Science.gov

Sample records for binary candidate slx1737-282

  1. 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.

  2. MICROLENSING BINARIES WITH CANDIDATE BROWN DWARF COMPANIONS

    SciTech Connect

    Shin, I.-G.; Han, C.; Gould, A.; Skowron, J.; Udalski, A.; Szymanski, M. K.; Kubiak, M.; Soszynski, I.; Pietrzynski, G.; Poleski, R.; Ulaczyk, K.; Pietrukowicz, P.; Kozlowski, S.; Wyrzykowski, L.; Sumi, T.; Dominik, M.; Beaulieu, J.-P.; Tsapras, Y.; Bozza, V.; Abe, F.; Collaboration: OGLE Collaboration; MOA Collaboration; muFUN Collaboration; and others

    2012-12-01

    Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation histories. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing events discovered during the 2004-2011 observation seasons. Based on the low mass ratio criterion of q < 0.2, we found seven candidate events: OGLE-2004-BLG-035, OGLE-2004-BLG-039, OGLE-2007-BLG-006, OGLE-2007-BLG-399/MOA-2007-BLG-334, MOA-2011-BLG-104/OGLE-2011-BLG-0172, MOA-2011-BLG-149, and MOA-201-BLG-278/OGLE-2011-BLG-012N. Among them, we are able to confirm that the companions of the lenses of MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149 are brown dwarfs by determining the mass of the lens based on the simultaneous measurement of the Einstein radius and the lens parallax. The measured masses of the brown dwarf companions are 0.02 {+-} 0.01 M {sub Sun} and 0.019 {+-} 0.002 M {sub Sun} for MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149, respectively, and both companions are orbiting low-mass M dwarf host stars. More microlensing brown dwarfs are expected to be detected as the number of lensing events with well-covered light curves increases with new-generation searches.

  3. An Improved Catalog of Halo Wide Binary Candidates

    NASA Astrophysics Data System (ADS)

    Allen, Christine; Monroy-Rodríguez, Miguel A.

    2014-08-01

    We present an improved catalog of halo wide binaries compiled from an extensive literature search. Most of our binaries stem from the common proper motion binary catalogs by Allen et al. and Chanamé & Gould, but we have also included binaries from the lists of Ryan and Zapatero-Osorio & Martín. All binaries were carefully checked and their distances and systemic radial velocities are included when available. Probable membership to the halo population was tested by means of reduced proper motion diagrams for 251 candidate halo binaries. After eliminating obvious disk binaries, we ended up with 211 probable halo binaries, 150 of which have radial velocities available. We compute galactic orbits for these 150 binaries and calculate the time they spend within the galactic disk. Considering the full sample of 251 candidate halo binaries as well as several subsamples, we find that the distribution of angular separations (or expected major semiaxes) follows a power law f(a) ~ a -1 (Oepik's relation) up to different limits. For the 50 most disk-like binaries, those that spend their entire lives within z = ±500 pc, this limit is found to be 19,000 AU (0.09 pc), while for the 50 most halo-like binaries, those that spend on average only 18% of their lives within z = ±500 pc, the limit is 63,000 AU (0.31 pc). In a companion paper, we employ this catalog to establish limits on the masses of the halo massive perturbers (massive compact halo objects).

  4. An improved catalog of halo wide binary candidates

    SciTech Connect

    Allen, Christine; Monroy-Rodríguez, Miguel A.

    2014-08-01

    We present an improved catalog of halo wide binaries compiled from an extensive literature search. Most of our binaries stem from the common proper motion binary catalogs by Allen et al. and Chanamé and Gould, but we have also included binaries from the lists of Ryan and Zapatero-Osorio and Martín. All binaries were carefully checked and their distances and systemic radial velocities are included when available. Probable membership to the halo population was tested by means of reduced proper motion diagrams for 251 candidate halo binaries. After eliminating obvious disk binaries, we ended up with 211 probable halo binaries, 150 of which have radial velocities available. We compute galactic orbits for these 150 binaries and calculate the time they spend within the galactic disk. Considering the full sample of 251 candidate halo binaries as well as several subsamples, we find that the distribution of angular separations (or expected major semiaxes) follows a power law f(a) ∼ a {sup –1} (Oepik's relation) up to different limits. For the 50 most disk-like binaries, those that spend their entire lives within z = ±500 pc, this limit is found to be 19,000 AU (0.09 pc), while for the 50 most halo-like binaries, those that spend on average only 18% of their lives within z = ±500 pc, the limit is 63,000 AU (0.31 pc). In a companion paper, we employ this catalog to establish limits on the masses of the halo massive perturbers (massive compact halo objects).

  5. TRIPLE-STAR CANDIDATES AMONG THE KEPLER BINARIES

    SciTech Connect

    Rappaport, S.; Deck, K.; Sanchis-Ojeda, R.; Levine, A.; Borkovits, T.; Carter, J.; El Mellah, I.; Kalomeni, B. E-mail: kdeck@mit.edu E-mail: aml@space.mit.edu E-mail: jacarter@cfa.harvard.edu

    2013-05-01

    We present the results of a search through the photometric database of Kepler eclipsing binaries looking for evidence of hierarchical triple-star systems. The presence of a third star orbiting the binary can be inferred from eclipse timing variations. We apply a simple algorithm in an automated determination of the eclipse times for all 2157 binaries. The ''calculated'' eclipse times, based on a constant period model, are subtracted from those observed. The resulting O - C (observed minus calculated times) curves are then visually inspected for periodicities in order to find triple-star candidates. After eliminating false positives due to the beat frequency between the {approx}1/2 hr Kepler cadence and the binary period, 39 candidate triple systems were identified. The periodic O - C curves for these candidates were then fit for contributions from both the classical Roemer delay and so-called physical delay, in an attempt to extract a number of the system parameters of the triple. We discuss the limitations of the information that can be inferred from these O - C curves without further supplemental input, e.g., ground-based spectroscopy. Based on the limited range of orbital periods for the triple-star systems to which this search is sensitive, we can extrapolate to estimate that at least 20% of all close binaries have tertiary companions.

  6. BINARY CANDIDATES IN THE JOVIAN TROJAN AND HILDA POPULATIONS FROM NEOWISE LIGHT CURVES

    SciTech Connect

    Sonnett, S.; Mainzer, A.; Masiero, J.; Bauer, J.; Grav, T.

    2015-02-01

    Determining the binary fraction for a population of asteroids, particularly as a function of separation between the two components, helps describe the dynamical environment at the time the binaries formed, which in turn offers constraints on the dynamical evolution of the solar system. We searched the NEOWISE archival data set for close and contact binary Trojans and Hildas via their diagnostically large light curve amplitudes. We present 48 out of 554 Hilda and 34 out of 953 Trojan binary candidates in need of follow-up to confirm their large light curve amplitudes and subsequently constrain the binary orbit and component sizes. From these candidates, we calculate a preliminary estimate of the binary fraction without confirmation or debiasing of 14%-23% for Trojans larger than ∼12 km and 30%-51% for Hildas larger than ∼4 km. Once the binary candidates have been confirmed, it should be possible to infer the underlying, debiased binary fraction through estimation of survey biases.

  7. On Orbital Elements of Extrasolar Planetary Candidates and Spectroscopic Binaries

    NASA Technical Reports Server (NTRS)

    Stepinski, T. F.; Black, D. C.

    2001-01-01

    We estimate probability densities of orbital elements, periods, and eccentricities, for the population of extrasolar planetary candidates (EPC) and, separately, for the population of spectroscopic binaries (SB) with solar-type primaries. We construct empirical cumulative distribution functions (CDFs) in order to infer probability distribution functions (PDFs) for orbital periods and eccentricities. We also derive a joint probability density for period-eccentricity pairs in each population. Comparison of respective distributions reveals that in all cases EPC and SB populations are, in the context of orbital elements, indistinguishable from each other to a high degree of statistical significance. Probability densities of orbital periods in both populations have P(exp -1) functional form, whereas the PDFs of eccentricities can he best characterized as a Gaussian with a mean of about 0.35 and standard deviation of about 0.2 turning into a flat distribution at small values of eccentricity. These remarkable similarities between EPC and SB must be taken into account by theories aimed at explaining the origin of extrasolar planetary candidates, and constitute an important clue us to their ultimate nature.

  8. On Orbital Elements of Extrasolar Planetary Candidates and Spectroscopic Binaries

    NASA Technical Reports Server (NTRS)

    Stepinski, T. F.; Black, D. C.

    2001-01-01

    We estimate probability densities of orbital elements, periods, and eccentricities, for the population of extrasolar planetary candidates (EPC) and, separately, for the population of spectroscopic binaries (SB) with solar-type primaries. We construct empirical cumulative distribution functions (CDFs) in order to infer probability distribution functions (PDFs) for orbital periods and eccentricities. We also derive a joint probability density for period-eccentricity pairs in each population. Comparison of respective distributions reveals that in all cases EPC and SB populations are, in the context of orbital elements, indistinguishable from each other to a high degree of statistical significance. Probability densities of orbital periods in both populations have P(exp -1) functional form, whereas the PDFs of eccentricities can he best characterized as a Gaussian with a mean of about 0.35 and standard deviation of about 0.2 turning into a flat distribution at small values of eccentricity. These remarkable similarities between EPC and SB must be taken into account by theories aimed at explaining the origin of extrasolar planetary candidates, and constitute an important clue us to their ultimate nature.

  9. A candidate sub-parsec supermassive binary black hole system.

    PubMed

    Boroson, Todd A; Lauer, Tod R

    2009-03-05

    The role of mergers in producing galaxies, together with the finding that most large galaxies harbour black holes in their nuclei, implies that binary supermassive black hole systems should be common. Here we report that the quasar SDSS J153636.22+044127.0 is a plausible example of such a system. This quasar shows two broad-line emission systems, separated in velocity by 3,500 km s(-1). A third system of unresolved absorption lines has an intermediate velocity. These characteristics are unique among known quasars. We interpret this object as a binary system of two black holes, having masses of 10(7.3) and 10(8.9) solar masses separated by approximately 0.1 parsec with an orbital period of approximately 100 years.

  10. Photometric CCD observations of four Pre-cataclysmic binary candidates

    NASA Astrophysics Data System (ADS)

    Hinojosa, R.; Vogt, N.; Colque, Juan Pablo

    We present preliminary results of differential photometric observations of Abell 65, HZ 9, GD 1401 and BPM 46460, obtained between September and December 2006 with the 42 cm telescope of the Cerro Armazones Observatory which belongs to the Universidad Catolica del Norte, Antofagasta. All four stars are close red dwarf/white dwarf binaries which could have formed be recent common envelope events. In two of the four cases we detected (or confirmed) significant variability. In one of them, the central star of a planetary nebula Abell 65, we confirmed the rather strong photometric variability with a period very near to 24 hours (Bond and Livio, 1990). In the white dwarf binary HZ9 we detected, for the first time, photometric variations with a period near 0.58 days which corresponds to the known orbital period (Lanning and Pesch, 1981; Stauffer, 1987). The amplitude of this variation is 0.08 mag, it probably refers to reflection of the white dwarf radiation on the surface of the red companion. - These observations are part of a larger on-going project which pretends to identify and to study pre-cataclysmic binaries by means of photometric and spectroscopic methods and to improve, this way, the hitherto poor statistics on the properties of these interesting stars.

  11. Near-Earth Asteroid 2005 CR37: Radar Images and Photometry of a Candidate Contact Binary

    NASA Technical Reports Server (NTRS)

    Benner, Lance A. M.; Nolan, Michael C.; Ostro, Steven J.; Giorgini, Jon D.; Pray, Donald P.; Harris, Alan W.; Magri, Christopher; Margot, Jean-Luc

    2006-01-01

    Arecibo (2380 MHz, 13 cm) radar observations of 2005 CR37 provide detailed images of a candidate contact binary: a 1.8-km-long, extremely bifurcated object. Although the asteroid's two lobes are round, there are regions of modest topographic relief, such as an elevated, 200-m-wide facet, that suggest that the lobes are geologically more complex than either coherent fragments or homogeneous rubble piles. Since January 1999, about 9% of NEAs larger than approx.200 m imaged by radar can be described as candidate contact binaries.

  12. Southern RS CVn systems - Candidate list. [spectral catalog of variable binary stars

    NASA Technical Reports Server (NTRS)

    Weiler, E. J.; Stencel, R. E.

    1979-01-01

    A list of 43 candidate RS CVn binary systems in the far southern hemisphere of the sky (south of -40 deg declination) is presented. The candidate systems were selected from the first two volumes of the Michigan Spectral Catalog (1975, 1978), which provides MK classifications for southern HD stars and identifies any unusual characteristics noted for individual stellar spectra. The selection criteria used were: (1) the occurrence of Ca II H and K emission; (2) known or suspected binary nature; (3) regular light variations of zero to one magnitude; and (4) spectral type between F0 and K2 and luminosity less than bright giant (II).

  13. Southern RS CVn systems - Candidate list. [spectral catalog of variable binary stars

    NASA Technical Reports Server (NTRS)

    Weiler, E. J.; Stencel, R. E.

    1979-01-01

    A list of 43 candidate RS CVn binary systems in the far southern hemisphere of the sky (south of -40 deg declination) is presented. The candidate systems were selected from the first two volumes of the Michigan Spectral Catalog (1975, 1978), which provides MK classifications for southern HD stars and identifies any unusual characteristics noted for individual stellar spectra. The selection criteria used were: (1) the occurrence of Ca II H and K emission; (2) known or suspected binary nature; (3) regular light variations of zero to one magnitude; and (4) spectral type between F0 and K2 and luminosity less than bright giant (II).

  14. Near-Earth Asteroid 2005 CR37: Radar Images and Photometry of a Candidate Contact Binary

    NASA Technical Reports Server (NTRS)

    Benner, Lance A. M.; Nolan, Michael C.; Ostro, Steven J.; Giorgini, Jon D.; Pray, Donald P.; Harris, Alan W.; Magri, Christopher; Margot, Jean-Luc

    2006-01-01

    Arecibo (2380 MHz, 13 cm) radar observations of 2005 CR37 provide detailed images of a candidate contact binary: a 1.8-km-long, extremely bifurcated object. Although the asteroid's two lobes are round, there are regions of modest topographic relief, such as an elevated, 200-m-wide facet, that suggest that the lobes are geologically more complex than either coherent fragments or homogeneous rubble piles. Since January 1999, about 9% of NEAs larger than approx.200 m imaged by radar can be described as candidate contact binaries.

  15. Surface segregation in binary alloy first wall candidate materials

    NASA Astrophysics Data System (ADS)

    Gruen, D. M.; Krauss, A. R.; Mendelsohn, M. H.; Susman, S.

    1982-12-01

    We have been studying the conditions necessary to produce a self-sustaining stable lithium monolayer on a metal substrate as a means of creating a low-Z film which sputters primarily as secondary ions. It is expected that because of the toroidal field, secondary ions originating at the first wall will be returned and contribute little to the plasma impurity influx [1,2]. Aluminum and copper have, because of their high thermal conductivity and low induced radioactivity, been proposed [3-5] as first wall candidate materials. The mechanical properties of the pure metals are very poorly suited to structural applications and an alloy must be used to obtain adequate hardness and tensile strength. In the case of aluminum, mechanical properties suitable for aircraft manufacture are obtained by the addition of a few at% Li. In order to investigate alloys of a similar nature as candidate structural materials for fusion machines we have prepared samples of Li-doped aluminum using both a pyro-metallurgical and a vapor-diffusion technique. The sputtering properties and surface composition have been studied as a function of sample temperature and heating time, and ion beam mass. The erosion rate and secondary ion yield of both the sputtered Al and Li have been raonitored by secondary ion mass spectroscopy and Auger analysis providing information on surface segregation, depth composition profiles, and diffusion rates. The surface composition and lithium depth profiles are compared with previously obtained computational results based on a regular solution model of segregation, while the partial sputtering yields of Al and Li are compared with results obtained with a modified version of the TRIM computer program.

  16. KIC 2831097 - a 2-yr-orbital-period RR Lyrae binary candidate

    NASA Astrophysics Data System (ADS)

    Sódor, Á.; Skarka, M.; Liška, J.; Bognár, Zs.

    2017-02-01

    We report the discovery of a new Kepler first-overtone RR Lyrae pulsator, KIC 2831097. The pulsation shows large, 0.1-d amplitude, systematic phase variations that can be interpreted as light traveltime effect caused by orbital motion in a binary system, superimposed on a linear pulsation-period decrease. The assumed eccentric (e = 0.47) orbit with the period of ≈2 yr is the shortest among the non-eclipsing RR Lyrae binary candidates. The binary model gives the lowest estimate for the mass of the companion of 8.4 M⊙, that places it among black hole candidates. Beside the first-overtone pulsation, numerous additional non-radial pulsation frequencies were also identified. We detected an ≈47-d Blazhko-like irregular light-curve modulation.

  17. THE Be STAR HD 215227: A CANDIDATE GAMMA-RAY BINARY

    SciTech Connect

    Williams, S. J.; Gies, D. R.; Matson, R. A.; Touhami, Y.; Grundstrom, E. D.; Huang, W.; McSwain, M. V. E-mail: gies@chara.gsu.ed E-mail: yamina@chara.gsu.ed E-mail: hwenjin@astro.washington.ed

    2010-11-01

    The emission-line Be star HD 215227 lies within the positional error circle of the newly identified gamma-ray source AGL J2241+4454. We present new blue spectra of the star, and we point out the morphological and variability similarities to other Be binaries. An analysis of the available optical photometry indicates a variation with a period of 60.37 {+-} 0.04 days, which may correspond to an orbital modulation of the flux from the disk surrounding the Be star. The distance to the star of 2.6 kpc and its relatively large Galactic latitude suggest that the binary was ejected from the plane by a supernova explosion that created the neutron star or black hole companion. The binary and runaway properties of HD 215227 make it an attractive candidate as the optical counterpart of AGL J2241+4454 and as a new member of the small class of gamma-ray emitting binaries.

  18. 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.

  19. High-Resolution Observations of a Binary Black Hole Candidate

    NASA Astrophysics Data System (ADS)

    Tsai, Chao-Wei; Phillips, Chris; Norris, Ray; Jarrett, Thomas; Emonts, Bjorn; Cluver, Michelle; Eisenhardt, Peter; Stern, Daniel; Assef, Roberto

    2012-10-01

    We propose a 12-hour 2.3 GHz continuum Long Baseline Array (LBA) observation of WISE J2332-5056, a newly discovered supermassive black hole (SMBH) merger candidate that is located in the nearby universe (z = 0.3447). Our recently acquired 9 GHz ATCA map shows unusual radio morphology: a one-sided, smaller (and likely younger) FR-I jet perpendicular to a larger, Doppler-boosted FR-II jet. Follow-up Gemini-S/GMOS spectroscopy of this WISE-selected radio galaxy reveals broad emission lines blue-shifted by > 3,500 km/s with respect to the narrow lines and host galaxy, hallmarks of a dual AGN system. Combined, the optical spectroscopy and radio morphology of this object are strongly suggestive of a black hole merger system. Even in the local universe these systems are extremely difficult to identify; yet the process of supermassive blackhole growth is vital toward understanding galaxy evolution from the early to the current universe. Moreover, nearby merging SMBHs may serve as outstanding targets for gravitational wave studies. The proposed high resolution LBA map, reaching 50 pc resolution at the source redshift will allow us to investigate the SMBH merger scenario hypothesis.

  20. High-Resolution Observations of a Binary Black Hole Candidate

    NASA Astrophysics Data System (ADS)

    Tsai, Chao-Wei; Phillips, Chris; Norris, Ray; Jarrett, Thomas; Bietenholz, Michael; Emonts, Bjorn; Cluver, Michelle; Oozeer, Nadeem; de Witt, Aletha; Stern, Daniel; Assef, Roberto

    2013-10-01

    We propose a 12-hour 2.3 GHz continuum Long Baseline Array (LBA) observation of WISE J2332-5056, a newly discovered supermassive black hole (SMBH) merger candidate (z = 0.3447). Our recently acquired 9 GHz ATCA map shows unusual radio morphology: a one-sided, smaller (and likely younger) FR-I jet perpendicular to a larger, Doppler-boosted FR-II jet. Follow-up Gemini-S/GMOS spectroscopy of this WISE-selected radio galaxy reveals broad emission lines blue-shifted by > 3,500 km/s with respect to the narrow lines and host galaxy, hallmarks of a dual AGN system. Combined, the optical spectroscopy and radio morphology of this object are strongly suggestive of a black hole merger system. Even in the local universe these systems are extremely difficult to identify; yet understanding the process of supermassive black hole growth is vital for understanding galaxy evolution from the early to the current universe. Moreover, nearby merging SMBHs may serve as outstanding targets for gravitational wave studies. The proposed high resolution LBA map, reaching 50 pc resolution at the source redshift, will allow us to investigate the SMBH merger scenario hypothesis.

  1. SINGLE-LINED SPECTROSCOPIC BINARY STAR CANDIDATES IN THE RAVE SURVEY

    SciTech Connect

    Matijevic, G.; Zwitter, T.; Bienayme, O.; Siebert, A.; Watson, F. G.; Bland-Hawthorn, J.; Parker, Q. A.; Freeman, K. C.; Gilmore, G.; Grebel, E. K.; Helmi, A.; Munari, U.; Siviero, A.; Navarro, J. F.; Reid, W.; Seabroke, G. M.; Steinmetz, M.; Williams, M.; Wyse, R. F. G.

    2011-06-15

    Repeated spectroscopic observations of stars in the RAdial Velocity Experiment (RAVE) database are used to identify and examine single-lined binary (SB1) candidates. The RAVE latest internal database (VDR3) includes radial velocities, atmospheric parameters, and other parameters for approximately a quarter of a million different stars with slightly less than 300,000 observations. In the sample of {approx}20,000 stars observed more than once, 1333 stars with variable radial velocities were identified. Most of them are believed to be SB1 candidates. The fraction of SB1 candidates among stars with several observations is between 10% and 15% which is the lower limit for binarity among RAVE stars. Due to the distribution of time spans between the re-observation that is biased toward relatively short timescales (days to weeks), the periods of the identified SB1 candidates are most likely in the same range. Because of the RAVE's narrow magnitude range most of the dwarf candidates belong to the thin Galactic disk while the giants are part of the thick disk with distances extending to up to a few kpc. The comparison of the list of SB1 candidates to the VSX catalog of variable stars yielded several pulsating variables among the giant population with radial velocity variations of up to few tens of km s{sup -1}. There are 26 matches between the catalog of spectroscopic binary orbits (S{sub B}{sup 9}) and the whole RAVE sample for which the given periastron time and the time of RAVE observation were close enough to yield a reliable comparison. RAVE measurements of radial velocities of known spectroscopic binaries are consistent with their published radial velocity curves.

  2. Single-lined Spectroscopic Binary Star Candidates in the RAVE Survey

    NASA Astrophysics Data System (ADS)

    Matijevič, G.; Zwitter, T.; Bienaymé, O.; Bland-Hawthorn, J.; Freeman, K. C.; Gilmore, G.; Grebel, E. K.; Helmi, A.; Munari, U.; Navarro, J. F.; Parker, Q. A.; Reid, W.; Seabroke, G. M.; Siebert, A.; Siviero, A.; Steinmetz, M.; Watson, F. G.; Williams, M.; Wyse, R. F. G.

