsing X-ray binary in M 33. Assuming a neutron star with a canonical mass of 1.4 M sun and the best-fit companion temperature of 33,000 K, a system inclination i = 72° and a companion mass of 10.9 M sun are implied.

  14. 2MASS J05162881+2607387: A New Low-mass Double-lined Eclipsing Binary

    NASA Astrophysics Data System (ADS)

    Bayless, Amanda J.; Orosz, Jerome A.

    2006-11-01

    We show that the star known as 2MASS J05162881+2607387 (hereafter J0516) is a double-lined eclipsing binary with nearly identical low-mass components. The spectroscopic elements derived from 18 spectra obtained with the High Resolution Spectrograph on the Hobby-Eberly Telescope during the fall of 2005 are K1=88.45+/-0.48 and K2=90.43+/-0.60 km s-1, resulting in a mass ratio of q=K1/K2=0.978+/-0.018 and minimum masses of M1sin3i=0.775+/-0.016 Msolar and M2sin3i=0.759+/-0.012 Msolar, respectively. We have extensive differential photometry of J0516 obtained over several nights between 2004 January and March (epoch 1) and between 2004 October and 2005 January plus 2006 January (epoch 2) using the 1 m telescope at the Mount Laguna Observatory. The source was roughly 0.1 mag brighter in all three bandpasses during epoch 1 when compared to epoch 2. Also, phased light curves from epoch 1 show considerable out-of-eclipse variability, presumably due to bright spots on one or both stars. In contrast, the phased light curves from epoch 2 show little out-of-eclipse variability. The light curves from epoch 2 and the radial velocity curves were analyzed using our ELC code with updated model atmospheres for low-mass stars. We find the following: M1=0.787+/-0.012 Msolar, R1=0.788+/-0.015 Rsolar, M2=0.770+/-0.009 Msolar, and R2=0.817+/-0.010 Rsolar. The stars in J0516 have radii that are significantly larger than model predictions for their masses, similar to what is seen in a handful of other well-studied low-mass double-lined eclipsing binaries. We compiled all recent mass and radius determinations from low-mass binaries and determine an empirical mass-radius relation of the form R(Rsolar)=0.0324+0.9343M(Msolar)+0.0374M2(Msolar). Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg

  15. The atmospheric structures of the companion stars of eclipsing binary x ray sources

    NASA Technical Reports Server (NTRS)

    Clark, George W.

    1992-01-01

    This investigation was aimed at determining structural features of the atmospheres of the massive early-type companion stars of eclipse x-ray pulsars by measurement of the attenuation of the x-ray spectrum during eclipse transitions and in deep eclipse. 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 eclipse 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 binaries 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.

  16. KIC 6220497: a new Algol-type eclipsing binary with multiperiodic pulsations

    NASA Astrophysics Data System (ADS)

    Lee, Jae Woo; Hong, Kyeongsoo; Kim, Seung-Lee; Koo, Jae-Rim

    2016-08-01

    We present both binarity and pulsation of KIC 6220497 from the Kepler observations. The light curve synthesis shows that the eclipsing 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 eclipse-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 eclipsing 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 eclipsing binary, compared with normal oEA stars.

  17. Orbital period variations of the eclipsing binaries TU Cnc, VZ Leo, and OS Ori

    NASA Astrophysics Data System (ADS)

    Khaliullina, A. I.

    2017-10-01

    Variations of the orbital periods of the eclipsing binaries TU Cnc, VZ Leo, and OS Ori are analyzed. Secular period decreases were earlier believed to occur in these systems. It is demonstrated that the period variations of TU Cnc can be represented using the light-time effect corresponding to the orbital motion of the eclipsing binary with a period of 78.6 years around the center ofmass of the triple system, with the mass of the third body being M 3 > 0.82 M ⊙. With the same accuracy, the period variations of VZ Leo and OS Ori can be represented either solely using the light-time effect, or a superposition of a secular period decrease and the light-time effect. For VZ Leo, the period of the long-term orbit is 63.8 years in the former case and 67.9 years in the latter case. Similar masses for the third body are indicated in both cases: M 3 > 0.55 M ⊙ and M 3 > 0.61 M ⊙. For OS Ori, the period of the long-term orbit is 46 years and M 3 > 0.5 M ⊙ in the former case, and the period is 36 years and M 3 > 0.6 M ⊙ in the latter case.

  18. On a possible additional component in an eclipsing binary system HS 2231 + 2441

    NASA Astrophysics Data System (ADS)

    Vidmachenko, A. P.; Romanyuk, Ya. O.; Shliahetskaya, Ya. O.

    2016-05-01

    Timing method based on the registration period of variations of a periodic process, associated with the star. The study of stellar eclipsing binary 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 eclipses. 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 binary 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

  19. ANALYSIS OF SPIN-ORBIT MISALIGNMENT IN THE ECLIPSING BINARY DI HERCULIS

    SciTech Connect

    Philippov, Alexander A.; Rafikov, Roman R.

    2013-05-10

    The eclipsing binary 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 binary 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 eclipses 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.

  20. APSIDAL MOTION AND A LIGHT CURVE SOLUTION FOR 13 LMC ECCENTRIC ECLIPSING BINARIES

    SciTech Connect

    Zasche, P.; Wolf, M.; Vraštil, J.; Pilarcik, L.

    2015-12-15

    New CCD observations for 13 eccentric eclipsing binaries 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 binaries 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 eclipsing 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.

  1. V850 Cyg: An eclipsing binary with a giant γ Dor pulsator

    NASA Astrophysics Data System (ADS)

    Çakırlı, Ö.; Ibanoglu, C.; Sipahi, E.; Akan, M. C.

    2017-04-01

    We present new spectroscopic observations of the double-lined eclipsing binary V850 Cyg. The long-cadence photometric observations obtained by Kepler were analysed and combined with the analysis of radial velocities for deriving the absolute parameters of the components. Masses and radii were determined as Mp=1.601 ± 0.076 M⊙ and Rp=4.239 ± 0.076 R⊙, Ms=0.851 ± 0.053 M⊙ and Rs=5.054 ± 0.087 R⊙ for the components of V850 Cyg. We estimate an interstellar reddening of 0.28 ± 0.12 mag and a distance of 1040 ± 160 pc for the system. The measured rotational velocity of the secondary appears to lower than that of synchronize rotation. However its spectral lines are too weak to be measured the rotational velocity with reasonable accuracy. We have extracted the synthetic light curve from the observations and excluded the data within the eclipses for the frequency analysis. We obtained at least nine frequencies in the γ Dor regime. It seems that the primary component oscillates with a dominant period of about 1.152549 ± 0.000009 days. We also compare pulsational properties of the primary star of V850 Cyg with the γ Dor type pulsating components in other binaries.

  2. New planetary and eclipsing binary candidates from campaigns 1-6 of the K2 mission

    NASA Astrophysics Data System (ADS)

    Barros, S. C. C.; Demangeon, O.; Deleuil, M.

    2016-10-01

    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 eclipsing binary candidates from campaigns 1, 2, 3, 4, 5, and 6 of K2. Both the planetary candidates and eclipsing binary 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

  3. Detached Red Giant Eclipsing Binary Twins: Rosetta Stones to the Galactic Bulge

    NASA Astrophysics Data System (ADS)

    Nataf, D. M.; Gould, A.; Pinsonneault, M. H.

    2012-03-01

    We identify 34 highly-probable detached, red giant eclipsing binary pairs among 315 candidates in Devor's catalog of ≍10 000 OGLE-II eclipsing binaries. We estimate that there should be at least 200 such systems in OGLE-III. We show that spectroscopic measurements of the metallicities and radial-velocity-derived masses of these systems would independently constrain both the age-metallicity and helium-metallicity relations of the Galactic bulge, potentially breaking the age-helium degeneracy that currently limits our ability to characterize the bulge stellar population. Mass and metallicity measurements alone would be sufficient to immediately validate or falsify recent claims about the age and helium abundance of the bulge. A spectroscopic survey of these systems would constrain models of Milky Way assembly, as well as provide significant auxiliary science on research questions such as mass loss on the red giant branch. We discuss the theoretical uncertainties in stellar evolution models that would need to be accounted for to maximize the scientific yield.

  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. Constraining Kepler Eclipsing Binary Properties with Time-Series and Multi-band Photometry

    NASA Astrophysics Data System (ADS)

    Windemuth, Diana; Agol, Eric

    2015-01-01

    We perform simultaneous fits to time-series (Kepler) and multi-band (SDSS griz + 2MASS JHKs) photometry to constrain stellar and orbital parameters of eclipsing binaries (EBs) from the Kepler Eclipsing Binary Catalogue. We infer the stellar parameters by comparing Padova stellar evolution models to the extinction-corrected multi-band photometric data, and use the results as inputs to a Keplerian orbit model for the lightcurves. This method yields a self-consistent analysis and jointly constrains properties of both stars (orbital elements e, ω, i, tpe, p + stellar parameters rA, rB, mA, mB, fB/fA, [Fe/H], age, and quadratic limb darkening coefficients uA1, uA2, uB1, uB2). We apply our coupled time-series photometry and SED model to a sub-sample of detached EBs with p = 10 - 40 d, to minimize the influence of tidal or Doppler effects. The results of this analysis will feed into our circumbinary planet search, wherein we apply barycentric corrections to the Kepler EB lightcurves to look for signals due to planetary companions.

  6. Artificial Neural Network Solutions to Eclipsing Binary Lightcurves from the Kepler Space Telescope Database

    NASA Astrophysics Data System (ADS)

    Hause, Connor; Prsa, Andrej; Matijevic, Gal; Guinan, Edward F.

    2017-01-01

    Fully automated methods of data analysis are necessary for surpassing the human bottleneck in astrophysical data processing and maximizing scientific results from the great volume of observations to be taken over the next few decades. Prsa et al. (2008, ApJ, 687:542) addressed this issue by introducing an artificial neural network (ANN) which estimates the principal parameters of detached eclipsing binary (EB) stars. Parameters obtained by the process can be passed on to advanced modeling engines to produce a qualified EB database. The ANN was originally developed and trained for the OGLE EBs. Our project focuses on retraining this ANN for EBs from NASA’s Kepler Space Telescope database and serves as an extension to the eclipsing binaries via artificial intelligence (EBAI) project. The Kepler photometry is much more precise than photometry available from OGLE and other previous ground-based studies.. For our training set, we generated theoretical lightcurves via a Monte Carlo based Python script utilizing PHOEBE which samples EB parameter values according to prior distribution functions. Novel to our analysis is the use of chi-squared statistical tests which serve to qualify the overlap between the calculated exemplars and observed data. This enables the trained ANN to more accurately parameterize each EB. We describe our training process, present principal parameter estimates of Kepler EBs obtained by the ANNs, and discuss ongoing endeavors to refine those solutions. This research was supported by the National Science Foundation grant #1517474 which we gratefully acknowledge.

  7. Long-term eclipse timing of white dwarf binaries: an observational hint of a magnetic mechanism at work

    NASA Astrophysics Data System (ADS)

    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.

    2016-08-01

    We present a long-term programme for timing the eclipses of white dwarfs in close binaries to measure apparent and/or real variations in their orbital periods. Our programme includes 67 close binaries, 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 eclipses. 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 binaries with baselines exceeding 10 yr, with secondaries of spectral type K2 - M5.5, show variations in the eclipse arrival times that in most cases amount to several minutes. In addition, among those with baselines shorter than 10 yr, binaries 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 binary orbits. We also present new eclipse 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 binaries in the eclipse timing programme, and therefore cannot yet draw robust conclusions about the cause of orbital period variations in evolved, white dwarf binaries.

  8. A LONG-PERIOD TOTALLY ECLIPSING BINARY STAR AT THE TURNOFF OF THE OPEN CLUSTER NGC 6819 DISCOVERED WITH KEPLER

    SciTech Connect

    Sandquist, Eric L.; Orosz, Jerome A.; Jeffries, Mark W. Jr.; Brewer, Lauren N. E-mail: orosz@sciences.sdsu.edu; and others

    2013-01-01

    We present the discovery of the totally eclipsing long-period (P = 771.8 days) binary system WOCS 23009 in the old open cluster NGC 6819 that contains both an evolved star near central hydrogen exhaustion and a low-mass (0.45 M {sub Sun }) star. This system was previously known to be a single-lined spectroscopic binary, but the discovery of an eclipse 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 eclipsing binaries in the cluster. The combination of the total eclipses 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 binaries, the low-mass 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 binaries, 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%.

  9. Measuring tides and binary parameters from gravitational wave data and eclipsing timings of detached white dwarf binaries

    SciTech Connect

    Shah, Sweta; Nelemans, Gijs

    2014-08-20

    The discovery of the most compact detached white dwarf (WD) binary 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 binaries with P {sub orb} ≲ 5 hr. We address the prospects of performing tidal studies using eLISA binaries 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 binaries. We find that f-dot and f{sup ¨} can be measured using GW data only for the most massive WD binaries observed at high frequencies. From timing the eclipses 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 binaries is (almost) impossible. We also investigate the improvement in the knowledge of the binary 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 binary parameters.

  10. DETERMINING THE AGE OF THE KEPLER OPEN CLUSTER NGC 6819 WITH A NEW TRIPLE SYSTEM AND OTHER ECLIPSING BINARY STARS

    SciTech Connect

    Brewer, Lauren N.; Sandquist, Eric L.; Jeffries, Mark W. Jr.; Orosz, Jerome A.; and others

    2016-03-15

    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 BVR{sub C}I{sub C}) and spectroscopic observations of the detached eclipsing binary 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 eclipsing binary using radial velocities and eclipse timing variations. The eclipsing binary components have masses M{sub B} = 1.090 ± 0.010 M{sub ⊙} and M{sub C} = 1.075 ± 0.013 M{sub ⊙}, and radii R{sub B} = 1.099 ± 0.006 ± 0.005 R{sub ⊙} and R{sub C} = 1.069 ± 0.006 ± 0.013 R{sub ⊙}. The bright non-eclipsing star resides at the cluster turnoff, and ultimately its mass will directly constrain the turnoff mass: our preliminary determination is M{sub A} = 1.251 ± 0.057 M{sub ⊙}. A careful examination of the light curves indicates that the fainter star in the eclipsing binary undergoes a very brief period of total eclipse, 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 eclipsing stars in NGC 6819 (WOCS 40007 and WOCS 23009) en route to a combined determination of the cluster’s distance modulus (m − M){sub 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 eclipsing binary 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.

  11. V342 Andromedae B is an eccentric-orbit eclipsing binary

    NASA Astrophysics Data System (ADS)

    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.

    2015-03-01

    We present a photometric and spectroscopic study of the visual binary 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 binary 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 eclipsing binary 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 eclipsing 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.

  12. The Eclipsing Binary Di Herculis: One Mystery Solved, But Another Takes Its Place

    NASA Astrophysics Data System (ADS)

    Zimmerman, Nicole; Guinan, E.; Maloney, F.

    2010-01-01

    The 8th-mag eclipsing binary DI Herculis has perplexed scientists for the past few decades due to its anomalously slow apsidal motion rate. DI Her consists of two main-sequence stars (B5V, B6V), with P(orb) = 10.55 days, and eccentricity(e= 0.489). Since the apsidal motion is dominated by General Relativity, the system is one of the few tests available for verifying the theory. Combining the expected classical (1.93°/100 yr) and relativistic (2.34°/100 yr) effects, the predicted apsidal motion rate is 4.27°/100 yr. Our recent determination of the apsidal motion yields 1.33°+/-0.25 /100 yr, based on eclipse timings from 1936-2008. Recently, Albrecht et al (2009, Nature 461) have apparently solved the apsidal motion anomaly of DI Her, finding that the axes of both stars are significantly inclined from the normal to the orbital plane. This was determined from the radial velocity curves and observing the Rossiter-McLaughlin effect during primary and secondary eclipses. Having significantly misaligned axes of rotation produces a perturbation that greatly reduces the classical apsidal motion effect, thus explaining the observed small apsidal motion rate. Even though this discovery apparently solves the problem, it raises new questions as to how the axes are so tilted. Additionally, tilted axes are expected to contribute to other orbital effects, such as changes in orbital inclination, which have not yet observed from the apparent constancy in eclipse depths over time. We have also searched for evidence of small periodic oscillations in the eclipse timings and found no evidence of a light travel time effect arising from a possible tertiary component. Further, we find evidence that the projected rotation axes of the stars may be precessing, since it appears that the value of V(rot)sini has increased over the past 30 years. This research was supported by NSF/RUI Grants AST05-07536/42.

  13. Erratum: "B.R.N.O. Contributions #38 Times of minima of eclipsing binary" (OEJV #160, [2013])

    NASA Astrophysics Data System (ADS)

    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.

    2014-08-01

    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 eclipsing binary" paper. The correct minima timings are presented hereafter.

  14. 1SWASP J200503.05-343726.5: A high mass ratio eclipsing binary near the period limit

    NASA Astrophysics Data System (ADS)

    Bin, Zhang; Shengbang, Qian; Zejda, Miloslav; Liying, Zhu; Nianping, Liu

    2017-07-01

    First CCD photometric light curves of the eclipsing binary system 1SWASP J200503.05-343726.5 are presented. Our complete light curves in V, R and I bands using the Bessell filter show an out-of-eclipsing distortion, which means that the components of the system may be active. The preliminary photometric solutions with a cool star-spot are derived by using the 2013 version of the Wilson-Devinney (W-D) code. The photometric solutions suggest that 1SWASP J200503.05-343726.5 is a shallow-contact eclipsing binary(f = 9.0 %) with a mass ratio of q = 1.0705 , which is very high for late-type binary systems near the period limit. The primary component is about 230 K hotter than the secondary component. Based on our new CCD eclipse times, the orbital period change was analyzed. According to O - C diagram, the orbital period of the 1SWASP J200503.05-343726.5 shows an increase at a rate of P˙ = + 5.43 ×10-8 days year-1. The period increase may be caused by mass transfer from the less massive component to the more massive one. This shallow-contact system may be formed from a detached short-period binary via orbital shrinkage because of dynamical interactions with a third component or by magnetic braking.

  15. Spectroscopic Results From Blue Hills Observatory of the 2009-2011 Eclipse of epsilon Aurigae

    NASA Astrophysics Data System (ADS)

    Gorodenski, S. A.

    2012-02-01

    The purpose of this paper is to report spectroscopic results of epsilon Aurigae during the 2009-2011 eclipse. Spectra of the sodium D lines and an absorption line occurring at approximately 5853Å were taken from February 13, 2010, to October 10, 2011, with an LHIRES III spectrograph and a 16-inch Meade telescope at Blue Hills Observatory in Dewey, Arizona. Equivalent width and radial velocity data support the presence of a void or ring structure within the eclipsing disk, and they support a central disk clearing around an unseen primary central object. The results also indicate the disk does not end at fourth contact but continues for a significant distance. Analysis of radial velocities demonstrated the profile of the 5853Å line has a disk component in addition to the primary F0 star component. A split line at this location was observed. From the equivalent width profile of the 5853Å line the duration of the split line event was estimated to be 101 days. Other lesser results are presented and discussed.

  16. Binary Evolution: Roche Lobe Overflow and Blue Stragglers

    NASA Astrophysics Data System (ADS)

    Ivanova, Natalia

    One of the principal mechanisms that is responsible for the origin of blue stragglers is mass transfer that takes place while one of the binary companions overfills its Roche lobe. In this Chapter, we overview the theoretical understanding of mass transfer via Roche lobe overflow: classification, how both the donor and of the accretor respond to the mass transfer on different timescales (adiabatic response, equilibrium response, superadiabatic response, time-dependent response) for different types of their envelopes (convective and radiative). These responses, as well as the assumption on how liberal the process is, are discussed in terms of the stability of the ensuing mass transfer. The predictions of the theory of mass transfer via Roche lobe overflow are then briefly compared with the observed mass-transferring systems with both degenerate and non-degenerate donors. We conclude with the discussion which cases of mass transfer and which primordial binaries could be responsible for blue stragglers formation via Roche lobe overflow, as well as how this can be enhanced for blue stragglers formed in globular clusters

  17. Orbital and physical parameters of eclipsing binaries from the ASAS catalogue - VIII. The totally eclipsing double-giant system HD 187669

    NASA Astrophysics Data System (ADS)

    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.

    2015-04-01

    We present the first full orbital and physical analysis of HD 187669, recognized by the All-Sky Automated Survey (ASAS) as the eclipsing binary 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) eclipse, lasting for about 6 d. A spectrum obtained during this eclipse 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 binary 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 eclipsing binary measured with such good accuracy, and as such it is a unique benchmark for studying the late stages of stellar evolution.

  18. Physical properties and catalog of EW-type eclipsing binaries observed by LAMOST

    NASA Astrophysics Data System (ADS)

    Qian, Sheng-Bang; He, Jia-Jia; Zhang, Jia; Zhu, Li-Ying; Shi, Xiang-Dong; Zhao, Er-Gang; Zhou, Xiao

    2017-08-01

    EW-type eclipsing binaries (hereafter called EWs) are strong interacting systems in which both component stars usually fill their critical Roche lobes and share a common envelope. Numerous EWs were discovered by several deep photometric surveys and there were about 40 785 EW-type binary systems listed in the international variable star index (VSX) by 2017 March 13. 7938 of them were observed with LAMOST by 2016 November 30 and their spectral types were identified. Stellar atmospheric parameters of 5363 EW-type binary stars were determined based on good spectroscopic observations. In the paper, those EWs are cataloged and their properties are analyzed. The distributions of orbital period (P), effective temperature (T), gravitational acceleration (log(g)), metallicity ([Fe/H]) and radial velocity (RV) are presented for these observed EW-type systems. It is shown that about 80.6% of sample stars have metallicity below zero, indicating that EW-type systems are old stellar populations. This is in agreement with the conclusion that EW binaries are formed from moderately close binaries through angular momentum loss via magnetic braking that takes a few hundred million to a few billion years. The unusually high metallicities of a few percent of EWs may be caused by contamination of material from the evolution of unseen neutron stars or black holes in the systems. The correlations between orbital period and effective temperature, gravitational acceleration and metallicity are presented and their scatters are mainly caused by (i) the presence of third bodies and (ii) sometimes wrongly determined periods. It is shown that some EWs contain evolved component stars and the physical properties of EWs mainly depend on their orbital periods. It is found that extremely short-period EWs may be older than their long-period cousins because they have lower metallicities. This reveals that they have a longer timescale of pre-contact evolution and their formation and evolution aremainly

  19. DIRECT Distances to Nearby Galaxies Using Detached Eclipsing Binaries and Cepheids. IX. Variables in the Field M31Y Discovered with Image Subtraction

    NASA Astrophysics Data System (ADS)

    Bonanos, A. Z.; Stanek, K. Z.; Sasselov, D. D.; Mochejska, B. J.; Macri, L. M.; Kaluzny, J.

    2003-07-01

    The DIRECT Project aims to obtain direct distances to two Local Group galaxies, M31 and M33, which occupy a crucial position near the base of the cosmological distance ladder. The first step is to search for detached eclipsing binaries (DEBs) and Cepheids using 1 m class telescopes to select good candidates, which will be followed up spectroscopically on 6.5-10 m class telescopes. In this ninth paper, we present a catalog of variable stars discovered with image subtraction in field M31Y (α=10.97d, δ=41.69d J2000.0). The data were obtained with the Fred Lawrence Whipple Observatory 1.2 m telescope on 25 nights, over a period of 6 months. In our search covering 22'×22', we discovered 41 eclipsing binaries, 126 Cepheids, and 97 other periodic or nonperiodic variables, including a luminous blue variable candidate, a nova, and a Galactic cataclysmic variable. The catalog of variables, as well as their photometry and finding charts, is available electronically via anonymous ftp and the World Wide Web. The complete set of the CCD frames is available upon request.

  20. Eclipse timing variations to detect possible Trojan planets in binary systems

    NASA Astrophysics Data System (ADS)

    Schwarz, R.; Bazsó, Á.; Funk, B.; Zechner, R.

    2015-11-01

    This paper is devoted to study the circumstances favourable to detect Trojan planets in close binary star systems by the help of eclipse timing variations (ETVs). To determine the probability of the detection of such variations with ground-based telescopes and space telescopes (like former missions CoRoT and Kepler and future space missions like PLATO, TESS and CHEOPS), we investigated the dynamics of binary star systems with a planet in tadpole motion. We did numerical simulations by using the full three-body problem as a dynamical model. The stability and the ETVs are investigated by computing stability/ETV maps for different masses of the secondary star and the Trojan planet. In addition, we changed the eccentricity of the possible Trojan planet. By the help of the libration amplitude σ, we could show whether or not all stable objects are moving in tadpole orbits. We can conclude that many amplitudes of ETVs are large enough to detect Earth-like Trojan planets in binary star systems. As an application, we prepared a list of possible candidates.

  1. Discovery of a double eclipsing binary with periods near a 3:2 ratio

    NASA Astrophysics Data System (ADS)

    Cagaš, P.; Pejcha, O.

    2012-08-01

    The evolution of multiple stellar systems can be driven by Kozai cycles and tidal friction (KCTF), which shrink the orbit of the inner binary. There is an interesting possibility that two close binaries on a common long-period orbit experience mutually-induced KCTF. We present the discovery of a possible new quadruple system composed of two unresolved eclipsing binaries (EBs), CzeV343 (V ~ 13.5 mag). We obtained photometric observations of CzeV343 that completely cover the two orbital periods and we successfully model the light curves as the sum of two detached EBs. We provide confidence intervals for the model parameters and minima timings by bootstrap resampling of our data. One of the EBs shows a distinctly eccentric orbit with a total eccentricity of about 0.18. The two orbital periods, 1.20937 and 0.80693 days, are within 0.1% of a 3:2 ratio. We speculate that this might be the result of KCTF-driven evolution of a quadruple system and we discuss this hypothesis in the context of other quadruple systems composed of two EBs. We make our double EB fitting code publicly available to provide a tool for long-term monitoring of the mutual orbit in such systems. Photometric measurements are only available 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/544/L3

  2. The Detached Eclipsing Binary KV 29 and the Age of the Open Cluster M11

    NASA Astrophysics Data System (ADS)

    Bavarsad, Ernest A.; Sandquist, Eric L.; Shetrone, Matthew D.; Orosz, Jerome A.

    2016-11-01

    We present an extensive set of photometry and radial velocities for the detached eclipsing binary 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 binary to be 4.64276 ± 0.00001 days. We find masses {3.604}-0.011+0.002{M}⊙ and {1.837}-0.006+0.001{M}⊙ and radii {5.392}-0.035+0.018{R}⊙ and {1.656}-0.044+0.007{R}⊙ for the primary and secondary stars, respectively. Because the primary star in the binary 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.

  3. A new look at the long-period eclipsing binary V383 Scorpii

    NASA Astrophysics Data System (ADS)

    Gałan, C.; Tomov, T.; Kato, T.; Pojmański, G.; Szczygieł, D. M.; Pilecki, B.; Graczyk, D.; Gromadzki, M.; Mikołajewski, M.; Gieren, W.; Strobel, A.; Roukema, B. F.

    2013-02-01

    Context. The system V383 Sco was discovered to be an eclipsing binary star at the beginning of the twentieth century. This system has one of the longest orbital periods known (13.5 yr) and was initially classified as a ζAur-type eclipsing variable. It was then forgotten about for decades, with no progress made in understanding it. Aims: This study provides a detailed look at the system V383 Sco, using new data obtained before, during, and after the last eclipse, which occurred in 2007/8. There was a suspicion that this system could be similar to eclipsing systems with extensive dusty disks like EE Cep and ɛ Aur. This and other, alternative hypotheses are considered here. Methods: The All Sky Automated Survey (ASAS-3) V and I light curves have been used to examine apparent magnitude and colour changes. Low- and high-resolution spectra have been obtained and used for spectral classification, to analyse spectral line profiles, as well as to determine the reddening, radial velocities and the distance to the system. The spectral energy distribution (SED) was analysed using all available photometric and spectroscopic data. Using our own original numerical code, we performed a very simplified model of the eclipse, taking into account the pulsations of one of the components. Results: The low-resolution spectrum shows apparent traces of molecular bands, characteristic of an M-type supergiant. The presence of this star in the system is confirmed by the SED, by a strong dependence of the eclipse depth on the photometric bands, and by the nature of pulsational changes. The presence of a very low excitation nebula around the system has been inferred from [O i] 6300 Å emission in the high-resolution spectrum. Analysis of the radial velocities, reddening, and period-luminosity relation for Mira-type stars imply a distance to the V383 Sco system of 8.4 ± 0.6 kpc. The distance to the nearby V381 Sco is 6.4 ± 0.8 kpc. The very different and oppositely directed radial velocities

  4. 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

  5. Photometric study and absolute parameters of the short-period eclipsing binary HH Bootis

    NASA Astrophysics Data System (ADS)

    Gürol, B.; Bradstreet, D. H.; Demircan, Y.; Gürsoytrak, S. H.