    2011-06-01

    Repeated spectroscopic observations of stars in the RAdial Velocity Experiment (RAVE) database are used to identify and examine single-lined binary (SB1) candidates. The RAVE latest internal database (VDR3) includes radial velocities, atmospheric parameters, and other parameters for approximately a quarter of a million different stars with slightly less than 300,000 observations. In the sample of ~20,000 stars observed more than once, 1333 stars with variable radial velocities were identified. Most of them are believed to be SB1 candidates. The fraction of SB1 candidates among stars with several observations is between 10% and 15% which is the lower limit for binarity among RAVE stars. Due to the distribution of time spans between the re-observation that is biased toward relatively short timescales (days to weeks), the periods of the identified SB1 candidates are most likely in the same range. Because of the RAVE's narrow magnitude range most of the dwarf candidates belong to the thin Galactic disk while the giants are part of the thick disk with distances extending to up to a few kpc. The comparison of the list of SB1 candidates to the VSX catalog of variable stars yielded several pulsating variables among the giant population with radial velocity variations of up to few tens of km s-1. There are 26 matches between the catalog of spectroscopic binary orbits (S_{B^9}) and the whole RAVE sample for which the given periastron time and the time of RAVE observation were close enough to yield a reliable comparison. RAVE measurements of radial velocities of known spectroscopic binaries are consistent with their published radial velocity curves.

  3. Exact Scale Invariance in Mixing of Binary Candidates in Voting Model

    NASA Astrophysics Data System (ADS)

    Mori, Shintaro; Hisakado, Masato

    2010-03-01

    We introduce a voting model and discuss the scale invariance in the mixing of candidates. The Candidates are classified into two categories μ\\in \\{0,1\\} and are called as “binary” candidates. There are in total N=N0+N1 candidates, and voters vote for them one by one. The probability that a candidate gets a vote is proportional to the number of votes. The initial number of votes (“seed”) of a candidate μ is set to be sμ. After infinite counts of voting, the probability function of the share of votes of the candidate μ obeys gamma distributions with the shape exponent sμ in the thermodynamic limit Z0=N1s1+N0s0\\to ∞. Between the cumulative functions \\{xμ\\} of binary candidates, the power-law relation 1-x1 ˜ (1-x0)α with the critical exponent α=s1/s0 holds in the region 1-x0,1-x1≪ 1. In the double scaling limit (s1,s0)\\to (0,0) and Z0 \\to ∞ with s1/s0=α fixed, the relation 1-x1=(1-x0)α holds exactly over the entire range 0≤ x0,x1 ≤ 1. We study the data on horse races obtained from the Japan Racing Association for the period 1986 to 2006 and confirm scale invariance.

  4. 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

  5. SpeX spectroscopy of unresolved very low mass binaries. II. Identification of 14 candidate binaries with late-M/early-L and T dwarf components

    SciTech Connect

    Bardalez Gagliuffi, Daniella C.; Burgasser, Adam J.; Nicholls, Christine P.; Gelino, Christopher R.; Looper, Dagny L.; Schmidt, Sarah J.; Cruz, Kelle; West, Andrew A.; Gizis, John E.; Metchev, Stanimir

    2014-10-20

    Multiplicity is a key statistic for understanding the formation of very low mass (VLM) stars and brown dwarfs. Currently, the separation distribution of VLM binaries remains poorly constrained at small separations (≤1 AU), leading to uncertainty in the overall binary fraction. We approach this problem by searching for late-M/early-L plus T dwarf spectral binaries whose combined light spectra exhibit distinct peculiarities, allowing for separation-independent identification. We define a set of spectral indices designed to identify these systems, and we use a spectral template fitting method to confirm and characterize spectral binary candidates from a library of 815 spectra from the SpeX Prism Spectral Libraries. We present 11 new binary candidates, confirm 3 previously reported candidates, and rule out 2 previously identified candidates, all with primary and secondary spectral types in the range M7-L7 and T1-T8, respectively. We find that subdwarfs and blue L dwarfs are the primary contaminants in our sample and propose a method for segregating these sources. If confirmed by follow-up observations, these systems may add to the growing list of tight separation binaries, whose orbital properties may yield further insight into brown dwarf formation scenarios.

  6. 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.

  7. The First Proto-Brown Dwarf Binary Candidate Identified through Dynamics of Jets

    NASA Astrophysics Data System (ADS)

    Hsieh, Tien-Hao; Lai, Shih-Ping; Belloche, Arnaud; Wyrowski, Friedrich

    The formation mechanism of brown dwarfs (BDs) is one of the long-standing problems in star formation because the typical Jeans mass in molecular clouds is too large to form these substellar objects. To answer this question, it is crucial to study a BD at the embedded phase (proto-brown dwarf). IRAS16253 is classified as a Very Low Luminosity Object (VeLLO, L int < 0.1L ⊙), which is considered as a proto-brown dwarf candidate. We use the IRAM 30m, APEX telescopes and the SMA to probe the molecular jet/outflow driven by IRAS 16253 in CO (2-1), (6-5), and (7-6) and study its dynamical features and physical properties. We detect a wiggling pattern in the position-velocity diagrams of the jets. Assuming that this pattern is due to the orbital motion of a binary system, we obtain the current mass of the binary is ~0.026 M ⊙. Together with the low parent core mass, IRAS16253 will likely form one or two proto-BD in the future. This is the first time that the current mass of a proto-BD binary system is identified through the dynamics of the jets. Since IRAS16253 is located in an isolated environment, we suggest that BDs can form through fragmentation and collapse like low mass stars.

  8. A candidate sub-parsec binary black hole in the Seyfert galaxy NGC 7674

    NASA Astrophysics Data System (ADS)

    Kharb, P.; Lal, D. V.; Merritt, D.

    2017-10-01

    The existence of binary supermassive black holes (SBHs) is predicted by models of hierarchical galaxy formation. To date, only a single binary SBH has been imaged, at a projected separation of 7.3 pc. Here, we report the detection of a candidate dual SBH with projected separation of 0.35 pc in the gas-rich interacting spiral galaxy NGC 7674 (Mrk 533). This peculiar Seyfert galaxy possesses a roughly 0.7 kpc Z-shaped radio jet. The leading model for the formation of such sources postulates the presence of an uncoalesced binary SBH created during the infall of a satellite galaxy. Using very long baseline interferometry, we imaged the central region of Mrk 533 at radio frequencies of 2, 5, 8 and 15 GHz. Two, possibly inverted-spectrum, radio cores were detected at 15 GHz only. The 8-15 GHz spectral indices of the two cores were ≥-0.33 and ≥-0.38 (±30%), consistent with accreting SBHs. We derived a jet speed of around 0.28c from multi-epoch parsec-scale data of the hotspot region and a source age of ≥ 8.2 × 103 years.

  9. NuSTAR observations of black hole binary candidates in the Galactic Center and its environs

    NASA Astrophysics Data System (ADS)

    Hailey, Charles James; Mori, Kaya

    2017-08-01

    The recent discovery of a diffuse, hard X-ray emission in the central 10 pc (Perez et al. 2015) interpreted as magnetic cataclysmic variables (Hailey et al. 2017) leaves open the question of whether a sub-dominant population of sources could exist much closer to the supermassive black hole (SMBH), which NuSTAR could not resolve. Here we report the recent NuSTAR observations of two new transient hard X-ray sources within ~ 1 pc of the Galactic Center, which were discovered by Swift. These sources have no known counterparts at other energies. The spectral properties of these sources rule out NS-HMXBs. Continuous monitoring of the Galactic Center by Swift, combined with the known short (<~ 5 year) recurrence time of neutron star LMXBs, strongly suggest that these new transients are black hole binary candidates (BHC). We will present 3-79 keV NuSTAR spectra of these sources that further support a black hole binary interpretation. These new BHCs, combined with at least one other previously discovered BHC near the Galactic Center, hint at a potential substantive black hole population in the vicinity of the SMBH, and we present an estimate of their numbers, given knowledge of the black hole binary giant outburst recurrence times. We also report recent results from the NuSTAR Galactic Legacy Survey of a larger region, ~ 0.7 square degrees, focusing on the search for more BHCs.

  10. A candidate sub-parsec binary black hole in the Seyfert galaxy NGC 7674

    NASA Astrophysics Data System (ADS)

    Kharb, P.; Lal, D. V.; Merritt, D.

    2017-09-01

    The existence of binary supermassive black holes (SBHs) is predicted by models of hierarchical galaxy formation. To date, only a single binary SBH has been imaged, at a projected separation of 7.3 pc. Here, we report the detection of a candidate dual SBH with projected separation of 0.35 pc in the gas-rich interacting spiral galaxy NGC 7674 (Mrk 533). This peculiar Seyfert galaxy possesses a roughly 0.7 kpc Z-shaped radio jet. The leading model for the formation of such sources postulates the presence of an uncoalesced binary SBH created during the infall of a satellite galaxy. Using very long baseline interferometry, we imaged the central region of Mrk 533 at radio frequencies of 2, 5, 8 and 15 GHz. Two, possibly inverted-spectrum, radio cores were detected at 15 GHz only. The 8-15 GHz spectral indices of the two cores were ≥-0.33 and ≥-0.38 (±30%), consistent with accreting SBHs. We derived a jet speed of around 0.28c from multi-epoch parsec-scale data of the hotspot region and a source age of ≥ 8.2 × 103 years.

  11. Giant Planet Candidates, Brown Dwarfs, and Binaries from the SDSS-III MARVELS Planet Survey.

    NASA Astrophysics Data System (ADS)

    Thomas, Neil; Ge, Jian; Li, Rui; de Lee, Nathan M.; Heslar, Michael; Ma, Bo; SDSS-Iii Marvels Team

    2015-01-01

    We report the discoveries of giant planet candidates, brown dwarfs, and binaries from the SDSS-III MARVELS survey. The finalized 1D pipeline has provided 18 giant planet candidates, 16 brown dwarfs, and over 500 binaries. An additional 96 targets having RV variability indicative of a giant planet companion are also reported for future investigation. These candidates are found using the advanced MARVELS 1D data pipeline developed at UF from scratch over the past three years. This pipeline carefully corrects most of the instrument effects (such as trace, slant, distortion, drifts and dispersion) and observation condition effects (such as illumination profile, fiber degradation, and tracking variations). The result is long-term RV precisions that approach the photon limits in many cases for the ~89,000 individual stellar observations. A 2D version of the pipeline that uses interferometric information is nearing completion and is demonstrating a reduction of errors to half the current levels. The 2D processing will be used to increase the robustness of the detections presented here and to find new candidates in RV regions not confidently detectable with the 1D pipeline. The MARVELS survey has produced the largest homogeneous RV measurements of 3300 V=7.6-12 FGK stars with a well defined cadence of 27 RV measurements over 2 years. The MARVELS RV data and other follow-up data (photometry, high contrast imaging, high resolution spectroscopy and RV measurements) will explore the diversity of giant planet companion formation and evolution around stars with a broad range in metallicity (Fe/H -1.5-0.5), mass ( 0.6-2.5M(sun)), and environment (thin disk and thick disk), and will help to address the key scientific questions identified for the MARVELS survey including, but not limited to: Do metal poor stars obey the same trends for planet occurrence as metal rich stars? What is the distribution of giant planets around intermediate-mass stars and binaries? Is the 'planet desert

  12. High-ionization accretion signatures in compact binary candidates from SOAR Telescope observations

    NASA Astrophysics Data System (ADS)

    Oliveira, A. S.; Rodrigues, C. V.; Cieslinski, D.; Jablonski, F.; Silva, K. M. G.; Almeida, L. A.

    2014-10-01

    The increasing number of synoptic surveys made by small robotic telescopes, like the photometric Catalina Real-Time Transient Survey (CRTS - Drake et al., 2009, ApJ, 696, 870), represents a unique opportunity for the discovery of new variable objects and also to improve the samples of many classes of variables. Our goal in this work was the discovery of new polars, a subclass of magnetic Cataclysmic Variables (mCVs) with no accretion disk, and Close Binary Supersoft X-ray Sources (CBSS), strong candidates to Type Ia Supernova progenitors. Both are rare objects and probe interesting accretion scenarios. Finding spectral features associated to high-ionization mass accretion constrains the CBSS or magnetic CV nature for the candidates, expanding the hitherto small samples of these classes (specially CBSS) and allowing for detailed observational follow-up. We used the Goodman Spectrograph on SOAR 4.1 m Telescope to search for signatures of high-ionization mass accretion, as He II 468,6 nm emission line and inverted Balmer decrement, on 39 variable objects selected mostly from CRTS. In this sample we found 14 strong candidates to mCVs, 1 Nova in the final stages of eruption, 14 candidates to Dwarf Novae, 5 extragalactic sources (AGN), 1 object previously identified as a Black Hole Nova, 3 objects with pure absorption spectral features and 1 unidentified object with low S/N ratio. The mCVs candidates found in this work will be studied using time-resolved spectroscopic, polarimetric, and photometric observations in a follow-up project.

  13. SpeX SPECTROSCOPY OF UNRESOLVED VERY LOW MASS BINARIES. I. IDENTIFICATION OF 17 CANDIDATE BINARIES STRADDLING THE L DWARF/T DWARF TRANSITION

    SciTech Connect

    Burgasser, Adam J.; Cruz, Kelle L.; Cushing, Michael; Looper, Dagny L.; Gelino, Christopher R.; Kirkpatrick, J. Davy; Faherty, Jacqueline K.; Reid, I. Neill

    2010-02-20

    We report the identification of 17 candidate brown dwarf binaries whose components straddle the L dwarf/T dwarf transition. These sources were culled from a large near-infrared spectral sample of L and T dwarfs observed with the Infrared Telescope Facility SpeX spectrograph. Candidates were selected on the basis of spectral ratios which segregate known (resolved) L dwarf/T dwarf pairs from presumably single sources. Composite templates, constructed by combining 13,581 pairs of absolute flux-calibrated spectra, are shown to provide statistically superior fits to the spectra of our 17 candidates as compared to single templates. Ten of these candidates appear to have secondary components that are significantly brighter than their primaries over the 1.0-1.3 {mu}m band, indicative of rapid condensate depletion at the L dwarf/T dwarf transition. Our results support prior indications of enhanced multiplicity amongst early-type T dwarfs; 53% +- 7% of the T0-T4 dwarfs in our spectral sample are found to be either resolved or unresolved (candidate) pairs, although this is consistent with an intrinsic (volume complete) brown dwarf binary fraction of only 15%. If verified, this sample of spectral binaries more than doubles the number of known L dwarf/T dwarf transition pairs, enabling a broader exploration of this poorly understood phase of brown dwarf atmospheric evolution.

  14. Fermi variability study of the candidate pulsar binary 2FGL J0523.3–2530

    SciTech Connect

    Xing, Yi; Wang, Zhongxiang; Ng, C.-Y.

    2014-11-01

    The Fermi source 2FGL J0523.3–2530 has recently been identified as a candidate millisecond pulsar binary with an orbital period of 16.5 hr. We have carried out detailed studies of the source's emission properties by analyzing data taken with the Fermi Large Area Telescope in the 0.2-300 GeV energy range. Long-term, yearly variability from the source has been found, with a factor of four flux variations in 1-300 GeV. From spectral analysis, we find an extra spectral component at 2-3 GeV that causes the source brightening. While no orbital modulations have been found from the Fermi data over the whole period of 2008-2014, orbital modulation in the source's >2 GeV emission is detected during the last 1.5 yr of the Fermi observation. Our results support the millisecond pulsar binary nature of 2FGL J0523.3–2530. Multi-wavelength observations of the source are warranted in order to find any correlated flux variations and thus help determine the origin of the long-term variability, which currently is not understood.

  15. Hogg 12 and NGC 3590: A New Open Cluster Binary System Candidate

    NASA Astrophysics Data System (ADS)

    Piatti, Andrés E.; Clariá, Juan J.; Ahumada, Andrea V.

    2010-05-01

    We have obtained CCD UBVIKC photometry down to V ∼ 22.0 for the open clusters Hogg 12 and NGC 3590 and the fields surrounding them. Based on photometric and morphological criteria, as well as on the stellar density in the region, our evidence is sufficient to confirm that Hogg 12 is a genuine open cluster. NGC 3590 was used as a control cluster. The color-magnitude diagrams of Hogg 12, cleaned from field star contamination, reveal that this is a solar metal content cluster, affected by E(B - V) = 0.40 ± 0.05, located at a heliocentric distance d = 2.0 ± 0.5 kpc, and of an age similar to that of NGC 3590 (t = 30 Myr). Both clusters are surprisingly small objects whose radii are barely ∼1 pc, andthey are separated in the sky by scarcely 3.6 pc. These facts, added to their similar ages, reddenings, and metallicities, allow us to consider them a new open cluster binary system candidate. Of the ∼180 open cluster binary systems estimated to exist in the Galaxy, of which 27 are actually well known, Hogg 12 and NGC 3590 appear to be one of the two closest pairs.

  16. Analysis on TeV Gamma-ray Binary Systems and Candidates in the Northern Hemisphere with HAWC

    NASA Astrophysics Data System (ADS)

    Rho, Chang Dong; HAWC Collaboration

    2017-01-01

    Binary systems, which emit high-energy radiation, are natural testbeds for studying astrophysical particle acceleration and the production of Galactic cosmic rays. The emitted radiation may be modulated in time by the orbital period of the system, or may occur in very strong and unpredictable flares. However, while hundreds of binary systems have been observed in X-rays and radio, only a handful has been detected through TeV gamma rays. The High Altitude Water Cherenkov (HAWC) Observatory is a wide-field and high-uptime detector of TeV gamma rays that is particularly well suited to observe transient systems such as TeV binaries. Preliminary measurements of the 3 known TeV binary systems and 28 TeV binary candidates in the Northern Hemisphere were analyzed with HAWC at > 1 TeV using 17 months of data. HAWC does not decisively observe any significant traces of the 31 systems / candidates yet. However, 95% upper limits were successfully assembled for the candidates with significance below 2 sigma.

  17. 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.

  18. A Candidate Binary Black Hole System at z=1.175

    NASA Astrophysics Data System (ADS)

    Barrows, Robert S.; Stern, D.; Madsen, K. K.; Harrison, F. A.; Cushing, M. C.; Fassnacht, C. D.; Griffith, R. L.; Gonzalez, A. H.; Kirkpatrick, J. D.; Lagattuta, D. J.

    2011-01-01

    We discuss properties of the X-ray source CXOXBJ142607.6+353351 (CXOJ1426+35) which shows double rest-frame optical/UV emission lines, separated spatially by 0.68 arcseconds and in velocity-space by 700 km/s. Emission line ratios in both systems indicate ionization by an AGN continuum, and the double-peaked profile resembles the optical spectrum of many candidate binary AGN. However, other physical processes involving complex gas kinematics may produce the double peaks. To better understand the source, we have also acquired near infrared (NIR) adaptive optics (AO) imaging and NIR slit spectroscopy and have analyzed available archival data. The AO image reveals only a single nucleus, implying that either there is only a single AGN present, or the second AGN is highly obscured. Interestingly, significant obscuration is consistent with the high level of extinction inferred from the X-ray data. CXOJ1426+35 may also represent the case of two narrow line regions (NLRs) present as the result of a recent merger, with each illuminated by a single AGN, or NLR clouds driven by an outflow from an accretion disk. Furthermore, that the source is radio-quiet argues strongly against any sort of jet-cloud interaction. Developing a clear understanding of the physical process producing the complex emission line profiles seen in CXOJ1426+35 and other sources is important to both the search for dual/binary SMBHs and the study of quasar/AGN emission line regions.

  19. 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

  20. Search for binary asteroids using Lick, Keck and VLT Adaptive Optics systems: new candidates, orbits and dynamical models

    NASA Astrophysics Data System (ADS)

    Marchis, F.; Berthier, J.; Descamps, P.; Hestroffer, D.; de Pater, I.; Vachier, F.; Conrad, A.; Le Mignant, D.; Chaffee, F.; Roos-Serote, M.

    2003-04-01

    Our group started a search program for binary asteroids in 2000, using Adaptive Optics systems on the Lick-3m, Keck-10m, and VLT-8m telescopes. Several techniques such as appulse observations (see http://astron.berkeley.edu/˜fmarchis/Science/TNOs_Appulse/), Laser Guide Star observations and direct imaging were used to observe more than 80 main-belt asteroids, 14 Trojans and 4 trans-neptunian objects. Among them we have identified as binary objects, four main-belt asteroids (22,87,90,121), one TNO (1996 TC36). A search amongst Trojan asteroids did not result in any candidates. Additional main-belts candidates may be confirmed in the following weeks. We will derive limits on the fraction of binary systems from our data. For some binary asteroids, such as 22 Kalliope, our observations span enough time to permit the determination of accurate orbital elements. We will present a dynamical model for the companion orbit of 22 Kalliope, which gives direct information on the internal structure of Kalliope itself.

  1. The search for isolated BH candidates based on kinematics of pulsars - their former companions in disrupted binaries

    NASA Astrophysics Data System (ADS)

    Chmyreva, E.; Beskin, G.; Dyachenko, V.; Karpov, S.

    We propose searching for isolated stellar-mass black hole (BH) candidates based on the fact that more than 50% of radio pulsars have originated in binary systems, where the other component could have evolved into a BH prior to the second supernova event of the system, which caused its disruption. We selected isolated, relatively young radio pulsars with known parallaxes and proper motions and traced their trajectories back to their presumed birth locations. These locations were then analyzed for possible BH candidates based on the available positional, photometric, and spectral data. We present the first results for 2 pulsars, J0139+5814 and J0922+0638. Seven BH candidates were selected for further analysis.

  2. KEPLER OBSERVATIONS OF THREE PRE-LAUNCH EXOPLANET CANDIDATES: DISCOVERY OF TWO ECLIPSING BINARIES AND A NEW EXOPLANET

    SciTech Connect

    Howell, Steve B.; Rowe, Jason F.; Bryson, Stephen T.; Sherry, William; Von Braun, Kaspar; Ciardi, David R.; Feldmeier, John J.; Horch, Elliott; Van Belle, Gerard T.

    2010-12-20

    Three transiting exoplanet candidate stars were discovered in a ground-based photometric survey prior to the launch of NASA's Kepler mission. Kepler observations of them were obtained during Quarter 1 of the Kepler mission. All three stars are faint by radial velocity follow-up standards, so we have examined these candidates with regard to eliminating false positives and providing high confidence exoplanet selection. We present a first attempt to exclude false positives for this set of faint stars without high-resolution radial velocity analysis. This method of exoplanet confirmation will form a large part of the Kepler mission follow-up for Jupiter-sized exoplanet candidates orbiting faint stars. Using the Kepler light curves and pixel data, as well as medium-resolution reconnaissance spectroscopy and speckle imaging, we find that two of our candidates are binary stars. One consists of a late-F star with an early M companion, while the other is a K0 star plus a late M-dwarf/brown dwarf in a 19 day elliptical orbit. The third candidate (BOKS-1) is an r = 15 G8V star hosting a newly discovered exoplanet with a radius of 1.12 R{sub Jupiter} in a 3.9 day orbit.

  3. Relativistic boost as the cause of periodicity in a massive black-hole binary candidate.

    PubMed

    D'Orazio, Daniel J; Haiman, Zoltán; Schiminovich, David

    2015-09-17

    Because most large galaxies contain a central black hole, and galaxies often merge, black-hole binaries are expected to be common in galactic nuclei. Although they cannot be imaged, periodicities in the light curves of quasars have been interpreted as evidence for binaries, most recently in PG 1302-102, which has a short rest-frame optical period of four years (ref. 6). If the orbital period of the black-hole binary matches this value, then for the range of estimated black-hole masses, the components would be separated by 0.007-0.017 parsecs, implying relativistic orbital speeds. There has been much debate over whether black-hole orbits could be smaller than one parsec (ref. 7). Here we report that the amplitude and the sinusoid-like shape of the variability of the light curve of PG 1302-102 can be fitted by relativistic Doppler boosting of emission from a compact, steadily accreting, unequal-mass binary. We predict that brightness variations in the ultraviolet light curve track those in the optical, but with a two to three times larger amplitude. This prediction is relatively insensitive to the details of the emission process, and is consistent with archival ultraviolet data. Follow-up ultraviolet and optical observations in the next few years can further test this prediction and confirm the existence of a binary black hole in the relativistic regime.