    2015-11-01

    We present the results of our investigation on the geometrical and physical parameters of the W UMa type binary system HH Bootis from new CCD (BVRI) light curves and published radial velocity data. The photometric data were obtained in 2011 and 2012 at Ankara University Observatory (AUO). Light and radial velocity observations were analyzed simultaneously using the Wilson-Devinney (2013 revision) code to obtain absolute and geometrical parameters. The system was determined to be a W-type W UMa system of a type different from that suggested by Dal and Sipahi (2013). An interesting cyclic period variation in the time intervals between primary and secondary eclipses ("half-period variation") was discovered and analyzed and its possible cause is discussed. Combining our photometric solution with the spectroscopic data we derived masses and radii of the eclipsing system to be M1 = 0.627M⊙ , M2 = 1.068M⊙ , R1 = 0.782R⊙ and R2 = 0.997R⊙ . New light elements were derived and finally the evolutionary status of the system is discussed.

  6. HS 0705+6700: a New Eclipsing sdB Binary

    NASA Astrophysics Data System (ADS)

    Drechsel, H.; Heber, U.; Napiwotzki, R.; Ostensen, R.; Solheim, J.-E.; Deetjen, J.; Schuh, S.

    HS 0705+6700 is a newly discovered eclipsing sdB binary system consisting of an sdB primary and a cool secondary main sequence star. CCD photometry obtained in October and November 2000 with the 2.5m Nordic (NOT) telescope (La Palma, Tenerife) in the B passband and with the 2.2m Calar Alto telescope (CAFOS, R filter) yielded eclipse light curves with complete orbital phase coverage at high time resolution. A periodogram analysis of 12 primary minimum times distributed over the time span from October 2000 to March 2001 allowed to derive the following exact period and linear ephemeris: prim. min. = HJD 2451822.759782(22) + 0.09564665(39) ṡ E A total of 15 spectra taken with the 3.5m Calar Alto telescope (TWIN spectrograph) on March 11-12, 2001, were used to establish the radial velocity curve of the primary star (K1 = 85.8 km/s) , and to determine its basic atmospheric parameters (Teff = 29300 K, log g = 5.47). The B and R light curves were solved using our Wilson-Devinney based light curve analysis code MORO (Drechsel et al. 1995, A&A 294, 723). The best fit solution yielded exact system parameters consistent with the spectroscopic results. Detailed results will be published elsewhere (Drechsel et al. 2001, A&A, in preparation).

  7. LONG-TERM PHOTOMETRIC BEHAVIOR OF THE ECLIPSING BINARY GW CEPHEI

    SciTech Connect

    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

    2010-03-15

    New CCD photometry over four successive years from 2005 is presented for the eclipsing binary 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 eclipsing pair.

  8. VV Orionis - A well-behaved early-type eclipsing binary system

    NASA Astrophysics Data System (ADS)

    Chambliss, C. R.

    1984-02-01

    VV Orionis is a detached eclipsing binary system consisting of stars of spectral types B1 V and B4 V with a period of 1.4854 d. There is also a third component whose orbital period about the eclipsing pair is about 120 days. Recently, there have been several new photoelectric and spectroscopic investigations of this system, and the results of these are compared. VV Ori A appears to be of normal size and mass for its spectral class, but VV Ori B seems to be somewhat smaller than would be expected for a normal B4 V star. Linear limb-darkening coefficients are derived for VV Ori A and are in good agreement with theory. This system is of particular importance, because it is only one of very few early-type systems for which reliable limb-darkening coefficients can be expected to be obtained. The contribution of the light of the third component to the system has also been determined, and it appears most likely that VV Ori C is a star of spectral type A3 V.

  9. Short apsidal period of three eccentric eclipsing binaries discovered in the Large Magellanic Cloud

    SciTech Connect

    Hong, Kyeongsoo; Lee, Chung-Uk; Kim, Seung-Lee; Kang, Young-Woon

    2014-06-01

    We present new elements of apsidal motion in three eccentric eclipsing binaries located in the Large Magellanic Cloud. The apsidal motions of the systems were analyzed using both light curves and eclipse 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.

  10. Short Apsidal Period of Three Eccentric Eclipsing Binaries Discovered in the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Hong, Kyeongsoo; Lee, Chung-Uk; Kim, Seung-Lee; Kang, Young-Woon

    2014-06-01

    We present new elements of apsidal motion in three eccentric eclipsing binaries located in the Large Magellanic Cloud. The apsidal motions of the systems were analyzed using both light curves and eclipse 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.

  11. Time-resolved spectroscopy and photometry of the eclipsing AM Herculis binary EXO 033319 - 2554. 2

    SciTech Connect

    Allen, R.G.; Berriman, G.; Smith, P.S.; Schmidt, G.D. )

    1989-12-01

    Time-resolved optical observations of the eclipsing AM Herculis binary EXO 033319 - 2554.2 are presented. High-speed photometry of an eclipse is presented and used to derive a new ephemeris for the system and to estimate the size of the region responsible for the cyclotron emission. Optical spectra that span the orbital cycle are presented, the cyclotron emission in these spectra is discussed, and the flux and radial velocity variations of H-beta, H-gamma, and He II 4686 A are examined. Models of the flux and radial velocity variations of the emission lines indicate that about half the line emission comes from low-velocity material that is about 1.4 x 10 to the 10th cm from the white dwarf. The rest comes from high-velocity material that is about 10 to the 10th cm from the white dwarf and is moving toward it at about 600 km/s. 13 refs.

  12. The Masses of the Most Massive Stars: Resolving the ``Mass Discrepancy" with Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Massey, Philip; Morrell, Nidia; Eastwood, Kathy; Gies, Douglas; Penny, Laura

    2007-02-01

    The physics of massive stars is complicated, and although great strides have been made both in massive star evolution (interior) modeling, and in stellar atmosphere modeling, the two methods produce large disagreements (factors of two) in the derived masses for some massive stars. Thus our knowledge of the mass-luminosity relation for massive stars, and our ability to measure the initial mass function at the upper end, is cast into doubt. We have set out to resolve this ``mass discrepancy" by using a third method, one that relies only on Newtonian physics, namely obtaining masses from orbit solutions for eclipsing massive binaries. We have completed six months of photometric monitoring of Galactic OB associations, and have identified a dozen promising systems that show eclipses. For some of these, we have only the brightness and promixity to the cluster's center to believe the star is interesting, and we now need spectra to determine if these systems are truly early O stars or not. In addition, we are asking for additional queue photometry time on the 1.3-m (or 1.0-m) to determine the period accurately. These are both necessarily preludes to the time- intensive spectroscoic radial velocity observations we plan to propose next year.

  13. KOI-1003: A New Spotted, Eclipsing RS CVn Binary in the Kepler Field

    NASA Astrophysics Data System (ADS)

    Roettenbacher, Rachael M.; Kane, Stephen R.; Monnier, John D.; Harmon, Robert O.

    2016-12-01

    Using the high-precision photometry from the Kepler space telescope, thousands of stars with stellar and planetary companions have been observed. The characterization of stars with companions is not always straightforward and can be contaminated by systematic and stellar influences on the light curves. Here, through a detailed analysis of starspots and eclipses, we identify KOI-1003 as a new, active RS CVn star—the first identified with data from Kepler. The Kepler light curve of this close binary system exhibits the system’s primary transit, secondary eclipse, and starspot evolution of two persistent active longitudes. The near equality of the system’s orbital and rotation periods indicates the orbit and primary star’s rotation are nearly synchronized ({P}{orb}=8.360613+/- 0.000003 {days}; {P}{rot}˜ 8.23 {days}). By assuming the secondary star is on the main sequence, we suggest the system consists of a {1.45}-0.19+0.11 {M}⊙ subgiant primary and a {0.59}-0.04+0.03 {M}⊙ main-sequence companion. Our work gives a distance of 4400 ± 600 pc and an age of t={3.0}+2.0-0.5 {Gyr}, parameters which are discrepant with previous studies that included the star as a member of the open cluster NGC 6791.

  14. Determination of the Fundamental Properties of the Eclipsing Binary V541 Cygni

    NASA Astrophysics Data System (ADS)

    McGruder, Chima; Torres, Guillermo; Siverd, Robert; Pepper, Joshua; Rodriguez, Joseph; KELT Collaboration

    2017-01-01

    We report new high-resolution spectroscopic observations of the B-type detached spectroscopic eclipsing binary V541 Cygni (e = 0.465 and P =15.34 days). We combine analysis of these new spectra with analysis of V-band photometry from the literature to obtain the most precise measurements of the fundamental properties of the stars to date (yielding ~1% errors in the masses and ~2% for the radii). A comparison with current stellar evolution models indicates good fits for an age of ~ 200 million years and [Fe/H] ~ -0.2. Available eclipse timings gathered over 40 years were used to re-determine the apsidal motion of the system, dω/dt = 0.993 degs/cent, which is larger than what theory suggests.The SAO REU program was funded in part by the National Science Foundation REU and Department of Defense ASSURE programs under NSF Grant no. 1262851, and by the Smithsonian Institution.

  15. GH Lib: A multi-periodic Mira, not an eclipsing binary

    NASA Astrophysics Data System (ADS)

    Siviero, Alessandro; Munari, Ulisse; Righetti, Gian Luigi; Graziani, Mauro

    2016-09-01

    Over the period 2012-2016 we have obtained accurate V and R band photometry and 3400-8000 Ang spectroscopy which show the poorly studied variable GH Lib to be a multi-periodic Mira and not an Algol-type eclipsing binary. The main pulsation periods are 157 and 1180 days, with amplitudes of 3.5 and 1.0 mag, respectively. The spectral type change from M2III at maximum to M7III at minimum. The intensity of Halpha and Hbeta emission lines in GH Lib is much larger than in normal Miras, suggesting that the region of Balmer line formation is located at a larger radius (more external atmospheric layers) as if mixed with and not deeply below the region where absorption by TiO molecules occurs.

  16. Multi-color Photometric Study of the Contact Eclipsing Binary V1062 Her

    NASA Astrophysics Data System (ADS)

    Hashimoto, Amanda; Han, Xianming L.; Zhang, Liyun; Wang, Daimei; Lu, Hongpeng

    2017-01-01

    We observed the short-period contact eclipsing binary of V1062 Her using SARA 0.9 meter telescope at Kitt Peak National Observatory on July 4, 2015. In this study, we obtained the system’s full phase coverage BVRI CCD light curves, analyzed the orbital period variation, and extracted the orbital parameters. We calculated the linear and quadratic ephemeris to observe the star’s change in period. By using the updated Wilson & Devinney program, we found the orbital parameters of V21062 Her, which, in turn, enables us to calculate the degree of contact factor. We will predict any changes in its degree of contact to see how the star will evolve with time.

  17. First photometric study of the eclipsing binary GSC 04371-0161

    NASA Astrophysics Data System (ADS)

    Elkhateeb, M. M.; Nouh, M. I.; Saad, S. M.

    2014-01-01

    We present the first light curve analysis of the new eclipsing binary of Algol-type GSC 04371-0161. We carried out detailed photometric analysis in BVRI bands by using the most recent version of Wilson-Devinney (WD) code. The absolute physical parameters of the system are obtained and the previously determined period and epoch are confirmed. Our results show that the primary and secondary stars of the studied system are of spectral types G7 and K2, respectively. Locations of the components on mass-radius relation show that both components are evolved stars. Comparison with mass-luminosity relation of low and intermediate detached systems gives a good agreement.

  18. Time-series Spectroscopy of the Pulsating Eclipsing Binary XX Cephei

    NASA Astrophysics Data System (ADS)

    Koo, Jae-Rim; Lee, Jae Woo; Hong, Kyeongsoo; Kim, Seung-Lee; Lee, Chung-Uk

    2016-03-01

    Oscillating Algol-type eclipsing binaries (oEA) are very interesting objects that have three observational features of eclipse, 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 binary 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.

  19. Absolute Properties of the Spotted Eclipsing Binary Star CV Boötis

    NASA Astrophysics Data System (ADS)

    Torres, Guillermo; Vaz, Luiz Paulo R.; Sandberg Lacy, Claud H.

    2008-11-01

    We present new V-band differential brightness measurements as well as new radial-velocity measurements of the detached, circular, 0.84 day period, double-lined eclipsing binary system, CV Boo. These data, along with other observations from the literature, are combined to derive improved absolute dimensions of the stars for the purpose of testing various aspects of theoretical modeling. Despite complications from intrinsic variability that we detect in the system, and despite the rapid rotation of the components, we are able to determine the absolute masses and radii to better than 1.3% and 2%, respectively. We obtain M A = 1.032 ± 0.013 M sun and R A = 1.262 ± 0.023 R sun for the hotter, larger, and more-massive primary (star A), and M B = 0.968 ± 0.012 M sun and R B = 1.173 ± 0.023 R sun for the secondary. The estimated effective temperatures are 5760 ± 150 K and 5670 ± 150 K, respectively. The intrinsic variability with a period ~1% shorter than the orbital period is interpreted as being due to modulation by spots on one or both components. This implies that the spotted star(s) must be rotating faster than the synchronous rate, which disagrees with predictions from current tidal evolution models according to which both stars should be synchronized. We also find that the radius of the secondary is larger than expected from stellar evolution calculations by ~10%, a discrepancy also seen in other (mostly lower-mass and active) eclipsing binaries. We estimate the age of the system to be approximately 9 Gyr. Both components are near the end of their main-sequence phase, and the primary may have started the shell hydrogen-burning stage.

  20. A Class Exercise: Studying the Eclipsing Binary Star RZ Cas Through Visual Observations

    NASA Astrophysics Data System (ADS)

    Balonek, T. J.; Davis, S. M.

    2000-05-01

    As part of the sophomore-junior level "Astronomical Techniques" course at Colgate University, students learn just how much science they can do with simple tools: a pair of binoculars, a clock, and pencil and paper. The students study the Algol type visual eclipsing binary star system RZ Cassiopeiae: observing and making a light curve for the primary minimum, determining the time of minimum using several techniques, calculating the binary star system's orbital period, and determining changes in the system's period over a thirty year interval by constructing an O-C curve. Through a series of preparatory exercises, the students learn how to read star maps and use the unaided eye, binoculars and telescopes to locate star fields and make visual magnitude measurements. By making multiple measurements of stars in the field of RZ Cas on several nights, the students determine the accuracy they can achieve in estimating the visual magnitude of a star -- typically 0.2 magnitude. (Some students even accidentally discover that one of the stars in the field is a variable star!) With this experience, the students use binoculars to observe the four hour primary eclipse of RZ Cas (magnitude 6.2 - 7.7), making magnitude measurements every five minutes. A light curve is then plotted. Several methods are used to determine the time of minimum, which is then converted to heliocentric Julian day. Using times of minima determined by former students (and the instructor) in previous years dating from 1968 to the present, the students determine the average period to a tenth of a second second. By constructing an O-C curve from the class's data and that obtained by the AAVSO, changes in the period of RZ Cas are noticeable -- possibly due to mass transfer in the system. It will be interesting for future classes to build on this knowledge using the primitive tools of our not so distant past.

  1. KIC 9246715: The Double Red Giant Eclipsing Binary with Odd Oscillations

    NASA Astrophysics Data System (ADS)

    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.

    2016-02-01

    We combine Kepler photometry with ground-based spectra to present a comprehensive dynamical model of the double red giant eclipsing binary 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 eclipsing binaries, an important benchmark for asteroseismology.

  2. A New sdO+dM Binary with Extreme Eclipses and Reflection Effect

    NASA Astrophysics Data System (ADS)

    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.

    2015-08-01

    We report the discovery of a new totally eclipsing binary (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 eclipse 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 binary 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.

  3. Advances in Modeling Eclipsing Binary Stars in the Era of Large All-Sky Surveys with EBAI and PHOEBE

    NASA Astrophysics Data System (ADS)

    Prša, A.; Guinan, E. F.; Devinney, E. J.; Degroote, P.; Bloemen, S.; Matijevič, G.

    2012-04-01

    With the launch of NASA's Kepler mission, stellar astrophysics in general, and the eclipsing binary 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 eclipsing binaries is revolutionizing the field. Amidst all this excitement, we came to realize that our best models to describe the physical and geometric properties of binaries are not good enough. Systematic errors are evident in a large range of binary light curves, and the residuals are anything but Gaussian. This is crucial because it limits us in the precision of the attained parameters. Since eclipsing binary 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.

  4. Light Curve Solutions of 12 Eccentric Kepler Binaries and Analysis of Their Out-of-eclipse Variability

    NASA Astrophysics Data System (ADS)

    Kjurkchieva, Diana; Vasileva, Doroteya; Dimitrov, Dinko

    2016-12-01

    The eccentricity, periastron angle, orbital inclination, mass ratio, stellar temperatures, and relative stellar radii of 12 eclipsing eccentric binaries were determined on the basis of Kepler data. The analysis of their out-of-eclipse variability led to the following results: (i) KIC 10490980 exhibits rotational (spot-type) variability. (ii) Four new heartbeat stars were found: KIC 9344623 and KIC 10296163, which have wide tidally induced light humps, and KIC 9119405 and KIC 9673173, which have narrow “W-shape” features. (iii) KIC 4932691 shows oscillations with approximately the 18th harmonic of the orbital period. We established that the eccentric Kepler binaries fall below the envelope P{(1-{e}2)}3/2≈ 5 days on the period-eccentricity diagram and that there is a surprising lack of eccentric binaries with periods of 25-35 days.

  5. A Young Eclipsing Binary and Its Luminous Neighbors in the Embedded Star Cluster Sh 2-252E

    NASA Astrophysics Data System (ADS)

    Lester, Kathryn V.; Gies, Douglas R.; Guo, Zhao

    2016-12-01

    We present a photometric and light curve analysis of an eccentric eclipsing binary in the K2 Campaign 0 field, which resides in Sh 2-252E, a young star cluster embedded in an H ii region. We describe a spectroscopic investigation of the three brightest stars in the crowded aperture to identify which is the binary system. We find that none of these stars are components of the eclipsing binary system, which must be one of the fainter nearby stars. These bright cluster members all have remarkable spectra: Sh 2-252a (EPIC 202062176) is a B0.5 V star with razor sharp absorption lines, Sh 2-252b is a Herbig A0 star with disk-like emission lines, and Sh 2-252c is a pre-main-sequence star with very red color.

  6. An Initial Ultraviolet Investigation of Rapidly Evolving Short Period Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Shaw, J. Scott

    A new class of short period, strongly interacting eclipsing binary systems undergoing rapid mass exchange and/or mass loss has been recently identified by one of us (JSS). This group of close binary systems is akin to W UMa-type systems but has somewhat longer orbital periods and components of very dissimilar temperatures. The systems SW Lyn, V1010 Oph, and RT Scl are the best known members of this class of binaries. These Systems appear to be in an early stage of case A binary evolution prior to becoming contact systems in which the more massive hotter (A to F) component is close to or at its Roche limiting surface. Analyses of their asymmetric light curves and period changes indicate substantial mass exchange and/or mass loss. Present groundbased spectra show variable asymmetric line profiles. The photometric studies indicate that the observed asymmetries in the light curves can be explained by the presence of a bright shock region ("hot spot") produced on the receding hemisphere of the cooler component, by the impact of a gas stream from the more massive component. In this initial UV study we propose to observe a small, but representative sample of these stars with the IUE satellite in the wavelength region 1175-3200 using the SWP and LWR cameras. Low dispersion SWP and LWR spectra will be taken during eclipses and at elongations to allow us to identify and map out gas flows and the interacting plasmas using resonance lines of Fe II and Mg II h and k in the near UV and lines such as CIII, CIV, NIV, NV, and SiIII and SiIV in the far UV. High dispersion UV spectra of the brightest member of the class, V1010 Oph, will be obtained for a detailed investigation of the velocities of the expected gas streaming as well as the thermal and mass flow properties of the interacting plasmas. We plan to obtain ground-based spectroscopic and photometric observations of V1010 Oph at or near the time the UV observations are made.

  7. PHYSICAL PROPERTIES OF THE LOW-MASS ECLIPSING BINARY NSVS 02502726

    SciTech Connect

    Lee, Jae Woo; Youn, Jae-Hyuck; Kim, Seung-Lee; Lee, Chung-Uk E-mail: jhyoon@kasi.re.kr E-mail: leecu@kasi.re.kr

    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 Cakirli 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 Multiplication-Sign 10{sup -7} day yr{sup -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{sub 1} = 0.689 {+-} 0.016 M{sub Sun }, M{sub 2} = 0.341 {+-} 0.009 M{sub Sun }, R{sub 1} = 0.707 {+-} 0.007 R{sub Sun }, and R{sub 2} = 0.657 {+-} 0.008 R{sub Sun }. The results are very different from those of Cakirli et al. with the primary's radius (0.674 {+-} 0.006 R{sub Sun }) smaller the secondary's (0.763 {+-} 0.007 R{sub Sun }). 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%.

  8. 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.

  9. V773 Cas, QS Aql, and BR Ind: Eclipsing Binaries as Parts of Multiple Systems

    NASA Astrophysics Data System (ADS)

    Zasche, P.; Juryšek, J.; Nemravová, J.; Uhlař, R.; Svoboda, P.; Wolf, M.; Hoňková, K.; Mašek, M.; Prouza, M.; Čechura, J.; Korčáková, D.; Šlechta, M.

    2017-01-01

    Eclipsing binaries remain crucial objects for our understanding of the universe. In particular, those that are components of multiple systems can help us solve the problem of the formation of these systems. Analysis of the radial velocities together with the light curve produced for the first time precise physical parameters of the components of the multiple systems V773 Cas, QS Aql, and BR Ind. Their visual orbits were also analyzed, which resulted in slightly improved orbital elements. What is typical for all these systems is that their most dominant source is the third distant component. The system V773 Cas consists of two similar G1-2V stars revolving in a circular orbit and a more distant component of the A3V type. Additionally, the improved value of parallax was calculated to be 17.6 mas. Analysis of QS Aql resulted in the following: the inner eclipsing pair is composed of B6V and F1V stars, and the third component is of about the B6 spectral type. The outer orbit has high eccentricity of about 0.95, and observations near its upcoming periastron passage between the years 2038 and 2040 are of high importance. Also, the parallax of the system was derived to be about 2.89 mas, moving the star much closer to the Sun than originally assumed. The system BR Ind was found to be a quadruple star consisting of two eclipsing K dwarfs orbiting each other with a period of 1.786 days; the distant component is a single-lined spectroscopic binary with an orbital period of about 6 days. Both pairs are moving around each other on their 148 year orbit. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programs 091.D-0122(A), 094.A-9029(D), 095.A-9032(A), and 096.A-9039(A) and also on data from the 2 m telescope at the Ondřejov observatory in the Czech Republic

  10. DE Canum Venaticorum: a bright, eclipsing red dwarf-white dwarf binary

    NASA Astrophysics Data System (ADS)

    van den Besselaar, E. J. M.; Greimel, R.; Morales-Rueda, L.; Nelemans, G.; Thorstensen, J. R.; Marsh, T. R.; Dhillon, V. S.; Robb, R. M.; Balam, D. D.; Guenther, E. W.; Kemp, J.; Augusteijn, T.; Groot, P. J.

    2007-05-01

    Context: Close white dwarf-red dwarf binaries must have gone through a common-envelope phase during their evolution. DE CVn is a detached white dwarf-red dwarf binary with a relatively short (~8.7 h) orbital period. Its brightness and the presence of eclipses makes this system ideal for a more detailed study. Aims: From a study of photometric and spectroscopic observations of DE CVn we derive the system parameters that we discuss in the framework of common-envelope evolution. Methods: Photometric observations of the eclipses are used to determine an accurate ephemeris. From a model fit to an average low-resolution spectrum of DE CVn, we constrain the temperature of the white dwarf and the spectral type of the red dwarf. The eclipse light curve is analysed and combined with the radial velocity curve of the red dwarf determined from time-resolved spectroscopy to derive constraints on the inclination and the masses of the components in the system. Results: The derived ephemeris is HJDmin = 2 452 784.5533(1) + 0.3641394(2) × E. The red dwarf in DE CVn has a spectral type of M3V and the white dwarf has an effective temperature of 8 000 K. The inclination of the system is 86+3°-2 and the mass and radius of the red dwarf are 0.41± 0.06 M⊙ and 0.37+0.06-0.007 R⊙, respectively, and the mass and radius of the white dwarf are 0.51+0.06-0.02 M⊙ and 0.0136+0.0008-0.0002 R⊙, respectively. Conclusions: We found that the white dwarf has a hydrogen-rich atmosphere (DA-type). Given that DE CVn has experienced a common-envelope phase, we can reconstruct its evolution and we find that the progenitor of the white dwarf was a relatively low-mass star (M≤ 1.6~M⊙). The current age of this system is 3.3-7.3× 109 years, while it will take longer than the Hubble time for DE CVn to evolve into a semi-detached system.

  11. Analysis of the Extreme Mass Ratio, High Contact Eclipsing Binary, V802 Aquilae

    NASA Astrophysics Data System (ADS)

    Samec, R. G.; Martin, M. W.; Faulkner, D. R.

    2004-05-01

    We present our observations and initial analysis of BVRI light curves of the solar type, high contact binary, V802 Aquilae [GSC 5119 948, α (2000) = 18h 58m 54.82s, δ (2000) = -03° 01' 11.5"]. The observations were taken on the evenings of 5, 6 and 8 June 2002, by RGS and DRF with the 0.9-m reflector at CTIO. Standard UBVRcIc filters were used. We took from 138 to 148 observations in each BVRI pass band and about 100 in U. Mean epochs of minimum light for one primary eclipse, HJD = 2452431.82156 (81) as well as two secondary eclipses 2452434.89764 (11) and 2452432.75617 (21) were calculated. We calculated the following linear ephemeris: J.D. Hel Min I = 2450300.43417 (69) + 0.26769479 (11) d*E. (2) The light curves are shallow (0.35 mag in V) yet show a broad time of constant light (width about 0.1 phase) in the secondary eclipse. Its depressed primary maxima (about 0.06 mag in B) suggest the presence of heavy spot activity. Our Wilson code BVRI simultaneous solution of the instrumental magnitude light curves yields a mass ratio of M2/M1 = 0.16, and a fill-out 32.7 %. The temperature difference is T2-T1 = 136 K with the tiny secondary component having the higher mean surface temperature. A 20.2° cool spot was modeled on the primary component. Its longitude, co-latitude and temperature factor were 281° , 67° , and 0.915 respectively. Further results are presented. The system is a part of a rare group of binaries with a very low mass secondary and high mass ratio that are near a phase of final coalescence into an FK Comae type star. Much of the work was done by an undergraduate student, MWM. We wish to thank Cerro Tololo InterAmerican Observatory for their allocation of observing time, and the grant from NASA administered by the American Astronomical Society.

  12. Searching for Potential Mergers among 22 500 Eclipsing Binary Stars in the OGLE-III Galactic Bulge Fields

    NASA Astrophysics Data System (ADS)

    Pietrukowicz, P.; Soszyński, I.; Udalski, A.; Szymański, M. K.; Wyrzykowski, Ł.; Poleski, R.; Kozłowski, S.; Skowron, J.; Mróz, P.; Pawlak, M.; Ulaczyk, K.

    2017-06-01

    Inspired by the discovery of the red nova V1309 Sco (Nova Scorpii 2008) and the fact that its progenitor was a binary system with a rapidly decreasing orbital period, we have searched for period changes in OGLE binary stars. We have selected a sample of 22 462 short-period (Porb<4 d) eclipsing binary stars observed toward the Galactic bulge by the OGLE-III survey in years 2001-2009. This dataset was extended with photometry from OGLE-II (1997-2000) and the first six years of OGLE-IV (2010-2015). For some stars, the data were supplemented with OGLE-I photometry (1992-1995). After close inspection of the whole sample we have found 56 systems with realistic period decrease and 52 systems with realistic period increase. We have also recognized 35 systems with cyclic period variations. The highest negative period change rate of -1.943×10-4 d/y has been detected in detached eclipsing binary OGLE-BLG-ECL-139622 with Porb=2.817 d, while all other found systems are contact binaries with orbital periods mostly shorter than 1.0 d. For 22 our systems with decreasing orbital period the absolute rate is higher than the value reported recently for eclipsing binary KIC 9832227. Interestingly, there is an excess of systems with high negative period change rate over systems with positive rate. We cannot exclude the possibility that some of the contact binaries with relatively long orbital period and high negative period change rate will merge in the future. However, our results rather point to the presence of tertiary companions in the observed systems and/or spot activity on the surface of the binary components.

  13. Orbital Period Variation Study of the Algol Eclipsing Binary DI Pegasi

    NASA Astrophysics Data System (ADS)

    Hanna, M. A.; Amin, S. M.

    2013-08-01

    We discuss the orbital period changes of the Algol semi-detached eclipsing binary 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 binary, 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 low-mass 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°.

  14. An Atlas of O-C Diagrams of Eclipsing Binary Stars

    NASA Astrophysics Data System (ADS)

    Kreiner, Jerzy M.; Kim, Chun-Hwey; Nha, Il-Seong

    The Atlas contains data for 1,138 eclipsing binaries 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: binary 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 http://www.as.ap.krakow.pl/o- c".

  15. The first orbital parameters and period variation of the short-period eclipsing binary AQ Boo

    NASA Astrophysics Data System (ADS)

    Wang, Shuai; Zhang, Liyun; Pi, Qingfeng; Han, Xianming L.; Zhang, Xiliang; Lu, Hongpeng; Wang, Daimei; Li, TongAn

    2016-10-01

    We obtained the first VRI CCD light curves of the short-period contact eclipsing binary 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 binary with a low contact factor of 14.43%, and will become an over-contact system as the mass transfer continues.

  16. Absolute parameters of the early-type double-lined eclipsing binary AL SCULPTORIS (HD 224113)

    NASA Astrophysics Data System (ADS)

    Haefner, R.; Skillen, I.; de Groot, M.

    1987-06-01

    Orbital elements have been determined from measurements of forty-six high-dispersion spectrograms obtained between 1970 and 1980 of the double-lined eclipsing binary AL Scl, and the published radial-velocity data of Archer and Feast (1958) have been rediscussed. The orbit is confirmed to be non-circular (e = 0.074), and the components are shown to be rotating non-synchronously. The possibility of a third body is discussed but not firmly established. Approximately 2800 uvby observations, obtained between 1978 and 1981, form the basis of a photometric solution using the synthesis code LIGHT (Hill, 1979). The absolute dimensions derived for the B6 V primary component are in good agreement with the compilation of empirical data for early-type binaries given by Popper (1980), but the mass (1.71 M_sun;) derived for the B9 V secondary is lower than expected. A comparison of the absolute parameters with evolutionary tracks (Hejlesen, 1980) indicates the age of the system to be 1.6×108yr.

  17. Surface activity and oscillation amplitudes of red giants in eclipsing binaries

    SciTech Connect

    Gaulme, P.; Jackiewicz, J.; Appourchaux, T.; Mosser, B.

    2014-04-10

    Among the 19 red-giant stars belonging to eclipsing binary 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 binaries, 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.

  18. New CCD photometry of the eclipsing binary system V1067 Her

    NASA Astrophysics Data System (ADS)

    Darwish, M. S.; Saad, M. S.; Hanna, M. A.; Nasser, M. A.; Hamdy, M. A.; Beheary, M. M.; Gadallah, K. A.; Shokry, A.

    2017-01-01

    We present a new set of CCD photometric observations for the short period eclipsing binary 1SWASP J1743 (= V1067 Her). We have determined the available times of light minima and two new linear and quadratic ephemerides have been obtained. The photometric solutions for the system have been performed using Wilson and Devinney Code. The 3D and fill out configuration revealed that V1067 Her is an over contact W UMa binary with relatively low fill-out factor of about 16%. We investigated the period variation for the system. It showed a strong evidence of period changes by using the (O-C) residual diagram method and we have concluded long-term orbital period decrease rate dP/dt= -3.0 × 10-7 d/yr, corresponding to a time scale 8.6 × 105 yr. Such period decrease in the A-type W UMa systems is usually interpreted to be due to mass transfer from the more to the less massive component.

  19. NSVS 1908107, an EB-type eclipsing binary in the open cluster NGC 869

    NASA Astrophysics Data System (ADS)

    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

    2016-07-01

    We present a time-series BV CCD photometry for an EB-type eclipsing binary 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 binary 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.

  20. Absolute parameters of eclipsing binaries in Southern Hemisphere sky - II: QY Tel

    NASA Astrophysics Data System (ADS)

    Erdem, A.; Sürgit, D.; Engelbrecht, C. A.; van Heerden, H. P.; Manick, R.

    2016-11-01

    This paper presents the first analysis of spectroscopic and photometric observations of the neglected southern eclipsing binary 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 binary 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.

  1. Pulsations and metallicity of the pre-main sequence eclipsing spectroscopic binary RS Cha

    NASA Astrophysics Data System (ADS)

    Alecian, E.; Catala, C.; van't Veer-Menneret, C.; Goupil, M.-J.; Balona, L.

    2005-11-01

    We present new spectroscopic observations of the pre-main sequence eclipsing spectroscopic binary RS Cha. A sample of 174 spectra were obtained with the GIRAFFE spectrograph at the SAAO at 32 000 resolution. The radial velocity curves derived from these spectra were combined with previous observations spanning a period of about 30 years to correct the ephemeris of the system, and the result indicates that the orbital period is not constant. Residuals of the binary radial velocity curve for both components with amplitudes up to a few km s-1 and periods on the order of 1 h are clearly seen in our data, which we interpret as the signatures of delta-Scuti type pulsations. We revisited the masses of both components and determined the surface metallicity Z of both components of the RS Cha system by fitting synthetic spectra to observed spectra in a set of selected spectral regions. The synthetic spectra are calculated with the SYNTH code using stellar atmosphere models computed with the Kurucz ATLAS 9 code, along with a list of lines obtained from the VALD database. A selection of the best spectra and the most relevant spectral regions allowed us to determine Z = 0.028 ± 0.005. We also derived new values of v sin i: 64 ± 6 km s-1 and 70 ± 6 km s-1 for the primary and the secondary star, respectively. Finally, we observationally confirm that the RS Cha system is a synchronized and circularized system.

  2. PREDICTING GAIA’S PARALLAX DISTANCE TO THE CYGNUS OB2 ASSOCIATION WITH ECLIPSING BINARIES

    SciTech Connect

    Kiminki, Daniel C.; Kobulnicky, Henry A.; Álvarez, Carlos A. Vargas; Alexander, Michael J.; Lundquist, Michael J.

    2015-10-01

    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 eclipsing double-lined OB-type spectroscopic binaries 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 binary Schulte 3(A+B), as a previously unrecognized Association member.

  3. SuperWASP discovery and SALT confirmation of a semi-detached eclipsing binary that contains a δ Scuti star

    NASA Astrophysics Data System (ADS)

    Norton, A. J.; Lohr, M. E.; Smalley, B.; Wheatley, P. J.; West, R. G.

    2016-03-01

    Aims: We searched the SuperWASP archive for objects that display multiply periodic photometric variations. Methods: Specifically we sought evidence for eclipsing binary 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 eclipsing binary 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 binary 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 eclipsing binary 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.

  4. The EBAI Project: Testing Artificial Intelligence / Neural Network Approaches to Automatically Solve Light Curves of Eclipsing Binary Systems

    NASA Astrophysics Data System (ADS)

    Guinan, Edward F.; Hollon, N.; Prsa, A.; Devinney, E.

    2007-12-01

    Advances in observing technology will greatly increase discovery rates of eclipsing binaries (EBs). For example, missions such as LSST and GAIA are expected to yield hundreds of thousands (even millions) of new EBs. Current personal interactive (and time consuming) methods of determining the orbital and physical parameters of EBs from their light curves will be totally inadequate to keep up with the overwhelming flood of new data. At present the currently used methods require significant technical skill, and even experienced light curve solvers take 2-3 weeks to model a single binary. We are therefore developing an Artificial Intelligence / Neural Network system with the hope of creating a fully automated, high throughput process for gleaning the orbital and physical properties of EB-systems from the observations of tens of thousands of eclipsing binaries at a time. This project is called EBAI - Studying Eclipsing Binaries with Artificial Intelligence (See: http://www.eclipsingbinaries.org). A preliminary test of the neural network's performance has been conducted, using as input the normalized Johnson V-filter flux curves for five detached EBs: KP Aql, AY Cam, WX Cep, DI Her, and BP Vul. These systems have well determined properties from previous detailed photometric and radial velocity analyses. The neural network system has met with promising success in analyzing these systems. The results of this test and additional tests on larger samples of stars will be presented and discussed. This research is supported by NSF/RUI Grant No. AST-05-07542 which we gratefully acknowledge.

  5. Detection of intrinsic variability in the eclipsing massive main-sequence O+B binary HD 165246

    NASA Astrophysics Data System (ADS)

    Johnston, C.; Buysschaert, B.; Tkachenko, A.; Aerts, C.; Neiner, C.

    2017-07-01

    We present the analysis of 29.77 d of K2 space photometry of the well-detached massive 4.6 d O+B binary HD 165246 (V = 7.6) obtained during Campaign 9b. This analysis reveals intrinsic variability in the residual light curve after subtraction of the binary model, in the frequency range [0, 10] d-1. This makes HD 165246 only the second O+B eclipsing binary with asteroseismic potential. While some of the frequencies are connected with the rotation of the primary, others are interpreted as due to oscillations with periodicities of order days. The frequency resolution of the current data set does not allow us to distinguish between frequencies due to standing coherent oscillation modes or travelling waves. Future time-resolved high-precision spectroscopy covering several binary orbits will reveal whether HD 165246 is a Rosetta stone for synergistic binary and seismic modelling of an O-type star.

  6. MOST Photometry and DDO Spectroscopy of the Eclipsing (White Dwarf + Red Dwarf) Binary V471 Tau

    NASA Astrophysics Data System (ADS)

    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.

    2007-09-01

    The Hyades K2 V + WD system 471 Tau is a prototype post-common envelope system and a likely cataclysmic binary 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 binary. 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 binary orbital phase. A detailed O - C analysis of the times of eclipse 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.

  7. A CHANDRA OBSERVATION OF THE ECLIPSING WOLF-RAYET BINARY CQ Cep

    SciTech Connect

    Skinner, Stephen L.; Zhekov, Svetozar A.; Güdel, Manuel; Schmutz, Werner E-mail: szhekov@space.bas.bg E-mail: werner.schmutz@pmodwrc.ch

    2015-02-01

    The short-period (1.64 d) near-contact eclipsing WN6+O9 binary 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 eclipse 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.

  8. YSOVAR: SIX PRE-MAIN-SEQUENCE ECLIPSING BINARIES IN THE ORION NEBULA CLUSTER

    SciTech Connect

    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.

    2012-07-10

    Eclipsing binaries (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 eclipse 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.

  9. Discovery of a stripped red giant core in a bright eclipsing binary system

    NASA Astrophysics Data System (ADS)

    Maxted, P. F. L.; Anderson, D. R.; Burleigh, M. R.; Collier Cameron, A.; Heber, U.; Gänsicke, B. T.; Geier, S.; Kupfer, T.; Marsh, T. R.; Nelemans, G.; O'Toole, S. J.; Østensen, R. H.; Smalley, B.; West, R. G.

    2011-12-01

    We have identified a star in the Wide Angle Search for Planets (WASP) archive photometry with an unusual light curve due to the total eclipse of a small, hot star by an apparently normal A-type star and with an orbital period of only 0.668 d. From an analysis of the WASP light curve together with V-band and IC-band photometry of the eclipse and a spectroscopic orbit for the A-type star we estimate that the companion star has a mass of 0.23 ± 0.03 M⊙ and a radius of 0.33 ± 0.01 R⊙, assuming that the A-type star is a main-sequence star with the metallicity appropriate for a thick-disc star. The effective temperature of the companion is 13 400 ± 1200 K from which we infer a luminosity of 3 ± 1 L⊙. From a comparison of these parameters to various models we conclude that the companion is most likely to be the remnant of a red giant star that has been very recently stripped of its outer layers by mass transfer on to the A-type star. In this scenario, the companion is currently in a shell hydrogen-burning phase of its evolution, evolving at nearly constant luminosity to hotter effective temperatures prior to ceasing hydrogen burning and fading to become a low-mass white dwarf composed of helium (He-WD). The system will then resemble the pre-He-WD/He-WD companions to A- and B-type stars recently identified from their Kepler satellite light curves (KOI-74, KOI-81 and KIC 10657664). This newly discovered binary offers the opportunity to study the evolution of a stripped red giant star through the pre-He-WD stage in great detail. Based on observations made with ESO Telescopes at the La Silla Observatory under programme ID 084.D-0348(A).

  10. PSR J1723–2837: AN ECLIPSING BINARY RADIO MILLISECOND PULSAR

    SciTech Connect

    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

    2013-10-10

    We present a study of PSR J1723–2837, an eclipsing, 1.86 ms millisecond binary 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 low-mass companion, and a measurable orbital period derivative. The eclipse 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.

  11. PSR J1723-2837: An Eclipsing Binary Radio Millisecond Pulsar

    NASA Astrophysics Data System (ADS)

    Crawford, Fronefield; Lyne, Andrew G.; Stairs, Ingrid H.; Kaplan, David L.; McLaughlin, Maura A.; Freire, Paulo C. C.; Burgay, Marta; Camilo, Fernando; D'Amico, Nichi; Faulkner, Andrew; Kramer, Michael; Lorimer, Duncan R.; Manchester, Richard N.; Possenti, Andrea; Steeghs, Danny

    2013-10-01

    We present a study of PSR J1723-2837, an eclipsing, 1.86 ms millisecond binary 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 low-mass companion, and a measurable orbital period derivative. The eclipse 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 ⊙ and an orbital inclination angle range of between 30° and 41°, assuming a pulsar mass range of 1.4-2.0 M ⊙. 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.

  12. Analysis of Pulsating Components in the Eclipsing Binary Systems LT Herculis, RZ Microscopii, LY Puppis, V632 Scorpii, and V638 Scorpii

    NASA Astrophysics Data System (ADS)

    Streamer, M.; Bohlsen, T.; Ogmen, Y.

    2016-06-01

    Eclipsing binary 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 eclipsing binary 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.

  13. RZ Cassiopeiae: Evidence for Spots on the Surface of the Primary Star in an Algol-type Eclipsing Binary System

    NASA Astrophysics Data System (ADS)

    Davis, S. M.; Balonek, T. J.

    1996-12-01

    The bright Algol-type eclipsing binary system RZ Cassiopeiae is known to exhibit irregular period changes as well as changes in the shape of the primary minimum light curve. Deviations from a simple partial eclipse light curve have been reported by other investigators in some, though not all, eclipses. We report CCD observations of five primary minima in 1996 obtained with the Colgate University Foggy Bottom Observatory 16-inch telescope. From these observations we construct an average "template" light curve in V for the primary eclipse and show that individual eclipses may differ significantly in shape from this template. Consecutive minima often have distinctly different shapes. The residuals between an individual light curve and the template show quasi-periodic oscillations with a "period" of about 25 minutes (corresponding to 0.013 in phase) and amplitude +/- 0.04 magnitude. The residuals of consectutive minima appear similar in structure, though displaced in time by about 15 minutes from each other. We interpret the oscillations in the light curves as evidence for hot and cool spots on the surface of the main sequence primary star resulting from mass exchange from the cooler subgiant secondary. The changes in the light curve shape indicate a non-synchronous rotation of the primary star.

  14. TESTING THE CORE OVERSHOOT MIXING DESCRIBED BY A TURBULENT CONVECTION MODEL ON THE ECLIPSING BINARY STAR HY VIR

    SciTech Connect

    Zhang, Q. S.

    2012-12-20

    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 eclipsing binary 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 eclipsing binary 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.

  15. The Surface Brightness-color Relations Based on Eclipsing Binary Stars: Toward Precision Better than 1% in Angular Diameter Predictions

    NASA Astrophysics Data System (ADS)

    Graczyk, Dariusz; Konorski, Piotr; Pietrzyński, Grzegorz; Gieren, Wolfgang; Storm, Jesper; Nardetto, Nicolas; Gallenne, Alexandre; Maxted, Pierre F. L.; Kervella, Pierre; Kołaczkowski, Zbigniew

    2017-03-01

    In this study we investigate the calibration of surface brightness–color (SBC) relations based solely on eclipsing binary stars. We selected a sample of 35 detached eclipsing binaries with trigonometric parallaxes from Gaia DR1 or Hipparcos whose absolute dimensions are known with an accuracy better than 3% and that lie within 0.3 kpc from the Sun. For the purpose of this study, we used mostly homogeneous optical and near-infrared photometry based on the Tycho-2 and 2MASS catalogs. We derived geometric angular diameters for all stars in our sample with a precision better than 10%, and for 11 of them with a precision better than 2%. The precision of individual angular diameters of the eclipsing binary components is currently limited by the precision of the geometric distances (∼5% on average). However, by using a subsample of systems with the best agreement between their geometric and photometric distances, we derived the precise SBC relations based only on eclipsing binary stars. These relations have precisions that are comparable to the best available SBC relations based on interferometric angular diameters, and they are fully consistent with them. With very precise Gaia parallaxes becoming available in the near future, angular diameters with a precision better than 1% will be abundant. At that point, the main uncertainty in the total error budget of the SBC relations will come from transformations between different photometric systems, disentangling of component magnitudes, and for hot OB stars, the main uncertainty will come from the interstellar extinction determination. We argue that all these issues can be overcome with modern high-quality data and conclude that a precision better than 1% is entirely feasible.

  16. The EB Factory Project. I. A Fast, Neural-net-based, General Purpose Light Curve Classifier Optimized for Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Paegert, Martin; Stassun, Keivan G.; Burger, Dan M.

    2014-08-01

    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 eclipsing binary 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 eclipsing binaries. Testing the classifier on the ASAS light curve database, we achieve a retrieval rate of 98% and a false-positive rate of 2% for eclipsing binaries. 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 eclipsing binaries, 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.

  17. VizieR Online Data Catalog: Light curves for the eclipsing binary V1094 Tau (Maxted+, 2015)

    NASA Astrophysics Data System (ADS)

    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.

    2015-04-01

    Photometric light curves of the detached eclipsing binary 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).

  18. The EB factory project. I. A fast, neural-net-based, general purpose light curve classifier optimized for eclipsing binaries

    SciTech Connect

    Paegert, Martin; Stassun, Keivan G.; Burger, Dan M.

    2014-08-01

    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 eclipsing binary 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 eclipsing binaries. Testing the classifier on the ASAS light curve database, we achieve a retrieval rate of 98% and a false-positive rate of 2% for eclipsing binaries. 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 eclipsing binaries, 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.

  19. Eclipsing binaries in open clusters - II. V453 Cyg in NGC 6871

    NASA Astrophysics Data System (ADS)

    Southworth, J.; Maxted, P. F. L.; Smalley, B.

    2004-07-01

    We derive absolute dimensions of the early B-type detached eclipsing binary V453 Cygni (B0.4 IV + B0.7 IV, P= 3.89 d), a member of the open cluster NGC 6871. From the analysis of new, high-resolution spectroscopy and the UBV light curves of Cohen, we find the masses to be 14.36 +/- 0.20 and 11.11 +/- 0.13 Msolar, the radii to be 8.55 +/- 0.06 and 5.49 +/- 0.06 Rsolar, and the effective temperatures to be 26600 +/- 500 and 25500 +/- 800 K for the primary and secondary stars, respectively. The surface gravity values of logg= 3.731 +/- 0.012 and 4.005 +/- 0.015 indicate that V453 Cyg is reaching the end of its main-sequence lifetime. We have determined the apsidal motion period of the system to be 66.4 +/- 1.8 yr using the technique of Lacy extended to include spectroscopic data as well as times of minimum light, giving a density concentration coefficient of logk2=-2.226 +/- 0.024. Contaminating (third) light has been detected for the first time in the light curve of V453 Cyg; previous analyses without this effect systematically underestimate the ratio of the radii of the two stars. The absolute dimensions of the system have been compared with the stellar evolution models of the Granada, Geneva, Padova and Cambridge groups. All model sets fit the data on V453 Cyg for solar helium and metal abundances and an age of 10.0 +/- 0.2 Myr. The Granada models also agree fully with the observed logk2 once general relativistic effects have been accounted for. The Cambridge models with convective core overshooting fit V453 Cyg better than those without. Given this success of the theoretical predictions, we briefly discuss which eclipsing binaries should be studied in order to challenge the models further.

  20. EC 19314 - 5915 - A bright, eclipsing cataclysmic variable from the Edinburgh-Cape Blue Object Survey

    NASA Technical Reports Server (NTRS)

    Buckley, D. A. H.; O'Donoghue, D.; Kilkenny, D.; Stobie, R. S.; Remillard, R. A.

    1992-01-01

    A deeply eclipsing cataclysmic variable, with an orbital period of 4.75 hr, has been discovered in the southern Edinburgh-Cape Blue Object Survey. The star, EC 19314 - 5915, lies close to the positional constraints of a previously unidentified HEAO-1 hard X-ray source, 1H1930 - 5989. Its optical spectrum is unusual in that it shows, apart from the emission lines characteristic of a novalike, or dwarf nova cataclysmic variable (Balmer, He I and He II), metallic absorption lines typical of a late-G star. The individual time-resolved spectra, with the tertiary absorption lines removed, show absorption reversals in the Balmer emission lines, increasing in strength for the higher series. The Balmer emission radial velocities are therefore severely distorted in comparison to the He II 4686-A emission and He I 4471-A absorption radial velocity curves. An independent distance estimate of about 600 pc is derived for EC19314 - 5915, from the spectroscopic parallax of the third star.

  1. LSPM J1112+7626: Detection of a 41 Day M-dwarf Eclipsing Binary from the MEarth Transit Survey

    NASA Astrophysics Data System (ADS)

    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.

    2011-12-01

    We report the detection of eclipses in LSPM J1112+7626, which we find to be a moderately bright (IC = 12.14 ± 0.05) very low mass binary system with an orbital period of 41.03236 ± 0.00002 days, and component masses M 1 = 0.395 ± 0.002 M ⊙ and M 2 = 0.275 ± 0.001 M ⊙ in an eccentric (e = 0.239 ± 0.002) orbit. A 65 day out-of-eclipse 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 binary 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+0.9 -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 eclipsing binary 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.

  2. LSPM J1112+7626: DETECTION OF A 41 DAY M-DWARF ECLIPSING BINARY FROM THE MEARTH TRANSIT SURVEY

    SciTech Connect

    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.

    2011-12-01

    We report the detection of eclipses in LSPM J1112+7626, which we find to be a moderately bright (I{sub C} = 12.14 {+-} 0.05) very low mass binary 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-eclipse 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 binary 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 eclipsing binary 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.

  3. Orbital-period variations of the Algol-type eclipsing binaries RW CrB and AO ser

    NASA Astrophysics Data System (ADS)

    Khaliullina, A. I.

    2016-09-01

    Orbital-period variations of the Algol-type eclipsing binaries 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 eclipsing binary's motion in its long-period orbit. The period variations of RW CrB are reproduced by motion of the eclipsing binary 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.

  4. BINARIES DISCOVERED BY THE MUCHFUSS PROJECT: SDSS J08205+0008-AN ECLIPSING SUBDWARF B BINARY WITH A BROWN DWARF COMPANION

    SciTech Connect

    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.

    2011-04-20

    Hot subdwarf B stars (sdBs) are extreme horizontal branch stars believed to originate from close binary evolution. Indeed about half of the known sdB stars are found in close binaries 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 binaries are the eclipsing HW Vir binaries 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 eclipses are total, the system parameters are very well constrained. J08205+0008 has the lowest unambiguously measured companion mass yet found in a subdwarf B binary. 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.

  5. Photometric Analysis of the Eclipsing Binary: DE Canis Venatici (RX J1326.9+4532)

    NASA Astrophysics Data System (ADS)

    Goker, U. D.; Tas, G.

    2007-08-01

    White dwarfs and red dwarfs represent two different evolutionary stages of low-mass stars. In our Galaxy, the low-mass stars form the most numerous group of objects. For members of binary systems among them, one can derive their physical parameters like mass and radius. In addition, they include valuable information about the mass distribution of our galaxy. Different evolution phases of the binary stars consisting of white dwarfs and red dwarfs are very important for the astronomy because they allow us to test the theories of the stellar evolution. In this study, a literature survey about the structure and evolution of these systems is done and theoretical and observational results for DE CVn are presented. After obtaining new light curves, we derived the geometrical and physical parameters of the eclipsing binary DE CVn consisting of a white dwarf and a red dwarf. We also discuss the problems of both DE CVn and related systems. DE CVn was observed with 3 different telescopes and 2 different receivers through the Johnson B, V, R filters in 2002-2003. Since the clearest variations were seen in the B filter, the B light curve was analysed using the Wilson-Devinney method with Mode 2 designed to solve detached binaries. The mass ratio q=1.1 was found. The visual magnitude of the white dwarf is 13.04 mag. in 0.0 phase and orbital period of the system is 0.364077 days. The DE CVn system consists of a DA-DB white dwarf (He-WDs) and a M1-M2 red dwarf according to our solution. The system conforms to the classical cataclysmic-variable definitions, but the P-M and P-R relation of cataclysmic variables which results from the light curve differs from that obtained from Patterson's P-T relation (1984). The latter indicates a different spectral class for the red dwarf. It is not well known whether the second companion of the system is in post-evolution phase or is not conformed to standard ZAMS M-R relation.

  6. TIME-SERIES SPECTROSCOPY OF THE ECLIPSING BINARY Y CAM WITH A PULSATING COMPONENT

    SciTech Connect

    Hong, Kyeongsoo; Lee, Jae Woo; Kim, Seung-Lee; Koo, Jae-Rim; Lee, Chung-Uk; Yushchenko, Alexander V.; Kang, Young-Woon

    2015-10-15

    We present the physical properties of the semi-detached Algol-type eclipsing binary 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 binary 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 low-mass 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.

  7. CHARACTERIZING THE COOL KOIs. V. KOI-256: A MUTUALLY ECLIPSING POST-COMMON ENVELOPE BINARY

    SciTech Connect

    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

    2013-04-20

    We report that Kepler Object of Interest 256 (KOI-256) is a mutually eclipsing post-common envelope binary (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 binary star systems as well as white dwarfs themselves, thanks largely to the availability of near-continuous, ultra-precise Kepler photometry.

  8. Late-Type Near-Contact Eclipsing Binary [HH97] FS Aur-79

    NASA Astrophysics Data System (ADS)

    Austin, S. J.; Robertson, J. W.; Tycner, C.; Campbell, T.; Honeycutt, R. K.

    2007-05-01

    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) eclipsing binary 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. Binary 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.

  9. Discovery and characterization of detached M dwarf eclipsing binaries in the WFCAM Transit Survey

    NASA Astrophysics Data System (ADS)

    Birkby, Jayne; Nefs, Bas; Hodgkin, Simon; Kovács, Gábor; Sipőcz, Brigitta; Pinfield, David; Snellen, Ignas; Mislis, Dimitris; Murgas, Felipe; Lodieu, Nicolas; de Mooij, Ernst; Goulding, Niall; Cruz, Patricia; Stoev, Hristo; Cappetta, Michele; Palle, Enric; Barrado, David; Saglia, Roberto; Martin, Eduardo; Pavlenko, Yakiv

    2012-10-01

    We report the discovery of 16 detached M dwarf eclipsing binaries with J < 16 mag and provide a detailed characterization of three of them, using high-precision infrared light curves from the WFCAM Transit Survey (WTS). Such systems provide the most accurate and model-independent method for measuring the fundamental parameters of these poorly understood yet numerous stars, which currently lack sufficient observations to precisely calibrate stellar evolution models. We fully solve for the masses and radii of three of the systems, finding orbital periods in the range 1.5 < P < 4.9 d, with masses spanning 0.35-0.50 M⊙ and radii between 0.38 and 0.50 R⊙, with uncertainties of ˜3.5-6.4 per cent in mass and ˜2.7-5.5 per cent in radius. Close companions in short-period binaries are expected to be tidally locked into fast rotational velocities, resulting in high levels of magnetic activity. This is predicted to inflate their radii by inhibiting convective flow and increasing starspot coverage. The radii of the WTS systems are inflated above model predictions by ˜3-12 per cent, in agreement with the observed trend, despite an expected lower systematic contribution from starspot signals at infrared wavelengths. We searched for correlation between the orbital period and radius inflation by combining our results with all existing M dwarf radius measurements of comparable precision, but we found no statistically significant evidence for a decrease in radius inflation for longer period, less active systems. Radius inflation continues to exists in non-synchronized systems, indicating that the problem remains even for very low activity M dwarfs. Resolving this issue is vital not only for understanding the most populous stars in the Universe, but also for characterizing their planetary companions, which hold the best prospects for finding Earth-like planets in the traditional habitable zone.