  4. A reduced orbital period for the supermassive black hole binary candidate in the quasar PG 1302-102?

    NASA Astrophysics Data System (ADS)

    D'Orazio, D. J.; Haiman, Z.; Duffell, P.; Farris, B. D.; MacFadyen, A. I.

    2015-09-01

    Graham et al. have detected a 5.2 yr periodic optical variability of the quasar PG 1302-102 at redshift z = 0.3, which they interpret as the redshifted orbital period (1 + z)tbin of a putative supermassive black hole binary (SMBHB). Here, we consider the implications of a 3-8 times shorter orbital period, suggested by hydrodynamical simulations of circumbinary discs (CBDs) with nearly equal-mass SMBHBs (q ≡ M2/M1 ≳ 0.3). With the corresponding 2-4 times tighter binary separation, PG 1302 would be undergoing gravitational wave dominated inspiral, and serve as a proof that the BHs can be fuelled and produce bright emission even in this late stage of the merger. The expected fraction of binaries with the shorter tbin, among bright quasars, would be reduced by one to two orders of magnitude, compared to the 5.2 yr period, in better agreement with the rarity of candidates reported by Graham et al. Finally, shorter periods would imply higher binary speeds, possibly imprinting periodicity on the light curves from relativistic beaming, as well as measurable relativistic effects on the Fe K α line. The CBD model predicts additional periodic variability on time-scales of tbin and ≈0.5tbin, as well as periodic variation of broad line widths and offsets relative to the narrow lines, which are consistent with the observations. Future observations will be able to test these predictions and hence the binary+CBD hypothesis for PG 1302.

  5. A search for binary candidates among the fundamental mode RR Lyrae stars observed by Kepler

    NASA Astrophysics Data System (ADS)

    Guggenberger, Elisabeth; Steixner, Jakob

    2015-09-01

    Although roughly half of all stars are considered to be part of binary or multiple systems, there are only two confirmed cases of RR Lyrae pulsators with companions. One of them is TU Uma [1] - a classical RR Lyrae star in a very eccentric orbit - and the other is OGLE-BLG-RRLYR-02792 [2]. Considering the wealth of well-studied RR Lyrae stars, this number is astoundingly low. Having more RR Lyrae stars in binary systems at hand would be extremely valuable to get independent measurements of the masses. The data from the Kepler mission with their unprecedented precision and the long time span of about four years offer a unique possibility to systematically search for the signatures of binarity in RR Lyrae stars. Using the pulsation as a clock, we studied the variations in the timing of maximum light to hunt for possible binary systems in the sample.

  6. THE PHASES DIFFERENTIAL ASTROMETRY DATA ARCHIVE. V. CANDIDATE SUBSTELLAR COMPANIONS TO BINARY SYSTEMS

    SciTech Connect

    Muterspaugh, Matthew W.; Lane, Benjamin F.; Kulkarni, S. R.; Konacki, Maciej; Burke, Bernard F.; Colavita, M. M.; Shao, M.; Hartkopf, William I.; Boss, Alan P.; Williamson, M. E-mail: blane@draper.co

    2010-12-15

    The Palomar High-precision Astrometric Search for Exoplanet Systems monitored 51 subarcsecond binary systems to evaluate whether tertiary companions as small as Jovian planets orbited either the primary or secondary stars, perturbing their otherwise smooth Keplerian motions. Six binaries are presented that show evidence of substellar companions orbiting either the primary or secondary star. Of these six systems, the likelihoods of two of the detected perturbations to represent real objects are considered to be 'high confidence', while the remaining four systems are less certain and will require continued observations for confirmation.

  7. KIC 2831097 A short orbital-period candidate RR Lyrae binary

    NASA Astrophysics Data System (ADS)

    Sódor, Ádám; Skarka, Marek; Liška, Jir̆í; Bognár, Zsófia

    2017-09-01

    KIC 2831097 was discovered to be a first-overtone RR Lyrae pulsator based on 4-year Kepler photometry (Sódor et al. 2017, MNRAS, 465, L1). The data show strong, 0.1 d amplitude systematic phase variations that can be explained by light travel-time effect caused by an about 2-year period orbital motion in a binary system, superimposed on a linear pulsation-period decrease. To verify the binary hypothesis, several well-timed radial-velocity observations will be sufficient.

  8. 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.

  9. A Cautionary Tale: MARVELS Brown Dwarf Candidate Reveals Itself to be a Very Long Period, Highly Eccentric Spectroscopic Stellar Binary

    NASA Astrophysics Data System (ADS)

    Mack, Claude E., III; Ge, Jian; Deshpande, Rohit; Wisniewski, John P.; Stassun, Keivan G.; Gaudi, B. Scott; Fleming, Scott W.; Mahadevan, Suvrath; De Lee, Nathan; Eastman, Jason; Ghezzi, Luan; González Hernández, Jonay I.; Femenía, Bruno; Ferreira, Letícia; Porto de Mello, Gustavo; Crepp, Justin R.; Mata Sánchez, Daniel; Agol, Eric; Beatty, Thomas G.; Bizyaev, Dmitry; Brewington, Howard; Cargile, Phillip A.; da Costa, Luiz N.; Esposito, Massimiliano; Ebelke, Garret; Hebb, Leslie; Jiang, Peng; Kane, Stephen R.; Lee, Brian; Maia, Marcio A. G.; Malanushenko, Elena; Malanushenko, Victor; Oravetz, Daniel; Paegert, Martin; Pan, Kaike; Allende Prieto, Carlos; Pepper, Joshua; Rebolo, Rafael; Roy, Arpita; Santiago, Basílio X.; Schneider, Donald P.; Simmons, Audrey; Siverd, Robert J.; Snedden, Stephanie; Tofflemire, Benjamin M.

    2013-05-01

    We report the discovery of a highly eccentric, double-lined spectroscopic binary star system (TYC 3010-1494-1), comprising two solar-type stars that we had initially identified as a single star with a brown dwarf companion. At the moderate resolving power of the MARVELS spectrograph and the spectrographs used for subsequent radial-velocity (RV) measurements (R <~ 30, 000), this particular stellar binary mimics a single-lined binary with an RV signal that would be induced by a brown dwarf companion (Msin i ~ 50 M Jup) to a solar-type primary. At least three properties of this system allow it to masquerade as a single star with a very-low-mass companion: its large eccentricity (e ~ 0.8), its relatively long period (P ~ 238 days), and the approximately perpendicular orientation of the semi-major axis with respect to the line of sight (ω ~ 189°). As a result of these properties, for ~95% of the orbit the two sets of stellar spectral lines are completely blended, and the RV measurements based on centroiding on the apparently single-lined spectrum is very well fit by an orbit solution indicative of a brown dwarf companion on a more circular orbit (e ~ 0.3). Only during the ~5% of the orbit near periastron passage does the true, double-lined nature and large RV amplitude of ~15 km s-1 reveal itself. The discovery of this binary system is an important lesson for RV surveys searching for substellar companions; at a given resolution and observing cadence, a survey will be susceptible to these kinds of astrophysical false positives for a range of orbital parameters. Finally, for surveys like MARVELS that lack the resolution for a useful line bisector analysis, it is imperative to monitor the peak of the cross-correlation function for suspicious changes in width or shape, so that such false positives can be flagged during the candidate vetting process.

  10. Recurring flares from supermassive black hole binaries: implications for tidal disruption candidates and OJ 287

    NASA Astrophysics Data System (ADS)

    Tanaka, Takamitsu L.

    2013-09-01

    I discuss the possibility that accreting supermassive black hole (SMBH) binaries with sub-parsec separations produce periodically recurring luminous outbursts that interrupt periods of relative quiescence. This hypothesis is motivated by two characteristics found generically in simulations of binaries embedded in prograde accretion discs: (i) the formation of a central, low-density cavity around the binary and (ii) the leakage of gas into this cavity, occurring once per orbit via discrete streams on nearly radial trajectories. The first feature would reduce the emergent optical/UV flux of the system relative to active galactic nuclei powered by a single SMBH, while the second can trigger quasi-periodic fluctuations in luminosity. I argue that the quasi-periodic accretion signature may be much more dramatic than previously thought, because the infalling gas streams can strongly shock-heat via self-collision and tidal compression, thereby enhancing viscous accretion. Any optically thick gas that is circularized about either SMBH can accrete before the next pair of streams is deposited, fuelling transient, luminous flares that recur every orbit. Due to the diminished flux in between accretion episodes, such cavity-accretion flares could plausibly be mistaken for the tidal disruptions of stars in quiescent nuclei. The flares could be distinguished from tidal disruption events if their quasi-periodic recurrence is observed, or if they are produced by very massive (≳109 M⊙) SMBHs that cannot disrupt solar-type stars. They may be discovered serendipitously in surveys such as LSST or eROSITA. I present a heuristic toy model as a proof of concept for the production of cavity-accretion flares, and generate mock light curves and spectra. I also apply the model to the active galaxy OJ 287, whose production of quasi-periodic pairs of optical flares has long fuelled speculation that it hosts an SMBH binary.

  11. A population of short-period variable quasars from PTF as supermassive black hole binary candidates

    NASA Astrophysics Data System (ADS)

    Charisi, M.; Bartos, I.; Haiman, Z.; Price-Whelan, A. M.; Graham, M. J.; Bellm, E. C.; Laher, R. R.; Márka, S.

    2016-12-01

    Supermassive black hole binaries (SMBHBs) at sub-parsec separations should be common in galactic nuclei, as a result of frequent galaxy mergers. Hydrodynamical simulations of circum-binary discs predict strong periodic modulation of the mass accretion rate on time-scales comparable to the orbital period of the binary. As a result, SMBHBs may be recognized by the periodic modulation of their brightness. We conducted a statistical search for periodic variability in a sample of 35 383 spectroscopically confirmed quasars in the photometric data base of the Palomar Transient Factory (PTF). We analysed Lomb-Scargle periodograms and assessed the significance of our findings by modelling each individual quasar's variability as a damped random walk (DRW). We identified 50 quasars with significant periodicity beyond the DRW model, typically with short periods of a few hundred days. We find 33 of these to remain significant after a re-analysis of their periodograms including additional optical data from the intermediate-PTF and the Catalina Real-Time Transient Survey. Assuming that the observed periods correspond to the redshifted orbital periods of SMBHBs, we conclude that our findings are consistent with a population of unequal-mass SMBHBs, with a typical mass ratio as low as q ≡ M2/M1 ≈ 0.01.

  12. A CENSUS OF AM CVn STARS: THREE NEW CANDIDATES AND ONE CONFIRMED 48.3-MINUTE BINARY

    SciTech Connect

    Rau, A.; Roelofs, G. H. A.; Steeghs, D.; Groot, P. J.; Nelemans, G.; Marsh, T. R.; Salvato, M.; Kasliwal, M. M.

    2010-01-01

    We present three new candidate AM CVn binaries, and one confirmed new system, from a spectroscopic survey of color-selected objects from the Sloan Digital Sky Survey (SDSS). All four systems were found from their helium emission lines in low-resolution spectra taken on the Hale telescope at Palomar, the Nordic Optical Telescope, and the William Herschel Telescope on La Palma. The ultra-compact binary nature of SDSS J090221.35+381941.9 was confirmed using phase-resolved spectroscopy at the Keck-I telescope. From the characteristic radial velocity 'S-wave' observed in the helium emission lines, we measure an orbital period of 48.31 +- 0.08 minutes. The continuum emission can be described with a blackbody or a helium white dwarf atmosphere of T{sub eff} approx 15,000 K, in agreement with theoretical cooling models for relatively massive accretors and/or donors. The absence in the spectrum of broad helium absorption lines from the accreting white dwarf suggests that the accreting white dwarf cannot be much hotter than 15,000 K, or that an additional component such as the accretion disk contributes substantially to the optical flux. Two of the candidate systems, SDSS J152509.57+360054.5 and SDSS J172102.48+273301.2, do show helium absorption in the blue part of their spectra in addition to the characteristic helium emission lines. This in combination with the high effective temperatures of approx18,000 K and approx16,000 K suggests both to be at orbital periods below approx40 minutes. The third candidate, SDSS J164228.06+193410.0, exhibits remarkably strong helium emission on top of a relatively cool (T{sub eff} approx 12,000 K) continuum, indicating an orbital period above approx50 minutes.

  13. Photometric variability of candidate white dwarf binary systems from Palomar Transient Factory archival data

    NASA Astrophysics Data System (ADS)

    Kao, Wil; Kaplan, David L.; Prince, Thomas A.; Tang, Sumin; Ene, Irina; Kim, Kyu Bin; Levitan, David; Kulkarni, Shrinivas R.; Laher, Russ R.

    2016-09-01

    We present a sample of 59 periodic variables from the Palomar Transient Factory, selected from published catalogues of white dwarf (WD) candidates. The variability can likely be attributed to ellipsoidal variation of the tidally distorted companion induced by the gravity of the primary (WD or hot subdwarf) or to the reflection of hot emission by a cooler companion. We searched 11 311 spectroscopically or photometrically selected WD candidates from three hot star/WD catalogues, using the Lomb-Scargle periodogram to single out promising sources. We present period estimates for the candidates, 45 of which were not previously identified as periodic variables, and find that most have a period shorter than a few days. Additionally, we discuss the eclipsing systems in our sample and present spectroscopic data on selected sources.

  14. The ultracompact nature of the black hole candidate X-ray binary 47 Tuc X9

    NASA Astrophysics Data System (ADS)

    Bahramian, Arash; Heinke, Craig O.; Tudor, Vlad; Miller-Jones, James C. A.; Bogdanov, Slavko; Maccarone, Thomas J.; Knigge, Christian; Sivakoff, Gregory R.; Chomiuk, Laura; Strader, Jay; Garcia, Javier A.; Kallman, Timothy

    2017-05-01

    47 Tuc X9 is a low-mass X-ray binary (LMXB) in the globular cluster 47 Tucanae, and was previously thought to be a cataclysmic variable. However, Miller-Jones et al. recently identified a radio counterpart to X9 (inferring a radio/X-ray luminosity ratio consistent with black hole LMXBs), and suggested that the donor star might be a white dwarf. We report simultaneous observations of X9 performed by Chandra, NuSTAR and Australia Telescope Compact Array. We find a clear 28.18 ± 0.02-min periodic modulation in the Chandra data, which we identify as the orbital period, confirming this system as an ultracompact X-ray binary. Our X-ray spectral fitting provides evidence for photoionized gas having a high oxygen abundance in this system, which indicates a C/O white dwarf donor. We also identify reflection features in the hard X-ray spectrum, making X9 the faintest LMXB to show X-ray reflection. We detect an ˜6.8-d modulation in the X-ray brightness by a factor of 10, in archival Chandra, Swiftand ROSAT data. The simultaneous radio/X-ray flux ratio is consistent with either a black hole primary or a neutron star primary, if the neutron star is a transitional millisecond pulsar. Considering the measured orbital period (with other evidence of a white dwarf donor), and the lack of transitional millisecond pulsar features in the X-ray light curve, we suggest that this could be the first ultracompact black hole X-ray binary identified in our Galaxy.

  15. Low-mass spectroscopic binaries in the Hyades: a candidate brown dwarf companion

    NASA Astrophysics Data System (ADS)

    Reid, I. Neill; Mahoney, S.

    2000-08-01

    We have used the HIRES echelle spectrograph on the Keck I telescope to obtain high-resolution spectroscopy of 51 late-type M dwarfs in the Hyades cluster. Cross-correlating the calibrated data against spectra of white dwarfs allows us to determine heliocentric velocities with an accuracy of +/-0.3kms-1. 27 stars were observed at two epochs in 1997; two stars, RHy 42 and RHy 403, are confirmed spectroscopic binaries. RHy 42 is a double-lined, equal-mass system; RHy 403 is a single-lined, short-period binary, P~1.275d. RHy 403A has an absolute magnitude of MI=10.85, consistent with a mass of 0.15Msolar. The systemic mass function has a value M2sin(i)]3/(M1+M2)2 =0.0085, which, combined with the non-detection of a secondary peak in the cross-correlation function, implies 0.095>M2>0.07Msolar, and the strong possibility that the companion is the first Hyades brown dwarf to be identified. Unfortunately, the maximum expected angular separation in the system is only ~0.25mas. Five other low-mass Hyads are identified as possible spectroscopic binaries, based either on repeat observations or on a comparison between the observed radial velocity and the value expected for Hyades cluster members. Combined with HST imaging data, we infer a binary fraction between 23 and 30per cent. All of the stars are chromospherically active. RHy 281 was caught in mid-flare and, based on that detection, we estimate a flaring frequency of ~2.5per cent for low-mass Hyades stars. Nine stars have rotational velocities, vsin(i), exceeding 20kms-1, and most of the sample have detectable rotation. We examine the H&alpha emission characteristics of low-mass cluster members, and show that there is no evidence for a correlation with rotation.

  16. A RADIO-SELECTED BLACK HOLE X-RAY BINARY CANDIDATE IN THE MILKY WAY GLOBULAR CLUSTER M62

    SciTech Connect

    Chomiuk, Laura; Ransom, Scott; Strader, Jay; Maccarone, Thomas J.; Miller-Jones, James C. A.; Heinke, Craig; Noyola, Eva; Seth, Anil C.

    2013-11-01

    We report the discovery of a candidate stellar-mass black hole in the Milky Way globular cluster M62. We detected the black hole candidate, which we call M62-VLA1, in the core of the cluster using deep radio continuum imaging from the Karl G. Jansky Very Large Array. M62-VLA1 is a faint source with a flux density of 18.7 ± 1.9 μJy at 6.2 GHz and a flat radio spectrum (α = –0.24 ± 0.42, for S{sub ν} = ν{sup α}). M62 is the second Milky Way cluster with a candidate stellar-mass black hole; unlike the two candidate black holes previously found in the cluster M22, M62-VLA1 is associated with a Chandra X-ray source, supporting its identification as a black hole X-ray binary. Measurements of its radio and X-ray luminosity, while not simultaneous, place M62-VLA1 squarely on the well-established radio-X-ray correlation for stellar-mass black holes. In archival Hubble Space Telescope imaging, M62-VLA1 is coincident with a star near the lower red giant branch. This possible optical counterpart shows a blue excess, Hα emission, and optical variability. The radio, X-ray, and optical properties of M62-VLA1 are very similar to those for V404 Cyg, one of the best-studied quiescent stellar-mass black holes. We cannot yet rule out alternative scenarios for the radio source, such as a flaring neutron star or background galaxy; future observations are necessary to determine whether M62-VLA1 is indeed an accreting stellar-mass black hole.

  17. A CAUTIONARY TALE: MARVELS BROWN DWARF CANDIDATE REVEALS ITSELF TO BE A VERY LONG PERIOD, HIGHLY ECCENTRIC SPECTROSCOPIC STELLAR BINARY

    SciTech Connect

    Mack, Claude E. III; Stassun, Keivan G.; De Lee, Nathan; Ge, Jian; Fleming, Scott W.; Deshpande, Rohit; Mahadevan, Suvrath; Wisniewski, John P.; Gaudi, B. Scott; Eastman, Jason; Beatty, Thomas G.; Ghezzi, Luan; Gonzalez Hernandez, Jonay I.; Femenia, Bruno; Mata Sanchez, Daniel; Ferreira, Leticia; Porto de Mello, Gustavo; Crepp, Justin R.; Agol, Eric; Bizyaev, Dmitry; and others

    2013-05-15

    We report the discovery of a highly eccentric, double-lined spectroscopic binary star system (TYC 3010-1494-1), comprising two solar-type stars that we had initially identified as a single star with a brown dwarf companion. At the moderate resolving power of the MARVELS spectrograph and the spectrographs used for subsequent radial-velocity (RV) measurements (R {approx}< 30, 000), this particular stellar binary mimics a single-lined binary with an RV signal that would be induced by a brown dwarf companion (Msin i {approx} 50 M{sub Jup}) to a solar-type primary. At least three properties of this system allow it to masquerade as a single star with a very-low-mass companion: its large eccentricity (e {approx} 0.8), its relatively long period (P {approx} 238 days), and the approximately perpendicular orientation of the semi-major axis with respect to the line of sight ({omega} {approx} 189 Degree-Sign ). As a result of these properties, for {approx}95% of the orbit the two sets of stellar spectral lines are completely blended, and the RV measurements based on centroiding on the apparently single-lined spectrum is very well fit by an orbit solution indicative of a brown dwarf companion on a more circular orbit (e {approx} 0.3). Only during the {approx}5% of the orbit near periastron passage does the true, double-lined nature and large RV amplitude of {approx}15 km s{sup -1} reveal itself. The discovery of this binary system is an important lesson for RV surveys searching for substellar companions; at a given resolution and observing cadence, a survey will be susceptible to these kinds of astrophysical false positives for a range of orbital parameters. Finally, for surveys like MARVELS that lack the resolution for a useful line bisector analysis, it is imperative to monitor the peak of the cross-correlation function for suspicious changes in width or shape, so that such false positives can be flagged during the candidate vetting process.

  18. DISCOVERY OF AN ULTRACOMPACT GAMMA-RAY MILLISECOND PULSAR BINARY CANDIDATE

    SciTech Connect

    Kong, Albert K. H.; Jin, Ruolan; Yen, T.-C.; Tam, P. H. T.; Lin, L. C. C.; Hu, C.-P.; Hui, C. Y.; Park, S. M.; Takata, J.; Cheng, K. S.; Kim, C. L.

    2014-10-20

    We report multi-wavelength observations of the unidentified Fermi object 2FGL J1653.6-0159. With the help of high-resolution X-ray observations, we have identified an X-ray and optical counterpart to 2FGL J1653.6-0159. The source exhibits a periodic modulation of 75 minutes in the optical and possibly also in the X-ray. We suggest that 2FGL J1653.6-0159 is a compact binary system with an orbital period of 75 minutes. Combining the gamma-ray and X-ray properties, 2FGL J1653.6-0159 is potentially a black-widow-/redback-type gamma-ray millisecond pulsar (MSP). The optical and X-ray light curve profiles show that the companion is mildly heated by the high-energy emission and that the X-rays are from intrabinary shock. Although no radio pulsation has yet been detected, we estimated that the spin period of the MSP is ∼ 2 ms based on a theoretical model. If pulsation can be confirmed in the future, 2FGL J1653.6-0159 will become the first ultracompact rotation-powered MSP.

  19. Infrared observations of low-mass X-ray binaries. I - Candidates for bright bulge sources

    NASA Astrophysics Data System (ADS)

    Naylor, T.; Charles, P. A.; Longmore, A. J.

    1991-09-01

    The first IR imaging of bright Galactic Bulge X-ray source fields is presented. In spite of the extreme crowding in these regions, found plausible candidates are found for the IR counterparts of GX17 + 2, GX13 + 1, and GX5 - 1. The optical/IR colors of the star at the radio position of GX17 + 2 cannot be reconciled with a normal star. It is suggested that there is a normal star superimposed on the IR counterpart of GX17 + 2, and the normal star dominates the optical flux, but GX17 + 2 makes a significant contribution to the combined flux in the IR. Bright IR objects are found within the radio error boxes of GX13 + 1 (K = 11) and GX5 - 1 (K of about 13.5) whose presence in small radio error boxes suggests that they are the IR counterparts of their respective X-ray sources.

  20. VLBA 24 and 43 GHz observations of massive binary black hole candidate PKS 1155 + 251

    NASA Astrophysics Data System (ADS)

    Yang, Xiaolong; Liu, Xiang; Yang, Jun; Mi, Ligong; Cui, Lang; An, Tao; Hong, Xiaoyu; Ho, Luis C.