  10. The Variable Magnetic White Dwarf in the Hyades Eclipsing Binary V471 Tauri

    NASA Astrophysics Data System (ADS)

    Sion, Edward

    2007-07-01

    V471 Tau is a detached eclipsing binary in the Hyades cluster consisting of a hot magnetic white dwarf and a rapidly rotating K dwarf companion. With an orbital period of only 12.5 hour, the stellar components emerged from common envelope interactions which drastically reduced their initially wide separations. It is the prototypical pre-cataclysmic binary. The white dwarf exhibits soft X-ray, EUV and optical variations on its 9.25 minutes rotation period. These variations are due to heavy elements accreted onto the WD's magnetic poles from the companion's wind. The implied accretion rate from the companion's wind, however, is so low that a magnetic propeller mechanism must be rejecting most of the material that attempts to accrete. We propose a comprehensive analysis of all existing HST STIS echelle spectroscopic observations that will focus on: {1} the variation of line strengths of accreted ions in the WD photosphere over the 9.25 minute rotation period of the WD, covering the four years over which STIS echelle spectra were taken; {2} probe the Zeeman splitting we first detected in a greater mix of metallic absorptions species, thus accurately determining the magnetic field strength and its variation at the rotational period; {3} determine the chemical abundances of accreted metals and study the process of magnetic accretion onto, and diffusion of heavy elements out of, the photosphere of the magnetic white dwarf using newly available models and diffusion parameters by Co-I J. Dupuis; {4} refine the mass of the WD and other system parameters with a more complete radial velocity curve.

  11. Absolute Dimensions of the Unevolved B-Type Eclipsing Binary GG Orionis

    NASA Astrophysics Data System (ADS)

    Torres, Guillermo; Lacy, Claud H. Sandberg; Claret, Antonio; Sabby, Jeffrey A.

    2000-12-01

    We present photometric observations in B and V, as well as spectroscopic observations of the detached, eccentric 6.6 day double-lined eclipsing binary GG Ori, a member of the Orion OB1 association. Absolute dimensions of the components, which are virtually identical, are determined to high accuracy (better than 1% in the masses and better than 2% in the radii) for the purpose of testing various aspects of theoretical modeling. We obtain MA=2.342+/-0.016 Msolar and RA=1.852+/-0.025 Rsolar for the primary, and MB=2.338+/-0.017 Msolar and RB=1.830+/-0.025 Rsolar for the secondary. The effective temperature of both stars is 9950+/-200 K, corresponding to a spectral type of B9.5. GG Ori is very close to the zero-age main sequence, and comparison with current stellar evolution models gives ages of 65-82 Myr or 7.7 Myr, depending on whether the system is considered to be burning hydrogen on the main sequence or still in the final stages of pre-main-sequence contraction. Good agreement is found in both scenarios for a composition close to solar. We have detected apsidal motion in the binary at a rate of ω=0.00061d+/-0.00025d cycle-1, corresponding to an apsidal period of U=10,700+/-4500 yr. A substantial fraction of this (~70%) is due to the contribution from general relativity, and our measurement is entirely consistent with theory. The eccentric orbit of GG Ori is well explained by tidal evolution models, but both theory and our measurements of the rotational velocity of the components are as yet inconclusive as to whether the stars are synchronized with the orbital motion. Some of the observations reported here were obtained with the Multiple Mirror Telescope, a joint facility of the Smithsonian Institution and the University of Arizona.

  12. V421 Pegasi: a detached eclipsing binary with a possible γ Doradus component

    NASA Astrophysics Data System (ADS)

    Özdarcan, O.; Çakırlı, Ö.; Akan, C.

    2016-07-01

    We present spectroscopic and photometric study of V421 Peg. This eclipsing binary 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.

  13. GSC 7672 2238: a new eclipsing binary system near the delta scuti star AI Vel

    NASA Astrophysics Data System (ADS)

    Santos-Júnior, J. M.; Pereira, P. C. R.; Cruz, W. S.; Andrade-Pilling, D. P.

    2003-08-01

    We report the discovery of a new eclipsing binary 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.

  14. Discovery of two young brown dwarfs in an eclipsing binary system.

    PubMed

    Stassun, Keivan G; Mathieu, Robert D; Valenti, Jeff A

    2006-03-16

    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 eclipsing binary 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 low-mass 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.

  15. Discovery of a Transiting Planet and Eight Eclipsing Binaries in HATNet Field G205

    NASA Astrophysics Data System (ADS)

    Latham, David W.; Bakos, Gáspár Á.; Torres, Guillermo; Stefanik, Robert P.; Noyes, Robert W.; Kovács, Géza; Pál, András; Marcy, Geoffrey W.; Fischer, Debra A.; Butler, R. Paul; Sipőcz, Brigitta; Sasselov, Dimitar D.; Esquerdo, Gilbert A.; Vogt, Steven S.; Hartman, Joel D.; Kovács, Gábor; Lázár, József; Papp, István; Sári, Pál

    2009-10-01

    We report the discovery of HAT-P-8b, a transiting planet with mass M p = 1.52+0.18 -0.16 M J, radius R p = 1.50+0.08 -0.06 R J, and photometric period P = 3.076 days. HAT-P-8b has a somewhat inflated radius for its mass, and a somewhat large mass for its period. The host star is a solar-metallicity F dwarf, with mass M sstarf = 1.28 ± 0.04 M sun and R sstarf = 1.58+0.08 -0.06 R sun. HAT-P-8b was initially identified as one of the 32 transiting-planet candidates in HATNet field G205. We describe the procedures that we have used to follow up these candidates with spectroscopic and photometric observations, and we present a status report on our interpretation for 28 of the candidates. Eight are eclipsing binaries with orbital solutions whose periods are consistent with their photometric ephemerides; two of these spectroscopic orbits are single-lined and six are double-lined. Based in part on observations obtained at the W. M. Keck Observatory, which is operated by the University of California and the California Institute of Technology. Keck time has been granted by NOAO (A285Hr).

  16. Kepler Eclipsing Binaries with Delta Scuti/Gamma Doradus Pulsating Components I: KIC 9851944

    NASA Astrophysics Data System (ADS)

    Guo, Zhao; Gies, Douglas R.; Matson, Rachel A.; García Hernández, Antonio

    2016-07-01

    KIC 9851944 is a short-period (P = 2.16 days) eclipsing binary 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.

  17. Chemical Composition of RR Lyn - an Eclipsing Binary System with Am and λ Boo Type Components

    NASA Astrophysics Data System (ADS)

    Jeong, Yeuncheol; Yushchenko, Alexander V.; Doikov, Dmytry N.; Gopka, Vira F.; Yushchenko, Volodymyr O.

    2017-06-01

    High-resolution spectroscopic observations of the eclipsing binary system RR Lyn were made using the 1.8 m telescope at the Bohuynsan Optical Astronomical Observatory in Korea. The spectral resolving power was R = 82,000, with a signal to noise ratio of S/N > 150. We found the effective temperatures and surface gravities of the primary and secondary components to be equal to Teff = 7,920 & 7,210 K and log(g) = 3.80 & 4.16, respectively. The abundances of 34 and 17 different chemical elements were found in the atmospheric components. Correlations between the derived abundances with condensation temperatures and the second ionization potentials of these elements are discussed. The primary component is a typical metallic line star with the abundances of light and iron group elements close to solar values, while elements with atomic numbers Z > 30 are overabundant by 0.5-1.5 dex with respect to solar values. The secondary component is a λ Boo type star. In this type of stars, CNO abundances are close to solar values, while the abundance pattern shows a negative correlation with condensation temperatures.

  18. First period investigation and light-curve study of the eclipsing contact binary V776 Cas

    NASA Astrophysics Data System (ADS)

    Noori, Hamid Reza; Abedi, Abbas

    2017-10-01

    CCD photometry of the eclipsing binary system V776 Cas was carried out through Johnson-Cousins UBVR filters in Dr. Mojtahedi observatory of Birjand University during August and September 2014. The physical and geometrical parameters of the system were obtained by analyzing the light curves. Radial velocity data were used to determine the absolute parameters. Five new times of minimum light were found. The O-C diagram was plotted relying on these times and the previously reported times of minimum. New ephemeris of the system, the rate of orbital period variations and the mass transfer rate of the system were derived from the O-C diagram analysis. A periodic variation of about 8 years was found from the O-C diagram analysis. At first light-time effect was considered. Although the results confirmed the probability of the presence of third body, Applegate mechanism was checked as the reason for this periodic variation and this mechanism is also in agreement with the observations.

  19. Masses and ages of Delta Scuti stars in eclipsing binary systems

    NASA Astrophysics Data System (ADS)

    Tsvetkov, Ts. G.; Petrova, Ts. C.

    1993-05-01

    By using data mainly from Frolov et al. (1982) for four Delta Scuti stars in eclipsing binary systems, AB Cas, Y Cam, RS Cha, and AI Hya, their physical parameters, distances, and radial pulsation modes are determined. The evolutionary track systems of Iben (1967), Paczynski (1970), and Maeder and Meynet (1988) are interpolated in order to estimate evolutionary masses Me and ages t of these variables. Their pulsation masses MQ are estimated from the fitting formulae of Faulkner (1977) and Fitch (1981). Our estimates of evolutionary masses M(e) and pulsation masses M(Q) are close to the masses M determined by Frolov et al. from the star binarity. The only exception is AB Cas, for which there is no agreement between certain star parameters. Another, independent approach is also applied to the stars RS Cha and AI Hya: by using their photometric indices b - y and c(1) from the catalog of Lopez de Coca et al. (1990) and appropriate photometric calibrations, other sets of physical parameters, distances, modes, ages, and evolutionary and pulsation masses of both variables are obtained.

  20. Testing the white dwarf mass-radius relationship with eclipsing binaries

    NASA Astrophysics Data System (ADS)

    Parsons, S. G.; Gänsicke, B. T.; Marsh, T. R.; Ashley, R. P.; Bours, M. C. P.; Breedt, E.; Burleigh, M. R.; Copperwheat, C. M.; Dhillon, V. S.; Green, M.; Hardy, L. K.; Hermes, J. J.; Irawati, P.; Kerry, P.; Littlefair, S. P.; McAllister, M. J.; Rattanasoon, S.; Rebassa-Mansergas, A.; Sahman, D. I.; Schreiber, M. R.

    2017-10-01

    We present high-precision, model-independent, mass and radius measurements for 16 white dwarfs in detached eclipsing binaries and combine these with previously published data to test the theoretical white dwarf mass-radius relationship. We reach a mean precision of 2.4 per cent in mass and 2.7 per cent in radius, with our best measurements reaching a precision of 0.3 per cent in mass and 0.5 per cent in radius. We find excellent agreement between the measured and predicted radii across a wide range of masses and temperatures. We also find the radii of all white dwarfs with masses less than 0.48 M⊙ to be fully consistent with helium core models, but they are on average 9 per cent larger than those of carbon-oxygen core models. In contrast, white dwarfs with masses larger than 0.52 M⊙ all have radii consistent with carbon-oxygen core models. Moreover, we find that all but one of the white dwarfs in our sample have radii consistent with possessing thick surface hydrogen envelopes (10-5 ≥ MH/MWD ≥ 10-4), implying that the surface hydrogen layers of these white dwarfs are not obviously affected by common envelope evolution.

  1. Absolute Properties of the Upper Main-Sequence Eclipsing Binary Star MU Cassiopeiae

    NASA Astrophysics Data System (ADS)

    Lacy, Claud H. Sandberg; Claret, Antonio; Sabby, Jeffrey A.

    2004-10-01

    We present 6151 differential observations in the V filter measured by a robotic telescope, as well as 29 pairs of radial velocities from high-resolution spectroscopic observations, of the detached, EA-type, 9.65 day period double-lined eclipsing binary star MU Cas. Absolute dimensions of the components are determined with good precision (better than 2% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 4.57+/-0.09 Msolar and 3.67+/-0.04 Rsolar for the hotter, but smaller, less massive and less luminous photometric primary (star A), and 4.66+/-0.10 Msolar and 4.19+/-0.05 Rsolar for the cooler, larger, more massive and more luminous photometric secondary (star B). The effective temperatures and interstellar reddening of the stars are accurately determined from uvbyβ photometry: 15,100+/-500 K for the primary, 14,750+/-500 K for the secondary-corresponding to spectral types of B5 and B5-and 0.356 mag for Eb-y. The stars are located at a distance of about 1.7 kpc near the plane of the Galactic disk. The orbits of the stars are eccentric, and spectral line widths give observed rotational velocities that are synchronous with the mean orbital motion for both components. The components of MU Cas are upper main-sequence stars with an age of about 65 Myr according to models.

  2. DISCOVERY OF A TRANSITING PLANET AND EIGHT ECLIPSING BINARIES IN HATNet FIELD G205

    SciTech Connect

    Latham, David W.; Bakos, Gaspar A.; Torres, Guillermo; Stefanik, Robert P.; Noyes, Robert W.; Pal, Andras; Sipocz, Brigitta; Sasselov, Dimitar D.; Esquerdo, Gilbert A.; Hartman, Joel D.; Kovacs, Gabor; Kovacs, Geza; Marcy, Geoffrey W.; Fischer, Debra A.; Butler, R. Paul; Vogt, Steven S.

    2009-10-20

    We report the discovery of HAT-P-8b, a transiting planet with mass M {sub p} = 1.52{sup +0.18} {sub -0.16} M {sub J}, radius R {sub p} = 1.50{sup +0.08} {sub -0.06} R {sub J}, and photometric period P = 3.076 days. HAT-P-8b has a somewhat inflated radius for its mass, and a somewhat large mass for its period. The host star is a solar-metallicity F dwarf, with mass M {sub *} = 1.28 +- 0.04 M {sub sun} and R {sub *} = 1.58{sup +0.08} {sub -0.06} R {sub sun}. HAT-P-8b was initially identified as one of the 32 transiting-planet candidates in HATNet field G205. We describe the procedures that we have used to follow up these candidates with spectroscopic and photometric observations, and we present a status report on our interpretation for 28 of the candidates. Eight are eclipsing binaries with orbital solutions whose periods are consistent with their photometric ephemerides; two of these spectroscopic orbits are single-lined and six are double-lined.

  3. HIDES spectroscopy of bright detached eclipsing binaries from the Kepler field - II. Double- and triple-lined objects

    NASA Astrophysics Data System (ADS)

    Hełminiak, K. G.; Ukita, N.; Kambe, E.; Kozłowski, S. K.; Sybilski, P.; Maehara, H.; Ratajczak, M.; Konacki, M.; Pawłaszek, R. K.

    2017-06-01

    We present the results of our spectroscopic observations of eight detached eclipsing binaries (DEBs), selected from the Kepler Eclipsing Binary Catalog. Radial velocities (RVs) were calculated from high-resolution spectra obtained with the HIgh-Dispersion Echelle Spectrograph (HIDES) spectrograph, attached to the 1.88-m telescope of the Okayama Astrophysical Observatory, and were used to characterize the targets in combination with the Kepler light curves. For each binary, we obtained a full set of orbital and physical parameters, reaching precision below 3 per cent in masses and radii for five pairs. By comparing our results with theoretical models, we assess the distance, age and evolutionary status of the researched objects. We also study eclipse timing variations of selected objects, and identify a new system with a γDor pulsator. Two systems are triples, and show lines coming from three components. In one case, the motion of the outer star and the perturbation in the RVs of the inner binary are clearly visible and periodical, which allows us to directly calculate the mass of the third star and inclination of the outer orbit. In the second case, we only see a clear motion of the tertiary and investigate two scenarios: that it is a linear trend coming from the orbital motion around the inner binary and that it is caused by a planetary mass companion. When possible, we also compare our results with the literature, and conclude that only by combining photometry with RVs, it is possible to obtain correct physical parameters of both components of a DEB.

  4. K2 Discovery of Young Eclipsing Binaries in Upper Scorpius: Direct Mass and Radius Determinations for the Lowest Mass Stars and Initial Characterization of an Eclipsing Brown Dwarf Binary

    NASA Astrophysics Data System (ADS)

    David, Trevor J.; Hillenbrand, Lynne A.; Cody, Ann Marie; Carpenter, John M.; Howard, Andrew W.

    2016-01-01

    We report the discovery of three low-mass double-lined eclipsing binaries 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 eclipsing pair of ˜25 MJup brown dwarfs with a wide M-type companion. If confirmed, it would constitute only the second double-lined eclipsing brown dwarf binary 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 eclipsing binary 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 eclipsing binary 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

  5. Lunar Eclipse

    NASA Image and Video Library

    2003-11-09

    In this lunar eclipse viewed from Merritt Island, Fla., the full moon takes on a dark red color because it is being lighted slightly by sunlight passing through the Earth's atmosphere. This light has the blue component preferentially scattered out (this is also why the sky appears blue from the surface of the Earth), leaving faint reddish light to illuminate the Moon. Eclipses occur when the Sun, Earth and Moon line up. They are rare because the Moon usually passes above or below the imaginary line connecting Earth and the Sun. The Earth casts a shadow that the Moon can pass through - when it does, it is called a lunar eclipse.

  6. Light curve solutions of six eclipsing binaries at the lower limit of periods for W UMa stars

    NASA Astrophysics Data System (ADS)

    Kjurkchieva, Diana P.; Dimitrov, Dinko P.; Ibryamov, Sunay I.

    2015-09-01

    Photometric observations are presented in V and I bands of six eclipsing binaries at the lower limit of the orbital periods for W UMa stars. Three of them are newly discovered eclipsing systems. The light curve solutions reveal that all short-period targets are contact or overcontact binaries and six new binaries are added to the family of short-period systems with estimated parameters. Four binaries 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.

  7. Eclipsing and density effects on the spectral behavior of Beta Lyrae binary system in the UV

    NASA Astrophysics Data System (ADS)

    Sanad, M. R.

    2010-01-01

    We analyze both long and short high resolution ultraviolet spectrum of Beta Lyrae eclipsing binary 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 eclipse 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.

  8. Recent Observations of the Neglected Southern Eclipsing Binary Systems V343 Cen, UY Mus, HT Aps, and V1961 Sgr

    NASA Astrophysics Data System (ADS)

    Faulkner, D. R.; Samec, R. G.; Stoddard, M. L.; McKenzie, R.; Rebar, D.; Lavoie, G. D.; Moody, S.; Miller, J.; Van Hamme, W.

    2002-12-01

    As a part of our continuing search for solar type binaries with impacting gas streams, we present light curves of V343 Cen, UY Mus, HT Aps, and V1961 Sgr. These are all neglected variables whose observing histories show little or no observations since their discovery. The CCD observations were taken at the 0.9-m at CTI0 in the UBVRI Johnson-Cousins system. The observations were taken in on 2002, May 31-June 8 and 2001, May 16 - 23 respectively. UY Mus is a near contact binary with a large difference in eclipse depths of V = 0.67 mag. Otherwise the curve appears symmetric. The times of minimum light determined from our data are HJD Min I = 242047.62316(6) and Min II = 2452050.4874(3) where the value in parentheses is the standard error in the last decimal place. V1961 Sgr (GCVS 6848 485) is a W UMa binary with a difference in eclipse depths of V = 0.11 mag and a possible variable spot area causing a V = 0.04 mag variation in MAX I from night to night. HT Aps is a near contact solar type binary with a large difference in eclipse depths of V= 0.47 mag and a somewhat asymmetric (difference in maxima, V= 0.4 mag) light curve. It is a possibly a candidate for a binary with a gas stream. One time of minimum light determined from our data is HJD Min I = 2452331.63725 (12). V343 Cen is a near contact binary with a large difference in eclipse depths of V= 0.42 mag and distortions that give evidence of a gas stream collision. The difference in maxima is V = 0.07 mag. The curve shows little variation over the 4 day interval of observation. Light curves analyses, new period determinations and photometric data will be presented for these variables. Acknowledgements: We wish to thank the American Astronomical Society for their continued support of our undergraduate research programs through their small research grants. Faulkner and Samec were visiting Astronomers, Cerro Tololo InterAmerican Observatory, National Optical Astronomical Observatories, which are operated by the

  9. A search for tight hierarchical triple systems amongst the eclipsing binaries in the CoRoT fields

    NASA Astrophysics Data System (ADS)

    Hajdu, T.; Borkovits, T.; Forgács-Dajka, E.; Sztakovics, J.; Marschalkó, G.; Benkő, J. M.; Klagyivik, P.; Sallai, M. J.

    2017-10-01

    We report a comprehensive search for hierarchical triple stellar system candidates amongst eclipsing binaries (EBs) observed by the CoRoT spacecraft. We calculate and check eclipse timing variation (ETV) diagrams for almost 1500 EBs in an automated manner. We identify five relatively short period Algol systems for which our combined light-curve and complex ETV analyses (including both the light-travel time effect and short-term dynamical third-body perturbations) resulted in consistent third-body solutions. The computed periods of the outer bodies are between 82 and 272 d (with an alternative solution of 831 d for one of the targets). We find that the inner and outer orbits are near coplanar in all but one case. The dynamical masses of the outer subsystems determined from the ETV analyses are consistent with both the results of our light-curve analyses and the spectroscopic information available in the literature. One of our candidate systems exhibits outer eclipsing events as well, the locations of which are in good agreement with the ETV solution. We also report another certain triply eclipsing triple system that, however, is lacking a reliable ETV solution due to the very short time range of the data, and four new blended systems (composite light curves of two EBs each), where we cannot decide whether the components are gravitationally bounded or not. Amongst these blended systems, we identify the longest period and highest eccentricity EB in the entire CoRoT sample.

  10. Luminous blue variables and superluminous supernovae from binary mergers

    SciTech Connect

    Justham, Stephen; Podsiadlowski, Philipp; Vink, Jorick S. E-mail: podsi@astro.ox.ac.uk

    2014-12-01

    Evidence suggests that the direct progenitor stars of some core-collapse supernovae (CCSNe) are luminous blue variables (LBVs), perhaps including some Type II 'superluminous supernovae' (SLSNe). We examine models in which massive stars gain mass soon after the end of core hydrogen burning. These are mainly intended to represent mergers following a brief contact phase during early Case B mass transfer, but may also represent stars which gain mass in the Hertzsprung Gap or extremely late during the main-sequence phase for other reasons. The post-accretion stars spend their core helium-burning phase as blue supergiants (BSGs), and many examples are consistent with being LBVs at the time of core collapse. Other examples are yellow supergiants at explosion. We also investigate whether such post-accretion stars may explode successfully after core collapse. The final core properties of post-accretion models are broadly similar to those of single stars with the same initial mass as the pre-merger primary star. More surprisingly, when early Case B accretion does affect the final core properties, the effect appears likely to favor a successful SN explosion, i.e., to make the core properties more like those of a lower-mass single star. However, the detailed structures of these cores sometimes display qualitative differences to any single-star model we have calculated. The rate of appropriate binary mergers may match the rate of SNe with immediate LBV progenitors; for moderately optimistic assumptions we estimate that the progenitor birthrate is ∼1% of the CCSN rate.

  11. Two white dwarfs in ultrashort binaries with detached, eclipsing, likely sub-stellar companions detected by K2

    NASA Astrophysics Data System (ADS)

    Parsons, S. G.; Hermes, J. J.; Marsh, T. R.; Gänsicke, B. T.; Tremblay, P.-E.; Littlefair, S. P.; Sahman, D. I.; Ashley, R. P.; Green, M.; Rattanasoon, S.; Dhillon, V. S.; Burleigh, M. R.; Casewell, S. L.; Buckley, D. A. H.; Braker, I. P.; Irawati, P.; Dennihy, E.; Rodríguez-Gil, P.; Winget, D. E.; Winget, K. I.; Bell, Keaton J.; Kilic, Mukremin

    2017-10-01

    Using data from the extended Kepler mission in K2 Campaign 10, we identify two eclipsing binaries containing white dwarfs with cool companions that have extremely short orbital periods of only 71.2 min (SDSS J1205-0242, a.k.a. EPIC 201283111) and 72.5 min (SDSS J1231+0041, a.k.a. EPIC 248368963). Despite their short periods, both systems are detached with small, low-mass companions, in one case a brown dwarf and in the other case either a brown dwarf or a low-mass star. We present follow-up photometry and spectroscopy of both binaries, as well as phase-resolved spectroscopy of the brighter system, and use these data to place preliminary estimates on the physical and binary parameters. SDSS J1205-0242 is composed of a 0.39 ± 0.02 M⊙ helium-core white dwarf that is totally eclipsed by a 0.049 ± 0.006 M⊙ (51 ± 6MJ) brown-dwarf companion, while SDSS J1231+0041 is composed of a 0.56 ± 0.07 M⊙ white dwarf that is partially eclipsed by a companion of mass ≲0.095 M⊙. In the case of SDSS J1205-0242, we look at the combined constraints from common-envelope evolution and brown-dwarf models; the system is compatible with similar constraints from other post-common-envelope binaries, given the current parameter uncertainties, but has potential for future refinement.

  12. What Makes Red Giants Tick? Linking Tidal Forces, Activity, and Solar-Like Oscillations via Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Rawls, Meredith L.; Gaulme, Patrick; McKeever, Jean; Jackiewicz, Jason

    2016-01-01

    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 binaries 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 eclipsing binaries observed by Kepler. The binaries 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.

  13. Analysis of GSC 2475-1587 and GSC 841-277: Two Eclipsing Binary Stars Found During Asteroid Lightcurve Observations

    NASA Astrophysics Data System (ADS)

    Stephens, R. D.; Warner, B. D.

    2006-05-01

    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 binaries and attempted to model the system using David Bradstreet's Binary Maker 3. Unfortunately, neither binary showed a total eclipse. Therefore, our results are not conclusive and present only one of many possibilities.

  14. Time-resolved spectroscopy and photometry of the eclipsing AM Herculis binary EXO 033319 - 2554.2

    NASA Technical Reports Server (NTRS)

    Allen, Richard G.; Berriman, Graham; Smith, Paul S.; Schmidt, Gary D.

    1989-01-01

    Time-resolved optical observations of the eclipsing AM Herculis binary EXO 033319 - 2554.2 are presented. High-speed photometry of an eclipse is presented and used to derive a new ephemeris for the system and to estimate the size of the region responsible for the cyclotron emission. Optical spectra that span the orbital cycle are presented, the cyclotron emission in these spectra is discussed, and the flux and radial velocity variations of H-beta, H-gamma, and He II 4686 A are examined. Models of the flux and radial velocity variations of the emission lines indicate that about half the line emission comes from low-velocity material that is about 1.4 x 10 to the 10th cm from the white dwarf. The rest comes from high-velocity material that is about 10 to the 10th cm from the white dwarf and is moving toward it at about 600 km/s.

  15. Three New Eclipsing White-dwarf-M-dwarf Binaries Discovered in a Search for Transiting Planets around M-dwarfs

    NASA Astrophysics Data System (ADS)

    Law, Nicholas M.; Kraus, Adam L.; Street, Rachel; Fulton, Benjamin J.; Hillenbrand, Lynne A.; Shporer, Avi; Lister, Tim; Baranec, Christoph; Bloom, Joshua S.; Bui, Khanh; Burse, Mahesh P.; Cenko, S. Bradley; Das, H. K.; Davis, Jack. T. C.; Dekany, Richard G.; Filippenko, Alexei V.; Kasliwal, Mansi M.; Kulkarni, S. R.; Nugent, Peter; Ofek, Eran O.; Poznanski, Dovi; Quimby, Robert M.; Ramaprakash, A. N.; Riddle, Reed; Silverman, Jeffrey M.; Sivanandam, Suresh; Tendulkar, Shriharsh P.

    2012-10-01

    We present three new eclipsing white-dwarf/M-dwarf binary systems discovered during a search for transiting planets around M-dwarfs. Unlike most known eclipsing 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 × 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 ⊙ (0.01 AU). The M-dwarfs have masses of approximately 0.35 M ⊙, and the white dwarfs have hydrogen-rich atmospheres with temperatures of around 8000 K and have masses of approximately 0.5 M ⊙. 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 ⊙ (95% confidence) in one of the systems. Accounting for our detection efficiency and geometric factors, we estimate that 0.08%^{+0.10%}_{-0.05%} (90% confidence) of M-dwarfs are in these short-period, post-common-envelope white-dwarf/M-dwarf binaries 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 binaries including these relatively low-temperature white dwarfs are preferentially found at relatively large orbital radii. Similar eclipsing

  16. THREE NEW ECLIPSING WHITE-DWARF-M-DWARF BINARIES DISCOVERED IN A SEARCH FOR TRANSITING PLANETS AROUND M-DWARFS

    SciTech Connect

    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

    2012-10-01

    We present three new eclipsing white-dwarf/M-dwarf binary systems discovered during a search for transiting planets around M-dwarfs. Unlike most known eclipsing 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 binaries 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 binaries including these relatively low-temperature white dwarfs are preferentially found at

  17. HIGH-RESOLUTION SPECTROSCOPY DURING ECLIPSE OF THE YOUNG SUBSTELLAR ECLIPSING BINARY 2MASS 0535-0546. II. SECONDARY SPECTRUM: NO EVIDENCE THAT SPOTS CAUSE THE TEMPERATURE REVERSAL

    SciTech Connect

    Mohanty, Subhanjoy; Stassun, Keivan G. E-mail: keivan.stassun@vanderbilt.edu

    2012-10-10

    We present high-resolution optical spectra of the young brown dwarf eclipsing binary 2M0535-05, obtained during eclipse 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 binary 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.