    2017-10-01

    PKS 1155+251 is a radio-loud quasar source at z = 0.203. Observations using very long baseline interferometry (VLBI) at ∼2, 5, 8 and 15 GHz show that the structure of the radio source is quite complicated on parsec scales and that the outer hotspots are apparently undergoing a significant contraction. Because these results cannot be fully explained based on the compact symmetric object (CSO) scenario with a radio core located between the northern and southern complexes, we made observations with the Very Long Baseline Array (VLBA) at 24 and 43 GHz to search for compact substructures and alternative interpretations. The results show that the radio core revealed in the previous VLBI observations remains compact with a flat spectrum in our sub-milli-arcsecond-resolution images; the northern lobe emission becomes faint at 24 GHz and is mostly resolving out at 43 GHz; the southern complex is more bright but has been resolved into the brightest southern-end (S1) and jet or tail alike components westwards. Explaining the southern components aligned westward with a standard CSO scenario alone remains a challenge. As for the flatter spectral index of the southern-end component S1 between 24 and 43 GHz in our observations and the significant 15 GHz VLBA flux variability of S1, an alternative scenario is that the southern complex may be powered by a secondary black hole residing at S1. But more sensitive and high-resolution VLBI monitoring is required to discriminate the CSO and the binary black hole scenarios.

  1. A milliparsec supermassive black hole binary candidate in the galaxy SDSS J120136.02+300305.5

    SciTech Connect

    Liu, F. K.; Li, Shuo; Komossa, S.

    2014-05-10

    Galaxy mergers play a key role in the evolution of galaxies and the growth of their central supermassive black holes (SMBHs). A search for (active) SMBH binaries (SMBHBs) at the centers of the merger remnants is currently ongoing. Perhaps the greatest challenge is to identify the inactive SMBHBs, which might be the most abundant, but are also the most difficult to identify. Liu et al. predicted characteristic drops in the light curves of tidal disruption events (TDEs), caused by the presence of a secondary SMBH. Here, we apply that model to the light curve of the optically inactive galaxy SDSS J120136.02+300305.5, which was identified as a candidate TDE with XMM-Newton. We show that the deep dips in its evolving X-ray light curve can be well explained by the presence of a SMBHB at its core. A SMBHB model with a mass of the primary of M {sub BH} = 10{sup 7} M {sub ☉}, a mass ratio q ≅ 0.08, and a semi-major axis a {sub b} ≅ 0.6 mpc is in good agreement with the observations. Given that primary mass, introducing an orbital eccentricity is needed, with e {sub b} ≅ 0.3. Alternatively, a lower mass primary of M {sub BH} = 10{sup 6} M {sub ☉} in a circular orbit fits the light curve well. Tight binaries like this one, which have already overcome the 'final parsec problem', are prime sources of gravitational wave radiation once the two SMBHs coalesce. Future transient surveys, which will detect TDEs in large numbers, will place tight constraints on the SMBHB fraction in otherwise non-active galaxies.

  2. Robust high-contrast companion detection from interferometric observations. The CANDID algorithm and an application to six binary Cepheids

    NASA Astrophysics Data System (ADS)

    Gallenne, A.; Mérand, A.; Kervella, P.; Monnier, J. D.; Schaefer, G. H.; Baron, F.; Breitfelder, J.; Le Bouquin, J. B.; Roettenbacher, R. M.; Gieren, W.; Pietrzyński, G.; McAlister, H.; ten Brummelaar, T.; Sturmann, J.; Sturmann, L.; Turner, N.; Ridgway, S.; Kraus, S.

    2015-07-01

    Context. Long-baseline interferometry is an important technique to spatially resolve binary or multiple systems in close orbits. By combining several telescopes together and spectrally dispersing the light, it is possible to detect faint components around bright stars in a few hours of observations. Aims: We provide a rigorous and detailed method to search for high-contrast companions around stars, determine the detection level, and estimate the dynamic range from interferometric observations. Methods: We developed the code CANDID (Companion Analysis and Non-Detection in Interferometric Data), a set of Python tools that allows us to search systematically for point-source, high-contrast companions and estimate the detection limit using all interferometric observables, i.e., the squared visibilities, closure phases and bispectrum amplitudes. The search procedure is made on a N × N grid of fit, whose minimum needed resolution is estimated a posteriori. It includes a tool to estimate the detection level of the companion in the number of sigmas. The code CANDID also incorporates a robust method to set a 3σ detection limit on the flux ratio, which is based on an analytical injection of a fake companion at each point in the grid. Our injection method also allows us to analytically remove a detected component to 1) search for a second companion; and 2) set an unbiased detection limit. Results: We used CANDID to search for the companions around the binary Cepheids V1334 Cyg, AX Cir, RT Aur, AW Per, SU Cas, and T Vul. First, we showed that our previous discoveries of the components orbiting V1334 Cyg and AX Cir were detected at >25σ and >13σ, respectively. The astrometric positions and flux ratios provided by CANDID for these two stars are in good agreement with our previously published values. The companion around AW Per is detected at more than 15σ with a flux ratio of f = 1.22 ± 0.30%, and it is located at ρ = 32.16 ± 0.29 mas and PA = 67.1 ± 0.3°. We made a

  3. High-Energy Electromagnetic Offline Follow-Up of Ligo-Virgo Gravitational-Wave Binary Coalescence Candidate Events

    NASA Technical Reports Server (NTRS)

    Blackburn, L.; Briggs, M. S.; Camp, J.; Christensen, N.; Connaughton, V.; Jenke, P.; Remillard, R. A.; Veitch, J.

    2015-01-01

    We present two different search methods for electromagnetic counterparts to gravitational-wave (GW) events from ground-based detectors using archival NASA high-energy data from the Fermi Gamma-ray Burst Monitor (GBM) and RXTE All-sky Monitor (ASM) instruments. To demonstrate the methods, we use a limited number of representative GW background noise events produced by a search for binary neutron star coalescence over the last two months of the LIGO-Virgo S6/VSR3 joint science run. Time and sky location provided by the GW data trigger a targeted search in the high-energy photon data. We use two custom pipelines: one to search for prompt gamma-ray counterparts in GBM, and the other to search for a variety of X-ray afterglow model signals in ASM. We measure the efficiency of the joint pipelines to weak gamma-ray burst counterparts, and a family of model X-ray afterglows. By requiring a detectable signal in either electromagnetic instrument coincident with a GW event, we are able to reject a large majority of GW candidates. This reduces the signal-to-noise ratio of the loudest surviving GW background event by around 15-20 percent.

  4. HIGH-ENERGY ELECTROMAGNETIC OFFLINE FOLLOW-UP OF LIGO-VIRGO GRAVITATIONAL-WAVE BINARY COALESCENCE CANDIDATE EVENTS

    SciTech Connect

    Blackburn, L.; Camp, J.; Christensen, N.; Remillard, R. A.; Veitch, J.

    2015-03-15

    We present two different search methods for electromagnetic counterparts to gravitational-wave (GW) events from ground-based detectors using archival NASA high-energy data from the Fermi Gamma-ray Burst Monitor (GBM) and RXTE All-sky Monitor (ASM) instruments. To demonstrate the methods, we use a limited number of representative GW background noise events produced by a search for binary neutron star coalescence over the last two months of the LIGO-Virgo S6/VSR3 joint science run. Time and sky location provided by the GW data trigger a targeted search in the high-energy photon data. We use two custom pipelines: one to search for prompt gamma-ray counterparts in GBM, and the other to search for a variety of X-ray afterglow model signals in ASM. We measure the efficiency of the joint pipelines to weak gamma-ray burst counterparts, and a family of model X-ray afterglows. By requiring a detectable signal in either electromagnetic instrument coincident with a GW event, we are able to reject a large majority of GW candidates. This reduces the signal-to-noise ratio of the loudest surviving GW background event by around 15–20%.

  5. High-Energy Electromagnetic Offline Follow-Up of Ligo-Virgo Gravitational-Wave Binary Coalescence Candidate Events

    NASA Technical Reports Server (NTRS)

    Blackburn, L.; Briggs, M. S.; Camp, J.; Christensen, N.; Connaughton, V.; Jenke, P.; Remillard, R. A.; Veitch, J.

    2015-01-01

    We present two different search methods for electromagnetic counterparts to gravitational-wave (GW) events from ground-based detectors using archival NASA high-energy data from the Fermi Gamma-ray Burst Monitor (GBM) and RXTE All-sky Monitor (ASM) instruments. To demonstrate the methods, we use a limited number of representative GW background noise events produced by a search for binary neutron star coalescence over the last two months of the LIGO-Virgo S6/VSR3 joint science run. Time and sky location provided by the GW data trigger a targeted search in the high-energy photon data. We use two custom pipelines: one to search for prompt gamma-ray counterparts in GBM, and the other to search for a variety of X-ray afterglow model signals in ASM. We measure the efficiency of the joint pipelines to weak gamma-ray burst counterparts, and a family of model X-ray afterglows. By requiring a detectable signal in either electromagnetic instrument coincident with a GW event, we are able to reject a large majority of GW candidates. This reduces the signal-to-noise ratio of the loudest surviving GW background event by around 15-20 percent.

  6. Planet Hunters. X. Searching for Nearby Neighbors of 75 Planet and Eclipsing Binary Candidates from the K2 Kepler extended mission

    NASA Astrophysics Data System (ADS)

    Schmitt, Joseph R.; Tokovinin, Andrei; Wang, Ji; Fischer, Debra A.; Kristiansen, Martti H.; LaCourse, Daryll M.; Gagliano, Robert; Tan, Arvin Joseff V.; Schwengeler, Hans Martin; Omohundro, Mark R.; Venner, Alexander; Terentev, Ivan; Schmitt, Allan R.; Jacobs, Thomas L.; Winarski, Troy; Sejpka, Johann; Jek, Kian J.; Boyajian, Tabetha S.; Brewer, John M.; Ishikawa, Sascha T.; Lintott, Chris; Lynn, Stuart; Schawinski, Kevin; Schwamb, Megan E.; Weiksnar, Alex

    2016-06-01

    We present high-resolution observations of a sample of 75 K2 targets from Campaigns 1-3 using speckle interferometry on the Southern Astrophysical Research (SOAR) telescope and adaptive optics imaging at the Keck II telescope. The median SOAR I-band and Keck Ks-band detection limits at 1\\prime\\prime were {{Δ }}{m}I=4.4 mag and {{Δ }}{m}{Ks}=6.1 mag, respectively. This sample includes 37 stars likely to host planets, 32 targets likely to be eclipsing binaries (EBs), and 6 other targets previously labeled as likely planetary false positives. We find nine likely physically bound companion stars within 3\\prime\\prime of three candidate transiting exoplanet host stars and six likely EBs. Six of the nine detected companions are new discoveries. One of these new discoveries, EPIC 206061524, is associated with a planet candidate. Among the EB candidates, companions were only found near the shortest period ones (P\\lt 3 days), which is in line with previous results showing high multiplicity near short-period binary stars. This high-resolution data, including both the detected companions and the limits on potential unseen companions, will be useful in future planet vetting and stellar multiplicity rate studies for planets and binaries.

  7. Searching for isolated stellar-mass black hole candidates by analyzing the kinematics of their former companions in disrupted binary systems

    NASA Astrophysics Data System (ADS)

    Chmyreva, L.; Beskin, G.; Karpov, S.

    2017-07-01

    We performed a search for isolated stellar-mass black hole candidates based on the fact that more than 50% of radio pulsars have originated in binary systems, now disrupted, where the other component could have evolved into a black hole prior to the second supernova event in the system which caused its disruption. To this end, several relatively young isolated pulsars with known parallaxes fitting the selection criteria were traced back to their presumed birth locations. These areas were then analyzed for possible black hole candidates based on the astrometric, photometric, and spectral data available. We present the results for the first 4 pulsars in our sample, J0139+5814, J0922+0638, J0358+5413, and J1395+1616. Several possible candidates were selected for further analysis.

  8. Investigation of a transiting planet candidate in Trumpler 37: An astrophysical false positive eclipsing spectroscopic binary star

    NASA Astrophysics Data System (ADS)

    Errmann, R.; Torres, G.; Schmidt, T. O. B.; Seeliger, M.; Howard, A. W.; Maciejewski, G.; Neuhäuser, R.; Meibom, S.; Kellerer, A.; Dimitrov, D. P.; Dincel, B.; Marka, C.; Mugrauer, M.; Ginski, Ch.; Adam, Ch.; Raetz, St.; Schmidt, J. G.; Hohle, M. M.; Berndt, A.; Kitze, M.; Trepl, L.; Moualla, M.; Eisenbeiß, T.; Fiedler, S.; Dathe, A.; Graefe, Ch.; Pawellek, N.; Schreyer, K.; Kjurkchieva, D. P.; Radeva, V. S.; Yotov, V.; Chen, W. P.; Hu, S. C.-L.; Wu, Z.-Y.; Zhou, X.; Pribulla, T.; Budaj, J.; Vaňko, M.; Kundra, E.; Hambálek, Ľ.; Krushevska, V.; Bukowiecki, Ł.; Nowak, G.; Marschall, L.; Terada, H.; Tomono, D.; Fernandez, M.; Sota, A.; Takahashi, H.; Oasa, Y.; Briceño, C.; Chini, R.; Broeg, C. H.

    We report our investigation of the first transiting planet candidate from the YETI project in the young (˜4 Myr old) open cluster Trumpler 37. The transit-like signal detected in the lightcurve of F8V star 2M21385603+5711345 repeats every 1.364894±0.000015 days, and has a depth of 54.5±0.8 mmag in R. Membership in the cluster is supported by its mean radial velocity and location in the color-magnitude diagram, while the Li diagnostic and proper motion are inconclusive in this regard. Follow-up photometric monitoring and adaptive optics imaging allow us to rule out many possible blend scenarios, but our radial-velocity measurements show it to be an eclipsing single-lined spectroscopic binary with a late-type (mid-M) stellar companion, rather than one of planetary nature. The estimated mass of the companion is 0.15-0.44 M⊙. The search for planets around very young stars such as those targeted by the YETI survey remains of critical importance to understand the early stages of planet formation and evolution. Based in part on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan. Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration (Proposal ID H215Hr). The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. Based on observations obtained with telescopes of the University Observatory Jena, which is operated by the Astrophysical Institute of the Friedrich-Schiller-University. Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC, Proposal IDs H10-3.5-015 and H10-2.2-004). Some of the observations reported here were obtained at

  9. The hot subdwarf B + white dwarf binary KPD 1930+2752. A supernova type Ia progenitor candidate

    NASA Astrophysics Data System (ADS)

    Geier, S.; Nesslinger, S.; Heber, U.; Przybilla, N.; Napiwotzki, R.; Kudritzki, R.-P.

    2007-03-01

    Context: The nature of the progenitors of type Ia supernovae is still under debate. KPD 1930+2752 is one of the best SN Ia progenitor candidates known today. The object is a double degenerate system consisting of a subluminous B star (sdB) and a massive white dwarf (WD). Maxted et al. ([CITE]) conclude that the system mass exceeds the Chandrasekhar mass. This conclusion, however, rests on the assumption that the sdB mass is 0.5 M⊙. However, recent binary population synthesis calculations suggest that the mass of an sdB star may range from 0.3 M⊙ to more than 0.7 M⊙. Aims: It is therefore important to measure the mass of the sdB star simultaneously with that of the white dwarf. Since the rotation of the sdB star is tidally locked to the orbit, the inclination of the system can be constrained if the sdB radius and the projected rotational velocity can be measured with high precision. An analysis of the ellipsoidal variations in the light curve allows the constraints derived from spectroscopy to be tightened. Methods: We derived the mass-radius relation for the sdB star from a quantitative spectral analysis of 150 low-resolution spectra obtained with the Calar Alto 2.2 m telescope using metal-rich, line-blanketed LTE model atmospheres with and without NLTE line formation. The projected rotational velocity was determined for the first time from 200 high-resolution spectra obtained with the Keck I 10 m and with the ESO-VLT 8.2 m telescopes. In addition a reanalysis of the published light curve was performed. Results: The atmospheric and orbital parameters were measured with unprecedented accuracy. In particular the projected rotational velocity <[(v_rot sin{i} = 92.3 ± 1.5 km s-1)]> was determined. Assuming the companion to be a white dwarf, the mass of the sdB is limited between <[(0.45 M⊙)]> and <[(0.64 M⊙)]> and the corresponding total mass of the system ranges from <[(1.33 M⊙)]> to <[(2.04 M⊙)]>. This constrains the inclination to i>68°. The

  10. Burying a binary: Dynamical mass loss and a continuous optically thick outflow explain the candidate stellar merger V1309 Scorpii

    SciTech Connect

    Pejcha, Ondřej

    2014-06-10

    V1309 Sco was proposed to be a stellar merger and a common envelope transient based on the pre-outburst light curve of a contact eclipsing binary with a rapidly decaying orbital period. Using published data, I show that the period decay timescale P/ P-dot of V1309 Sco decreased from ∼1000 to ∼170 yr in ≲ 6 yr, which implies a very high value of P{sup ¨}. I argue that V1309 Sco experienced an onset of dynamical mass loss through the outer Lagrange point, which eventually obscured the binary. The photosphere of the resulting continuous optically thick outflow expands as the mass-loss rate increases, explaining the ∼200 day rise to optical maximum. The model yields the mass-loss rate of the binary star as a function of time and fits the observed light curve remarkably well. It is also possible to observationally constrain the properties of the surface layers undergoing the dynamical mass loss. V1309 Sco is thus a prototype of a new class of stellar transients distinguished by a slow rise to optical maximum that are driven by dynamical mass loss from a binary. I discuss the implications of these findings for stellar transients and other suggested common envelope events.

  11. IRAS 16253-2429: The First Proto-brown Dwarf Binary Candidate Identified through the Dynamics of Jets

    NASA Astrophysics Data System (ADS)

    Hsieh, Tien-Hao; Lai, Shih-Ping; Belloche, Arnaud; Wyrowski, Friedrich

    2016-07-01

    The formation mechanism of brown dwarfs (BDs) is one of the long-standing problems in star formation because the typical Jeans mass in molecular clouds is too large to form these substellar objects. To answer this question, it is crucial to study a BD in the embedded phase. IRAS 16253-2429 is classified as a very low-luminosity object (VeLLO) with an internal luminosity of <0.1 L ⊙. VeLLOs are believed to be very low-mass protostars or even proto-BDs. We observed the jet/outflow driven by IRAS 16253-2429 in CO (2-1), (6-5), and (7-6) using the IRAM 30 m and Atacama Pathfinder Experiment telescopes and the Submillimeter Array (SMA) in order to study its dynamical features and physical properties. Our SMA map reveals two protostellar jets, indicating the existence of a proto-binary system as implied by the precessing jet detected in H2 emission. We detect a wiggling pattern in the position-velocity diagrams along the jet axes, which is likely due to the binary orbital motion. Based on this information, we derive the current mass of the binary as ˜0.032 M⊙. Given the low envelope mass, IRAS 16253-2429 will form a binary that probably consist of one or two BDs. Furthermore, we found that the outflow force as well as the mass accretion rate are very low based on the multi-transition CO observations, which suggests that the final masses of the binary components are at the stellar/substellar boundary. Since IRAS 16253 is located in an isolated environment, we suggest that BDs can form through fragmentation and collapse, similar to low-mass stars. Based on observations carried out with the IRAM 30 m Telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).

  12. Observation of the black hole candidate X-ray binary Swift J1357.2 0933 in quies

    NASA Astrophysics Data System (ADS)

    Armas Padilla, Montserrat

    2012-10-01

    We propose a 40 ksec XMM Newton observation of the low mass X-ray binary black hole system Swift J1357.2 0933 in the quiescent state. The low column density towards the source makes it possible to obtain its quiescent lumi- nosity down to LX ~1E30 ergs s-1. This limit, together with its short orbital period of 2.8 hours makes it possible to test the ADAF interpretation for emission in quiescent black holes systems by testing the quiescent luminosity-orbital period correlation in the unexplored regime of very short orbital periods.

  13. CXOGBS J173620.2-293338: A candidate symbiotic X-ray binary associated with a bulge carbon star

    SciTech Connect

    Hynes, Robert I.; Britt, C. T.; Johnson, C. B.; Torres, M. A. P.; Jonker, P. G.; Heinke, C. O.; Maccarone, T. J.; Mikles, V. J.; Knigge, C.; Greiss, S.; Steeghs, D.; Nelemans, G.; Bandyopadhyay, R. M.

    2014-01-01

    The Galactic Bulge Survey (GBS) is a wide but shallow X-ray survey of regions above and below the Plane in the Galactic Bulge. It was performed using the Chandra X-ray Observatory's ACIS camera. The survey is primarily designed to find and classify low luminosity X-ray binaries. The combination of the X-ray depth of the survey and the accessibility of optical and infrared counterparts makes this survey ideally suited to identification of new symbiotic X-ray binaries (SyXBs) in the Bulge. We consider the specific case of the X-ray source CXOGBS J173620.2-293338. It is coincident to within 1 arcsec with a very red star, showing a carbon star spectrum and irregular variability in the Optical Gravitational Lensing Experiment data. We classify the star as a late C-R type carbon star based on its spectral features, photometric properties, and variability characteristics, although a low-luminosity C-N type cannot be ruled out. The brightness of the star implies it is located in the Bulge, and its photometric properties are overall consistent with the Bulge carbon star population. Given the rarity of carbon stars in the Bulge, we estimate the probability of such a close chance alignment of any GBS source with a carbon star to be ≲ 10{sup –3}, suggesting that this is likely to be a real match. If the X-ray source is indeed associated with the carbon star, then the X-ray luminosity is around 9 × 10{sup 32} erg s{sup –1}. Its characteristics are consistent with a low luminosity SyXB, or possibly a low accretion rate white dwarf symbiotic.

  14. Binary stars.

    PubMed

    Paczynacuteski, B

    1984-07-20

    Most stars in the solar neighborhood are either double or multiple systems. They provide a unique opportunity to measure stellar masses and radii and to study many interesting and important phenomena. The best candidates for black holes are compact massive components of two x-ray binaries: Cygnus X-1 and LMC X-3. The binary radio pulsar PSR 1913 + 16 provides the best available evidence for gravitational radiation. Accretion disks and jets observed in close binaries offer a very good testing ground for models of active galactic nuclei and quasars.

  15. 1RXS J180408.9-342058: An ultra compact X-ray binary candidate with a transient jet

    NASA Astrophysics Data System (ADS)

    Baglio, M. C.; D'Avanzo, P.; Campana, S.; Goldoni, P.; Masetti, N.; Muñoz-Darias, T.; Patiño-Álvarez, V.; Chavushyan, V.

    2016-03-01

    Aims: We present a detailed near-infrared/optical/UV study of the transient low-mass X-ray binary 1RXS J180408.9-342058 performed during its 2015 outburst, which is aimed at determining the nature of its companion star. Methods: We obtained three optical spectra (R ~ 1000) at the 2.1 m San Pedro Mártir Observatory telescope (México). We performed optical and NIR photometric observations with both the REM telescope and the New Technology Telescope (NTT) in La Silla. We obtained optical and UV observations from the Swift archive. Finally, we performed optical polarimetry of the source using the EFOSC2 instrument mounted on the NTT. Results: The optical spectrum of the source is almost featureless since the hydrogen and He I emissions lines, typically observed in LMXBs, are not detected. Similarly, carbon and oxygen lines are not observed either. We marginally detect the He II 4686 Å emission line, suggesting the presence of helium in the accretion disc. No significant optical polarisation level was observed. Conclusions: The lack of hydrogen and He I emission lines in the spectrum implies that the companion is likely not a main-sequence star. Driven by the tentative detection of the He II 4686 Å emission line, we suggest that the system could harbour a helium white dwarf. If this is the case, 1RXS J180408.9-342058 would be an ultra-compact X-ray binary. By combining an estimate of the mass accretion rate together with evolutionary tracks for a He white dwarf, we obtain a tentative orbital period of ~40 min. We also built the NIR-optical-UV spectral energy distribution (SED) of the source at two different epochs. One SED was gathered when the source was in the soft X-ray state and this SED is consistent with the presence of a single thermal component. The second SED, obtained when the source was in the hard X-ray state, shows a thermal component along with a tail in the NIR, which likely indicates the presence of a (transient) jet. Based on observations made with

  16. Parsec-Scale Localization of the Quasar SDSS J1536+0441A, a Candidate Binary Black Hole System

    NASA Astrophysics Data System (ADS)

    Wrobel, J. M.; Laor, A.