  18. THE PERIOD VARIATION OF AND A SPOT MODEL FOR THE ECLIPSING BINARY AR BOOTIS

    SciTech Connect

    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

    2009-08-15

    New CCD photometric observations of the eclipsing 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 binary class, consisting of a hotter, less massive primary star with a spectral type of G9 and a companion of spectral type K1.

  19. Eclipsing Binaries as Benchmarks for Trigonometric Parallaxes in the Gaia Era

    NASA Astrophysics Data System (ADS)

    Stassun, Keivan G.; Torres, Guillermo

    2016-12-01

    We present fits to the broadband photometric spectral energy distributions (SEDs) of 158 eclipsing binaries (EBs) in the Tycho-2 catalog. These EBs were selected because they have highly precise stellar radii, effective temperatures, and in many cases metallicities previously determined in the literature, and thus have bolometric luminosities that are typically good to ≲10%. In most cases the available broadband photometry spans a wavelength range 0.4-10 μm, and in many cases spans 0.15-22 μm. The resulting SED fits, which have only extinction as a free parameter, provide a virtually model-independent measure of the bolometric flux at Earth. The SED fits are satisfactory for 156 of the EBs, for which we achieve typical precisions in the bolometric flux of ≈3%. Combined with the accurately known bolometric luminosity, the result for each EB is a predicted parallax that is typically precise to ≲5%. These predicted parallaxes—with typical uncertainties of 200 μas—are 4-5 times more precise than those determined by Hipparcos for 99 of the EBs in our sample, with which we find excellent agreement. There is no evidence among this sample for significant systematics in the Hipparcos parallaxes of the sort that notoriously afflicted the Pleiades measurement. The EBs are distributed over the entire sky, span more than 10 mag in brightness, reach distances of more than 5 kpc, and in many cases our predicted parallaxes should also be more precise than those expected from the Gaia first data release. The EBs studied here can thus serve as empirical, independent benchmarks for these upcoming fundamental parallax measurements.

  20. 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.

  1. ABSOLUTE PROPERTIES OF THE HIGHLY ECCENTRIC, SOLAR-TYPE ECLIPSING BINARY HD 74057

    SciTech Connect

    Sowell, James R.; Henry, Gregory W.; Fekel, Francis C. E-mail: gregory.w.henry@gmail.com

    2012-01-15

    We have obtained Stroemgren b and y differential photometric observations of the solar-type eclipsing binary HD 74057 plus follow-up high-resolution, red wavelength spectroscopic observations. The system has an orbital period of 31.2198 days, a high eccentricity of 0.47, and is seen almost exactly edge on with an inclination of 89.{sup 0}8. The two main-sequence G0 stars are nearly identical in all physical characteristics. We used the Wilson-Devinney program to obtain a simultaneous solution of our photometric and spectroscopic observations. The resulting masses of the components are M{sub 1} = 1.138 {+-} 0.003 M{sub Sun} and M{sub 2} = 1.131 {+-} 0.003 M{sub Sun }, and the radii are R{sub 1} = 1.064 {+-} 0.002 R{sub Sun} and R{sub 2} = 1.049 {+-} 0.002 R{sub Sun }. The effective temperatures are 5900 K (fixed) and 5843 K, and the iron abundance, [Fe/H], is estimated to be +0.07. A comparison with evolutionary tracks suggests that the system may be even more metal rich. The components rotate with periods of 8.4 days, significantly faster than the predicted pseudosynchronous period of 12.7 days. We see evidence that one or both components have cool spots. Both stars are close to the zero-age main sequence and are about 1.0 Gyr old.

  2. Absolute Properties of the Main-Sequence Eclipsing Binary Star V885 Cygni

    NASA Astrophysics Data System (ADS)

    Lacy, Claud H. Sandberg; Vaz, Luiz Paulo Ribeiro; Claret, Antonio; Sabby, Jeffrey A.

    2004-09-01

    We present 4179 differential observations in the V filter measured by a robotic telescope, as well as 25 pairs of radial velocities from high-resolution spectroscopic observations, of the detached, EB-type, 1.69 day period double-lined eclipsing binary star V885 Cyg. Absolute dimensions of the components are determined with high precision (better than 1.5% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 2.005+/-0.029 Msolar and 2.345+/-0.012 Rsolar for the hotter, but smaller, less massive and less luminous photometric primary (star A), and 2.234+/-0.026 Msolar and 3.385+/-0.026 Rsolar for the cooler, larger, more massive and more luminous photometric secondary (star B). The effective temperatures and interstellar reddening of the stars are accurately determined from uvbyβ photometry: 8375+/-150 K for the primary, 8150+/-150 K for the secondary-corresponding to spectral types of A3m and A4m-and 0.058 mag for Eb-y. The metallic-lined character of the stars is revealed by high-resolution spectroscopy and uvbyβ photometry. The orbits are circular, and spectral line widths give observed rotational velocities that are synchronous with the orbital motion for both components. The components of V885 Cyg are main-sequence stars with an age of about 500 Myr according to models. Our estimate of the age of this system would seem to favor the hydrodynamic damping formalism of Tassoul & Tassoul in this particular case, since both the components' spins are synchronous and the orbit is circular.

  3. Absolute Properties of the Main-Sequence Eclipsing Binary Star BP Vulpeculae

    NASA Astrophysics Data System (ADS)

    Lacy, Claud H. Sandberg; Torres, Guillermo; Claret, Antonio; Sabby, Jeffrey A.

    2003-10-01

    We present 5236 differential observations in the V filter measured by a robotic telescope, as well as radial velocities from spectroscopic observations, of the detached, eccentric 1.9 day double-lined eclipsing binary star BP Vul. Absolute dimensions of the components are determined with high precision (better than 1% in the masses and radii) for the purpose of testing various aspects of theoretical modeling. We obtain 1.737+/-0.015 Msolar and 1.852+/-0.014 Rsolar for the primary, and 1.408+/-0.009 Msolar and 1.489+/-0.014 Rsolar for the secondary. The effective temperatures and interstellar reddening of the stars are accurately determined from uvbyβ photometry: 7700+/-150 K for the primary, 6800+/-150 K for the secondary-corresponding to spectral types of A7m and F2m-and 0.022 mag for Eb-y. The metallic-lined character of the stars is revealed by high-resolution spectroscopy and uvbyβ photometry. Spectral line widths give rotational velocities that are synchronous with the orbital motion for the secondary component, but subsynchronous for the primary component, in a slightly eccentric orbit (e=0.0345). Apsidal motion based on times of minimum light appears to be negative with a period of about 75 years based on recent observations of minima, but this result is not confirmed by the radial velocity measurements, and it is indeterminate when older photographic and visual data are included. The components of BP Vul are main-sequence stars with an age of about 1 Gyr according to models. Some of the observations reported here were obtained with the Multiple Mirror Telescope, a joint facility of the Smithsonian Institution and the University of Arizona.

  4. A precision study of two eclipsing white dwarf plus M dwarf binaries

    NASA Astrophysics Data System (ADS)

    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.

    2012-03-01

    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 eclipsing post common envelope binaries 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 low mass and in a short period binary 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.

  5. Discovery of a 3.6-hr Eclipsing Luminous X-Ray Binary in the Galaxy NGC 4214

    NASA Technical Reports Server (NTRS)

    Ghosh, Kajal K.; Rappaport, Saul; Tennant, Allyn F.; Swartz, Douglas A.; Pooley, David; Madhusudhan, N.

    2006-01-01

    We report the discovery of an eclipsing X-ray binary 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 binary, 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 binary 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 binary----perhaps related to Cyg X-3. Other less likely possibilities include a conventional low-mass X-ray binary 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 binary 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.

  6. Discovery of a 3.6-hr Eclipsing Luminous X-Ray Binary in the Galaxy NGC 4214

    NASA Technical Reports Server (NTRS)

    Ghosh, Kajal K.; Rappaport, Saul; Tennant, Allyn F.; Swartz, Douglas A.; Pooley, David; Madhusudhan, N.

    2006-01-01

    We report the discovery of an eclipsing X-ray binary 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 binary, 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 binary 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 binary----perhaps related to Cyg X-3. Other less likely possibilities include a conventional low-mass X-ray binary 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 binary 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.

  7. Probing the Masses and Radii of Donor Stars in Eclipsing X-Ray Binaries with the Swift Burst Alert Telescope

    NASA Astrophysics Data System (ADS)

    Coley, Joel B.; Corbet, Robin H. D.; Krimm, Hans A.

    2015-08-01

    Physical parameters of both the mass donor and compact object can be constrained in X-ray binaries with well-defined eclipses, as our survey of wind-fed supergiant X-ray binaries 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 eclipse 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” binaries IGR J18027-2016 and XTE J1855-026. The eclipse 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 eclipse 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}⊙ . Eclipse profiles are asymmetric in IGR J18027-2016 and XTE J1855-026, which we attribute to accretion wakes.

  8. Binaries discovered by the MUCHFUSS project. SDSS J162256.66+473051.1: An eclipsing subdwarf B binary with a brown dwarf companion

    NASA Astrophysics Data System (ADS)

    Schaffenroth, V.; Geier, S.; Heber, U.; Kupfer, T.; Ziegerer, E.; Heuser, C.; Classen, L.; Cordes, O.

    2014-04-01

    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 binaries. Their short orbital periods of 1.2 h to a few days suggest that they are post common-envelope systems. Eclipsing hot subdwarf binaries are rare but are important in determining the fundamental stellar parameters. Low-mass 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 eclipsing hot subdwarf binary 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 eclipses 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

  9. An Abundance Analysis of the Primary Star of the Peculiar Eclipsing Binary ɛ Aurigae out of the Eclipsing Phase

    NASA Astrophysics Data System (ADS)

    Sadakane, Kozo; Kambe, Eiji; Sato, Bun'ei; Honda, Satoshi; Hashimoto, Osamu

    2010-12-01

    A detailed abundance analysis of the primary star of ɛ Aur before an eclipse was carried out using a very high signal-to-noise ratio optical-region spectrum. An A7 Iab supergiant HD 81471, presumably a member of the Vela OB1 association, was used as a reference. We obtained atmospheric parameters (Teff, log g, and ξt) to be (8025 K, 1.0 and 10 km s-1) and (8050 K, 1.0 and 7 km s-1) for ɛ Aur and HD 81471, respectively. The abundances of Mg, Si, S, Ca, Sc, Ti, Cr, and Fe were very close to the solar abundances in both stars. Light elements C and O were under-abundant, while N and Na were over-abundant in both stars, after correcting for non-LTE effects. Definite under-abundances of Sr were detected in both stars. Slight, but definite, over-abundances were found in ɛ Aur for the s-process elements Y, Zr, and Ba, when compared with the results of HD 81471. Enhancements in the abundances of N, Na, and s-process elements might indicate the occurences of thermal dredge-up and the s-process nucleosynthesis in ɛ Aur during the past evolution.

  10. Observations and light curve solutions of the eclipsing W UMa binaries CSS J071813.2+505000, NSVS 2459652, NSVS 7178717 and NSVS 7377875

    NASA Astrophysics Data System (ADS)

    Kjurkchieva, D. P.; Popov, V. A.; Vasileva, D. L.; Petrov, N. I.

    2017-04-01

    Photometric observations in Sloan g' and i' bands of four eclipsing W UMa binaries are presented. They allowed the improvement of system ephemerides. The light curve solutions led to the following results: (i) CSS J071813.2+505000 is barely an overcontact system, NSVS 2459652 and NSVS 7377875 are overcontact binaries with an intermediate fillout factor, while NSVS 7178717 has a deep-contact configuration; (ii) NSVS 7178717 undergoes total eclipses while the other three targets exhibit partial eclipses; (iii) The components of each target are almost the same in temperature: those of CSS J071813.2+505000 are early G stars while those of the other three targets are of K spectral type; (iv) The targets with late components reveal spot activity; (v) NSVS 2459652 and NSVS 7377875 are W UMa binaries of H subtype; (vi) The relation mass ratio - luminosity ratio of our targets confirms the results from previous statistical analysis of W UMa systems.

  11. MML 53: a new low-mass, pre-main sequence eclipsing binary in the Upper Centaurus-Lupus region discovered by SuperWASP

    NASA Astrophysics Data System (ADS)

    Hebb, L.; Stempels, H. C.; Aigrain, S.; Collier-Cameron, A.; Hodgkin, S. T.; Irwin, J. M.; Maxted, P. F. L.; Pollacco, D.; Street, R. A.; Wilson, D. M.; Stassun, K. G.

    2010-11-01

    We announce the discovery of a new low-mass, pre-main sequence eclipsing binary, MML 53. Previous observations of MML 53 found it to be a pre-main sequence spectroscopic multiple associated with the 15-22 Myr Upper Centaurus-Lupus cluster. We identify the object as an eclipsing binary for the first time through the analysis of multiple seasons of time series photometry from the SuperWASP transiting planet survey. Re-analysis of a single archive spectrum shows MML 53 to be a spatially unresolved triple system of young stars which all exhibit significant lithium absorption. Two of the components comprise an eclipsing binary with period, P = 2.097891(6) ± 0.000005 and mass ratio, q ~ 0.8. Here, we present the analysis of the discovery data.

  12. Precise orbit solution of MML 53, a low-mass, pre-main sequence eclipsing binary in Upper Centaurus Lupus

    NASA Astrophysics Data System (ADS)

    Hebb, L.; Cegla, H. M.; Stassun, K. G.; Stempels, H. C.; Cargile, P. A.; Palladino, L. E.

    2011-07-01

    Aims: We present a double-lined orbit solution for MML 53, the recently discovered low-mass pre-main sequence eclipsing binary. Methods: Using high-resolution spectra from the SMARTS 1.5 m echelle spectrograph, we measure precise radial velocities and derive the orbital parameters of the system. Results: The 2.1 d orbit of the eclipsing pair is circular, and we find the minimum masses of the eclipsing components to be M1sin3i = 0.97 M⊙ and M2sin3i = 0.84 M⊙, with formal uncertainties of 2.0% and an additional systematic uncertainty of ≈2.5% most likely caused by large star spots on the primary star. MML 53 has been previously identified as a member of the Upper Centaurus Lupus (UCL) star forming region (age ~15 Myr). The systemic radial velocity from our orbit solution, vγ = +1.4 ± 0.3 ± 0.8 km s-1 (statistical and systematic), is also consistent with kinematic membership in this association. In addition, we detect a change in vγ between 2006 and 2009 providing further evidence for the presence of a the third body in a wide (several year) orbit.

  13. Dust Scattering Halo from an Eclipsing X-ray Binary at 1.5 arcmin from Sgr A*

    NASA Astrophysics Data System (ADS)

    Jin, Chichuan; Haberl, Frank; Ponti, Gabriele

    2016-07-01

    AX J1745.6-2901 is an eclipsing neutron star low mass X-ray binary. This source is bright in X-rays and it has a high column density of absorbing gas along the line of sight, showcasing a strong dust scattering halo. Moreover, the dust scattering halo shows time evolution during the eclipsing phase. The combination of these phenomena can provide important information about the location of the neutron star and the dust properties along the line of sight. In this talk, I will show that based on a large set of XMM-Newton and Chandra data, we can conduct, for the first time, a powerful combined analysis of the radial profile of the dust scattering halo and the time evolution of the halo during the eclipsing phase. Our study can put constraints on the location of the source, the distribution and composition of the dust, and the metal abundance towards the source. Due to the proximity of the source to Sgr A* (only 1.5 arcmin), these properties are highly relevant to the dust in the Galactic centre, and are likely to be similar as the dust properties on the line of sight towards Sgr A*.

  14. The orbital ephemeris and eclipse transitions of the low-mass X-ray binary EXO 0748 - 676

    SciTech Connect

    Parmar, A.N.; Smale, A.P.; Verbunt, F.; Corbet, R.H.D. NASA, Goddard Space Flight Center, Greenbelt, MD Utrecht Rijksuniversitet Institute of Space and Astronautical Science, Sagamihara )

    1991-01-01

    Using the eclipses as fiducial markers, an updated ephemeris for EXO 0748 - 676 is derived and evidence is found that between February 1985 and March 1989 the 3.82-h orbital period of EXO 0748 - 676 decreased with a time scale of -5 x 10 to the 6th yr. The sense of this change is the same as that predicted by simple models for the evolution of low-mass X-ray binaries containing main-sequence companions, but is a factor about 100 faster than expected. This rapid change in orbital period could result from the expansion of the companion due to the effects of X-ray heating. The eclipse transition durations are variable, with the shortest observed taking 1.5 s and the longest 40 s. This latter figure is about an order of magnitude too large to be due to absorption effects in the atmosphere of the secondary assuming a Roche geometry and likely stellar temperature. Either flaring activity or the presence of an X-ray heated evaporative wind or a corona may enhance the scale height of the companion's atmosphere producing the extended eclipse transitions. 38 refs.

  15. DISCOVERY OF AN ACCRETING MILLISECOND PULSAR IN THE ECLIPSING BINARY SYSTEM SWIFT J1749.4-2807

    SciTech Connect

    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.

    2011-01-20

    We report on the discovery and the timing analysis of the first eclipsing 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 binary 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 eclipse 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 eclipsing 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.

  16. The orbital ephemeris and eclipse transitions of the low-mass X-ray binary EXO 0748 - 676

    NASA Technical Reports Server (NTRS)

    Parmar, A. N.; Smale, A. P.; Verbunt, F.; Corbet, R. H. D.

    1991-01-01

    Using the eclipses as fiducial markers, an updated ephemeris for EXO 0748 - 676 is derived and evidence is found that between February 1985 and March 1989 the 3.82-h orbital period of EXO 0748 - 676 decreased with a time scale of -5 x 10 to the 6th yr. The sense of this change is the same as that predicted by simple models for the evolution of low-mass X-ray binaries containing main-sequence companions, but is a factor about 100 faster than expected. This rapid change in orbital period could result from the expansion of the companion due to the effects of X-ray heating. The eclipse transition durations are variable, with the shortest observed taking 1.5 s and the longest 40 s. This latter figure is about an order of magnitude too large to be due to absorption effects in the atmosphere of the secondary assuming a Roche geometry and likely stellar temperature. Either flaring activity or the presence of an X-ray heated evaporative wind or a corona may enhance the scale height of the companion's atmosphere producing the extended eclipse transitions.

  17. The first study of the light-travel time effect in massive LMC eclipsing binaries

    NASA Astrophysics Data System (ADS)

    Zasche, P.; Wolf, M.; Vraštil, J.; Pilarčík, L.; Juryšek, J.

    2016-05-01

    Aims: New CCD observations for semidetached and detached eclipsing binaries 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

  18. Eclipsing binaries in open clusters - I. V615 Per and V618 Per in h Persei

    NASA Astrophysics Data System (ADS)

    Southworth, J.; Maxted, P. F. L.; Smalley, B.

    2004-04-01

    We derive absolute dimensions for two early-type main-sequence detached eclipsing binaries in the young open cluster h Persei (NGC 869). V615 Persei has a spectral type of B7 V and a period of 13.7 d. V618 Persei is A2 V and has a period of 6.4 d. New ephemerides are calculated for both systems. The masses of the component stars have been derived using high-resolution spectroscopy and are 4.08 +/- 0.06 and 3.18 +/- 0.05 Msolar for V615 Per and 2.33 +/- 0.03 and 1.56 +/- 0.02 Msolar for V618 Per. The radii have been measured by fitting the available light curves using EBOP and are 2.29 +/- 0.14 and 1.90 +/- 0.09 Rsolar for V615 Per and 1.64 +/- 0.07 and 1.32 +/- 0.07 Rsolar for V618 Per. By comparing the observed spectra of V615 Per with synthetic spectra from model atmospheres we find that the effective temperatures of the stars are 15000 +/- 500 K for the primary and 11000 +/- 500 K for the secondary. The equatorial rotational velocities of the primary and secondary components of V615 Per are 28 +/- 5 and 8 +/- 5 km s-1, respectively. Both components of V618 Per rotate at 10 +/- 5 km s-1. The equatorial rotational velocities for synchronous rotation are about 10 km s-1 for all four stars. The time-scales for orbital circularization for both systems, and the time-scale for rotational synchronization of V615 Per, are much greater than the age of h Per. Their negligible eccentricities and equatorial rotational velocities therefore support the hypothesis that they were formed by delayed break-up. We have compared the radii of these stars with models by the Granada and the Padova groups for stars of the same masses but different compositions. We conclude that the metallicity of the stars is Z~ 0.01. This appears to be the first estimate of the bulk metallicity of h Per. Recent photometric studies have assumed a solar metallicity so their results should be reviewed.

  19. 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

  20. DISCOVERY OF A RED GIANT WITH SOLAR-LIKE OSCILLATIONS IN AN ECLIPSING BINARY SYSTEM FROM KEPLER SPACE-BASED PHOTOMETRY

    SciTech Connect

    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.

    2010-04-20

    Oscillating stars in binary 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 eclipsing binary 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 eclipse 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.

  1. LUT Reveals an Algol-type Eclipsing Binary With Three Additional Stellar Companions in a Multiple System

    NASA Astrophysics Data System (ADS)

    Zhu, L.-Y.; Zhou, X.; Hu, J.-Y.; Qian, S.-B.; Li, L.-J.; Liao, W.-P.; Tian, X.-M.; Wang, Z.-H.

    2016-04-01

    A complete light curve of the neglected eclipsing binary Algol V548 Cygni in the UV band was obtained with the Lunar-based Ultraviolet Telescope in 2014 May. Photometric solutions are obtained using the Wilson-Devinney method. It is found that solutions with and without third light are quite different. The mass ratio without third light is determined to be q = 0.307, while that derived with third light is q = 0.606. It is shown that V548 Cygni is a semi-detached binary where the secondary component is filling the critical Roche lobe. An analysis of all available eclipse times suggests that there are three cyclic variations in the O-C diagram that are interpreted by the light travel-time effect via the presence of three additional stellar companions. This is in agreement with the presence of a large quantity of third light in the system. The masses of these companions are estimated as m sin i‧ ˜ 1.09, 0.20, and 0.52 M⊙. They are orbiting the central binary with orbital periods of about 5.5, 23.3, and 69.9 years, i.e., in 1:4:12 resonance orbit. Their orbital separations are about 4.5, 13.2, and 26.4 au, respectively. Our photometric solutions suggest that they contribute about 32.4% to the total light of the multiple system. No obvious long-term changes in the orbital period were found, indicating that the contributions of the mass transfer and the mass loss due to magnetic braking to the period variations are comparable. The detection of three possible additional stellar components orbiting a typical Algol in a multiple system make V548 Cygni a very interesting binary to study in the future.

  2. LUT REVEALS AN ALGOL-TYPE ECLIPSING BINARY WITH THREE ADDITIONAL STELLAR COMPANIONS IN A MULTIPLE SYSTEM

    SciTech Connect

    Zhu, L.-Y.; Zhou, X.; Qian, S.-B.; Li, L.-J.; Liao, W.-P.; Tian, X.-M.; Wang, Z.-H.; Hu, J.-Y.

    2016-04-15

    A complete light curve of the neglected eclipsing binary Algol V548 Cygni in the UV band was obtained with the Lunar-based Ultraviolet Telescope in 2014 May. Photometric solutions are obtained using the Wilson–Devinney method. It is found that solutions with and without third light are quite different. The mass ratio without third light is determined to be q = 0.307, while that derived with third light is q = 0.606. It is shown that V548 Cygni is a semi-detached binary where the secondary component is filling the critical Roche lobe. An analysis of all available eclipse times suggests that there are three cyclic variations in the O–C diagram that are interpreted by the light travel-time effect via the presence of three additional stellar companions. This is in agreement with the presence of a large quantity of third light in the system. The masses of these companions are estimated as m sin i′ ∼ 1.09, 0.20, and 0.52 M{sub ⊙}. They are orbiting the central binary with orbital periods of about 5.5, 23.3, and 69.9 years, i.e., in 1:4:12 resonance orbit. Their orbital separations are about 4.5, 13.2, and 26.4 au, respectively. Our photometric solutions suggest that they contribute about 32.4% to the total light of the multiple system. No obvious long-term changes in the orbital period were found, indicating that the contributions of the mass transfer and the mass loss due to magnetic braking to the period variations are comparable. The detection of three possible additional stellar components orbiting a typical Algol in a multiple system make V548 Cygni a very interesting binary to study in the future.

  3. Solar and Stellar Eclipse Mapping

    NASA Astrophysics Data System (ADS)

    Budding, E.

    2007-05-01

    The special circumstance of solar eclipse 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 eclipses, topics of particular note concern: choice of fitting functions, disk eclipses, spot eclipses and the gravity-darkening effect. These topics arise within new era eclipsing binary studies and are relevant to active researches on remote binaries and extrasolar planets.

  4. Discovery and Characterization of Eclipsing Binary Stars and Transiting Planets in Young Benchmark Clusters: The Pleiades and Hyades

    NASA Astrophysics Data System (ADS)

    Stassun, Keivan; David, Trevor J.; Conroy, Kyle E.; Hillenbrand, Lynne; Stauffer, John R.; Pepper, Joshua; Rebull, Luisa M.; Cody, Ann Marie

    2016-06-01

    Prior to K2, only one eclipsing binary in the Pleiades was known (HD 23642). We present the discovery and characterization of three additional eclipsing binaries (EBs) in this ~120 Myr old benchmark open cluster. Unlike HD 23642, all three of the new EBs are low mass (Mtot < 1 M⊙) and thus their components are still undergoing pre-main-sequence contraction at the Pleiades age. Low mass 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.

  5. The Chandra Delta Ori Large Project: Occultation Measurements of the Shocked Gas tn the Nearest Eclipsing O-Star Binary

    NASA Technical Reports Server (NTRS)

    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

    2013-01-01

    Delta Ori is the nearest massive, single-lined eclipsing binary (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 eclipsing O-type binary 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.

  6. Variations in the orbital periods of the Algol-type eclipsing binaries RZ Cas and Z Dra

    NASA Astrophysics Data System (ADS)

    Khaliullina, A. I.

    2016-05-01

    A detailed study of variations of the orbital periods of the Algol-type eclipsing binary 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 eclipsing binaries 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.

  7. Photometric investigation of the totally eclipsing contact binary V12 in the intermediate-age open cluster NGC 7789

    SciTech Connect

    Qian, S.-B.; Wang, J.-J.; Liu, L.; Zhou, X.; Essam, A.; Ali, G. B.; Haroon, A.-A.

    2015-02-01

    NGC 7789 is an intermediate-age open cluster with an age similar to the mean age of contact binary stars. V12 is a bright W UMa-type binary 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 binary (f=43.0(±2.2)%) with a mass ratio of 3.848, and it is a W-type contact binary 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 eclipsing binary, 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 binary in an intermediate-age open cluster may suggest that some contact binaries 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.

  8. A Wide-field Survey for Transiting Hot Jupiters and Eclipsing Pre-main-sequence Binaries in Young Stellar Associations

    NASA Astrophysics Data System (ADS)

    Oelkers, Ryan J.; Macri, Lucas M.; Marshall, Jennifer L.; DePoy, Darren L.; Lambas, Diego G.; Colazo, Carlos; Stringer, Katelyn

    2016-09-01

    The past two decades have seen a significant advancement in the detection, classification, and understanding of exoplanets and binaries. 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 binary 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 binaries 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 eclipse 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 binary 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.

  9. The variable He 10830 A line of Algol. [eclipsing binary star

    NASA Technical Reports Server (NTRS)

    Zirin, H.; Liggett, M. A.

    1982-01-01

    Spectra of several eclipses 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 eclipse, 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 eclipse. 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.

  10. The Remarkable Eclipsing Asynchronous AM Herculis Binary RX J19402-1025

    NASA Astrophysics Data System (ADS)

    Patterson, Joseph; Skillman, David R.; Thorstensen, John; Hellier, Coel

    1995-04-01

    We report on two years of photometric and spectroscopic observation of the recently discovered AM Herculis star RX J19402-1025. A sharp eclipse feature is present in the optical and X-ray light curves, repeating with a period of 12116.290 +- 0.003 s. The out-of-eclipse 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 eclipse period is the underlying orbital period, while the magnetic white dwarf rotates with P = 12150 s. The eclipses appear to be eclipses 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 eclipses 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)

  11. The remarkable eclipsing asynchronous AM Herculis binary RX J19402-1025

    NASA Technical Reports Server (NTRS)

    Patterson, Joseph; Skillman, David R.; Thorstensen, John; Hellier, Coel

    1995-01-01

    We report on two years of photometric and spectroscopic observation of the recently discovered AM Herculis star RX J19402-1025. A sharp eclipse feature is present in the optical and X-ray light curves, repeating with a period of 12116.290 +/- 0.003 s. The out-of-eclipse optical waveform contains approximately equal contributions from a signal at the same period and another signal at 12150 s. As these signals drift in and out of phase, the wave form of the light curve changes in a complex but predictable manner. After one entire 'supercycle' 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 eclipse period is the underlying orbital period, while the magnetic white dwarf rotates with P = 12150 s. The eclipses appear to be eclipses 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 eclipses 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.

  12. OGLE-BLG182.1.162852: an eclipsing binary with a circumstellar disc

    NASA Astrophysics Data System (ADS)

    Rattenbury, N. J.; Wyrzykowski, Ł.; Kostrzewa-Rutkowska, Z.; Udalski, A.; Kozłowski, S.; Szymański, M. K.; Pietrzyński, G.; Soszyński, I.; Poleski, R.; Ulaczyk, K.; Skowron, J.; Pietrukowicz, P.; Mróz, P.; Skowron, D.

    2015-02-01

    We present the discovery of a plausible disc-eclipse system OGLE-BLG182.1.162852. The OGLE light curve for OGLE-BLG182.1.162852 shows three episodes of dimming by I ≃ 2-3 mag, separated by 1277 d. The shape of the light curve during dimming events is very similar to that of known disc-eclipse system OGLE-LMC-ECL-11893. The event is presently undergoing a dimming event, predicted to end on 2014 December 30. The next dimming episode for OGLE-BLG182.1.162852 is expected to occur in 2018 March.

  13. THE ARAUCARIA PROJECT. DETERMINATION OF THE LARGE MAGELLANIC CLOUD DISTANCE FROM LATE-TYPE ECLIPSING BINARY SYSTEMS. I. OGLE-051019.64-685812.3

    SciTech Connect

    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

    2009-05-20

    We have analyzed the double-lined eclipsing binary 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 binary system measured outside the eclipses has allowed us to obtain an accurate orbit solution for this eclipsing binary 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 eclipsing binary 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.

  14. Absolute dimensions of eclipsing binaries. XXVIII. BK Pegasi and other F-type binaries: Prospects for calibration of convective core overshoot

    NASA Astrophysics Data System (ADS)

    Clausen, J. V.; Frandsen, S.; Bruntt, H.; Olsen, E. H.; Helt, B. E.; Gregersen, K.; Juncher, D.; Krogstrup, P.

    2010-06-01

    Context. Double-lined, detached eclipsing binaries are our main source for accurate stellar masses and radii. In this paper we focus on the 1.15-1.70 M⊙ interval where convective core overshoot is gradually ramped up in theoretical evolutionary models. Aims: We aim to determine absolute dimensions and abundances for the F-type detached eclipsing binary BK Peg, and to perform a detailed comparison with results from recent stellar evolutionary models, including a sample of previously studied systems with accurate parameters. Methods: uvby light curves and uvbyβ standard photometry were obtained with the Strömgren Automatic Telescope, ESO, La Silla, and high-resolution spectra were acquired with the FIES spectrograph at the Nordic Optical Telescope, La Palma. Results: The 5 fd 49 period orbit of BK Peg is slightly eccentric (e = 0.053). The two components are quite different with masses and radii of (1.414 ± 0.007 M⊙, 1.988 ± 0.008 Rsun) and (1.257 ± 0.005 M⊙, 1.474 ± 0.017 Rsun), respectively. The measured rotational velocities are 16.6 ± 0.2 (primary) and 13.4 ± 0.2 (secondary) km s-1. For the secondary component this corresponds to (pseudo)synchronous rotation, whereas the primary component seems to rotate at a slightly lower rate. We derive an iron abundance of [Fe/H] = -0.12 ± 0.07 and similar abundances for Si, Ca, Sc, Ti, Cr and Ni. The stars have evolved to the upper half of the main-sequence band. Yonsei-Yale and Victoria-Regina evolutionary models for the observed metal abundance reproduce BK Peg at ages of 2.75 and 2.50 Gyr, respectively, but tend to predict a lower age for the more massive primary component than for the secondary. We find the same age trend for three other upper main-sequence systems in a sample of well studied eclipsing binaries with components in the 1.15-1.70 M⊙ range. We also find that the Yonsei-Yale models systematically predict higher ages than the Victoria-Regina models. The sample includes BW Aqr, and as a

  15. Eclipsing binaries and fast rotators in the Kepler sample. Characterization via radial velocity analysis from Calar Alto

    NASA Astrophysics Data System (ADS)

    Lillo-Box, J.; Barrado, D.; Mancini, L.; Henning, Th.; Figueira, P.; Ciceri, S.; Santos, N.

    2015-04-01

    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 eclipsing binaries. 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 eclipsing binaries (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 eclipse. 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

  16. Predicting the Alpha Comae Berenices Time of Eclipse: How 3 Ambiguous Measurements Out of 609 Caused a 26 Year Binary’s Eclipse to be Missed

    DTIC Science & Technology

    2015-11-01

    PREDICTING THE α COMAE BERENICES TIME OF ECLIPSE: HOW 3 AMBIGUOUS MEASUREMENTS OUT OF 609 CAUSED A 26 YEAR BINARY’S ECLIPSE TO BE MISSED Matthew W...been realized recently that the position angle measurements for three of the observations from ∼100 years ago were in error by 180°, which warped the...rected through this method). The final orbital solution was similarly skewed, which caused errors in the timing of the eclipse. 2. CATCHING THE

  17. Eclipsing Binaries as Astrophysical Laboratories: Probing the Internal Structure of the Moderate Mass Stars of CO Lacertae

    NASA Astrophysics Data System (ADS)

    Volgenau, N. H.; Guinan, E. F.; Etzel, P. B.; Bradstreet, D. H.; Gimenez, A.

    1995-03-01

    CO Lac is an important 10th mag eclipsing and double-line spectroscopic binary with P = 1.542 days. This system consists of two nearly identical B8.5 V and B9.5 V stars moving in an eccentric orbit with e = 0.03. CO Lac has relatively deep, narrow eclipses which permit the times of primary and secondary eclipses to be accurately measured, even from early photographic plate material. Analyses of these timings reveal an apsidal motion period of U = 43.4+/-0.1 yrs. CO Lac is a vital laboratory for studying the internal structure of stars because of its well-determined apsidal motion rate and also because the physical properties of its components can be accurately determined from its light and radial velocity curves. A significant problem with previous interpretations of CO Lac has been the uncertainty in determining the masses of the component stars. To refine the masses of the system, a new radial velocity study of the star was undertaken during 1993/94 at Mt. Laguna Observatory using a 1M telescope and a CCD detector. A preliminary analysis of the recent spectroscopy indicates that the masses of the B8.5 V and B9.5 V are 3.2Msun and 2.8Msun, respectively. These masses are considerably lower than earlier values and are in accord with the stars' spectral types. We will present new analyses of the light and RV curves using the Wilson-Devinney code and give revised values for the masses and radii of the component stars. These values are used to determine the internal structure parameters (k2) from the most recent interior models of Gimenez and Claret. The internal structure parameters will be compared to those found from the rate of apsidal motion to check the interior models. This research is supported by NSF grant AST93-15365.

  18. Swift reveals the eclipsing nature of the high-mass X-ray binary IGR J16195-4945

    NASA Astrophysics Data System (ADS)

    Cusumano, G.; La Parola, V.; Segreto, A.; D'Aì, A.

    2016-03-01

    IGR J16195-4945 is a hard X-ray source discovered by INTEGRAL during the Core Programme observations performed in 2003. We analysed the X-ray emission of this source exploiting the Swift-Burst Alert Telescope (BAT) survey data from 2004 December to 2015 March, and all the available Swift-X-ray Telescope (XRT)-pointed observations. The source is detected at a high significance level in the 123-month BAT survey data, with an average 15-150 keV flux of the source of ˜1.6 mCrab. The timing analysis on the BAT data reveals with a significance higher than six standard deviations the presence of a modulated signal with a period of 3.945 d, that we interpret as the orbital period of the binary system. The folded light curve shows a flat profile with a narrow full eclipse lasting ˜3.5 per cent of the orbital period. We requested phase-constrained XRT observations to obtain a more detailed characterization of the eclipse in the soft X-ray range. Adopting reasonable guess values for the mass and radius of the companion star, we derive a semimajor orbital axis of ˜ 31 R⊙, equivalent to ˜1.8 times the radius of the companion star. From these estimates and from the duration of the eclipse, we derive an orbital inclination between 55 and 60 deg. The broad-band time-averaged XRT+BAT spectrum is well modelled with a strongly absorbed flat power law, with absorbing column NH = 7 × 1022 cm-2 and photon index Γ = 0.5, modified by a high energy exponential cutoff at Ecut = 14 keV.

  19. Multi-period g-mode Pulsations of a Pre-He-WD Star in the Eclipsing Binary KIC 9164561

    NASA Astrophysics Data System (ADS)

    Zhang, X. B.; Fu, J. N.; Li, Y.; Ren, A. B.; Luo, C. Q.

    2016-04-01

    We report the discovery of a new pulsating pre-He-WD in the EL CVn-type binary KIC 9164561. Light curve modeling and frequency analysis of the binary system were carried out based on short-cadence Kepler photometry. Combined with the radial-velocity solution, revised physical parameters of the binary system were determined. The component KIC 9164561B was confirmed to be a pre-He-WD star with M\\=\\0.213+/- 0.012{M}⊙ , R\\=\\0.283+/- 0.006{R}⊙ , and {T}{eff}\\=\\10650+/- 200 K. In addition to the light changes due to an eclipse, pulsational light variations of the pre-He-WD star were detected. The Fourier analysis reveals at least 52 frequencies, with the dominant one at 313.4 μHz. A brief mode identification indicates that the pre-He-WD star pulsates in g-modes with an average period spacing of {{Δ }}{{{\\Pi }}}l=1 = 80.87 s. Moreover, a number of multiplets due to rotational splitting were identified from the frequency spectra. The rotational period of the pulsating pre-He-WD star was found to equal to the orbital period, indicating that KIC 9164561B is in synchronous rotation.

  20. A 15.65-solar-mass black hole in an eclipsing binary in the nearby spiral galaxy M 33.

    PubMed

    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

    2007-10-18

    Stellar-mass black holes are found in X-ray-emitting binary 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 binaries 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 eclipsing binary. 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.

  1. HIGH-RESOLUTION SPECTROSCOPY DURING ECLIPSE OF THE YOUNG SUBSTELLAR ECLIPSING BINARY 2MASS 0535-0546. I. PRIMARY SPECTRUM: COOL SPOTS VERSUS OPACITY UNCERTAINTIES

    SciTech Connect

    Mohanty, Subhanjoy; Stassun, Keivan G.; Doppmann, Greg W. E-mail: keivan.stassun@vanderbilt.ed

    2010-10-20

    We present high-resolution Keck optical spectra of the very young substellar eclipsing binary 2MASS J05352184-0546085, obtained during eclipse of the lower-mass (secondary) brown dwarf. The observations yield the spectrum of the higher-mass (primary) brown dwarf alone, with negligible ({approx}1.6%) contamination by the secondary. We perform a simultaneous fine analysis of the TiO-{epsilon} band and the red lobe of the K I doublet, using state-of-the-art PHOENIX DUSTY and COND synthetic spectra. Comparing the effective temperature and surface gravity derived from these fits to the empirically determined surface gravity of the primary (log g = 3.5) then allows us to test the model spectra as well as probe the prevailing photospheric conditions. We find that: (1) fits to TiO-{epsilon} alone imply T{sub eff} = 2500 {+-} 50 K; (2) at this T{sub eff}, fits to K I imply log g = 3.0, 0.5 dex lower than the true value; and (3) at the true log g, K I fits yield T{sub eff} = 2650 {+-} 50 K, {approx}150 K higher than from TiO-{epsilon} alone. On the one hand, these are the trends expected in the presence of cool spots covering a large fraction of the primary's surface (as theorized previously to explain the observed T{sub eff} reversal between the primary and secondary). Specifically, our results can be reproduced by an unspotted stellar photosphere with T{sub eff} = 2700 K and (empirical) log g = 3.5, coupled with axisymmetric cool spots that are 15% cooler (2300 K), have an effective log g = 3.0 (0.5 dex lower than photospheric), and cover 70% of the surface. On the other hand, the trends in our analysis can also be reproduced by model opacity errors: there are lacks in the synthetic TiO-{epsilon} opacities, at least for higher-gravity field dwarfs. Stringently discriminating between the two possibilities requires combining the present results with an equivalent analysis of the secondary (predicted to be relatively unspotted compared to the primary).

  2. Absolute parameter determination in low-mass eclipsing binaries - Radiative parameters for BH Vir, ZZ UMA and CR CAS

    NASA Astrophysics Data System (ADS)

    Clement, R.; Reglero, V.; Garcia, M.; Fabregat, J.; Bravo, A.; Suso, J.

    1993-01-01

    A new uvby and H-beta monitoring program of low mass eclipsing binaries is currently being carried out in the framework of a 5-yr observational program which also involves radial velocity determinations. The scope of this work is to provide very accurate absolute astrophysical parameters: mass, radius, and effective temperatures, for main-sequence late-type stars. One of the main goals is to improve the mass-luminosity relation in the low and intermediate mass range. A second objective is to perform accurate tests of the most recent grids of evolutionary models. This program is complementary to that currently being implemented by the Copenhagen group. In this contribution we present the photometric preliminary results obtained for three of the systems included in our long-term survey: BH Vir, ZZ UMa, and CR Cas for which primary eclipses have been observed. Particular attention is paid to the determination of reddening, distances, and radiative properties. A more detailed study will be carried out when the light curves and radial velocity measurements are completed.

  3. A critical review of period analyses and implications for mass exchange in W UMa eclipsing binaries: Part 2

    NASA Astrophysics Data System (ADS)

    Nelson, R. H.; Terrell, D.; Milone, E. F.

    2015-12-01

    This is the second of a series of four papers, the goal of which is to identify the overcontact eclipsing binary star systems for which a solid case can be made for mass exchange. To reach this goal, it is necessary first to identify those systems for which there is a strong case for period change. We have identified 60 candidate systems; in the first paper (Nelson et al., 2014) we discussed 20 individual cases; this paper continues with the next 20. For each system, we present a detailed discussion and evaluation concerning the observational and interpretive material presented in the literature. An eclipse timing (ET) diagram (or diagrams), commonly referred to as an "O-C diagram", that includes the latest available data accompanies each discussion. In paper 4, we will discuss the mechanisms that can effect period change and which of the 60 systems can be reliably concluded to exhibit mass exchange; we will also provide a list of marginal and rejected cases suitable for future work.

  4. A critical review of period analyses and implications for mass exchange in W UMa eclipsing binaries: Paper 3

    NASA Astrophysics Data System (ADS)

    Nelson, R. H.; Terrell, D.; Milone, E. F.

    2016-02-01

    This is the third of a series of four papers, the goal of which is to identify the overcontact eclipsing binary star systems for which a solid case can be made for mass exchange. To reach this goal, it is necessary first to identify those systems for which there is a strong case for period change. We have identified 60 candidate systems; in the first two papers (Nelson et al. 2014, 2016) we discussed 40 individual cases; this paper continues with the last 20. For each system, we present a detailed discussion and evaluation concerning the observational and interpretive material presented in the literature. At least one eclipse timing (ET) diagram, commonly referred to as an "O-C diagram", that includes the latest available data, accompanies each discussion. In paper 4, we will discuss the mechanisms that can cause period change and which of the 60 systems can be reliably concluded to exhibit mass exchange; we will also provide a list of marginal and rejected cases - suitable for future work.

  5. Light-curve solutions of 20 eclipsing Kepler binaries, most of them with pronounced spot and flare activity

    NASA Astrophysics Data System (ADS)

    Kjurkchieva, D.; Atanasova, T.; Dimitrov, D.

    2016-07-01

    We carried out light curve solutions of the Kepler light curves of twenty detached eclipsing binaries with circular orbits and determined the orbital inclinations, temperatures. relative radii and luminosities of their components. We studied the quality of the solutions with respect to the adopted limb-darkening law and its coefficients. The detailed tracing of the numerous and uninterrupted data of our targets gave us an unique possibility to detect and learn their spot and flare activity. We established that the out-of-eclipse variability of the most targets gradually changes from small-amplitude two-waved type to big-amplitude one-waved type and vice versa, i.e. their spot activity cycles pass through phase of two almost diametrically opposite spots and phase of big polar cool spot. We found that the low-temperature targets show flare activity of UV Cet-type with amplitudes of 0.002-0.22 mag and duration of up to several hours. Data from Kepler

  6. Light curve solutions of the eclipsing Kepler binaries KIC 5080652, KIC 5285607, KIC 9236858 and KIC 11975363

    NASA Astrophysics Data System (ADS)

    Kjurkchieva, Diana; Atanasova, Teodora

    2016-11-01

    We carried out light curve solutions of four detached binaries with circular orbits, observed by Kepler. As a result their orbital inclinations, temperatures and relative stellar radii were determined. We estimated also their global parameters on the base of the obtained solutions and empirical relation "temperature, luminosity" for MS stars. The out-of-eclipse light curves of KIC 5080652, KIC 9236858 and KIC 11975363 reveal a trend the bigger amplitudes to correspond to single-waved shape while the two-waved shape to be inherent to the smaller amplitudes. This type of variability was attributed to gradually transition between state with two almost opposite cool spots and state with bigger in size polar spot. We detected also several microflares of KIC 11975363 with amplitudes of 0.002-0.003 mag.

  7. A CLASSICAL CEPHEID IN A LARGE MAGELLANIC CLOUD ECLIPSING BINARY: EVIDENCE OF SHORTCOMINGS IN CURRENT STELLAR EVOLUTIONARY MODELS?

    SciTech Connect

    Cassisi, S.; Salaris, M. E-mail: ms@astro.livjm.ac.uk

    2011-02-20

    The recent discovery and analysis of a classical Cepheid in the well-detached, double-lined, eclipsing binary OGLE-LMC-CEP0227 has provided the first determination of the dynamical mass of a classical Cepheid variable to an unprecedented 1% accuracy. We show here that modern stellar evolution models, widely employed to study Galactic and extragalactic stellar systems, are able to match simultaneously the mass and radius (and effective temperature) of the two components with a single value for the age of the system, without any specific fine-tuning, assuming the typical metallicity of LMC Cepheids. Our conclusion is that there is no obvious discrepancy between dynamical and evolutionary masses for the Cepheid star in this system, contrary to previous claims of an overestimate of the Cepheid mass by stellar evolution theory.

  8. Eclipse of epsilon Aurigae

    NASA Astrophysics Data System (ADS)

    Templeton, Matthew R.

    2009-07-01

    The bright, long-period, eclipsing binary star epsilon Aurigae is predicted to begin its next eclipse late July or early August of 2009. Epsilon Aurigae is now past solar conjunction and has reappeared as a morning object. All observers -- both visual and instrumental -- are encouraged to contribute observations of the eclipse during the next two years, beginning immediately for morning observers. Observations are urgently requested right now because it is less likely to be observed in the morning, and the eclipse will begin within the next month. The AAVSO is participating in a global campaign to record this eclipse as part of the International Year of Astronomy 2009 celebrations, organized by the Citizen Sky project (http://www.citizensky.org). For experienced visual observers, please observe this star on a weekly basis, using charts available via VSP from the AAVSO website. For novice visual observers, we recommend participating in this observing program by following the Citizen Sky 10-Star tutorial program, which provides a simple training experience in variable star observing. Photoelectric observers belonging to the AAVSO PEP-V program may submit data as usual via the WebObs feature of the AAVSO website Blue&Gold section. Photoelectric observers may also contribute reduced observations in all filters (including infrared J- and H-bands) directly to the AAVSO via WebObs. Observers using wide-field CCD and DSLR systems are also encouraged to participate; avoid saturating the star. For those with narrower-field systems (D < 2 degrees), we recommend taking a large number (10-100) of very short exposures and then stacking the resulting images. Observations should be submitted to the AAVSO International Database. Aaron Price is coordinating Citizen Sky for the AAVSO, and Dr. Robert Stencel and Jeffrey Hopkins are co-leading the precision photometry efforts.

  9. BVRI Photometric 2015 WD Analysis of the Southern Totally Eclipsing, Solar-type, Shallow-contact W UMa Binary, DD Indus

    NASA Astrophysics Data System (ADS)

    Samec, Ronald G.; Norris, Cody L.; Van Hamme, Walter; Faulkner, Danny R.; Hill, Robert L.

    2016-12-01

    Observations and a 2015 Wilson-Devinney Program analysis are undertaken for the first precision observations of DD Indi. DD Indi is of solar-type (T 1 ˜ 5750 K) and was determined to be a shallow-contact eclipsing binary. It was observed from 2013 June through September at Cerro Tololo InterAmerican Observatory in remote mode. The 24 inch Boller and Chivens reflector, now under management by The Southeastern Association for Resarch in Astronomomy (SARA) was used. Five new eclipse timings were obtained, for three primary and two secondary eclipses. Seven more eclipse timings were calculated from All Sky Automated Survey data. A possibly increasing period was found from all available eclipse timings with a 5 ± 2 × 10-11 × E 2 quadratic term. A BVR c I c simultaneous synthetic light-curve analysis reveals that the system has a mass ratio of ˜0.46, a ˜ 140 K component temperature difference, and two weak cool spots. The Roche Lobe fill-out of this W-type binary is only ˜11%, and an inclination of ˜86° was determined. A time of constant light of ˜16 minutes is measured around phase zero. More detail is included in this report.

  10. THE ROMER DELAY AND MASS RATIO OF THE sdB+dM BINARY 2M 1938+4603 FROM KEPLER ECLIPSE TIMINGS

    SciTech Connect

    Barlow, Brad N.; Wade, Richard A.; Liss, Sandra E.

    2012-07-10

    The eclipsing binary system 2M 1938+4603 consists of a pulsating hot subdwarf B star and a cool M dwarf companion in an effectively circular three-hour orbit. The light curve shows both primary and secondary eclipses, along with a strong reflection effect from the cool companion. Here, we present constraints on the component masses and eccentricity derived from the Romer delay of the secondary eclipse. Using six months of publicly available Kepler photometry obtained in short-cadence mode, we fit model profiles to the primary and secondary eclipses to measure their centroid values. We find that the secondary eclipse arrives on average 2.06 {+-} 0.12 s after the midpoint between primary eclipses. Under the assumption of a circular orbit, we calculate from this time delay a mass ratio of q = 0.2691 {+-} 0.0018 and individual masses of M{sub sd} = 0.372 {+-} 0.024 M{sub Sun} and M{sub c} = 0.1002 {+-} 0.0065 M{sub Sun} for the sdB and M dwarf, respectively. These results differ slightly from those of a previously published light-curve modeling solution; this difference, however, may be reconciled with a very small eccentricity, ecos {omega} Almost-Equal-To 0.00004. We also report a decrease in the orbital period of P-dot = (-1.23 {+-} 0.07) Multiplication-Sign 10{sup -10}.

  11. Cyclic period changes and the light-time effect in eclipsing binaries: A low-mass companion around the system VV Ursae Majoris

    NASA Astrophysics Data System (ADS)

    Tanrıver, Mehmet

    2015-04-01

    In this article, a period analysis of the late-type eclipsing binary VV UMa is presented. This work is based on the periodic variation of eclipse timings of the VV UMa binary. 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 eclipse 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 eclipsing binary stars is 0.787 ± 0.02 M⊙, and the semi-major axis of its orbit is 10.75 AU.

  12. A refined analysis of the low-mass eclipsing binary system T-Cyg1-12664

    NASA Astrophysics Data System (ADS)

    Iglesias-Marzoa, Ramón; López-Morales, Mercedes; Arévalo, María J.; Coughlin, Jeffrey L.; Lázaro, Carlos

    2017-03-01

    Context. The observational mass-radius relation of main sequence stars with masses between 0.3 and 1.0 M⊙ reveals deviations between the stellar radii predicted by models and the observed radii of stars in detached binaries. Aims: We generate an accurate physical model of the low-mass eclipsing binary T-Cyg1-12664 in the Kepler mission field to measure the physical parameters of its components and to compare them with the prediction of theoretical stellar evolution models. Methods: We analyze the Kepler mission light curve of T-Cyg1-12664 to accurately measure the times and phases of the primary and secondary eclipse. In addition, we measure the rotational period of the primary component by analyzing the out-of-eclipse oscillations that are due to spots. We accurately constrain the effective temperature of the system using ground-based absolute photometry in B, V, RC, and IC. We also obtain and analyze VRCIC differential light curves to measure the eccentricity and the orbital inclination of the system, and a precise Teff ratio. From the joint analysis of new radial velocities and those in the literature we measure the individual masses of the stars. Finally, we use the PHOEBE code to generate a physical model of the system. Results: T-Cyg1-12664 is a low eccentricity system, located d = 360 ± 22 pc away from us, with an orbital period of P = 4.1287955(4) days, and an orbital inclination i = 86.969 ± 0.056 degrees. It is composed of two very different stars with an active G6 primary with Teff1 = 5560 ± 160 K, M1 = 0.680 ± 0.045 M⊙, R1 = 0.799 ± 0.017 R⊙, and a M3V secondary star with Teff2 = 3460 ± 210 K, M2 = 0.376 ± 0.017 M⊙, and R2 = 0.3475 ± 0.0081 R⊙. Conclusions: The primary star is an oversized and spotted active star, hotter than the stars in its mass range. The secondary is a cool star near the mass boundary for fully convective stars (M 0.35 M⊙), whose parameters appear to be in agreement with low-mass stellar model. Full Tables 1

  13. Precise mass and radius measurements for the components of the bright solar-type eclipsing binary star V1094 Tauri

    NASA Astrophysics Data System (ADS)

    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.

    2015-06-01

    Context. V1094 Tau is a bright eclipsing binary star with an orbital period close to nine days that contains two stars similar to the Sun. Aims: Our aim is to test models of Sun-like stars using precise and accurate mass and radius measurements for both stars in V1094 Tau. Methods: We present new spectroscopy of V1094 Tau, which we use to estimate the effective temperatures of both stars and to refine their spectroscopic orbits. We also present new, high-quality photometry covering both eclipses of V1094 Tau in the Strömgren uvby system and in the Johnson V-band. Results: The masses, radii, and effective temperatures of the stars in V1094 Tau are found to be MA = 1.0965 ± 0.0040 M⊙, RA = 1.4109 ± 0.0058 R⊙, Teff,A = 5850 ± 100 K, MB = 1.0120 ± 0.0028 M⊙, RB = 1.1063 ± 0.0066 R⊙, and Teff,B = 5700 ± 100 K. An analysis of the times of mid-eclipse and the radial velocity data reveals apsidal motion with a period of 14 500 ± 3700 years. Conclusions: The observed masses, radii, and effective temperatures are consistent with stellar models for an age ≈6 Gyr if the stars are assumed to have a metallicity similar to the Sun. This estimate is in reasonable agreement with our estimate of the metallicity derived using Strömgren photometry and treating the binary as a single star ([ Fe/H ] = -0.09 ± 0.11). The rotation velocities of the stars suggest that V1094 Tau is close to the limit at which tidal interactions between the stars force them to rotate pseudo-synchronously with the orbital motion. The table of the light curves shown in Fig. 1 is 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/578/A25

  14. Demystifying the Confounding Long-Period Eclipsing Binary Epsilon Aurigae - Investigating Clues from its past behavior and possible Stellar Associates

    NASA Astrophysics Data System (ADS)

    Johnston, Cole; Guinan, E. F.; Harmanec, P.; Mayer, P.

    2012-01-01

    This research is focused on demystifying the unusual bright long-period (P = 27.1 years) eclipsing binary ɛ Aurigae (F0 Ia + disk). We are attempting to cut the "Gordian Knot” to distinguish between two attractive competing models that have been advanced to explain the many unusual properties of this unique binary. According to the "Higher mass" model, the F-supergiant is assumed to be a luminous young (high mass: M > 15 M⊙) F0 Ia star. In this case its huge, cool disk-companion is a proto-planetary disk or an embedded high-mass main-sequence star that has captured a significant mass from the winds of its rapidly evolving companion. In "Lower mass” model the F-supergiant star is assumed to be a post-AGB star ( 2-3 M⊙) while the large disk companion (of similar mass) is the remnant of a recent mass-losing episode that Post-AGB stars frequently undergo. To distinguish between these models we have followed two approaches. We have investigated the measured brightness of ɛ Aur over two millennia (using transformed visual measures from Ptolemy and Sufi and others up to the present). We investigated possible brightness changes expected from mass-loss/ exchange events. No significant (larger than 0.5 mag) changes in brightness were found. We also have estimated the distance to the binary by identifying stars within ½ degree that appear be associated with the binary. Stars with similar kinematics, color-excesses and ISM lines to ɛ Aur were found. This association of ɛ Aur with these possible common cluster stars indicates d 1.0 +/- 0.15 kpc. In this case, the F-supergiant would have Mv -8.0-mag which is appropriate for high-mass F-supergiant but too luminous for a post-AGB object. This research is supported by NSF/RUI Grant AST-1009903.