    2011-01-01

    The radio-quiet quasar (RQQ) SDSS J1536+0441A shows two broad-line emission systems, recently interpreted as a binary black hole (BBH) system with a subparsec separation; as a double-peaked emitter (DPE); or as both types of systems. The NRAO VLBA was used to search for 8.4 GHz emission from SDSS J1536+0441A, focusing on the localization region for the broad-line emission, of area 5400 mas2 (0.15 kpc2). One source was detected, with a diameter of less than 1.63 mas (8.5 pc) and a brightness temperature Tb > 1.2 x 107 K. New NRAO VLA photometry at 22.5 GHz, and earlier photometry at 8.5 GHz, gives a rising spectral slope of alpha = 0.35+/-0.08. The slope implies an optically thick synchrotron source, with a radius of about 0.04 pc, and thus Tb 4.8 x 1010 K. The implied radio sphere at the rest frequency 31.2 GHz has a radius of 800 gravitational radii, just below the size of the broad line region in this object. Observations at higher frequencies with the EVLA and ALMA can probe whether or not the radio sphere is as compact as expected from the coronal framework for the radio emission of RQQs. The NRAO is a facility of the NSF operated under cooperative agreement by AUI.

  17. DIRECT IMAGING AND SPECTROSCOPY OF A CANDIDATE COMPANION BELOW/NEAR THE DEUTERIUM-BURNING LIMIT IN THE YOUNG BINARY STAR SYSTEM, ROXs 42B

    SciTech Connect

    Currie, Thayne; Daemgen, Sebastian; Jayawardhana, Ray; Debes, John; Lafreniere, David; Itoh, Yoichi; Ratzka, Thorsten; Correia, Serge

    2014-01-10

    We present near-infrared high-contrast imaging photometry and integral field spectroscopy of ROXs 42B, a binary M0 member of the 1-3 Myr old ρ Ophiuchus star-forming region, from data collected over 7 years. Each data set reveals a faint companion—ROXs 42Bb—located ∼1.''16 (r {sub proj} ≈ 150 AU) from the primaries at a position angle consistent with a point source identified earlier by Ratzka et al.. ROXs 42Bb's astrometry is inconsistent with a background star but consistent with a bound companion, possibly one with detected orbital motion. The most recent data set reveals a second candidate companion at ∼0.''5 of roughly equal brightness, though preliminary analysis indicates it is a background object. ROXs 42Bb's H and K{sub s} band photometry is similar to dusty/cloudy young, low-mass late M/early L dwarfs. K band VLT/SINFONI spectroscopy shows ROXs 42Bb to be a cool substellar object (M8-L0; T {sub eff} ≈ 1800-2600 K), not a background dwarf star, with a spectral shape indicative of young, low surface gravity planet-mass companions. We estimate ROXs 42Bb's mass to be 6-15 M{sub J} , either below the deuterium-burning limit and thus planet mass or straddling the deuterium-burning limit nominally separating planet-mass companions from other substellar objects. Given ROXs 42b's projected separation and mass with respect to the primaries, it may represent the lowest mass objects formed like binary stars or a class of planet-mass objects formed by protostellar disk fragmentation/disk instability, the latter slightly blurring the distinction between non-deuterium-burning planets like HR 8799 bcde and low-mass, deuterium-burning brown dwarfs.

  18. FIRST LONG-TERM OPTICAL SPECTRAL MONITORING OF A BINARY BLACK HOLE CANDIDATE E1821+643. I. VARIABILITY OF SPECTRAL LINES AND CONTINUUM

    SciTech Connect

    Shapovalova, A. I.; Burenkov, A. N.; Zhdanova, V. E.; Popović, L. Č.; Chavushyan, V. H.; Valdés, J. R.; Patiño-Álvarez, V.; León-Tavares, J.; Torrealba, J.; Ilić, D.; Kovačević, A.; Kollatschny, W.

    2016-02-15

    We report the results of the first long-term (1990–2014) optical spectrophotometric monitoring of a binary black hole candidate QSO E1821+643, a low-redshift, high-luminosity, radio-quiet quasar. In the monitored period, the continua and Hγ fluxes changed about two times, while the Hβ flux changed about 1.4 times. We found periodical variations in the photometric flux with periods of 1200, 1850, and 4000 days, and 4500-day periodicity in the spectroscopic variations. However, the periodicity of 4000–4500 days covers only one cycle of variation and should be confirmed with a longer monitoring campaign. There is an indication of the period around 1300 days in the spectroscopic light curves, buts with small significance level, while the 1850-day period could not be clearly identified in the spectroscopic light curves. The line profiles have not significantly changed, showing an important red asymmetry and broad line peak redshifted around +1000 km s{sup −1}. However, Hβ shows a broader mean profile and has a larger time lag (τ ∼ 120 days) than Hγ (τ ∼ 60 days). We estimate that the mass of the black hole is ∼2.6 × 10{sup 9} M{sub ⊙}. The obtained results are discussed in the frame of the binary black hole hypothesis. To explain the periodicity in the flux variability and high redshift of the broad lines, we discuss a scenario where dense, gas-rich, cloudy-like structures are orbiting around a recoiling black hole.

  19. A NuSTAR Observation of the Gamma-ray-emitting X-ray Binary and Transitional Millisecond Pulsar Candidate 1RXS J154439.4-112820

    NASA Astrophysics Data System (ADS)

    Bogdanov, Slavko

    2016-07-01

    I present a 40 ks Nuclear Spectroscopic Telescope Array observation of the recently identified low-luminosity X-ray binary and transitional millisecond pulsar (tMSP) candidate 1RXS J154439.4-112820, which is associated with the high-energy γ-ray source 3FGL J1544.6-1125. The system is detected up to ˜30 keV with an extension of the same power-law spectrum and rapid large-amplitude variability between two flux levels observed in soft X-rays. These findings provide further evidence that 1RXS J154439.4-112820 belongs to the same class of objects as the nearby bona fide tMSPs PSR J1023+0038 and XSS J12270-4859 and therefore almost certainly hosts a millisecond pulsar accreting at low luminosity. I also examine the long-term accretion history of 1RXS J154439.4-112820 based on archival optical, ultraviolet, X-ray, and γ-ray light curves covering approximately the past decade. Throughout this period, the source has maintained similar flux levels at all wavelengths, which is an indication that it has not experienced prolonged episodes of a non-accreting radio pulsar state but may spontaneously undergo such events in the future.

  20. Diverse Long-Term Variability of Five Candidate High-Mass X-ray Binaries from Swift Burst Alert Telescope Observations

    NASA Astrophysics Data System (ADS)

    Corbet, Robin; Coley, Joel Barry; Krimm, Hans A.

    2017-08-01

    We present an investigation of long-term modulation in the X-ray light curves of five little-studied candidate high-mass X-ray binaries using the Swift Burst Alert Telescope. IGR J14488-5942 and AX J1700.2-4220 show strong modulation at periods of 49.6 and 44 days, respectively, which are interpreted as orbital periods of Be star systems. For IGR J14488-5942, observations with Swift X-ray Telescope show a hint of pulsations at 33.4 s. For AX J1700.2-4220, 54 s pulsations were previously found with XMM-Newton. Swift J1816.7-1613 exhibits complicated behavior. The strongest peak in the power spectrum is at a period near 150 days, but this conflicts with a determination of a period of 118.5 days by La Parola et al. (2014). AX J1820.5-1434 has been proposed to exhibit modulation near 54 days, but the extended BAT observations suggest modulation at slightly longer than double this at approximately 111 days. There appears to be a long-term change in the shape of the modulation near 111 days, which may explain the apparent discrepancy. The X-ray pulsar XTE J1906+090, which was previously proposed to be a Be star system with an orbital period of ˜30 days from pulse timing, shows peaks in the power spectrum at 81 and 173 days. The origins of these periods are unclear, although they might be the orbital period and a superorbital period respectively. For all five sources, the long-term variability, together with the combination of orbital and proposed pulse periods, suggests that the sources contain Be star mass donors.

  1. Diverse Long-term Variability of Five Candidate High-mass X-Ray Binaries from Swift  Burst Alert Telescope Observations

    NASA Astrophysics Data System (ADS)

    Corbet, Robin H. D.; Coley, Joel B.; Krimm, Hans A.

    2017-09-01

    We present an investigation of long-term modulation in the X-ray light curves of five little-studied candidate high-mass X-ray binaries using the Swift Burst Alert Telescope. IGR J14488-5942 and AX J1700.2-4220 show strong modulation at periods of 49.6 and 44 days, respectively, which are interpreted as orbital periods of Be star systems. For IGR J14488-5942, observations with the Swift X-ray Telescope show a hint of pulsations at 33.4 s. For AX J1700.2-4220, 54 s pulsations were previously found with XMM-Newton. Swift J1816.7-1613 exhibits complicated behavior. The strongest peak in the power spectrum is at a period near 150 days, but this conflicts with a determination of a period of 118.5 days by La Parola et al. AX J1820.5-1434 has been proposed to exhibit modulation near 54 days, but the extended BAT observations suggest modulation at slightly longer than double this at approximately 111 days. There appears to be a long-term change in the shape of the modulation near 111 days, which may explain the apparent discrepancy. The X-ray pulsar XTE J1906+090, which was previously proposed to be a Be star system with an orbital period of ∼30 days from pulse timing, shows peaks in the power spectrum at 81 and 173 days. The origins of these periods are unclear, although they might be the orbital period and a superorbital period respectively. For all five sources, the long-term variability, together with the combination of orbital and proposed pulse periods, suggests that the sources contain Be star mass donors.

  2. A Periodically Varying Luminous Quasar at z = 2 from the Pan-STARRS1 Medium Deep Survey: A Candidate Supermassive Black Hole Binary in the Gravitational Wave-Driven Regime

    NASA Astrophysics Data System (ADS)

    Liu, Tingting; Gezari, Suvi

    Supermassive black hole binaries (SMBHBs) should be an inevitable consequence of the hierarchical growth of massive galaxies through mergers and the strongest sirens of gravitational waves (GWs) in the cosmos. Yet, their direct detection has remained elusive due to the compact (sub-parsec) orbital separations of gravitationally bound SMBHBs. Here we exploit a theoretically predicted signature of SMBHBs in the time domain. We have begun a systematic search for SMBHB candidates in the Pan-STARRS1 Medium Deep Survey (MDS) and reported our first significant detection of such a candidate from our pilot study of MD09 in Liu et al. (2015). Our candidate PSO J334.2028+01.4075 has a detected period of 542 days, varying persistently over the available baseline. From its archival spectrum, we estimated the black hole mass of the z = 2.06 quasar to be ~1010 M⊙. The inferred ~7 R s binary separation therefore puts this candidate in the regime of GW-dominated orbital decay, opening up the exciting possibility of finding GW sources detectable by pulsar timing arrays (PTAs) in a wide-field optical synoptic survey.

  3. Very Low-mass Stellar and Substellar Companions to Solar-like Stars from MARVELS. VI. A Giant Planet and a Brown Dwarf Candidate in a Close Binary System HD 87646

    NASA Astrophysics Data System (ADS)

    Ma, Bo; Ge, Jian; Wolszczan, Alex; Muterspaugh, Matthew W.; Lee, Brian; Henry, Gregory W.; Schneider, Donald P.; Martín, Eduardo L.; Niedzielski, Andrzej; Xie, Jiwei; Fleming, Scott W.; Thomas, Neil; Williamson, Michael; Zhu, Zhaohuan; Agol, Eric; Bizyaev, Dmitry; Nicolaci da Costa, Luiz; Jiang, Peng; Martinez Fiorenzano, A. F.; González Hernández, Jonay I.; Guo, Pengcheng; Grieves, Nolan; Li, Rui; Liu, Jane; Mahadevan, Suvrath; Mazeh, Tsevi; Nguyen, Duy Cuong; Paegert, Martin; Sithajan, Sirinrat; Stassun, Keivan; Thirupathi, Sivarani; van Eyken, Julian C.; Wan, Xiaoke; Wang, Ji; Wisniewski, John P.; Zhao, Bo; Zucker, Shay

    2016-11-01

    We report the detections of a giant planet (MARVELS-7b) and a brown dwarf (BD) candidate (MARVELS-7c) around the primary star in the close binary system, HD 87646. To the best of our knowledge, it is the first close binary system with more than one substellar circumprimary companion that has been discovered. The detection of this giant planet was accomplished using the first multi-object Doppler instrument (KeckET) at the Sloan Digital Sky Survey (SDSS) telescope. Subsequent radial velocity observations using the Exoplanet Tracker at the Kitt Peak National Observatory, the High Resolution Spectrograph at the Hobby Eberley telescope, the “Classic” spectrograph at the Automatic Spectroscopic Telescope at the Fairborn Observatory, and MARVELS from SDSS-III confirmed this giant planet discovery and revealed the existence of a long-period BD in this binary. HD 87646 is a close binary with a separation of ˜22 au between the two stars, estimated using the Hipparcos catalog and our newly acquired AO image from PALAO on the 200 inch Hale Telescope at Palomar. The primary star in the binary, HD 87646A, has {T}{eff} = 5770 ± 80 K, log g = 4.1 ± 0.1, and [Fe/H] = -0.17 ± 0.08. The derived minimum masses of the two substellar companions of HD 87646A are 12.4 ± 0.7 {M}{Jup} and 57.0 ± 3.7 {M}{Jup}. The periods are 13.481 ± 0.001 days and 674 ± 4 days and the measured eccentricities are 0.05 ± 0.02 and 0.50 ± 0.02 respectively. Our dynamical simulations show that the system is stable if the binary orbit has a large semimajor axis and a low eccentricity, which can be verified with future astrometry observations.

  4. Search for Binary Trojans

    NASA Astrophysics Data System (ADS)

    Noll, Keith S.; Grundy, W. M.; Ryan, E. L.; Benecchi, S. D.

    2015-11-01

    We have reexamined 41 Trojan asteroids observed with the Hubble Space Telescope (HST) to search for unresolved binaries. We have identified one candidate binary with a separation of 53 milliarcsec, about the width of the diffraction limited point-spread function (PSF). Sub-resolution-element detection of binaries is possible with HST because of the high signal-to-noise ratio of the observations and the stability of the PSF. Identification and confirmation of binary Trojans is important because a Trojan Tour is one of five possible New Frontiers missions. A binary could constitute a potentially high value target because of the opportunity to study two objects and to test models of the primordial nature of binaries. The potential to derive mass-based physical information from the binary orbit could yield more clues to the origin of Trojans.

  5. ATCA radio detection of MAXI J1535-571 indicates it is a strong black hole X-ray binary candidate

    NASA Astrophysics Data System (ADS)

    Russell, T. D.; Miller-Jones, J. C. A.; Sivakoff, G. R.; Tetarenko, A. J.; Jacpot Xrb Collaboration

    2017-09-01

    MAXI J1535-571 is a newly discovered Galactic hard X-ray transient (GCN #21788, ATels #10699, 10700). Following its identification as a potential hard-state low-mass X-ray binary (ATel #10702) and a potential black hole system (ATel #10708), we conducted target of opportunity observations of this source with the Australia Telescope Compact Array (ATCA).

  6. From Binaries to Triples

    NASA Astrophysics Data System (ADS)

    Freismuth, T.; Tokovinin, A.

    2002-12-01

    About 10% of all binary systems are close binaries (P<1000 days). Among those with P<10d, over 40% are known to belong to higher-multiplicity systems (triples, quadruples, etc.). Do ALL close systems have tertiary companions? For a selection of 12 nearby, and apparently "single" close binaries with solar-mass dwarf primary components from the 8-th catalogue of spectroscopic binary orbits, images in the B and R filters were taken at the CTIO 0.9m telescope and suitable tertiary candidates were be identified on color-magnitude diagrams (CMDs). Of the 12 SBs, four were found to have tertiary candidates: HD 67084, HD 120734, HD 93486, and VV Mon. However, none of these candidates were found to be common proper motion companions. Follow up observations using adaptive optics reveal a companion to HD 148704. Future observations are planned.

  7. A Periodically Varying Luminous Quasar at z = 2 from the Pan-STARRS1 Medium Deep Survey: A Candidate Supermassive Black Hole Binary in the Gravitational Wave-Driven Regime

    NASA Astrophysics Data System (ADS)

    Liu, Tingting; Gezari, Suvi

    2015-08-01

    Supermassive black hole binaries (SMBHBs) should be an inevitable consequence of the hierarchical growth of massive galaxies through mergers, and the strongest sirens of gravitational waves (GWs) in the cosmos. And yet, their direct detection has remained elusive due to the compact (sub-parsec) orbital separations of gravitationally bound SMBHBs. Here we exploit a theoretically predicted signature of a SMBHB in the time domain: periodic variability caused by a mass accretion rate that is modulated by the binary's orbital motion. We report our first significant periodically varying quasar detection from the systematic search in the Pan-STARRS1 (PS1) Medium Deep Survey, a result recently accepted for publication in The Astrophysical Journal Letters. Our SMBHB candidate, PSO J334.2028+01.4075, is a luminous radio-loud quasar at z = 2.060, with extended baseline photometry from the Catalina Real-Time Transient Survey, as well as archival spectroscopy from the FIRST Bright Quasar Survey. The observed period (542 ± 15 days) and estimated black hole mass (log(MBH/M⊙) = 9.97 ± 0.50), correspond to an orbital separation of 7+8-4 Schwarzschild radii (~ 0.006+0.007-0.003 pc), assuming the rest-frame period of the quasar variability traces the orbital period of the binary. This SMBHB candidate, discovered at the peak redshift for SMBH mergers, is in a physically stable configuration for a circumbinary accretion disk, and within the regime of GW-driven orbital decay. Our search with PS1 is a benchmark study for the exciting capabilities of LSST, which will have orders of magnitude larger survey power, and will potentially pinpoint the locations of thousands of SMBHBs in the variable night sky.

  8. A Periodically Varying Luminous Quasar at z = 2 from the Pan-STARRS1 Medium Deep Survey: A Candidate Supermassive Black Hole Binary in the Gravitational Wave-driven Regime

    NASA Astrophysics Data System (ADS)

    Liu, Tingting; Gezari, Suvi; Heinis, Sebastien; Magnier, Eugene A.; Burgett, William S.; Chambers, Kenneth; Flewelling, Heather; Huber, Mark; Hodapp, Klaus W.; Kaiser, Nicholas; Kudritzki, Rolf-Peter; Tonry, John L.; Wainscoat, Richard J.; Waters, Christopher

    2015-04-01

    Supermassive black hole binaries (SMBHBs) should be an inevitable consequence of the hierarchical growth of massive galaxies through mergers and the strongest sirens of gravitational waves (GWs) in the cosmos. Yet, their direct detection has remained elusive due to the compact (sub-parsec) orbital separations of gravitationally bound SMBHBs. Here, we exploit a theoretically predicted signature of an SMBHB in the time domain: periodic variability caused by a mass accretion rate that is modulated by the binary’s orbital motion. We report our first significant periodically varying quasar detection from the systematic search in the Pan-STARRS1 (PS1) Medium Deep Survey. Our SMBHB candidate, PSO J334.2028+01.4075, is a luminous radio-loud quasar at z = 2.060, with extended baseline photometry from the Catalina Real-Time Transient Survey, as well as archival spectroscopy from the FIRST Bright Quasar Survey. The observed period (542 ± 15 days) and estimated black hole mass (log ({{M}BH}/{{M}⊙ })=9.97+/- 0.50) correspond to an orbital separation of 7-4+8 Schwarzschild radii (˜ 0.006-0.003+0.007 pc), assuming the rest-frame period of the quasar variability traces the orbital period of the binary. This SMBHB candidate, discovered at the peak redshift for SMBH mergers, is in a physically stable configuration for a circumbinary accretion disk and within the regime of GW-driven orbital decay. Our search with PS1 is a benchmark study for the exciting capabilities of LSST, which will have orders of magnitude larger survey power and will potentially pinpoint the locations of thousands of SMBHBs in the variable night sky.

  9. VERY LARGE TELESCOPE/X-SHOOTER SPECTROSCOPY OF THE CANDIDATE BLACK HOLE X-RAY BINARY MAXI J1659-152 IN OUTBURST

    SciTech Connect

    Kaur, Ramanpreet; Kaper, Lex; Ellerbroek, Lucas E.; Russell, David M.; Altamirano, Diego; Wijnands, Rudy; Yang Yijung; Van der Horst, Alexander; Van der Klis, Michiel; D'Avanzo, Paolo; De Ugarte Postigo, Antonio; Fynbo, Johan P. U.; Flores, Hector; Goldoni, Paolo; Thoene, Christina C.; Kuulkers, Erik

    2012-02-20

    We present the optical to near-infrared spectrum of MAXI J1659-152 during the onset of its 2010 X-ray outburst. The spectrum was obtained with X-shooter on the ESO Very Large Telescope early in the outburst simultaneous with high-quality observations at both shorter and longer wavelengths. At the time of the observations, the source was in the low-hard state. The X-shooter spectrum includes many broad ({approx}2000 km s{sup -1}), double-peaked emission profiles of H, He I, and He II, characteristic signatures of a low-mass X-ray binary during outburst. We detect no spectral signatures of the low-mass companion star. The strength of the diffuse interstellar bands results in a lower limit to the total interstellar extinction of A{sub V} {approx_equal} 0.4 mag. Using the neutral hydrogen column density obtained from the X-ray spectrum we estimate A{sub V} {approx_equal} 1 mag. The radial velocity structure of the interstellar Na I D and Ca II H and K lines results in a lower limit to the distance of {approx}4 {+-} 1 kpc, consistent with previous estimates. With this distance and A{sub V} , the dereddened spectral energy distribution represents a flat disk spectrum. The two 10 minute X-shooter spectra show significant variability in the red wing of the emission-line profiles, indicating a global change in the density structure of the disk, though on a timescale much shorter than the typical viscous timescale of the disk.

  10. New RR Lyrae variables in binary systems

    NASA Astrophysics Data System (ADS)

    Hajdu, G.; Catelan, M.; Jurcsik, J.; Dékány, I.; Drake, A. J.; Marquette, J.-B.

    2015-04-01

    Despite their importance, very few RR Lyrae (RRL) stars have been known to reside in binary systems. We report on a search for binary RRL in the OGLE-III Galactic bulge data. Our approach consists in the search for evidence of the light-travel time effect in so-called observed minus calculated (O-C) diagrams. Analysis of 1952 well-observed fundamental-mode RRL in the OGLE-III data revealed an initial sample of 29 candidates. We used the recently released OGLE-IV data to extend the baselines up to 17 yr, leading to a final sample of 12 firm binary candidates. We provide O-C diagrams and binary parameters for this final sample, and also discuss the properties of eight additional candidate binaries whose parameters cannot be firmly determined at present. We also estimate that ≳ 4 per cent of the RRL reside in binary systems.

  11. Binary Plutinos

    NASA Astrophysics Data System (ADS)

    Noll, Keith S.

    2015-08-01

    The Pluto-Charon binary was the first trans-neptunian binary to be identified in 1978. Pluto-Charon is a true binary with both components orbiting a barycenter located between them. The Pluto system is also the first, and to date only, known binary with a satellite system consisting of four small satellites in near-resonant orbits around the common center of mass. Seven other Plutinos, objects in 3:2 mean motion resonance with Neptune, have orbital companions including 2004 KB19 reported here for the first time. Compared to the Cold Classical population, the Plutinos differ in the frequency of binaries, the relative sizes of the components, and their inclination distribution. These differences point to distinct dynamical histories and binary formation processes encountered by Plutinos.

  12. Astrometric Binaries: White Dwarfs?

    NASA Astrophysics Data System (ADS)

    Oliversen, Nancy A.

    We propose to observe a selection of astrometric or spectroscopicastrometric binaries nearer than about 20 pc with unseen low mass companions. Systems of this type are important for determining the luminosity function of low mass stars (white dwarfs and very late main sequence M stars), and their contribution to the total mass of the galaxy. Systems of this type are also important because the low mass, invisible companions are potential candidates in the search for planets. Our target list is selected primarily from the list of 31 astrometric binaries near the sun by Lippincott (1978, Space Sci. Rev., 22, 153), with additional candidates from recent observations by Kamper. The elimination of stars with previous IUE observations, red companions resolved by infrared speckle interferometry, or primaries later than M1 (because if white dwarf companions are present they should have been detected in the visible region) reduces the list to 5 targets which need further information. IUE SWP low dispersion observations of these targets will show clearly whether the remaining unseen companions are white dwarfs, thus eliminating very cool main sequence stars or planets. This is also important in providing complete statistical information about the nearest stars. The discovery of a white dwarf in such a nearby system would provide important additional information about the masses of white dwarfs. Recent results by Greenstein (1986, A. J., 92, 859) from binary systems containing white dwarfs imply that 80% of such systems are as yet undetected. The preference of binaries for companions of approximately equal mass makes the Lippincott-Kamper list of A through K primaries with unseen companions a good one to use to search for white dwarfs. The mass and light dominance of the current primary over the white dwarf in the visible makes ultraviolet observations essential to obtain an accurate census of white dwarf binaries.

  13. Microlensing Signature of Binary Black Holes

    NASA Technical Reports Server (NTRS)

    Schnittman, Jeremy; Sahu, Kailash; Littenberg, Tyson

    2012-01-01

    We calculate the light curves of galactic bulge stars magnified via microlensing by stellar-mass binary black holes along the line-of-sight. We show the sensitivity to measuring various lens parameters for a range of survey cadences and photometric precision. Using public data from the OGLE collaboration, we identify two candidates for massive binary systems, and discuss implications for theories of star formation and binary evolution.

  14. Validating Kepler Planet Candidates

    NASA Astrophysics Data System (ADS)

    Lissauer, Jack J.; Torres, G.; Marcy, G.; Brown, T.; Gilliland, R.; Gautier, T. N.; Isaacson, H.; Dupree, A.; Kepler Science Team

    2011-01-01

    The Kepler Science Team has identified more than 700 transit-like signatures in the first 43 days of data returned from the spacecraft (Borucki et al. 2010, arXiv1006.2799B). However, only 7 of these candidates have been confirmed as planets as of late September 2010. The number of true planets in this sample is clearly far larger than 7, but the sample is also 'contaminated' with false-positives, including many from eclipsing binary stars. Separating the wheat from the chaff requires a careful study of individual candidates using both Kepler photometry and spectroscopic and imaging data from the ground. Techniques that the Science Team is developing to address these issues, which include detailed analysis of the photometric data and follow-up observations with ground-based telescopes, will be presented. Kepler was selected as the 10th mission of the Discovery Program. Funding for this mission is provided by NASA, Science Mission Directorate.

  15. Binary stars in moving groups

    NASA Astrophysics Data System (ADS)

    Azulay, R.; Guirado, J. C.; Marcaide, J. M.; Martí-Vidal, I.; Ros, E.

    Precise determination of dynamical masses of pre-main-sequence (PMS) stars is necessary to calibrate PMS stellar evolutionary models, whose predictions are in disagreement with measurements for masses below 1.2 M_sun. Binary stars in young, nearby loose associations are particularly good candidates, since all members share a common age. We present phase-reference EVN observations of the binary system HD 160934 A/c, that belongs to the AB Doradus moving group, from which we have measured both the relative and absolute orbital motion. Accordingly, we obtained precise estimates of the mass of the components of this binary. Also we report on other PMS binary systems as EK Dra and AB Dor B.

  16. Section candidates

    NASA Astrophysics Data System (ADS)

    Eos has carried biographies and photographs of candidates for President-Elect of the Union and for President-Elect and Secretary of each section. In addition, statements by the candidates for Union and Section President-Elect have appeared. T h e material for the petition candidate for President-Elect of the Solar-Planetary Relationships Section and a correction to the biography of one candidate for President-Elect of t h e Geodesy Section appear below. The material for the original slate for Solar-Planetary Relationships appeared in the August 6 issue, that for the Seismology Section in the August 13 issue, that for the Geodesy Section in the August 20 issue, that for the Atmospheric Sciences Section in the August 27 issue, that for the Hydrology Section in the September 3 issue, that for the Tectonophysics Section in the September 10 issue, that for the Volcanology, Geochemistry, and Petrology Section in the September 17 issue, that for the Planetology Section in the September 24 issue, that for the Ocean Sciences Section in the October 1 issue, that for the Geomagnetism and Paleomagnetism Section in the October 8 issue, and that for Union President-Elect in the October 15 issue. T h e slate of candidates for all offices was carried in the July 2 issue.

  17. Binary Planets

    NASA Astrophysics Data System (ADS)

    Ryan, Keegan; Nakajima, Miki; Stevenson, David J.

    2014-11-01

    Can a bound pair of similar mass terrestrial planets exist? We are interested here in bodies with a mass ratio of ~ 3:1 or less (so Pluto/Charon or Earth/Moon do not qualify) and we do not regard the absence of any such discoveries in the Kepler data set to be significant since the tidal decay and merger of a close binary is prohibitively fast well inside of 1AU. SPH simulations of equal mass “Earths” were carried out to seek an answer to this question, assuming encounters that were only slightly more energetic than parabolic (zero energy). We were interested in whether the collision or near collision of two similar mass bodies would lead to a binary in which the two bodies remain largely intact, effectively a tidal capture hypothesis though with the tidal distortion being very large. Necessarily, the angular momentum of such an encounter will lead to bodies separated by only a few planetary radii if capture occurs. Consistent with previous work, mostly by Canup, we find that most impacts are disruptive, leading to a dominant mass body surrounded by a disk from which a secondary forms whose mass is small compared to the primary, hence not a binary planet by our adopted definition. However, larger impact parameter “kissing” collisions were found to produce binaries because the dissipation upon first encounter was sufficient to provide a bound orbit that was then rung down by tides to an end state where the planets are only a few planetary radii apart. The long computational times for these simulation make it difficult to fully map the phase space of encounters for which this outcome is likely but the indications are that the probability is not vanishingly small and since planetary encounters are a plausible part of planet formation, we expect binary planets to exist and be a non-negligible fraction of the larger orbital radius exoplanets awaiting discovery.

  18. 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.

  19. New White Dwarf-Brown Dwarf Binaries

    NASA Astrophysics Data System (ADS)

    Casewell, S. L.; Geier, S.; Lodieu, N.

    2017-03-01

    We present follow-up spectroscopy to 12 candidate white dwarf-brown dwarf binaries. We have confirmed that 8 objects do indeed have a white dwarf primary (7 DA, 1 DB) and two are hot subdwarfs. We have determined the Teff and log g for the white dwarfs and subdwarfs, and when combining these values with a model spectrum and the photometry, we have 3 probable white dwarf-substellar binaries with spectral types between M6 and L6.

  20. Very Wide Binaries

    NASA Astrophysics Data System (ADS)

    Olling, Robert; Shaya, E.

    2011-01-01

    We develop Bayesian statistical methods for discovering and assigning probabilities to physical stellar companions. The probabilities depend on similarities in "corrected" proper motion, parallax, and the phase-space density of field stars. Very wide binaries with separations over 10,000 AU have recently been predicted to form during the dissolution process of low-mass star clusters. In this case, these wide systems would still carry information about the density and size of the star cluster in which they formed. Alternatively, Galactic tides and weak interactions with passing stars peel off stars from such very wide binaries in less than 1/2 of a Hubble time. In the past, these systems have been used to rule in/out MACHOs or less compact dark (matter) objects. Ours is the first all-sky survey to locate escaped companions that are still drifting along with each other, long after their binary bond has been broken. We test stars for companionship up to an apparent separation of 8 parsec: 10 to 100 times wider than previous searches. Among Hipparcos stars within 100 pc, we find about 260 systems with separations between 0.01 and 1 pc, and another 190 with separation from 1 to 8 parsec. We find a number of previously unnoticed naked-eye companions, among which: Capella & 50 Per; Alioth, Megrez & Alcor; gamma & tau Cen; phi Eri & eta Hor; 62 & 63 Cnc; gamma & tau Per; zeta & delta Hya; beta01, beta02 & beta03 Tuc; 44 & 58 Oph and pi & rho Cep. At least 15 of our candidates are exoplanet host stars.

  1. Binary classification of items of interest in a repeatable process

    DOEpatents

    Abell, Jeffrey A.; Spicer, John Patrick; Wincek, Michael Anthony; Wang, Hui; Chakraborty, Debejyo

    2014-06-24

    A system includes host and learning machines in electrical communication with sensors positioned with respect to an item of interest, e.g., a weld, and memory. The host executes instructions from memory to predict a binary quality status of the item. The learning machine receives signals from the sensor(s), identifies candidate features, and extracts features from the candidates that are more predictive of the binary quality status relative to other candidate features. The learning machine maps the extracted features to a dimensional space that includes most of the items from a passing binary class and excludes all or most of the items from a failing binary class. The host also compares the received signals for a subsequent item of interest to the dimensional space to thereby predict, in real time, the binary quality status of the subsequent item of interest.

  2. EXTraS discovery of two pulsators in the direction of the LMC: a Be/X-ray binary pulsar in the LMC and a candidate double-degenerate polar in the foreground

    NASA Astrophysics Data System (ADS)

    Haberl, F.; Israel, G. L.; Rodriguez Castillo, G. A.; Vasilopoulos, G.; Delvaux, C.; De Luca, A.; Carpano, S.; Esposito, P.; Novara, G.; Salvaterra, R.; Tiengo, A.; D'Agostino, D.; Udalski, A.

    2017-02-01

    Context. The Exploring the X-ray Transient and variable Sky (EXTraS) project searches for coherent signals in the X-ray archival data of XMM-Newton. Aims: XMM-Newton performed more than 400 pointed observations in the region of the Large Magellanic Cloud (LMC). We inspected the results of the EXTraS period search to systematically look for new X-ray pulsators in our neighbour galaxy. Methods: We analysed the XMM-Newton observations of two sources from the 3XMM catalogue which show significant signals for coherent pulsations. Results: 3XMM J051259.8-682640 was detected as a source with a hard X-ray spectrum in two XMM-Newton observations, revealing a periodic modulation of the X-ray flux with 956 s. As optical counterpart we identify an early-type star with Hα emission. The OGLE I-band light curve exhibits a regular pattern with three brightness dips which mark a period of 1350 d. The X-ray spectrum of 3XMM J051034.6-670353 is dominated by a super-soft blackbody-like emission component (kT 70 eV) which is modulated by nearly 100% with a period of 1418 s. From GROND observations we suggest a star with r' = 20.9 mag as a possible counterpart of the X-ray source. Conclusions: 3XMM J051259.8-682640 is confirmed as a new Be/X-ray binary pulsar in the LMC. We discuss the long-term optical period as the likely orbital period which would be the longest known from a high-mass X-ray binary. The spectral and temporal properties of the super-soft source 3XMM J051034.6-670353 are very similar to those of RX J0806.3+1527 and RX J1914.4+2456 suggesting that it belongs to the class of double-degenerate polars and is located in our Galaxy rather than in the LMC.

  3. Searching for Binary Supermassive Black Holes via Variable Broad Emission Line Shifts: Low Binary Fraction

    NASA Astrophysics Data System (ADS)

    Wang, Lile; Greene, Jenny E.; Ju, Wenhua; Rafikov, Roman R.; Ruan, John J.; Schneider, Donald P.

    2017-01-01

    Supermassive black hole binaries (SMBHs) are expected to result from galaxy mergers, and thus are natural byproducts (and probes) of hierarchical structure formation in the universe. They are also the primary expected source of low-frequency gravitational wave emission. We search for binary BHs using time-variable velocity shifts in broad Mg ii emission lines of quasars with multi-epoch observations. First, we inspect velocity shifts of the binary SMBH candidates identified in Ju et al., using Sloan Digital Sky Survey spectra with an additional epoch of data that lengthens the typical baseline to ∼10 yr. We find variations in the line of sight velocity shifts over 10 yr that are comparable to the shifts observed over 1–2 yr, ruling out the binary model for the bulk of our candidates. We then analyze 1438 objects with eight-year median time baselines, from which we would expect to see velocity shifts >1000 {km} {{{s}}}-1 from sub-parsec binaries. We find only one object with an outlying velocity of 448 {km} {{{s}}}-1, indicating—based on our modeling—that ≲1% (the value varies with different assumptions) of SMBHs that are active as quasars reside in binaries with ∼0.1 pc separations. Binaries either sweep rapidly through these small separations or stall at larger radii.

  4. Detection of binaries with projected separations as large as 0.1 parsec

    NASA Technical Reports Server (NTRS)

    Latham, D. W.; Schechter, P.; Tonry, J.; Bahcall, J. N.; Soneira, R. M.

    1984-01-01

    Repeated, accurate radial velocity measurements have been made of the 19 candidate wide binary stellar pairs of Bahcall and Soneira. There are 16 unambiguous cases of which six pairs are physical binaries. Projected separations of the binaries are estimated using the observed angular separations and well-determined spectroscopic parallaxes. The projected separations vary from about 0.002 pc to 0.08 pc. This validation of the statistical techniques used in identifying the candidate wide binaries opens up the possibility of large-scale systematic studies of the characteristics of wide binaries.

  5. 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.

  6. Binary classification of items of interest in a repeatable process

    DOEpatents

    Abell, Jeffrey A; Spicer, John Patrick; Wincek, Michael Anthony; Wang, Hui; Chakraborty, Debejyo

    2015-01-06

    A system includes host and learning machines. Each machine has a processor in electrical communication with at least one sensor. Instructions for predicting a binary quality status of an item of interest during a repeatable process are recorded in memory. The binary quality status includes passing and failing binary classes. The learning machine receives signals from the at least one sensor and identifies candidate features. Features are extracted from the candidate features, each more predictive of the binary quality status. The extracted features are mapped to a dimensional space having a number of dimensions proportional to the number of extracted features. The dimensional space includes most of the passing class and excludes at least 90 percent of the failing class. Received signals are compared to the boundaries of the recorded dimensional space to predict, in real time, the binary quality status of a subsequent item of interest.

  7. Elucidating the True Binary Fraction of VLM Stars and Brown Dwarfs with Spectral Binaries

    NASA Astrophysics Data System (ADS)

    Bardalez Gagliuffi, Daniella; Burgasser, Adam J.; Gelino, Christopher R.; SAHLMANN, JOHANNES; Schmidt, Sarah J.; Gagne, Jonathan; Skrzypek, Nathalie

    2017-01-01

    The very lowest-mass (VLM) stars and brown dwarfs are found in abundance in nearly all Galactic environments, yet their formation mechanism(s) remain an open question. One means of testing current formation theories is to use multiplicity statistics. The majority of VLM binaries have been discovered through direct imaging, and current angular resolution limits (0.05”-0.1") are coincident with the 1-4 AU peak in the projected separation distribution of known systems, suggesting an observational bias. I have developed a separation-independent method to detect T dwarf companions to late-M/early-L dwarfs by identifying methane absorption in their unresolved, low-resolution, near-infrared spectra using spectral indices and template fitting. Over 60 spectral binary candidates have been identified with this and comparable methods. I discuss follow-up observations, including laser-guide star adaptive optics imaging with Keck/NIRC2, which have confirmed 9 systems; and radial velocity and astrometric monitoring observations that have confirmed 7 others. The direct imaging results indicate a resolved binary fraction of 18%, coincident with current estimates of the VLM binary fraction; however, our sample contained 5 previously confirmed binaries, raising its true binary fraction to 47%. To more accurately measure the true VLM binary fraction, I describe the construction of an unbiased, volume-limited, near-infrared spectral sample of M7-L5 dwarfs within 25 pc, of which 4 (1%) are found to be spectral binary candidates. I model the complex selection biases of this method through a population simulation, set constraints on the true binary fraction as traced by these systems, and compare to the predictions of current formation theories. I also describe how this method may be applied to conduct a separation-unbiased search for giant exoplanets orbiting young VLM stars and brown dwarfs.

  8. Binary stars in loose associations

    NASA Astrophysics Data System (ADS)

    Azulay, R.; Guirado, J. C.; Marcaide, J. M.; Martí-Vidal, I.

    2013-05-01

    Precise determinations of dynamical masses of pre-main-sequence (PMS) stars are necessary to calibrate PMS stellar evolutionary models, whose predictions are in disagreement with measurements for masses below 1.2 M_{⊙}. Binary stars in young, nearby loose associations (moving groups) are particularly good candidates, primarily because all members share a common age. Belonging to the AB Doradus moving group, we have observed the binary AB Dor Ba/Bb, 0.06" separation, with the Australian Long Baseline Array at 8.4 GHz. We have detected the two components Ba/Bb, which facilitates (i) a measurement of the relative orbital motion through subsequent radio maps, and (ii) an estimate of the orbital parameters, once combined the radio information with infrared relative astrometry. Our preliminary analysis shows that best-fit orbit corresponds to that with a period of 1.1 yr and semi major axis of 0.068". The sum of the masses AB Dor Ba/Bb is 0.3±0.1 M_{⊙}. The study of this binary, along with other stars of the same association, will constitute a benchmark for testing PMS models of low-mass stars.

  9. Ultra-short period binaries from the Catalina Surveys

    SciTech Connect

    Drake, A. J.; Djorgovski, S. G.; Graham, M. J.; Mahabal, A. A.; Donalek, C.; Williams, R.; García-Álvarez, D.; Catelan, M.; Torrealba, G.; Prieto, J. L.; Abraham, S.; Larson, S.; Christensen, E.

    2014-08-01

    We investigate the properties of 367 ultra-short period binary candidates selected from 31,000 sources recently identified from Catalina Surveys data. Based on light curve morphology, along with WISE, Sloan Digital Sky Survey, and GALEX multi-color photometry, we identify two distinct groups of binaries with periods below the 0.22 day contact binary minimum. In contrast to most recent work, we spectroscopically confirm the existence of M dwarf+M dwarf contact binary systems. By measuring the radial velocity variations for five of the shortest-period systems, we find examples of rare cool white dwarf (WD)+M dwarf binaries. Only a few such systems are currently known. Unlike warmer WD systems, their UV flux and optical colors and spectra are dominated by the M-dwarf companion. We contrast our discoveries with previous photometrically selected ultra-short period contact binary candidates and highlight the ongoing need for confirmation using spectra and associated radial velocity measurements. Overall, our analysis increases the number of ultra-short period contact binary candidates by more than an order of magnitude.

  10. Ultra-Short-Period Binary Systems in the OGLE Fields Toward the Galactic Bulge

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

    We present a sample of 242 ultra-short-period (Porb<0.22 d) eclipsing and ellipsoidal binary stars identified in the OGLE fields toward the Galactic bulge. Based on the light curve morphology, we divide the sample into candidates for contact binaries and non-contact binaries. In the latter group we distinguish binary systems consisting of a cool main-sequence star and a B-type subdwarf (HW Vir stars) and candidates for cataclysmic variables, including five eclipsing dwarf novae. One of the detected eclipsing binary systems - OGLE-BLG-ECL-000066 - with the orbital period below 0.1 d, likely consists of M dwarfs in a nearly contact configuration. If confirmed, this would be the shortest-period M-dwarf binary system currently known. We discuss possible evolutionary mechanisms that could lead to the orbital period below 0.1 d in an M-dwarf binary.

  11. 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.

  12. 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.

  13. On binary channels to anomalous Cepheids

    NASA Astrophysics Data System (ADS)

    Gautschy, Alfred; Saio, Hideyuki

    2017-07-01

    Anomalous Cepheids are a rather rare family of pulsating variables preferably found in dwarf galaxies. Attempts to model these variable stars via single-star evolution scenarios still leave space for improvements to better grasp their origin. Focusing on the Large Magellanic Cloud with its rich population of anomalous Cepheids to compare against, we probe the role binary stars might play to understand the nature of anomalous Cepheids. The evolution of donors and accretors undergoing Case-B mass transfer along the first red giant branch as well as merger-like models was calculated. First results show that in binary scenarios, a larger range of star masses and metallicities up to Z ≲ 0.008, higher than deemed possible hitherto, enter and pass through the instability strip. If binary stars play a role in anomalous Cepheid populations, mass donors, mass accretors or even mergers are potential candidates to counteract constraints imposed by the single-star approach.

  14. 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.

  15. X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Lewin, Walter H. G.; van Paradijs, Jan; van den Heuvel, Edward Peter Jacobus

    1997-01-01

    Preface; 1. The properties of X-ray binaries, N. E. White, F. Nagase and A. N. Parmar; 2. Optical and ultraviolet observations of X-ray binaries J. van Paradijs and J. E. McClintock; 3. Black-hole binaries Y. Tanaka and W. H. G. Lewin; 4. X-ray bursts Walter H. G. Lewin, Jan Van Paradijs and Ronald E. Taam; 5. Millisecond pulsars D. Bhattacharya; 6. Rapid aperiodic variability in binaries M. van der Klis; 7. Radio properties of X-ray binaries R. M. Hjellming and X. Han; 8. Cataclysmic variable stars France Anne-Dominic Córdova; 9. Normal galaxies and their X-ray binary populations G. Fabbiano; 10. Accretion in close binaries Andrew King; 11. Formation and evolution of neutron stars and black holes in binaries F. Verbunt and E. P. J. van den Heuvel; 12. The magnetic fields of neutron stars and their evolution D. Bhattacharya and G. Srinivasan; 13. Cosmic gamma-ray bursts K. Hurley; 14. A catalogue of X-ray binaries Jan van Paradijs; 15. A compilation of cataclysmic binaries with known or suspected orbital periods Hans Ritter and Ulrich Kolb; References; Index.

  16. RR Lyrae binary systems in the Galactic bulge

    NASA Astrophysics Data System (ADS)

    Hajdu, Gergely; Catelan, Márcio

    2017-09-01

    The possibility of a direct mass measurement of RR Lyrae variable stars in binary systems has remained elusive for many years, due to the apparent paucity of such systems. Motivated by our recent success of finding a population of high confidence candidates, we have been continuing the search for RR Lyrae variables in binary systems towards the Galactic bulge. We describe the preliminary results of our project in these proceedings.

  17. (24495) 2001 AV1 - A Suspected Very Wide Binary

    NASA Astrophysics Data System (ADS)

    Stephens, Robert D.; Warner, Brian D.; Aznar Macias, Amadeo; Benishek, Vladimir

    2017-10-01

    We report that asteroid (24495) 2001 AV1 is a binary asteroid. It is another candidate for the special case of very wide binaries. The primary lightcurve has a period of 24.083 ± 0.005 h and an amplitude 0.58 ± 0.05 mag. and the secondary lightcurve has a period of 2.7375 ± 0.0001 h.