  15. MML 53: A New Low-Mass, Pre-Main Sequence Eclipsing Binary in the Lupus Cloud Discovered By SuperWASP

    NASA Astrophysics Data System (ADS)

    Cegla, Heather; Hebb, L.; Stassun, K. G.; Stempels, H. C.; Cargile, P. A.; Palladino, L. E.; SuperWASP Consortium

    2010-01-01

    We announce the discovery of a new low-mass, pre-main sequence (PMS) eclipsing binary star in the Lupus Cloud, MML 53. This is only the 6th sub-solar mass PMS eclipsing binary known. Previous observations of MML 53 found it to be a spectroscopic multiple associated with the 15-22 Myr Upper Centaurus Lupus (UCL) cluster. Here, we identify the object as an eclipsing binary for the first time through the analysis of photometric time series photometry from the SuperWASP transiting planet survey. We derive an accurate ephemeris for the system and present a double-lined orbit solution based on high resolution spectra. The spectra confirm MML 53 to be a triple system of young stars composed of an eclipsing binary and a stationary third component all of which show strong lithium absorption as expected for low-mass, PMS stars. The 2.1 d orbit of the eclipsing pair is circular, and we find the minimum masses of M1 sin3 i = 0.94 M⊙ and M2 sin3 i = 0.81 M⊙ with formal uncertainties of 2.0 %.We find a systemic radial velocity, vγ = +1.00 ± 0.33 ± 0.81 km s-1, consistent with kinematic membership in the UCL association, and the radii of the component stars are 30 % larger than expected for main sequence stars. Follow-up modeling of high cadence, multi-band light-curve data will provide precise fundamental properties of the components of the system which will ultimately be used to place constraints on theoretical models of PMS stellar evolution. This research is supported by an NSF REU grant to the Vanderbilt Physics & Astronomy Department, and by an NSF PAARE grant to Fisk University.

  16. The Phases Differential Astrometry Data Archive. 2. Updated Binary Star Orbits and a Long Period Eclipsing Binary

    DTIC Science & Technology

    2010-12-01

    measurements from the Palomar High-precision Astrometric Search for Exoplanet Systems have been combined with lower precision single-aperture...the Palomar High-precision Astrometric Search for Exoplanet Systems (PHASES) program during 2002–2008. PHASES science results included precision binary...ABSTRACT Differential astrometry measurements from the Palomar High-precision Astrometric Search for Exoplanet Systems have been combined with

  17. VizieR Online Data Catalog: Detached M dwarf eclipsing binaries in WTS (Birkby+, 2012)

    NASA Astrophysics Data System (ADS)

    Birkby, J.; Nefs, B.; Hodgkin, S.; Kovacs, G.; Sipocz, B.; Pinfield, D.; Snellen, I.; Mislis, D.; Murgas, F.; Lodieu, N.; de Mooij, E.; Goulding, N.; Cruz, P.; Stoev, H.; Cappetta, M.; Palle, E.; Barrado, D.; Saglia, R.; Martin, E.; Pavlenko, Y.

    2013-04-01

    We identified our new MEBs using observations from the WTS (WFCAM Transit Survey). The WTS is an ongoing photometric monitoring campaign that operates on the 3.8-m United Kingdom Infrared Telescope (UKIRT) at Mauna Kea, Hawaii. The survey began on 2007 August 5, and the eclipsing systems presented in this paper are all found in just one of the four WTS fields. Photometric follow-up observations to help test and refine our light-curve models were obtained in the Sloan i band using the Wide-Field Camera (WFC) on the 2.5-m INT at Roque de Los Muchachos, La Palma. (6 data files).

  18. Orbital and physical parameters of eclipsing binaries from the ASAS catalogue - IX. Spotted pairs with red giants

    NASA Astrophysics Data System (ADS)

    Ratajczak, M.; Hełminiak, K. G.; Konacki, M.; Smith, A. M. S.; Kozłowski, S. K.; Espinoza, N.; Jordán, A.; Brahm, R.; Hempel, M.; Anderson, D. R.; Hellier, C.

    2016-09-01

    We present spectroscopic and photometric solutions for three spotted systems with red giant components. Absolute physical and orbital parameters for these double-lined detached eclipsing binary stars are presented for the first time. These were derived from the V-, and I-band ASAS and WASP photometry, and new radial velocities calculated from high quality optical spectra we obtained with a wide range of spectrographs and using the two-dimensional cross-correlation technique (TODCOR). All of the investigated systems (ASAS J184949-1518.7, BQ Aqr, and V1207 Cen) show the differential evolutionary phase of their components consisting of a main-sequence star or a subgiant and a red giant, and thus constitute very informative objects in terms of testing stellar evolution models. Additionally, the systems show significant chromospheric activity of both components. They can be also classified as classical RS CVn-type stars. Besides the standard analysis of radial velocities and photometry, we applied spectral disentangling to obtain separate spectra for both components of each analysed system which allowed for a more detailed spectroscopic study. We also compared the properties of red giant stars in binaries that show spots, with those that do not, and found that the activity phenomenon is substantially suppressed for stars with Rossby number higher than ˜1 and radii larger than ˜20 R⊙.

  19. Apsidal motion in southern eccentric eclipsing binaries: GL Car, QX Car, NO Pup and V366 Pup

    NASA Astrophysics Data System (ADS)

    Wolf, M.; Zejda, M.; de Villiers, S. N.

    2008-08-01

    The study of apsidal motion in eccentric eclipsing binaries (EEB) provides an important observational test of theoretical models of stellar structure and evolution. The Southern hemisphere contains many interesting and also neglected binary systems. New accurate photoelectric times of minimum light have been obtained for the detached early-type Southern hemisphere EEB GL Car (P = 2.42d,e = 0.15), QX Car (4.48d, 0.15), NO Pup (1.26d, 0.13) and V366 Pup (2.48d, 0.47). The O-C diagrams are analysed using all reliable timings found in the literature and improved or new values for the elements of the apsidal motion are computed. We find more precise, relatively short periods of apsidal motion of about 25.2, 362, 38.3 and 285yr and corresponding internal structure constants, log k2, -1.88, -2.08, -2.32 and -2.38 for GL Car, QX Car, NO Pup and V366 Pup, respectively, with the assumption that the component stars rotate pseudo-synchronously. The relativistic effects are small, being about 3-12 per cent of the total apsidal motion rate in all systems. Based on observations made at the South Africa Astronomical Observatory, Sutherland, South Africa and Mt John University Observatory, University of Canterbury, Lake Tekapo, New Zealand. E-mail: wolf@cesnet.cz

  20. CCD Photometry and Roche Modeling of the Eclipsing Overcontact Binary Star System TYC 01963-0488-1

    NASA Astrophysics Data System (ADS)

    Alton, K. B.

    2016-12-01

    TYC 01963-0488-1 (ASAS J094440+2632.1) is a W UMa binary system (P=0.427036 d) which has been largely overlooked since first being detected nearly 15 years ago by the ROTSE-I telescope. Other than the monochromatic ROTSE-I survey data, no multi-colored light curves (LC) have been published. Photometric data collected in three bandpasses (B, V and Ic) at UnderOak Observatory (UO) produced 5 new times-of-minimum for TYC 01963-0488-1 which were used to establish a linear ephemeris from the first Min I epoch (HJD0). No published radial velocity data are available for this system; however, since this W UMa binary undergoes very obvious total eclipses, Roche modeling yielded a well-constrained photometric value for q ( 0.25). There is a suggestion from the ROTSE-I data and new results herein that Max II is more variable than Max I. Therefore, Roche model fits for the TYC 01963-0488-1 LCs collected in 2015 were assessed with and without spots.

  1. Orbital period variability in the eclipsing pulsar binary PSR B1957+20: Evidence for a tidally powered star

    NASA Technical Reports Server (NTRS)

    Applegate, James H.; Shaham, Jacob

    1994-01-01

    Recent observations indicate that the eclipsing pulsar binary PSR B1957+20 undergoes alternating epochs of orbital period increase and decrease. We apply a model developed to explain orbital period changes of alternating sign in other binaries to the PSR B1957+20 system and find that it fits the pulsars observations well. The novel feature of the PSR B1957+20 system is that the energy flow in the companion needed to power the orbital period change mechanism can be supplied by tidal dissipation, making the companion the first identified tidally powered star. The flow of energy in the companion drives magnetic activity, which underlies the observed orbital period variations. The magnetic activity and the wind driven by the pulsar irradiation results in a torque on the spin of the companion. This torque holds the companion out of synchronous rotation, causing tidal dissipation of energy. We propose that the progenitor had a approximately 2 hr orbital period and a companion mass of 0.1-0.2 solar mass, and the system is evolving to longer orbital periods by mass and angular momentum loss on a timescale of 10(exp 8) yr.

  2. The "Cool Algol" BD+05 706 : Photometric observations of a new eclipsing double-lined spectroscopic binary

    NASA Astrophysics Data System (ADS)

    Marschall, L. A.; Torres, G.; Neuhauser, R.

    1998-05-01

    BVRI Observations of the star BD+05 706, carried out between January, 1997, and April 1998 using the 0.4m reflector and Photometrics CCD camera at the Gettysburg College Observatory, show that the star is an eclipsing binary system with a light curve characteristic of a class of semi-detached binaries known as the "cool Algols". These results are in good agreement with the previous report of BD+05 706 as a cool Algol by Torres, Neuhauser, and Wichmann,(Astron. J., 115, May 1998) who based their classification on the strong X-ray emission detected by Rosat and on a series of spectroscopic observations of the radial velocities of both components of the system obtained at the Oak Ridge Observatory, the Fred L. Whipple Observatory, and the Multiple Mirror Telescope. Only 10 other examples of cool Algols are known, and the current photometric light curve, together with the radial velocity curves obtained previously, allows us to derive a complete solution for the physical parameters of each component, providing important constraints on models for these interesting systems.

  3. The Interior Structure Constants as an Age Diagnostic for Low-mass, Pre-main-sequence Detached Eclipsing Binary Stars

    NASA Astrophysics Data System (ADS)

    Feiden, Gregory A.; Dotter, Aaron

    2013-03-01

    We propose a novel method for determining the ages of low-mass, pre-main-sequence stellar systems using the apsidal motion of low-mass detached eclipsing binaries. The apsidal motion of a binary system with an eccentric orbit provides information regarding the interior structure constants of the individual stars. These constants are related to the normalized stellar interior density distribution and can be extracted from the predictions of stellar evolution models. We demonstrate that low-mass, pre-main-sequence stars undergoing radiative core contraction display rapidly changing interior structure constants (greater than 5% per 10 Myr) that, when combined with observational determinations of the interior structure constants (with 5%-10% precision), allow for a robust age estimate. This age estimate, unlike those based on surface quantities, is largely insensitive to the surface layer where effects of magnetic activity are likely to be most pronounced. On the main sequence, where age sensitivity is minimal, the interior structure constants provide a valuable test of the physics used in stellar structure models of low-mass stars. There are currently no known systems where this technique is applicable. Nevertheless, the emphasis on time domain astronomy with current missions, such as Kepler, and future missions, such as LSST, has the potential to discover systems where the proposed method will be observationally feasible.

  4. Analysis of 2007 UBVRcIc Observations of the Totally Eclipsing, Extreme Mass Ratio Binary, GSC 1283 0053

    NASA Astrophysics Data System (ADS)

    Samec, Ronald G.; Behn, G. A.; Labadorf, C. M.; Hawkins, N. C.; Faulkner, D. R.; VanHamme, W.

    2008-05-01

    We present a UBVRcIc analyses of a recently discovered (ROTSE-I, AJ 131, 623, 2006) totally eclipsing, extreme mass ratio eclipsing binary, GSC 1283 0053 from observations taken with the 0.81-m Lowell Reflector with NURO granted time on December 26,29,30 and 31, 2007. Light curves, a period study and a light curve solution is presented. The light curves were premodeled with Binary 3.0 and then solved with the 2004 version Wilson code. We obtained 269 U, 271 B, 183 V, 269 R and 272 I individual CCD observations with the 2K X 2K NASACAM. Standard star and comp star observations suggest the primary component is spectral type G6.5V (5450 K). Four mean times of minimum light were determined: HJDMin I= 2454464.8998 (±0.0005)d, 2454465.8577 (±0.0008)d, 2454466.8142 (±0.0005)d, and HJDMin II=2454465.6656 (±0.0002)d. The following linear ephemeris was calculated from these and previous timings: HJD Min I =2454464.8997 (±0.0006)d + 0. 3830009 (±0.0000007)*E (1) Not enough data is presently available to determine the nature of the period variation. We suspect that the period is decreasing due to stellar winds and resulting magnetic breaking. GSC 1283 0053 is an W-type contact binary (the less massive component is the hotter) with a 0.45 mag amplitude in U. The system parameters from the Wilson Code include a mass ratio of only 0.20, a slight temperature difference of 150 K and an inclination of 78.9o. Two magnetic spots were modeled on the primary, more massive component with colatitudes of 120o and 104o, longitudes of 76 o and 283 o, radii of 18 degrees each and with a T-factor of 0.87 and 0.90, respectively. We wish to thank the American Astronomical Society and its small research grant program for supporting this research.

  5. Multi-site, multi-year monitoring of the oscillating Algol-type eclipsing binary CT Herculis

    NASA Astrophysics Data System (ADS)

    Lampens, P.; Strigachev, A.; Kim, S.-L.; Rodríguez, E.; López-González, M. J.; Vidal-Saínz, J.; Mkrtichian, D.; Koo, J.-R.; Kang, Y. B.; van Cauteren, P.; Wils, P.; Kraicheva, Z.; Dimitrov, D.; Southworth, J.; García Melendo, E.; Gómez Forellad, J. M.

    2011-10-01

    We present the results of a multi-site photometric campaign carried out in 2004-2008 for the Algol-type eclipsing binary system CT Her, the primary component of which displays δ Scuti-type oscillations. Our data consist of differential light curves collected in the filters B and V, which were analysed using the method of Wilson-Devinney (Phoebe). After identifying an adequate binary model and removing the best-fit light-curve solution, we performed a Fourier analysis of the residual B and V light curves to investigate the pulsational behaviour. We confirm the presence of rapid pulsations with a main period of 27.2 min. Up to eight significant frequencies with semi-amplitudes in the range 3 to 1 mmag were detected, all of which lie in the frequency range 43.5-53.5 d-1. This result is independent of the choice of the primary's effective temperature (8200 or 8700 K) since the light-curve models of the binary are very similar in both cases. This is yet another case of a complex frequency spectrum observed for an accreting δ Scuti-type star (after Y Cam). In addition, we demonstrate that the amplitudes of several pulsation frequencies provide evidence of variability on timescales as short as 1-2 years, perhaps even less. Moreover, our analysis takes into account some recently acquired spectra, from which we obtained the corresponding radial velocities for the years 2007-2009. Investigation of the O-C diagram shows that further monitoring of the epochs of eclipse minima of CT Her will cast new light on the evolution of its orbital period. Based on photometric data collected at the observatories listed in Table 1 and spectra acquired at the NAO, Bulgaria, and Calar Alto Observatory, Spain. The Skinakas Observatory is a collaborative project of the University of Crete, the Foundation for Research and Technology - Hellas, and the Max-Planck-Institut für Extraterrestrische Physik.Full Tables 3, 4, 9 and 12 are only available at the CDS via anonymous ftp to cdsarc

  6. Calibrating the updated overshoot mixing model on eclipsing binary stars: HY Vir, YZ Cas, χ{sup 2} Hya, and VV Crv

    SciTech Connect

    Meng, Y.; Zhang, Q. S.

    2014-06-01

    Detached eclipsing binary stars with convective cores provide a good tool to investigate convective core overshoot. It has been performed on some binary 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 eclipsing binary 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 eclipsing binary 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 low-mass stars with convective cores, is removed by partial overshoot mixing.

  7. Luminous Blue Variable Eruptions Triggered and Powered by Binary Interaction

    NASA Astrophysics Data System (ADS)

    Kashi, Amit

    2010-12-01

    We suggest that major Luminous Blue Variable (LBV) eruptions are a result of a periastron passage interaction with the secondary star. The interaction must take place when the primary envelope is in an unstable phase. In our model the mass transferred to the secondary accounts for the energy and light curve of the eruption. We propose that all major LBV eruptions are triggered by stellar companions, and that in extreme cases a short duration event with a huge mass transfer rate can lead to a bright transient event on time scales of weeks to months (a `supernova impostor').

  8. Direct Distance Estimation applied to Eclipsing Binaries in Star Clusters:Case Study of DS Andromedae in NGC 752

    NASA Astrophysics Data System (ADS)

    Milone, Eugene F.; Schiller, Stephen Joseph

    2015-08-01

    Eclipsing binaries (EB) with well-calibrated photometry and precisely measured double-lined radial velocities are candidate standard candles when analyzed with a version of the Wilson-Devinney (WD) light curve modeling program that includes the direct distance estimation (DDE) algorithm. In the DDE procedure, distance is determined as a system parameter, thus avoiding the assumption of stellar sphericity and yielding a well-determined standard error for distance. The method therefore provides a powerful way to calibrate the distances of other objects in any aggregate that contains suitable EB's. DDE has been successfully applied to nearby systems and to a small number of EB's in open clusters. Previously we reported on one of the systems in our Binaries-in-Clusters program, HD27130 = V818 Tau, that had been analyzed with earlier versions of the WD program (see 1987 AJ 93, 1471; 1988 AJ 95, 1466; and 1995 AJ 109, 359 for examples). Results from those early solutions were entered as starting parameters in the current work with the WD 2013 version.Here we report several series of ongoing modeling experiments on a 1.01-d period, early type EB in the intermediate age cluster NGC 752. In one series, ranges of interstellar extinction and hotter star temperature were assumed, and in another series both component temperatures were adjusted. Consistent parameter sets, including distance, confirm DDE's advantages, essentially limited only by knowledge of interstellar extinction, which is small for DS And. Uncertainties in the bandpass calibration constants (flux in standard units from a zero magnitude star) are much less important because derived distance scales (inversely) only with the calibration's square root. This work was enabled by the unstinting help of Bob Wilson. We acknowledge earlier support for the Binaries-in-Clusters program from NSERC of Canada, and the Research Grants Committee and Department of Physics & Astronomy of the University of Calgary.

  9. Photometric Studies of Two Neglected Eclipsing Binaries AX Cassiopeia and V1107 Cassiopeia with Possibly Additional Companions

    NASA Astrophysics Data System (ADS)

    Yang, Yuangui; Li, Kai; Li, Qun; Dai, Haifeng

    2016-04-01

    New photometry for two eclipsing binaries, AX Cas and V1107 Cas, was carried out during the 2014-2015 observing season. With an updated version of the W-D program, photometric solutions were simultaneously derived from BV light curves. Results indicate that AX Cas is a semi-detached binary with a mass ratio of q=0.400(+/- 0.003) and a fill-out factor of {f}p=88.1(+/- 0.5)%, while V1107 Cas is a contact one with a mass ratio of q=0.667(+/- 0.003) and a degree of contact of f=11.3%(+/- 0.3%). Based on all collected times of light minimum together with newly observed data, we constructed the (O-C) curves for the two systems. From the period analysis, it is found that orbital period variations may evidently appear that show light-time effect. The modulated period and amplitude are {P}{mod}=17.63(+/- 0.17)\\quad {years} and A=0\\buildrel{{d}}\\over{.} 0133(+/- 0\\buildrel{{d}}\\over{.} 0016) for AX Cas and {P}{mod}=7.23(+/- 0.14)\\quad {years} and A=0\\buildrel{{d}}\\over{.} 0023(+/- 0\\buildrel{{d}}\\over{.} 0002) for V1107 Cas, respectively. From 26 EB/EW binaries with only cyclic variations, we derived the relation between periods and total masses, indicating that mass loss from the system occurs from the semi-detached configuration to the contact case. The cyclic oscillations for 22 sample stars (including AX Cas and V1107 Cas) may be attributed to third bodies. Additional companions could remove angular momentum from the central systems, which may play a key role in the evolutionary process.

  10. Discovery of an unusual bright eclipsing binary with the longest known period: TYC 2505-672-1/MASTER OT J095310.04+335352.8

    NASA Astrophysics Data System (ADS)

    Lipunov, V.; Gorbovskoy, E.; Afanasiev, V.; Tatarnikova, A.; Denisenko, D.; Makarov, D.; Tiurina, N.; Krushinsky, V.; Vinokurov, A.; Balanutsa, P.; Kuznetsov, A.; Gress, O.; Sergienko, Yu.; Yurkov, V.; Gabovich, A.; Tlatov, A.; Senik, V.; Vladimirov, V.; Popova, E.

    2016-04-01

    We report on the MASTER Global Robotic Net discovery of an eclipsing binary, MASTER OT J095310.04+335352.8, previously known as unremarkable star TYC 2505-672-1, which displays extreme orbital parameters. The orbital period P = 69.1 yr is more than 2.5 times longer than that of ɛ-Aurigae, which is the previous record holder. The light curve is characterized by an extremely deep total eclipse with a depth of more than 4.5 mag, which is symmetrically shaped and has a total duration of 3.5 yr. The eclipse is essentially gray. The spectra acquired with the Russian 6 m BTA telescope both at minimum and maximum light mainly correspond to an M0-1III-type red giant, but the spectra taken at the bottom of eclipse show small traces of a sufficiently hot source. The observed properties of this system can be better explained as the red giant eclipsed by a large cloud (the disk) of small particles surrounding the invisible secondary companion.

  11. The first photometric study of W UMa eclipsing binary OQ Dra

    NASA Astrophysics Data System (ADS)

    Heidarnia, R.; Ebadi, H.; Rooydargard, H.

    2016-11-01

    The present study is an analysis of V-band CCD observations of new W UMa contact binary OQ Dra. To carry out the analysis, Primary and secondary minimum were obtained and new epoch was calculated. The computed period of system was 0.33967 day. Light curve analysis was performed using Binary Maker 3 and PHOEBE that uses the latest Wilson-Devinney code. We obtained photometric mass ratio of qptm = 0.55. O'Connell effect also was seen in the fitted model. Finally, the best model was achieved by introducing 2 spots on each component.

  12. A Multi-wavelength Study of the Close M-dwarf Eclipsing Binary System BX Tri

    NASA Astrophysics Data System (ADS)

    Perdelwitz, V.; Czesla, S.; Robrade, J.; Schmitt, J. H. M. M.

    2015-01-01

    We present the first detailed X-ray study of the close dMe binary system BX Tri, whose optical variation has been continously monitored in the frame of the DWARF project (Pribulla et al.(2012)). We observed BX Tri with XMM-Newton for two full orbital periods and confirm that the system is an ultra-active M-dwarf binary showing frequent flares and an X-ray luminosity close to the saturation limit. The strong magnetic activity could have influenced the angular momentum evolution of the system via magnetic braking.

  13. The first photometric study of semi-detached eclipsing binary V504 Cyg

    NASA Astrophysics Data System (ADS)

    Heidarnia, R.; Shamsollahi, H.; Jahan, A.; Ebadi, H.

    2017-01-01

    In this paper, we analyze photometry of V504 Cyg semi-detached binary system. For this purpose, after taking the photometric data, primary and secondary minimum and new epoch were calculated. The period of system is found to be 0.3516916 day. Analysis of light curve was performed by PHOEBE software which uses last version of Wilson-Devinney code. 3D model of the system is worked out using Binary Maker software. The O'Connell effect in the light curve is observed and an accurate model of this system is presented by introducing four spots on the components.

  14. The F-type eclipsing binaries ZZ Bootis, CW Eridani, and BK Pegasi

    NASA Astrophysics Data System (ADS)

    Popper, D. M.

    1983-08-01

    Spectrographic orbits of these three double-lined binaries are determined from spectrograms obtained at the Lick Observatory. The photometric observations of ZZ Boo by McNamara et al. and of CW Eri by Chen are reanalyzed, and revised properties of the components are derived. The properties of the most definitive F-type stars are shown in the mass-radius, mass-luminosity, and color-magnitude planes, along with zero-age relations. The components of the three systems analyzed here are among the more evolved binaries having both components in the state of core hydrogen burning.

  15. Colliding stellar winds in the eclipsing Wolf-Rayet binary V444 Cygni

    NASA Technical Reports Server (NTRS)

    Brown, Douglas N.; Shore, Steven N.

    1988-01-01

    High resolution spectra of V444 Cygni have been obtained using the International Ultraviolet Explorer Satellite. These spectra span both eclipses and include one observation at third quadrature. Together with seven archival spectra, they provide reasonably complete phase coverage for the system. The variations in the P Cygni profiles of the He(II) and N(IV) lines, imply the existence of a low density region in the WR wind. This region occupies a relatively narrow range of orbital phase coinciding with the highest terminal velocities observed in C IV. These data are interpreted to be evidence of an interaction region separating the winds of the O-star and Wolf-Rayet star.

  16. Evolutionary history of four binary blue stragglers from the globular clusters ω Cen, M 55, 47 Tuc, and NGC 6752

    NASA Astrophysics Data System (ADS)

    Stȩpień, K.; Pamyatnykh, A. A.; Rozyczka, M.

    2017-01-01

    Context. Origin and evolution of blue stragglers in globular clusters is still a matter of debate. Aims: The aim of the present investigation is to reproduce the evolutionary history of four binary blue stragglers in four different clusters, for which precise values of global parameters are known. Methods: Using the model for cool close binary evolution that we developed, progenitors of all investigated binaries were found and their parameters evolved into the presently observed values. Results: The results show that the progenitors of the binary blue stragglers are cool close binaries with period of a few days, which transform into stragglers by rejuvenation of the initially less massive component as a result of mass transfer from its more massive companion overflowing the inner critical Roche surface. The parameters of V209 from ω Cen indicate that the binary is substantially enriched in helium. This is an independent and strong evidence of the existence of the helium rich subpopulation in this cluster.

  17. An eclipsing double-line spectroscopic binary at the stellar/substellar boundary in the Upper Scorpius OB association

    NASA Astrophysics Data System (ADS)

    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.

    2015-12-01

    Aims: We aim at constraining evolutionary models at low mass 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 eclipsing binary 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 eclipsing binaries in the low-mass 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

  18. A matched filter method for ground-based sub-noise detection of terrestrial extrasolar planets in eclipsing binaries: application to CM Draconis

    NASA Technical Reports Server (NTRS)

    Jenkins, J. M.; Doyle, L. R.; Cullers, D. K.

    1996-01-01

    The photometric detection of extrasolar planets by transits in eclipsing binary systems can be significantly improved by cross-correlating the observational light curves with synthetic models of possible planetary transit features, essentially a matched filter approach. We demonstrate the utility and application of this transit detection algorithm for ground-based detections of terrestrial-sized (Earth-to-Neptune radii) extrasolar planets in the dwarf M-star eclipsing binary system CM Draconis. Preliminary photometric observational data of this system demonstrate that the observational noise is well characterized as white and Gaussian at the observational time steps required for precision photometric measurements. Depending on planet formation scenarios, terrestrial-sized planets may form quite close to this low-luminosity system. We demonstrate, for example, that planets as small as 1.4 Earth radii with periods on the order of a few months in the CM Draconis system could be detected at the 99.9% confidence level in less than a year using 1-m class telescopes from the ground. This result contradicts commonly held assumptions limiting present ground-based efforts to, at best, detections of gas giant planets after several years of observation. This method can be readily extended to a number of other larger star systems with the utilization of larger telescopes and longer observing times. Its extension to spacecraft observations should also allow the determination of the presence of terrestrial-sized planets in nearly 100 other known eclipsing binary systems.

  19. A Bright Short Period M-M Eclipsing Binary from the KELT Survey: Magnetic Activity and the Mass-Radius Relationship for M Dwarfs

    NASA Astrophysics Data System (ADS)

    Lubin, Jack B.; Rodriguez, Joseph E.; Zhou, George; Conroy, Kyle E.; Stassun, Keivan G.; Collins, Karen; Stevens, Daniel J.; Labadie-Bartz, Jonathan; Stockdale, Christopher; Myers, Gordon; Colón, Knicole D.; Bento, Joao; Kehusmaa, Petri; Petrucci, Romina; Jofré, Emiliano; Quinn, Samuel N.; Lund, Michael B.; Kuhn, Rudolf B.; Siverd, Robert J.; Beatty, Thomas G.; Harlingten, Caisey; Pepper, Joshua; Gaudi, B. Scott; James, David; Jensen, Eric L. N.; Reichart, Daniel; Kedziora-Chudczer, Lucyna; Bailey, Jeremy; Melville, Graeme

    2017-08-01

    We report the discovery of KELT J041621-620046, a moderately bright (J ˜ 10.2) M-dwarf eclipsing binary system at a distance of 39 ± 3 pc. KELT J041621-620046 was first identified as an eclipsing binary using observations from the Kilodegree Extremely Little Telescope (KELT) survey. The system has a short orbital period of ˜1.11 days and consists of components with {M}1={0.447}+0.052-0.047 {M}⊙ and {M}2={0.399}+0.046-0.042 {M}⊙ in nearly circular orbits. The radii of the two stars are {R}1={0.540}+0.034-0.032 {R}⊙ and {\\text{}}{R}2=0.453+/- 0.017 {R}⊙ . Full system and orbital properties were determined (to ˜10% error) by conducting an EBOP (Eclipsing Binary Orbit Program) global modeling of the high precision photometric and spectroscopic observations obtained by the KELT Follow-up Network. Each star is larger by 17%-28% and cooler by 4%-10% than predicted by standard (non-magnetic) stellar models. Strong Hα emission indicates chromospheric activity in both stars. The observed radii and temperature discrepancies for both components are more consistent with those predicted by empirical relations that account for convective suppression due to magnetic activity.