  18. Forming the wide asynchronous binary asteroid population

    NASA Astrophysics Data System (ADS)

    Jacobson, S.; Scheeres, D.; McMahon, J.

    2014-07-01

    We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semi-major axes relative to most near-Earth-asteroid and main-belt-asteroid systems as shown in the attached table. Confirmed members have rapidly rotating primaries and satellites that are not tidally locked. Previously suggested formation mechanisms from impact ejecta, from planetary flybys, and directly from rotational-fission events cannot satisfy all of the observations. The newly hypothesized mechanism works as follows: (1) these systems are formed from rotational fission, (2) their satellites are tidally locked, (3) their orbits are expanded by the binary Yarkovsky-O'Keefe-Radzievskii-Paddack (BYORP) effect, (4) their satellites desynchronize as a result of the adiabatic invariance between the libration of the secondary and the mutual orbit, and (5) the secondary avoids resynchronization because of the YORP effect. This seemingly complex chain of events is a natural pathway for binaries with satellites that have particular shapes, which define the BYORP effect torque that acts on the system. After detailing the theory, we analyze each of the wide-asynchronous-binary members and candidates to assess their most likely formation mechanism. Finally, we suggest possible future observations to check and constrain our hypothesis.

  19. Simulations of binary neutron star mergers

    NASA Astrophysics Data System (ADS)

    Kiuchi, Kenta

    2017-01-01

    The merger of a binary composed of a neutron star and/or a black hole is one of the most promising sources of gravitational waves. If we detected gravitational waves from them, it could tell us a validity of the general relativity in a strong gravitational field and the equation of state of neutron star matter. Furthermore, if gravitational waves from a compact binary merger and a short-hard gamma-ray burst are observed simultaneously, a long-standing puzzle on the central engine of short gamma-ray bursts could be resolved. In addition, compact binary mergers are a theoretical candidate of the rapid process nucleosynthesis site. Motivated by these facts, it is mandatory to build a physically reliable model of compact binary mergers and numerical relativity is a unique approach for this purpose. We are tackling this problem from several directions; the magneto-hydrodynamics, the neutrino radiation transfer, and a comprehensive study with simplified models. I will talk a current status of Kyoto Numerical Relativity group and future prospect on the compact binary mergers.

  20. DETECTION OF LOW-MASS-RATIO STELLAR BINARY SYSTEMS

    SciTech Connect

    Gullikson, Kevin; Dodson-Robinson, Sarah

    2013-01-01

    O- and B-type stars are often found in binary systems, but the low binary mass-ratio regime is relatively unexplored due to observational difficulties. Binary systems with low mass ratios may have formed through fragmentation of the circumstellar disk rather than molecular cloud core fragmentation. We describe a new technique sensitive to G- and K-type companions to early B stars, a mass ratio of roughly 0.1, using high-resolution, high signal-to-noise spectra. We apply this technique to a sample of archived VLT/CRIRES observations of nearby B stars in the CO bandhead near 2300 nm. While there are no unambiguous binary detections in our sample, we identify HIP 92855 and HIP 26713 as binary candidates warranting follow-up observations. We use our non-detections to determine upper limits to the frequency of FGK stars orbiting early B-type primaries.

  1. Lifetime of binary asteroids versus gravitational encounters and collisions

    NASA Technical Reports Server (NTRS)

    Chauvineau, Bertrand; Farinella, Paolo; Mignard, F.

    1992-01-01

    We investigate the effect on the dynamics of a binary asteroid in the case of a near encounter with a third body. The dynamics of the binary is modeled as a two-body problem perturbed by an approaching body in the following ways: near encounters and collisions with a component of the system. In each case, the typical value of the two-body energy variation is estimated, and a random walk for the cumulative effect is assumed. Results are applied to some binary asteroid candidates. The main conclusion is that the collisional disruption is the dominant effect, giving lifetimes comparable to or larger than the age of the solar system.

  2. Optical candidates for two X-ray sources.

    NASA Technical Reports Server (NTRS)

    Brucato, R. J.; Kristian, J.

    1972-01-01

    Suggestion of the bright stars X Per and HD 77581 as possible candidates for the X-ray sources 2U 0352+30 and 2U 0900-40 respectively. The first is an active, rapidly rotating Be star which is losing mass. The second is similar to BD+34.3815 deg, a likely candidate for Cyg X-1, in spectral type and in the possibility that it may be a short-period binary.

  3. Case A Binary Evolution

    SciTech Connect

    Nelson, C A; Eggleton, P P

    2001-03-28

    We undertake a comparison of observed Algol-type binaries with a library of computed Case A binary evolution tracks. The library consists of 5500 binary tracks with various values of initial primary mass M{sub 10}, mass ratio q{sub 0}, and period P{sub 0}, designed to sample the phase-space of Case A binaries in the range -0.10 {le} log M{sub 10} {le} 1.7. Each binary is evolved using a standard code with the assumption that both total mass and orbital angular momentum are conserved. This code follows the evolution of both stars until the point where contact or reverse mass transfer occurs. The resulting binary tracks show a rich variety of behavior which we sort into several subclasses of Case A and Case B. We present the results of this classification, the final mass ratio and the fraction of time spent in Roche Lobe overflow for each binary system. The conservative assumption under which we created this library is expected to hold for a broad range of binaries, where both components have spectra in the range G0 to B1 and luminosity class III - V. We gather a list of relatively well-determined observed hot Algol-type binaries meeting this criterion, as well as a list of cooler Algol-type binaries where we expect significant dynamo-driven mass loss and angular momentum loss. We fit each observed binary to our library of tracks using a {chi}{sup 2}-minimizing procedure. We find that the hot Algols display overall acceptable {chi}{sup 2}, confirming the conservative assumption, while the cool Algols show much less acceptable {chi}{sup 2} suggesting the need for more free parameters, such as mass and angular momentum loss.

  4. Close Binary Progenitors and Ejected Companions of Thermonuclear Supernovae

    NASA Astrophysics Data System (ADS)

    Geier, S.; Kupfer, T.; Heber, U.; Nemeth, P.; Ziegerer, E.; Irrgang, A.; Schindewolf, M.; Marsh, T. R.; Gänsicke, B. T.; Barlow, B. N.; Bloemen, S.

    2017-03-01

    Hot subdwarf stars (sdO/Bs) are evolved core helium-burning stars with very thin hydrogen envelopes, which can be formed by common envelope ejection. Close sdB binaries with massive white dwarf (WD) companions are potential progenitors of thermonuclear supernovae type Ia (SN Ia). We discovered such a progenitor candidate as well as a candidate for a surviving companion star, which escapes from the Galaxy. More candidates for both types of objects have been found by cross-matching known sdB stars with proper motion and light curve catalogues. We found 72 sdO/B candidates with high Galactic restframe velocities, 12 of them might be unbound to our Galaxy. Furthermore, we discovered the second-most compact sdB+WD binary known. However, due to the low mass of the WD companion, it is unlikely to be a SN Ia progenitor.

  5. Binary Galaxies in Clusters

    NASA Astrophysics Data System (ADS)

    Ip, Peter Shun Sang

    1994-01-01

    CCD images of the binary-rich clusters of galaxies A373, A408, A667, A890, and A1250 taken at the Canada-France-Hawaii telescope show that about half the binary galaxies' are actually star-galaxy or star-star pairs. These clusters are not binary-rich. N-body simulations are used to study the effect of static cluster potentials on binary and single galaxies. The softening procedure is discussed in detail. Since Plummer softening is not self-consistent, and since the force laws for various other density models are similar to each other, uniform-density softening is used. The choice of the theoretical galaxy model in terms of the potential at various locations. A fixed cluster potential cannot stabilize binary galaxies against merger, but can disrupt even quite tightly bound binaries. A moderately good predictor of whether a binary merges or disrupts is the mean torque over a quarter of the initial binary period. But the dynamics of the situation is quite complicated, and depends on an interplay between the motion of the binary through the cluster and the absorption of orbital energy by the galaxies. There is also a substantial amount of mass loss. Simulations of single galaxies in cluster show that this mass loss is due mainly to the cluster potential, and not to an interplay between the merging binary and the cluster. This mass loss is driven partially by virial equilibrium responding to the initial tidal truncation by the cluster. Besides verifying some general results of mass loss from satellite systems in the tidal field of larger bodies, it was found that the galaxy loses mass at an exponential rate.

  6. X-ray spectroscopy of a recoiling SMBH candidate

    NASA Astrophysics Data System (ADS)

    Predehl, Peter

    2008-09-01

    Recent numerical relativity simulations of coalescencing supermassive black hole (SMBH) binaries predict that SMBHs can receive kicks with velocities up to several thousand km/s due to anisotropic emission of gravitational waves. We have recently found the best candidate todate for such a recoiling SMBH (Komossa et al. 2008). We apply for a 25 ks ACIS-S exposure of this exceptional source.

  7. Taming the binaries

    NASA Astrophysics Data System (ADS)

    Pourbaix, D.

    2008-07-01

    Astrometric binaries are both a gold mine and a nightmare. They are a gold mine because they are sometimes the unique source of orbital inclination for spectroscopic binaries, thus making it possible for astrophysicists to get some clues about the mass of the often invisible secondary. However, this is an ideal situation in the sense that one benefits from the additional knowledge that it is a binary for which some orbital parameters are somehow secured (e.g. the orbital period). On the other hand, binaries are a nightmare, especially when their binary nature is not established yet. Indeed, in such cases, depending on the time interval covered by the observations compared to the orbital period, either the parallax or the proper motion can be severely biased if the successive positions of the binary are modelled assuming it is a single star. With large survey campaigns sometimes monitoring some stars for the first time ever, it is therefore crucial to design robust reduction pipelines in which such troublesome objects are quickly identified and either removed or processed accordingly. Finally, even if an object is known not to be a single star, the binary model might turn out not to be the most appropriate for describing the observations. These different situations will be covered.

  8. EXTRASOLAR BINARY PLANETS. II. DETECTABILITY BY TRANSIT OBSERVATIONS

    SciTech Connect

    Lewis, K. M.; Ida, S.; Ochiai, H.; Nagasawa, M.

    2015-05-20

    We discuss the detectability of gravitationally bound pairs of gas-giant planets (which we call “binary planets”) in extrasolar planetary systems that are formed through orbital instability followed by planet–planet dynamical tides during their close encounters, based on the results of N-body simulations by Ochiai et al. (Paper I). Paper I showed that the formation probability of a binary is as much as ∼10% for three giant planet systems that undergo orbital instability, and after post-capture long-term tidal evolution, the typical binary separation is three to five times the sum of the physical radii of the planets. The binary planets are stable during the main-sequence lifetime of solar-type stars, if the stellarcentric semimajor axis of the binary is larger than 0.3 AU. We show that detecting modulations of transit light curves is the most promising observational method to detect binary planets. Since the likely binary separations are comparable to the stellar diameter, the shape of the transit light curve is different from transit to transit, depending on the phase of the binary’s orbit. The transit durations and depth for binary planet transits are generally longer and deeper than those for the single planet case. We point out that binary planets could exist among the known inflated gas-giant planets or objects classified as false positive detections at orbital radii ≳0.3 AU, propose a binary planet explanation for the CoRoT candidate SRc01 E2 1066, and show that binary planets are likely to be present in, and could be detected using, Kepler-quality data.

  9. Massive Stars in Interactive Binaries

    NASA Astrophysics Data System (ADS)

    St.-Louis, Nicole; Moffat, Anthony F. J.

    Massive stars start their lives above a mass of ~8 time solar, finally exploding after a few million years as core-collapse or pair-production supernovae. Above ~15 solar masses, they also spend most of their lives driving especially strong, hot winds due to their extreme luminosities. All of these aspects dominate the ecology of the Universe, from element enrichment to stirring up and ionizing the interstellar medium. But when they occur in close pairs or groups separated by less than a parsec, the interaction of massive stars can lead to various exotic phenomena which would not be seen if there were no binaries. These depend on the actual separation, and going from wie to close including colliding winds (with non-thermal radio emission and Wolf-Rayet dust spirals), cluster dynamics, X-ray binaries, Roche-lobe overflow (with inverse mass-ratios and rapid spin up), collisions, merging, rejuventation and massive blue stragglers, black-hole formation, runaways and gamma-ray bursts. Also, one wonders whether the fact that a massive star is in a binary affects its parameters compared to its isolated equivalent. These proceedings deal with all of these phenomena, plus binary statistics and determination of general physical properties of massive stars, that would not be possible with their single cousins. The 77 articles published in these proceedings, all based on oral talks, vary from broad revies to the lates developments in the field. About a third of the time was spent in open discussion of all participants, both for ~5 minutes after each talk and 8 half-hour long general dialogues, all audio-recorded, transcribed and only moderately edited to yield a real flavour of the meeting. The candid information in these discussions is sometimes more revealing than the article(s) that preceded them and also provide entertaining reading. The book is suitable for researchers and graduate students interested in stellar astrophysics and in various physical processes involved when

  10. Binary Minor Planets

    NASA Astrophysics Data System (ADS)

    Richardson, Derek C.; Walsh, Kevin J.

    2006-05-01

    A review of observations and theories regarding binary asteroids and binary trans-Neptunian objects [collectively, binary minor planets (BMPs)] is presented. To date, these objects have been discovered using a combination of direct imaging, lightcurve analysis, and radar. They are found throughout the Solar System, and present a challenge for theorists modeling their formation in the context of Solar System evolution. The most promising models invoke rotational disruption for the smallest, shortest-lived objects (the asteroids nearest to Earth), consistent with the observed fast rotation of these bodies; impacts for the larger, longer-lived asteroids in the main belt, consistent with the range of size ratios of their components and slower rotation rates; and mutual capture for the distant, icy, trans-Neptunian objects, consistent with their large component separations and near-equal sizes. Numerical simulations have successfully reproduced key features of the binaries in the first two categories; the third remains to be investigated in detail.

  11. Binaries in globular clusters

    NASA Technical Reports Server (NTRS)

    Hut, Piet; Mcmillan, Steve; Goodman, Jeremy; Mateo, Mario; Phinney, E. S.; Pryor, Carlton; Richer, Harvey B.; Verbunt, Frank; Weinberg, Martin

    1992-01-01

    Recent observations have shown that globular clusters contain a substantial number of binaries most of which are believed to be primordial. We discuss different successful optical search techniques, based on radial-velocity variables, photometric variables, and the positions of stars in the color-magnitude diagram. In addition, we review searches in other wavelengths, which have turned up low-mass X-ray binaries and more recently a variety of radio pulsars. On the theoretical side, we give an overview of the different physical mechanisms through which individual binaries evolve. We discuss the various simulation techniques which recently have been employed to study the effects of a primordial binary population, and the fascinating interplay between stellar evolution and stellar dynamics which drives globular-cluster evolution.

  12. Double Degenerate Binary Systems

    SciTech Connect

    Yakut, K.

    2011-09-21

    In this study, angular momentum loss via gravitational radiation in double degenerate binary (DDB)systems (NS + NS, NS + WD, WD + WD, and AM CVn) is studied. Energy loss by gravitational waves has been estimated for each type of systems.

  13. Binary Populations and Stellar Dynamics in Young Clusters

    NASA Astrophysics Data System (ADS)

    Vanbeveren, D.; Belkus, H.; Van Bever, J.; Mennekens, N.

    2008-06-01

    We first summarize work that has been done on the effects of binaries on theoretical population synthesis of stars and stellar phenomena. Next, we highlight the influence of stellar dynamics in young clusters by discussing a few candidate UFOs (unconventionally formed objects) like intermediate mass black holes, η Car, ζ Pup, γ2 Velorum and WR 140.

  14. A new open cluster binary system in the Milky Way

    NASA Astrophysics Data System (ADS)

    Piatti, A. E.; Clariá, J. J.; Ahumada, A. V.

    2011-10-01

    We have obtained CCD UBVI_{KC} photometry for the open clusters (OCs) Hogg 12 and NGC 3590. Based on photometric and morphological criteria, as well as on the stellar density in the region, our evidence is sufficient to consider them a new open cluster binary system candidate.

  15. Binary technetium halides

    NASA Astrophysics Data System (ADS)

    Johnstone, Erik Vaughan

    In this work, the synthetic and coordination chemistry as well as the physico-chemical properties of binary technetium (Tc) chlorides, bromides, and iodides were investigated. Resulting from these studies was the discovery of five new binary Tc halide phases: alpha/beta-TcCl3, alpha/beta-TcCl 2, and TcI3, and the reinvestigation of the chemistries of TcBr3 and TcX4 (X = Cl, Br). Prior to 2009, the chemistry of binary Tc halides was poorly studied and defined by only three compounds, i.e., TcF6, TcF5, and TcCl4. Today, ten phases are known (i.e., TcF6, TcF5, TcCl4, TcBr 4, TcBr3, TcI3, alpha/beta-TcCl3 and alpha/beta-TcCl2) making the binary halide system of Tc comparable to those of its neighboring elements. Technetium binary halides were synthesized using three methods: reactions of the elements in sealed tubes, reactions of flowing HX(g) (X = Cl, Br, and I) with Tc2(O2CCH3)4Cl2, and thermal decompositions of TcX4 (X = Cl, Br) and alpha-TcCl 3 in sealed tubes under vacuum. Binary Tc halides can be found in various dimensionalities such as molecular solids (TcF6), extended chains (TcF5, TcCl4, alpha/beta-TcCl2, TcBr 3, TcI3), infinite layers (beta-TcCl3), and bidimensional networks of clusters (alpha-TcCl3); eight structure-types with varying degrees of metal-metal interactions are now known. The coordination chemistry of Tc binary halides can resemble that of the adjacent elements: molybdenum and ruthenium (beta-TcCl3, TcBr3, TcI 3), rhenium (TcF5, alpha-TcCl3), platinum (TcCl 4, TcBr4), or can be unique (alpha-TcCl2 and beta-TcCl 2) in respect to other known transition metal binary halides. Technetium binary halides display a range of interesting physical properties that are manifested from their electronic and structural configurations. The thermochemistry of binary Tc halides is extensive. These compounds can selectively volatilize, decompose, disproportionate, or convert to other phases. Ultimately, binary Tc halides may find application in the nuclear fuel

  16. X-ray binaries

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Satellite X-ray experiments and ground-based programs aimed at observation of X-ray binaries are discussed. Experiments aboard OAO-3, OSO-8, Ariel 5, Uhuru, and Skylab are included along with rocket and ground-based observations. Major topics covered are: Her X-1, Cyg X-3, Cen X-3, Cyg X-1, the transient source A0620-00, other possible X-ray binaries, and plans and prospects for future observational programs.

  17. Learning binary matroid ports

    SciTech Connect

    Coullard, C.; Hellerstein, L.

    1994-12-31

    Given a binary matroid M specified by a port oracle, we can in polynomial number of calls to the oracle construct a binary representation for M. For general matroids, we can in polynomial number of calls to a port oracle determine whether a given subset is independent (that is, we can simulate an independence oracle with a port oracle). The work is related to a theorem of Lehman on matroid ports, and is motivated by issues in computational learning theory.

  18. Binary-Symmetry Detection

    NASA Technical Reports Server (NTRS)

    Lopez, Hiram

    1987-01-01

    Transmission errors for zeros and ones tabulated separately. Binary-symmetry detector employs psuedo-random data pattern used as test message coming through channel. Message then modulo-2 added to locally generated and synchronized version of test data pattern in same manner found in manufactured test sets of today. Binary symmetrical channel shows nearly 50-percent ones to 50-percent zeroes correspondence. Degree of asymmetry represents imbalances due to either modulation, transmission, or demodulation processes of system when perturbed by noise.

  19. Spectroscopic Binary Stars

    NASA Astrophysics Data System (ADS)

    Batten, A.; Murdin, P.

    2000-11-01

    Historically, spectroscopic binary stars were binary systems whose nature was discovered by the changing DOPPLER EFFECT or shift of the spectral lines of one or both of the component stars. The observed Doppler shift is a combination of that produced by the constant RADIAL VELOCITY (i.e. line-of-sight velocity) of the center of mass of the whole system, and the variable shift resulting from the o...

  20. Scattering from binary optics

    NASA Technical Reports Server (NTRS)

    Ricks, Douglas W.

    1993-01-01

    There are a number of sources of scattering in binary optics: etch depth errors, line edge errors, quantization errors, roughness, and the binary approximation to the ideal surface. These sources of scattering can be systematic (deterministic) or random. In this paper, scattering formulas for both systematic and random errors are derived using Fourier optics. These formulas can be used to explain the results of scattering measurements and computer simulations.

  1. RADIO-SELECTED BINARY ACTIVE GALACTIC NUCLEI FROM THE VERY LARGE ARRAY STRIPE 82 SURVEY

    SciTech Connect

    Fu, Hai; Myers, A. D.; Djorgovski, S. G.; Yan, Lin; Wrobel, J. M.; Stockton, A.

    2015-01-20

    Galaxy mergers play an important role in the growth of galaxies and their supermassive black holes. Simulations suggest that tidal interactions could enhance black hole accretion, which can be tested by the fraction of binary active galactic nuclei (AGNs) among galaxy mergers. However, determining the fraction requires a statistical sample of binaries. We have identified kiloparsec-scale binary AGNs directly from high-resolution radio imaging. Inside the 92 deg{sup 2} covered by the high-resolution Very Large Array survey of the Sloan Digital Sky Survey (SDSS) Stripe 82 field, we identified 22 grade A and 30 grade B candidates of binary radio AGNs with angular separations less than 5'' (10 kpc at z = 0.1). Eight of the candidates have optical spectra for both components from the SDSS spectroscopic surveys and our Keck program. Two grade B candidates are projected pairs, but the remaining six candidates are all compelling cases of binary AGNs based on either emission line ratios or the excess in radio power compared to the Hα-traced star formation rate. Only two of the six binaries were previously discovered by an optical spectroscopic search. Based on these results, we estimate that ∼60% of our binary candidates would be confirmed once we obtain complete spectroscopic information. We conclude that wide-area high-resolution radio surveys offer an efficient method to identify large samples of binary AGNs. These radio-selected binary AGNs complement binaries identified at other wavelengths and are useful for understanding the triggering mechanisms of black hole accretion.

  2. Radio-selected Binary Active Galactic Nuclei from the Very Large Array Stripe 82 Survey

    NASA Astrophysics Data System (ADS)

    Fu, Hai; Myers, A. D.; Djorgovski, S. G.; Yan, Lin; Wrobel, J. M.; Stockton, A.