  20. A matched filter method for ground-based sub-noise detection of terrestrial extrasolar planets in eclipsing binaries: application to CM Draconis.

    PubMed

    Jenkins, J M; Doyle, L R; Cullers, D K

    1996-02-01

    The photometric detection of extrasolar planets by transits in eclipsing binary systems can be significantly improved by cross-correlating the observational light curves with synthetic models of possible planetary transit features, essentially a matched filter approach. We demonstrate the utility and application of this transit detection algorithm for ground-based detections of terrestrial-sized (Earth-to-Neptune radii) extrasolar planets in the dwarf M-star eclipsing binary system CM Draconis. Preliminary photometric observational data of this system demonstrate that the observational noise is well characterized as white and Gaussian at the observational time steps required for precision photometric measurements. Depending on planet formation scenarios, terrestrial-sized planets may form quite close to this low-luminosity system. We demonstrate, for example, that planets as small as 1.4 Earth radii with periods on the order of a few months in the CM Draconis system could be detected at the 99.9% confidence level in less than a year using 1-m class telescopes from the ground. This result contradicts commonly held assumptions limiting present ground-based efforts to, at best, detections of gas giant planets after several years of observation. This method can be readily extended to a number of other larger star systems with the utilization of larger telescopes and longer observing times. Its extension to spacecraft observations should also allow the determination of the presence of terrestrial-sized planets in nearly 100 other known eclipsing binary systems.

  1. Photometric Observations of the low mass Eclipsing Binaries GU Boo and TrES-Her0-07621 from Mount Laguna Observatory

    NASA Astrophysics Data System (ADS)

    Rosenfield, P. A.; Huk, L.; Garcia, D.; Downum, C.; Etzel, P. B.; Orosz, J. A.

    2005-12-01

    Low mass double-lined eclipsing binaries are of general interest because precise masses and radii can be derived for the component stars, and these data can in turn be used to test evolutionary models on the lower main sequence. The low mass double-lined eclipsing binaries GU Boo and TrES-Her0-07621 were observed in several bandpasses from the Mount Laguna Observatory (MLO) 2005 May - June with the goal of obtaining precise light curves that can be used to derive accurate radii. Lopez-Morales & Ribas (2005) present light curves of GU Boo covering both eclipses and radial velocity curves for each component and derive component masses and radii accurate to 1.3% and 2.3%, respectively. Their light curves were not symmetric about the primary eclipse, and Lopez-Morales & Ribas modelled the asymmetry using two dark spots on the primary. Our light curves of GU Boo from MLO show only a slight asymmetry, which indicates the spotted region is much smaller. The radii we derive for the component stars are consistent with the measurements of Lopez-Morales & Ribas, showing that the presence of large star spots did not lead to any systematic errors in the derived radii. TrES-Her0-07621 was discovered by the Trans-Atlantic Exoplanet Survey (TrES, e.g. Alonso et al. 2004). Creevey et al. (2005) obtained radial velocity curves for both components and derive component masses and radii accurate to 0.6% and 13%, respectively. The radii are poorly constrained since the light curve presented in Creevey et al. is somewhat noisy. Our light curves from MLO have a high signal-to-noise ratio, but unfortunately only cover the secondary eclipse. We see evidence of a sinusoidal variation in the out-of-eclipse phases (also noted by Creevey et al.). More observations will be needed to cover the primary eclipse and to establish the nature of the out-of-eclipse variation.

  2. UBVR{sub c} I{sub c} ANALYSIS OF THE RECENTLY DISCOVERED TOTALLY ECLIPSING EXTREME MASS RATIO BINARY V1853 ORIONIS, AND A STATISTICAL LOOK AT 25 OTHER EXTREME MASS RATIO SOLAR-TYPE CONTACT BINARIES

    SciTech Connect

    Samec, R. G.; Labadorf, C. M.; Hawkins, N. C.; Faulkner, D. R.; Van Hamme, W.

    2011-10-15

    We present precision CCD light curves, a period study, photometrically derived standard magnitudes, and a five-color simultaneous Wilson code solution of the totally eclipsing, yet shallow amplitude (A{sub v} {approx} 0.4 mag) eclipsing, binary V1853 Orionis. It is determined to be an extreme mass ratio, q = 0.20, W-type W UMa overcontact binary. From our standard star observations, we find that the variable is a late-type F spectral-type dwarf, with a secondary component of about 0.24 solar masses (stellar type M5V). Its long eclipse duration (41 minutes) as compared to its period, 0.383 days, attests to the small relative size of the secondary. Furthermore, it has reached a Roche lobe fill-out of {approx}50% of its outer critical lobe as it approaches its final stages of binary star evolution, that of a fast spinning single star. Finally, a summary of about 25 extreme mass ratio solar-type binaries is given.

  3. CCD Photometry, Roche Modeling and Evolutionary History of the WUMa-type Eclipsing Binary TYC01664-0110-1

    NASA Astrophysics Data System (ADS)

    Alton, K. B.; Stępień, K.

    2016-09-01

    TYC 01664-0110-1 (ASAS J212915+1604.9), a W UMa-type variable system (P=0.282962 d), was first detected over 17 years ago by the ROTSE-I telescope. Photometric data (B, V and Ic) collected at UnderOak Observatory (UO) resulted in five new times-of-minima for this variable star which were used to establish a revised linear ephemeris. No published radial velocity (RV) data are available for this system. However, since this W UMa binary undergoes a total eclipse, Roche modeling based on the Wilson-Devinney (W-D) code yielded a well-constrained photometric value for M2/M1 (q=0.356±0.001). There is a suggestion from ROTSE-I (1999) and ASAS survey data (2003, 2005, and 2008) that the secondary maximum is more variable than the primary one probably due to the so-called O'Connell effect. However, peak asymmetry in light curves (LC) from 2015 was barely evident during quadrature. Therefore, W-D model fits of these most recent data did not yield any substantive improvement with the addition of spot(s). Using the evolutionary model of cool close binaries we searched for a possible progenitor of TYC 01664-0110-1. The best fit is obtained if the initial binary has an orbital period between 3.3-3.8 d and component masses between 1.0-1.1 M⊙ and 0.30-0.35 M⊙. The model progenitor needs about 10 Gyr to attain the presently observed parameters of the variable. Its period slowly increases and the mass ratio decreases. According to the model predictions TYC 01664-0110-1 will go through the common envelope (CE) phase in the future, followed by merging of both components or formation of a double degenerate. Due to its apparent brightness (mV,max≍10.9 mag) and unique properties, the star is an excellent target for spectroscopic investigation of any possible deviations from a simple static model of a contact binary.

  4. Follow-up Observations and Analysis of V530 Andromedae: A Totally Eclipsing Shallow Contact Solar Type Binary

    NASA Astrophysics Data System (ADS)

    Chamberlain, Heather; Samec, Ronald G.; Caton, Daniel B.; Faulkner, Danny R.; Clark, Jeremy; Shebs, Travis

    2015-01-01

    We follow up on early, single coverage, UBVRcIc light curves (2013) and analyses. These early curves were taken in September 27 and 29 2011. Our present, BVRcIc, but full coverage light curves were taken on 6 nights: October 1,2,9, November 4,5, 2013 and January 4, 2014 by RGS, DBC, JDC, TS with the Dark Sky Observatory 0.81-m reflector of Appalachian State University and a (-40ºC) 2KX2K Apogee Alta CCD. Our present curves reveal V530 Andromedae as a totally eclipsing, shallow contact solar type binary rather than semidetached, near contact one. The newly determined times of minima include:HJD MinI = 2456566.84275 ±0.00007HJD MinII = 2456598.881995±0.0004, 24556600.6111±0.0002, 2456601.76665±0.00046.Using a new method of obtaining minima from earlier patrol light curves, in this case, NSVS, nine low weight timings of minimum light were added to the period study. Including these additional timings, we uncovered a period change. In our now, extended, period study over 9000 epochs, a 14.25 year interval, we find that the period is decreasing. This fits the scenario of magnetic breaking for solar type binaries. The temperatures of the primary and secondary components are estimated at 7000 and 6300 K, respectively, a large temperature difference for a contact binary. The fill-out, however, is a mere 4%. (Our earlier scant light curves modeled very nearly in contact.) The mass ratio, M2/M1, was found to be 0.385, almost identical with our first curves solution. The two star spots, probably magnetic in origin, were determined. A hot spot was modeled by the iterative process on the polar region of the smaller star. A cool spot is on the larger star facing the smaller star. The spot parameters have changed appreciably over the course of the two intervening years. We believe the binary has recently come into contact and thermal contact has not yet been achieved.

  5. The multi-band CCD photometric investigation of short-period eclipsing binary V1044 Her

    NASA Astrophysics Data System (ADS)

    Lu, Hongpeng; Zhang, Liyun; Han, Xianming L.; Pi, Qingfeng; Wang, Daimei

    2016-10-01

    We present new CCD photometric observations of V1044 Her obtained on May 22, 23 and 24, 2015. From our data, we derived five new light curve minimum times. Combining our new results with previously available CCD light minimum times, we derived an updated ephemeris and discovered that the period of this binary system exhibits an oscillation. The cyclic variation may be caused by the light-time effect via the presence of a third body or magnetic activity cycle. We calculated the corresponding period of the third body to be 14.1 ± 1.4 years or magnetic cycle to be 12.2 ± 0.7 years. We analyzed our new asymmetric light curves to obtain photometric solutions and starspot parameters using the Wilson and Devinney program. The final results show that V1044 Her is a contact binary system with a degree of contact factor f = 3.220(± 0.002)%.

  6. V346 Centauri: Early-type eclipsing binary with apsidal motion and abrupt change of orbital period

    NASA Astrophysics Data System (ADS)

    Mayer, Pavel; Harmanec, Petr; Wolf, Marek; Nemravová, Jana; Prša, Andrej; Frémat, Yves; Zejda, Miloslav; Liška, Jiři; Juryšek, Jakub; Hoňková, Kateřina; Mašek, Martin

    2016-06-01

    New physical elements of the early B-type eclipsing binary V346 Cen are derived using the HARPS spectra downloaded from the ESO archive and also numerous photometric observations from various sources. A model of the observed times of primary and secondary minima that fits them best is a combination of the apsidal motion and an abrupt decrease in the orbital period from 6.^d322123 to 6.^d321843 (shortening by 24 s), which occurred somewhere around JD 2 439 000. Assumption of a secularly decreasing orbital period provides a significantly worse fit. Local times of minima and the final solution of the light curve were obtained with the program PHOEBE. Radial velocities of both binary components, free of line blending, were derived via 2D cross-correlation with a program built on the principles of the program TODCOR. The oxygen lines in the secondary spectra are weaker than those in the model spectra of solar chemical composition. Using the component spectra disentangled with the program KOREL, we find that both components rotate considerably faster than would correspond to the synchronization at periastron. The apside rotation known from earlier studies is confirmed and compared to the theoretical value. Based on observations made with the ESO telescopes at the La Silla Paranal Observatory under programmes ID 083.D-0040(A), 085.C-0614(A), and 178.D-0361(B).Tables A.2-A.6 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/591/A129

  7. THE SDSS-HET SURVEY OF KEPLER ECLIPSING BINARIES: SPECTROSCOPIC DYNAMICAL MASSES OF THE KEPLER-16 CIRCUMBINARY PLANET HOSTS

    SciTech Connect

    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.

    2012-06-01

    We have used high-resolution spectroscopy to observe the Kepler-16 eclipsing binary 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 low-mass stars and provide an important direct test of the results from the PDM technique.

  8. The Catalogue of Stellar Parameters from the Detached Double-Lined Eclipsing Binaries in the Milky Way

    NASA Astrophysics Data System (ADS)

    Eker, Z.; Bilir, S.; Soydugan, F.; Gökçe, E. Yaz; Soydugan, E.; Tüysüz, M.; Şenyüz, T.; Demircan, O.

    2014-05-01

    The most accurate stellar astrophysical parameters were collected from the solutions of the light and the radial velocity curves of 257 detached double-lined eclipsing binaries in the Milky Way. The catalogue contains masses, radii, surface gravities, effective temperatures, luminosities, projected rotational velocities of the component stars, and the orbital parameters. The number of stars with accurate parameters increased 67% in comparison to the most recent similar collection by Torres, Andersen, & Giménez (2010). Distributions of some basic parameters were investigated. The ranges of effective temperatures, masses, and radii are 2 750

  9. The first multi-color photometric study of the short-period contact eclipsing binary DE Lyn

    NASA Astrophysics Data System (ADS)

    Hashimoto, Amanda; Zhang, Liyun; Han, Xianming L.; Lu, Hongpeng; Wang, Daimei

    2016-05-01

    We observed the contact eclipsing binary of DE Lyn using SARA 0.9 m telescope at Kitt Peak National Observatory on February 9, 11, and 27, 2015. In this study, we obtained the first full phase coverage BVRI CCD light curves, analyzed the orbital period variation, and extracted the orbital parameters. We calculated the linear and quadratic ephemeris, and thereby found that DE Lyn has a decreasing orbital period rate of - 5.1(± 0.4) × 10-7 days/year. We assume this decreasing trend is the result of the more massive component (secondary) transferring mass to the less massive component (primary), and we obtained a mass transfer rate of dm / dt = 7.06 ×10-7M⊙ /year . By using the updated Wilson & Devinney program, we found the orbital parameters of DE Lyn, which, in turn, enabled us to calculate the low degree of contact factor as f = 9.02(± 0.01)%. In the future, its degree of contact will continue to increase and will evolve into an over-contact system.

  10. The first multi-color photometric study of the short-period contact Eclipsing Binary DE Lyn

    NASA Astrophysics Data System (ADS)

    Hashimoto, Amanda; Zhang, Liyun; Han, Xianming L.; Hongpeng, Lu; Wang, Daimei

    2016-01-01

    We observed the contact eclipsing binary of DE Lyn using SARA 0.9 meter telescope at Kitt Peak National Observatory on February 9, 11, and 27, 2015. In this study, we obtained the first full phase coverage BVRI CCD light curves, analyzed the orbital period variation, and extracted the orbital parameters. We calculated the linear and quadratic ephemeris, and thereby found that DE Lyn has a decreasing orbital period rate of -5.1(±0.4)×10-7 days/year. We believe this decreasing trend is the result of the more massive component (secondary) transferring mass to the less massive component (primary), and we obtained a mass transfer rate of dm/dt = 7.06×10-7M⊙/year. By using the updated Wilson & Devinney program, we found the orbital parameters of DE Lyn, which, in turn, enabled us to calculate the low degree of contact factor as f = 9.02(± 0.01)%. Its degree of contact will continue to increase and will evolve into an over-contact system.

  11. Study of Eclipsing Binary and Multiple Systems in OB Associations IV: Cas OB6 Member DN Cas

    NASA Astrophysics Data System (ADS)

    Bakış, V.; Bakış, H.; Bilir, S.; Eker, Z.

    2016-09-01

    An early-type, massive, short-period (Porb=2d.310951) eclipsing spectroscopic binary DN Cas has been re-visited with new spectral and photometric data. The masses and radii of the components have been obtained as M1=19.04± 0.07 M⊙, M2=13.73± 0.05 M⊙ and R1=7.22± 0.06 R⊙, R2=5.79± 0.06 R⊙, respectively. Both components present synchronous rotation (Vrot1=160 km s-1, Vrot2=130 km s-1) with their orbit. Orbital period analysis yielded a physically bound additional component in the system with a minimum mass of M3=0.88 M⊙ orbiting in an eccentric orbit (e = 0.37 ± 0.2) with an orbital period of P 12 = 42 ± 9 yr. High precision absolute parameters of the system allowed us to derive a distance to DN Cas as 1.7 ± 0.2 kpc which locates the system within the borders of the Cas OB6 association (d = 1.8 kpc). The space velocities and the age of DN Cas are in agreement with those of Cas OB6. The age of DN Cas (τ = 3-5 Myr) is found to be 1-2 Myr older than the embedded clusters (IC 1795, IC 1805, and IC 1848) in the Cas OB6 association, which implies a sequential star formation in the association.

  12. The Vanderbilt EB Factory: Development of Light Curve Analysis Tools for Precision Stellar Astrophysics with Kepler Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Stassun, Keivan; Paegert, M.; De Lee, N. M.; Cargile, P.

    2013-01-01

    The goal of the Vanderbilt EB Factory is to develop an end-to-end computational pipeline that allows automatic processing of massive amounts of light curve data -- from period finding, to object classification, to determination of the stellar physical properties -- in order to find the most scientifically interesting eclipsing binaries (EBs) and to permit accurate modeling of these EBs for detailed tests and benchmarking of theoretical stellar evolution models. We are integrating the most successful algorithms into a single, cohesive workflow environment, and are applying this 'EB Factory' to the full public Kepler dataset to find and characterize new "benchmark grade" EBs, and will disseminate both the enhanced data products from this pipeline and the pipeline itself to the broader NASA science community, especially other Kepler mission researchers. More generally, we are developing the EB Factory as a flexible, open source, modular framework in order to permit simple modifications by other users for a wide array of other types of variable stars of interest, such as RR Lyraes. Finally, we will present our developing suite of light-curve analysis tools available to the community from the Vanderbilt Initiative in Data-intensive Astrophysics (VIDA), including the Filtergraph instant data portal service, and the web-based LCchopper and LCanimator light-curve analysis services.

  13. Eclipse timings of the low-mass X-ray binary EXO 0748-676: Statistical arguments against orbital period changes

    NASA Technical Reports Server (NTRS)

    Hertz, Paul; Wood, Kent S.; Cominsky, Lynn

    1995-01-01

    EXO 0748-676, an eclipsing low-mass X-ray binary, is one of only about four or five low-mass X-ray binaries for which orbital period evolution has been reported. We observed a single eclipse 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 eclipse 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 binary system, and that it is correlated from observation to observation with a variance which increases as a function of the number of binary 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 binaries and cataclysmic variables have previously reported orbital period changes which may also be due to intrinsic variability rather than orbital period evolution.

  14. Eclipsing Binaries in the Local Group: III - Unprecedented Accuracy in Distance Determination to M33 and Calibration of the Cosmic Distance Scale

    NASA Astrophysics Data System (ADS)

    Guinan, Edward

    2009-07-01

    The Great Spiral Galaxy in Triangulum {M33} is a crucial calibrator for the Cosmic Distance Scale, and thus for determining the age and evolution of the Universe. M33 is viewed face-on, has a simple geometry, large and diverse stellar populations, and morphologies similar to our Galaxy and other more distant galaxies used for distance determinations. Yet currently the M33 distance {d 830 +/- 120 kpc} still has measurement dispersions of 10-15%. Moreover, the distance to M33 derived from Cepheids, RR Lyrae stars, H2O masers, RGB stars, and EBs is currently discrepant by 15% {Bonanos et al. 2006}. In our work on the LMC and M31 distances we have demonstrated that double-line eclipsing binaries serve as excellent "standard candles." Distances derived from eclipsing binaries are basically geometric and essentially free from many assumptions and uncertainties that plague other less direct methods, such as metallicity differences and calibration zeropoints. The absolute radii of the component stars of eclipsing binaries can be determined to better than a few percent from the time-tested analyses of their light and radial velocity curves. With accurate determinations of radii, temperatures, and ISM absorption it is possible to determine reliable distances. In Cycle 15 we extended our program of using eclipsing binaries as standard candles to M33 using ACS/SBS and WFPC/2 spectrophotometry of a well suited 19th mag O7+O7 eclipsing binary system. Although insightful, ACS/SBC data alone do not provide sufficient accuracy for the unambigous determination of individual temperatures, [Fe/H], and ISM extinction, which are central to distance determination. We propose a 4 orbit follow-up spectrophotometry with the newly installed HST/COS G140L and the repaired HST/STIS G230L and G430L to obtain the single missing key element of this program. These quantities, when combined with the results from existing light and radial velocity curves for the target {cf. Bonanos et al. 2006

  15. Blue Supergiant X-Ray Binaries in the Nearby Dwarf Galaxy IC 10

    NASA Astrophysics Data System (ADS)

    Laycock, Silas G. T.; Christodoulou, Dimitris M.; Williams, Benjamin F.; Binder, Breanna; Prestwich, Andrea

    2017-02-01

    In young starburst galaxies, the X-ray population is expected to be dominated by the relics of the most massive and short-lived stars, black hole and neutron-star high-mass X-ray binaries (XRBs). In the closest such galaxy, IC 10, we have made a multi-wavelength census of these objects. Employing a novel statistical correlation technique, we have matched our list of 110 X-ray point sources, derived from a decade of Chandra observations, against published photometric data. We report an 8σ correlation between the celestial coordinates of the two catalogs, with 42 X-ray sources having an optical counterpart. Applying an optical color-magnitude selection to isolate blue supergiant (SG) stars in IC 10, we find 16 matches. Both cases show a statistically significant overabundance versus the expectation value for chance alignments. The blue objects also exhibit systematically higher {f}x/{f}v ratios than other stars in the same magnitude range. Blue SG-XRBs include a major class of progenitors of double-degenerate binaries, hence their numbers are an important factor in modeling the rate of gravitational-wave sources. We suggest that the anomalous features of the IC 10 stellar population are explained if the age of the IC 10 starburst is close to the time of the peak of interaction for massive binaries.

  16. New Spectroscopic Analysis and Light Curve Model of the Eclipsing Binary V356 Sgr

    NASA Astrophysics Data System (ADS)

    Cabezas, M.; Mennickent, R.; Djurasević, G.

    2017-02-01

    We present a new orbital solution for the V356 Sgr binary system based on new and accurate radial velocities. It consists of a B3 V star accreting matter from a Roche-Lobe filling A2 II star. The spectra were disentangled using KOREL. The UBV light curves by Popper (1957) and Wilson & Woodward (1995) as well as the ASAS V-band light curve were modeled with a multicomponent synthesis code including an accretion disk. The system parameters, such as the effective temperature and surface gravity for both stars as well as the disk temperature and radius, were determined.

  17. a Photometric Study of Eb-Type Eclipsing Binary V388 CYG

    NASA Astrophysics Data System (ADS)

    Oh, Kyu-Dong; Kim, Ho-Il; Lee, Woo-Baik

    1997-06-01

    New BVR CCD photometric observations of EB type close binary V388 Cyg were obtained at the Sobaeksan Astronomy Observatory during 10 nights from October to December 1995. We analyse new 3 coler (B, V & R) light curves simultaneously using the Wilson-Devinney code. Now, it is not yet clear whether V388 Cyg is contact or semidetached system. Published epochs of times of minima to date were used to study the changes in period of the system, and calculated a new light elements with the secular hems, -4.83 x 10-10, which indicated the continuous decrease of the period.

  18. DEEP MULTI-TELESCOPE PHOTOMETRY OF NGC 5466. I. BLUE STRAGGLERS AND BINARY SYSTEMS

    SciTech Connect

    Beccari, G.; Dalessandro, E.; Lanzoni, B.; Ferraro, F. R.; Miocchi, P.; Sollima, A.; Bellazzini, M.

    2013-10-10

    We present a detailed investigation of the radial distribution of blue straggler star (BSS) and binary populations in the Galactic globular cluster NGC 5466, over the entire extension of the system. We used a combination of data acquired with the Advanced Camera for Survey on board the Hubble Space Telescope, the LBC-blue mounted on the Large Binocular Telescope, and MEGACAM on the Canada-France-Hawaii Telescope. BSSs show a bimodal distribution with a mild central peak and a quite internal minimum. This feature is interpreted in terms of a relatively young dynamical age in the framework of the 'dynamical clock' concept proposed by Ferraro et al. The estimated fraction of binaries is ∼6%-7% in the central region (r < 90'') and slightly lower (∼5.5%) in the outskirts, at r > 200''. Quite interestingly, the comparison with the results of Milone et al. suggests that binary systems may also display a bimodal radial distribution, with the position of the minimum consistent with that of BSSs. If confirmed, this feature would give additional support to the scenario where the radial distribution of objects more massive than the average cluster stars is primarily shaped by the effect of dynamical friction. Moreover, this would also be consistent with the idea that the unperturbed evolution of primordial binaries could be the dominant BSS formation process in low-density environments.

  19. The Light and Period Variations of the Eclipsing Binary BX Draconis

    NASA Astrophysics Data System (ADS)

    Park, Jang-Ho; Lee, Jae Woo; Kim, Seung-Lee; Lee, Chung-Uk; Jeon, Young-Beom

    2013-02-01

    New CCD photometric observations of BX Dra were carried out on 26 nights during the period from 2009 April to 2010 June. The long-term photometric behaviors of the system are obtained from detailed studies of the period and light variations, based on historical data and our new observations. All available light curves display total eclipses at secondary minima and inverse O'Connell effects with Max I fainter than Max II, which were satisfactorily modeled by adding a slightly time-varying hot spot on the primary star. A total of 87 times of minimum lights spanning over ˜74 yr, including our 22 timing measurements, were used for ephemeris computations. A detailed analysis of the O - C diagram disclosed that the orbital period shows an upward parabola in combination with a sinusoidal variation. The continuous increase of period at a rate of +5.65 × 10-7 d yr-1 is consistent with that calculated from the Wilson-Devinney synthesis code. It can be interpreted as a mass transfer from the secondary star to the primary at a rate of 2.74 × 10-7 M⊙ yr-1, which is one of the largest rates between components of the contact system. The most likely explanation of the sinusoidal variation having a period of 30.2 yr and a semiamplitude of 0.0062 d is a light-travel-time effect due to the existence of a circumbinary object. We suggest that BX Dra is probably a triple system, consisting of a primary star with a spectral type of F0, its secondary component of spectral type F1-2, and an unseen circumbinary object with a minimum mass of M3 = 0.23 M⊙.

  20. Multi-color photometric investigation of the totally eclipsing binary NO Camelopardalis

    NASA Astrophysics Data System (ADS)

    Zhou, Xiao; Qian, Shengbang; Zhang, Bin

    2017-04-01

    Multi-color photometric light curves of NO Camelopardalis in V, RC, and IC bands are obtained and analyzed simultaneously using the Wilson-Devinney program. The solutions suggest that NO Cam is an A-subtype overcontact binary with a mass ratio of q = 0.439 and a contact degree of f = 55.5%. The small temperature difference (ΔT = 44 K) between its two components indicates that the system is under thermal contact. The high orbital inclination (i = 84.5°) strengthens our confidence in the parameters determined from the light curves. All available times of minimum light are collected and period variations are analyzed for the first time. The O - C curve reveals that its period is increasing continuously at a rate of dP/dt = +1.46 × 10-9, which can be explained by mass transfer from the less massive component to the more massive one. After the upward parabolic variation is subtracted, the residuals suggest that there may be a cyclic variation with a period of 2.23 yr and an amplitude of A3 = 0.00153 d, which may due to the light-travel-time effect arising from the gravitational influence of a close-in tertiary component. The close-in companion reveals that early dynamic interaction among a triple system may have played a very important role in the formation of the W UMa-type binaries.

  1. Multi-periodic pulsations of a stripped red-giant star in an eclipsing binary system.

    PubMed

    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

    2013-06-27

    Low-mass white-dwarf stars are the remnants of disrupted red-giant stars in binary millisecond pulsars and other exotic binary star systems. Some low-mass 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 low-mass white dwarfs as independent clocks with which to test the spin-down ages of pulsars or as probes of the extreme environments in which low-mass white dwarfs form cannot fully be exploited. Here we report precise mass and radius measurements for the precursor to a low-mass 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 low-mass 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 low-mass 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.

  2. Multi-color photometric investigation of the totally eclipsing binary NO Camelopardalis

    NASA Astrophysics Data System (ADS)

    Zhou, Xiao; Qian, Shengbang; Zhang, Bin

    2017-03-01

    Multi-color photometric light curves of NO Camelopardalis in V, RC, and IC bands are obtained and analyzed simultaneously using the Wilson-Devinney program. The solutions suggest that NO Cam is an A-subtype overcontact binary with a mass ratio of q = 0.439 and a contact degree of f = 55.5%. The small temperature difference (ΔT = 44 K) between its two components indicates that the system is under thermal contact. The high orbital inclination (i = 84.5°) strengthens our confidence in the parameters determined from the light curves. All available times of minimum light are