    2015-01-01

    Galaxy mergers play an important role in the growth of galaxies and their supermassive black holes. Simulations suggest that tidal interactions could enhance black hole accretion, which can be tested by the fraction of binary active galactic nuclei (AGNs) among galaxy mergers. However, determining the fraction requires a statistical sample of binaries. We have identified kiloparsec-scale binary AGNs directly from high-resolution radio imaging. Inside the 92 deg2 covered by the high-resolution Very Large Array survey of the Sloan Digital Sky Survey (SDSS) Stripe 82 field, we identified 22 grade A and 30 grade B candidates of binary radio AGNs with angular separations less than 5'' (10 kpc at z = 0.1). Eight of the candidates have optical spectra for both components from the SDSS spectroscopic surveys and our Keck program. Two grade B candidates are projected pairs, but the remaining six candidates are all compelling cases of binary AGNs based on either emission line ratios or the excess in radio power compared to the Hα-traced star formation rate. Only two of the six binaries were previously discovered by an optical spectroscopic search. Based on these results, we estimate that ~60% of our binary candidates would be confirmed once we obtain complete spectroscopic information. We conclude that wide-area high-resolution radio surveys offer an efficient method to identify large samples of binary AGNs. These radio-selected binary AGNs complement binaries identified at other wavelengths and are useful for understanding the triggering mechanisms of black hole accretion. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  3. WHITE-DWARF-MAIN-SEQUENCE BINARIES IDENTIFIED FROM THE LAMOST PILOT SURVEY

    SciTech Connect

    Ren Juanjuan; Luo Ali; Li Yinbi; Wei Peng; Zhao Jingkun; Zhao Yongheng; Song Yihan; Zhao Gang E-mail: lal@nao.cas.cn

    2013-10-01

    We present a set of white-dwarf-main-sequence (WDMS) binaries identified spectroscopically from the Large sky Area Multi-Object fiber Spectroscopic Telescope (LAMOST, also called the Guo Shou Jing Telescope) pilot survey. We develop a color selection criteria based on what is so far the largest and most complete Sloan Digital Sky Survey (SDSS) DR7 WDMS binary catalog and identify 28 WDMS binaries within the LAMOST pilot survey. The primaries in our binary sample are mostly DA white dwarfs except for one DB white dwarf. We derive the stellar atmospheric parameters, masses, and radii for the two components of 10 of our binaries. We also provide cooling ages for the white dwarf primaries as well as the spectral types for the companion stars of these 10 WDMS binaries. These binaries tend to contain hot white dwarfs and early-type companions. Through cross-identification, we note that nine binaries in our sample have been published in the SDSS DR7 WDMS binary catalog. Nineteen spectroscopic WDMS binaries identified by the LAMOST pilot survey are new. Using the 3{sigma} radial velocity variation as a criterion, we find two post-common-envelope binary candidates from our WDMS binary sample.

  4. Very massive binaries in R 136

    NASA Astrophysics Data System (ADS)

    Chené, André-Nicolas; Schnurr, Olivier; Crowther, Paul A.; Fernández-Lajús, Eduardo; Moffat, Anthony F. J.

    2011-07-01

    As recent observations have shown, luminous, hydrogen-rich WN5-7h stars (and their somewhat less extreme cousins, O3f/WN6 stars) are the most massive main-sequence stars known. However, not nearly enough very massive stars have been reliably weighed to yield a clear picture of the upper initial-mass function (IMF). We therefore have carried out repeated high-quality spectroscopy of four new O3f/WN6 and WN5-7h binaries in R136 in the LMC with GMOS at Gemini-South, to derive Keplerian orbits for both components, respectively, and thus to directly determine their masses. We also monitored binary candidates and other, previously unsurveyed stars, to increase the number of very massive stars that can be directly weighed.

  5. Computational selection and prioritization of candidate genes for Fetal Alcohol Syndrome

    PubMed Central

    Lombard, Zané; Tiffin, Nicki; Hofmann, Oliver; Bajic, Vladimir B; Hide, Winston; Ramsay, Michèle

    2007-01-01

    Background Fetal alcohol syndrome (FAS) is a serious global health problem and is observed at high frequencies in certain South African communities. Although in utero alcohol exposure is the primary trigger, there is evidence for genetic- and other susceptibility factors in FAS development. No genome-wide association or linkage studies have been performed for FAS, making computational selection and -prioritization of candidate disease genes an attractive approach. Results 10174 Candidate genes were initially selected from the whole genome using a previously described method, which selects candidate genes according to their expression in disease-affected tissues. Hereafter candidates were prioritized for experimental investigation by investigating criteria pertinent to FAS and binary filtering. 29 Criteria were assessed by mining various database sources to populate criteria-specific gene lists. Candidate genes were then prioritized for experimental investigation using a binary system that assessed the criteria gene lists against the candidate list, and candidate genes were scored accordingly. A group of 87 genes was prioritized as candidates and for future experimental validation. The validity of the binary prioritization method was assessed by investigating the protein-protein interactions, functional enrichment and common promoter element binding sites of the top-ranked genes. Conclusion This analysis highlighted a list of strong candidate genes from the TGF-β, MAPK and Hedgehog signalling pathways, which are all integral to fetal development and potential targets for alcohol's teratogenic effect. We conclude that this novel bioinformatics approach effectively prioritizes credible candidate genes for further experimental analysis. PMID:17961254

  6. The Cool Surfaces of Binaries Near-Earth Asteroids

    NASA Astrophysics Data System (ADS)

    Delbo, Marco; Walsh, K.; Mueller, M.

    2008-09-01

    We present results from thermal-infrared observations of binary near-Earth asteroids (NEAs). These objects, in general, have surface temperatures cooler than the average values for non-binary NEAs. We discuss how this may be evidence of higher-than-average surface thermal inertia. The comparison of these binary NEAs with all NEAs and rapidly rotating NEAs suggests a binary formation mechanism capable of altering surface properties, possibly removing regolith: an obvious candidate is the YORP effect. --- Acknowledgments This research was carried out while Marco Delbo and Kevin Walsh were Henri Poincare Fellows at the Observatoire de la Cote d'Azur. The Henri Poincare Fellowship is funded by the CNRS-INSU, the Conseil General des Alpes-Maritimes and the Rotary International -- District 1730.

  7. Solar System binaries

    NASA Astrophysics Data System (ADS)

    Noll, Keith S.

    The discovery of binaries in each of the major populations of minor bodies in the solar system is propelling a rapid growth of heretofore unattainable physical information. The availability of mass and density constraints for minor bodies opens the door to studies of internal structure, comparisons with meteorite samples, and correlations between bulk-physical and surface-spectral properties. The number of known binaries is now more than 70 and is growing rapidly. A smaller number have had the extensive followup observations needed to derive mass and albedo information, but this list is growing as well. It will soon be the case that we will know more about the physical parameters of objects in the Kuiper Belt than has been known about asteroids in the Main Belt for the last 200 years. Another important aspect of binaries is understanding the mechanisms that lead to their formation and survival. The relative sizes and separations of binaries in the different minor body populations point to more than one mechanism for forming bound pairs. Collisions appear to play a major role in the Main Belt. Rotational and/or tidal fission may be important in the Near Earth population. For the Kuiper Belt, capture in multi-body interactions may be the preferred formation mechanism. However, all of these conclusions remain tentative and limited by observational and theoretical incompleteness. Observational techniques for identifying binaries are equally varied. High angular resolution observations from space and from the ground are critical for detection of the relatively distant binaries in the Main Belt and the Kuiper Belt. Radar has been the most productive method for detection of Near Earth binaries. Lightcurve analysis is an independent technique that is capable of exploring phase space inaccessible to direct observations. Finally, spacecraft flybys have played a crucial paradigm-changing role with discoveries that unlocked this now-burgeoning field.

  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. Binaries and the dynamical evolution of globular clusters

    NASA Astrophysics Data System (ADS)

    Ji, Jun

    Binaries are thought to be the primary heating source in globular clusters, since they can heat the environment of globular clusters by converting their binding energy to the kinetic energy of the incoming stars through the dynamical interactions. Even a small primordial binary fraction is sufficient to postpone globular clusters from the core collapse for many relaxation times. So the binary fraction is an essential parameter which can dramatically affect the dynamical evolution of globular clusters. In this thesis work, I determined the binary fractions for a sample of 35 Galactic globular clusters with their color-magnitude diagrams (CMDs), which covers a wide range of the dynamical ages and metallicity. Those CMDs were constructed with the PSF photometry by Dolphot (V1.2) from their HST ACS archival data. Three different methods were used to estimate the binary fractions within the core, the half-mass radius, and the whole field of view regions. The binary fractions along the cluster radial bins were also analyzed. From the results, I found that the mean binary fractions within the core and the half-mass radii are 7.0% and 5.6%, respectively. The binary fractions within the core and the half-mass radii correlate with the cluster ages, with decreasing binary fractions against time, but not with their dynamical times and metallicity. The binary fractions within the half-mass radius also correlate with the cluster absolute V magnitudes, with fainter clusters having higher binary fractions. The radial distribution of the binary fractions show a significant correlation with the cluster radii, with decreasing values outwards. This is consistent with the mass segregation effect predicted by the simulations of the dynamical evolution of globular clusters. I also compiled a catalog containing 6,004 high mass-ratio binary candidates selected from 23 Galactic globular clusters in our sample through their CMDs, which can be used to search the main

  10. Binary Cepheids From High-Angular Resolution

    NASA Astrophysics Data System (ADS)

    Gallenne, A.; Mérand, A.; Kervella, P.

    2015-12-01

    Optical interferometry is the only technique giving access to milli-arcsecond (mas) spatial resolution. This is a powerful and unique tool to detect the close orbiting companions of Cepheids, and offers an unique opportunity to make progress in resolving the Cepheid mass discrepancy. Our goal in studying binary Cepheids is to measure the astrometric position of the high-contrast companion, and then combine them with spectroscopic measurements to derive the orbital elements, distances, and dynamical masses. In the course of this program, we developed a new tool, CANDID, to search for high-contrast companions and set detection limits from interferometric observations

  11. Candidate CDTI procedures study

    NASA Technical Reports Server (NTRS)

    Ace, R. E.

    1981-01-01

    A concept with potential for increasing airspace capacity by involving the pilot in the separation control loop is discussed. Some candidate options are presented. Both enroute and terminal area procedures are considered and, in many cases, a technologically advanced Air Traffic Control structure is assumed. Minimum display characteristics recommended for each of the described procedures are presented. Recommended sequencing of the operational testing of each of the candidate procedures is presented.

  12. SEARCH FOR SUPERMASSIVE BLACK HOLE BINARIES IN THE SLOAN DIGITAL SKY SURVEY SPECTROSCOPIC SAMPLE

    SciTech Connect

    Ju, Wenhua; Greene, Jenny E.; Rafikov, Roman R.; Bickerton, Steven J.; Badenes, Carles

    2013-11-01

    Supermassive black hole (SMBH) binaries are expected in a ΛCDM cosmology given that most (if not all) massive galaxies contain a massive black hole (BH) at their center. So far, however, direct evidence for such binaries has been elusive. We use cross-correlation to search for temporal velocity shifts in the Mg II broad emission lines of 0.36 < z < 2 quasars with multiple observations in the Sloan Digital Sky Survey. For ∼10{sup 9} M{sub ☉} BHs in SMBH binaries, we are sensitive to velocity drifts for binary separations of ∼0.1 pc with orbital periods of ∼100 yr. We find seven candidate sub-parsec-scale binaries with velocity shifts >3.4σ ∼ 280 km s{sup –1}, where σ is our systematic error. Comparing the detectability of SMBH binaries with the number of candidates (N ≤ 7), we can rule out that most 10{sup 9} M{sub ☉} BHs exist in ∼0.03-0.2 pc scale binaries, in a scenario where binaries stall at sub-parsec scales for a Hubble time. We further constrain that ≤16% (one-third) of quasars host SMBH binaries after considering gas-assisted sub-parsec evolution of SMBH binaries, although this result is very sensitive to the assumed size of the broad line region. We estimate the detectability of SMBH binaries with ongoing or next-generation surveys (e.g., Baryon Oscillation Spectroscopic Survey, Subaru Prime Focus Spectrograph), taking into account the evolution of the sub-parsec binary in circumbinary gas disks. These future observations will provide longer time baselines for searches similar to ours and may in turn constrain the evolutionary scenarios of SMBH binaries.

  13. Binary ferrihydrite catalysts

    DOEpatents

    Huffman, G.P.; Zhao, J.; Feng, Z.

    1996-12-03

    A method of preparing a catalyst precursor comprises dissolving an iron salt and a salt of an oxoanion forming agent, in water so that a solution of the iron salt and oxoanion forming agent salt has a ratio of oxoanion/Fe of between 0.0001:1 to 0.5:1. Next is increasing the pH of the solution to 10 by adding a strong base followed by collecting of precipitate having a binary ferrihydrite structure. A binary ferrihydrite catalyst precursor is also prepared by dissolving an iron salt in water. The solution is brought to a pH of substantially 10 to obtain ferrihydrite precipitate. The precipitate is then filtered and washed with distilled water and subsequently admixed with a hydroxy carboxylic acid solution. The admixture is mixed/agitated and the binary ferrihydrite precipitate is then filtered and recovered. 3 figs.

  14. Binary and Millisecond Pulsars.

    PubMed

    Lorimer, Duncan R

    2008-01-01

    We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1800. There are now 83 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 140 pulsars in 26 of the Galactic globular clusters. Recent highlights include the discovery of the young relativistic binary system PSR J1906+0746, a rejuvination in globular cluster pulsar research including growing numbers of pulsars with masses in excess of 1.5 M⊙, a precise measurement of relativistic spin precession in the double pulsar system and a Galactic millisecond pulsar in an eccentric (e = 0.44) orbit around an unevolved companion.

  15. Binary ferrihydrite catalysts

    DOEpatents

    Huffman, Gerald P.; Zhao, Jianmin; Feng, Zhen

    1996-01-01

    A method of preparing a catalyst precursor comprises dissolving an iron salt and a salt of an oxoanion forming agent, in water so that a solution of the iron salt and oxoanion forming agent salt has a ratio of oxoanion/Fe of between 0.0001:1 to 0.5:1. Next is increasing the pH of the solution to 10 by adding a strong base followed by collecting of precipitate having a binary ferrihydrite structure. A binary ferrihydrite catalyst precursor is also prepared by dissolving an iron salt in water. The solution is brought to a pH of substantially 10 to obtain ferrihydrite precipitate. The precipitate is then filtered and washed with distilled water and subsequently admixed with a hydroxy carboxylic acid solution. The admixture is mixed/agitated and the binary ferrihydrite precipitate is then filtered and recovered.

  16. Binary catalogue of exoplanets

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

    Since 1995 there is a database which list most of the known exoplanets (The Extrasolar Planets Encyclopaedia at http://exoplanet.eu/). With the growing number of detected exoplanets in binary and multiple star systems it became more important to mark and to separate them into a new database, which is not available in the Extrasolar Planets Encyclopaedia. Therefore we established an online database (which can be found at: http://www.univie.ac.at/adg/schwarz/multiple.html) for all known exoplanets in binary star systems and in addition for multiple star systems, which will be updated regularly and linked to the Extrasolar Planets Encyclopaedia. The binary catalogue of exoplanets is available online as data file and can be used for statistical purposes. Our database is divided into two parts: the data of the stars and the planets, given in a separate list. We describe also the different parameters of the exoplanetary systems and present some applications.

  17. Binary and Millisecond Pulsars.

    PubMed

    Lorimer, Duncan R

    2005-01-01

    We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1700. There are now 80 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 103 pulsars in 24 of the Galactic globular clusters. Recent highlights have been the discovery of the first ever double pulsar system and a recent flurry of discoveries in globular clusters, in particular Terzan 5.

  18. Binary Oscillatory Crossflow Electrophoresis

    NASA Technical Reports Server (NTRS)

    Molloy, Richard F.; Gallagher, Christopher T.; Leighton, David T., Jr.

    1996-01-01

    We present preliminary results of our implementation of a novel electrophoresis separation technique: Binary Oscillatory Cross flow Electrophoresis (BOCE). The technique utilizes the interaction of two driving forces, an oscillatory electric field and an oscillatory shear flow, to create an active binary filter for the separation of charged species. Analytical and numerical studies have indicated that this technique is capable of separating proteins with electrophoretic mobilities differing by less than 10%. With an experimental device containing a separation chamber 20 cm long, 5 cm wide, and 1 mm thick, an order of magnitude increase in throughput over commercially available electrophoresis devices is theoretically possible.

  19. Identification list of binaries

    NASA Astrophysics Data System (ADS)

    Malkov,, O.; Karchevsky,, A.; Kaygorodov, P.; Kovaleva, D.

    The Identification List of Binaries (ILB) is a star catalogue constructed to facilitate cross-referencing between different catalogues of binary stars. As of 2015, it comprises designations for approximately 120,000 double/multiple systems. ILB contains star coordinates and cross-references to the Bayer/Flemsteed, DM (BD/CD/CPD), HD, HIP, ADS, WDS, CCDM, TDSC, GCVS, SBC9, IGR (and some other X-ray catalogues), PSR designations, as well as identifications in the recently developed BSDB system. ILB eventually became a part of the BDB stellar database.

  20. Beam scanning binary logic

    NASA Astrophysics Data System (ADS)

    Itoh, Hideo; Mukai, Seiji; Watanabe, Masanobu; Mori, Masahiko; Yajima, Hiroyoshi

    1990-07-01

    A beam-scanning laser diode (BSLD) is presently applied to a novel optoelectronic logic operation, designated 'beam-scanning binary logic' (BSBL), that covers the implementation of both the basic logic gates and a spatial code encoder for photodetection, while allowing a greater reduction of the number of active devices than ordinary binary logic operations. BSBL executes multifunctional logic operations simultaneously. The data connections between logic gates in BSLD are flexible, due to the ability to electrically control both output power and laser-beam direction.

  1. T Tauri Spectroscopic Binaries

    NASA Astrophysics Data System (ADS)

    Dudorov, A. E.; Eretnova, O. V.

    2017-06-01

    The Hertzsprung-Russell diagram, the excess radius-age, and the eccentricity-period relations are constructed for double-lined spectroscopic T Tauri binaries. The masses and the ages of the classical T Tauri and the weak-line T Tauri stars are compared. All components of T Tauri stars have the excess radius in comparison with initial Main Sequence stars of corresponding mass. The younger the star the more excess radius it has. The overwhelming majority of close binaries (P<10d) have eccentricity near to zero. The fraction of quadruple systems in our sample are higher than for Main Sequence stars.

  2. DOUBLE-LINED SPECTROSCOPIC BINARY STARS IN THE RAVE SURVEY

    SciTech Connect

    Matijevic, G.; Zwitter, T.; Munari, U.; Siviero, A.; Bienayme, O.; Siebert, A.; Binney, J.; Bland-Hawthorn, J.; Boeche, C.; Steinmetz, M.; Campbell, R.; Freeman, K. C.; Gibson, B.; Gilmore, G.; Grebel, E. K.; Helmi, A.; Navarro, J. F.; Parker, Q. A.; Seabroke, G. M.; Watson, F. G.

    2010-07-15

    We devise a new method for the detection of double-lined binary stars in a sample of the Radial Velocity Experiment (RAVE) survey spectra. The method is both tested against extensive simulations based on synthetic spectra and compared to direct visual inspection of all RAVE spectra. It is based on the properties and shape of the cross-correlation function, and is able to recover {approx}80% of all binaries with an orbital period of order 1 day. Systems with periods up to 1 yr are still within the detection reach. We have applied the method to 25,850 spectra of the RAVE second data release and found 123 double-lined binary candidates, only eight of which are already marked as binaries in the SIMBAD database. Among the candidates, there are seven that show spectral features consistent with the RS CVn type (solar type with active chromosphere) and seven that might be of W UMa type (over-contact binaries). One star, HD 101167, seems to be a triple system composed of three nearly identical G-type dwarfs. The tested classification method could also be applicable to the data of the upcoming Gaia mission.

  3. Binary coding for hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Chang, Chein-I.; Chang, Chein-Chi; Lin, Chinsu

    2004-10-01

    Binary coding is one of simplest ways to characterize spectral features. One commonly used method is a binary coding-based image software system, called Spectral Analysis Manager (SPAM) for remotely sensed imagery developed by Mazer et al. For a given spectral signature, the SPAM calculates its spectral mean and inter-band spectral difference and uses them as thresholds to generate a binary code word for this particular spectral signature. Such coding scheme is generally effective and also very simple to implement. This paper revisits the SPAM and further develops three new SPAM-based binary coding methods, called equal probability partition (EPP) binary coding, halfway partition (HP) binary coding and median partition (MP) binary coding. These three binary coding methods along with the SPAM well be evaluated for spectral discrimination and identification. In doing so, a new criterion, called a posteriori discrimination probability (APDP) is also introduced for performance measure.

  4. 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.

  5. Separation in Binary Alloys

    NASA Technical Reports Server (NTRS)

    Frazier, D. O.; Facemire, B. R.; Kaukler, W. F.; Witherow, W. K.; Fanning, U.

    1986-01-01

    Studies of monotectic alloys and alloy analogs reviewed. Report surveys research on liquid/liquid and solid/liquid separation in binary monotectic alloys. Emphasizes separation processes in low gravity, such as in outer space or in free fall in drop towers. Advances in methods of controlling separation in experiments highlighted.

  6. Orbits For Sixteen Binaries

    NASA Astrophysics Data System (ADS)

    Cvetkovic, Z.; Novakovic, B.

    2006-12-01

    In this paper orbits for 13 binaries are recalculated and presented. The reason is that recent observations show higher residuals than the corresponding ephemerides calculated by using the orbital elements given in the Sixth Catalog of Orbits of Visual Binary Stars. The binaries studied were: WDS 00182+7257 = A 803, WDS 00335+4006 = HO 3, WDS 00583+2124 = BU 302, WDS 01011+6022 = A 926, WDS 01014+1155 = BU 867, WDS 01112+4113 = A 655, WDS 01361-2954 + HJ 3447, WDS 02333+5219 = STT 42 AB, WDS 04362+0814 = A 1840 AB, WDS 08017-0836 = A 1580, WDS 08277-0425 = A 550, WDS 17471+1742 = STF 2215 and WDS 18025+4414 = BU 1127 Aa-B. In addition, for three binaries - WDS 01532+1526 = BU 260, WDS 02563+7253 =STF 312 AB and WDS 05003+3924 = STT 92 AB - the orbital elements are calculated for the first time. In this paper the authors present not only the orbital elements, but the masses, dynamical parallaxes, absolute magnitudes and ephemerides for the next five years, as well.

  7. XMM-Newton Survey of Globular Cluster Ultracompact Binaries

    NASA Technical Reports Server (NTRS)

    Chakrabarty, Deepto

    2005-01-01

    Our program consisted of an observation of a single source, 4U 0513-40, which we had previously identified as a candidate ultracompact binary (a system with an orbital period below 1 hour). Several other known or suspected ultracompact binaries have shown unusual elemental abundance ratios in their X-ray spectra. In this program, however, our observation found no unusual abundance ratios in the spectrum of 4U 0513-40. This result was included, along with results from a separate Chandra program, in a paper submitted for publication in the Astrophysical Journal.

  8. XMM-Newton Survey of Globular Cluster Ultracompact Binaries

    NASA Technical Reports Server (NTRS)

    Chakrabarty, Deepto

    2005-01-01

    Our program consisted of an observation of a single source, 4U 0513-40, which we had previously identified as a candidate ultracompact binary (a system with an orbital period below 1 hour). Several other known or suspected ultracompact binaries have shown unusual elemental abundance ratios in their X-ray spectra. In this program, however, our observation found no unusual abundance ratios in the spectrum of 4U 0513-40. This result was included, along with results from a separate Chandra program, in a paper submitted for publication in the Astrophysical Journal.

  9. Planetary systems in binaries

    NASA Astrophysics Data System (ADS)

    Takeda, Genya

    In this thesis we investigate the orbital evolution of planets in binaries. Unlike our own Solar System, at least one out of five planetary systems known to date is associated with additional stellar companions. Despite their large distances from the planetary systems, these stellar companions play an important role in significantly altering the planetary architecture over very long timescales. Most of the planets in binaries are found in hierarchical configurations in which a planet orbits around a component of a wide stellar binary. The evolution of such hierarchical triples has been analytically understood through the framework of the Kozai mechanism, in which the orbital eccentricity of a planet secularly grows through angular momentum exchange with the stellar companion. The aim of our first study is to investigate the global effect of stellar companions in exciting planetary eccentricities through the Kozai mechanism, using synthetic eccentricity distributions computed numerically from various initial assumptions motivated by observational studies. As inferred from observations and theoretical planet formation simulations, newly formed planetary systems are more likely to be oligarchic, containing multiple giant planets. However, the long-term evolution of gravitationally coupled planets perturbed by a stellar companion has been little understood in the previous studies. From a large ensemble of numerical integrations of double-planet systems in binaries, we have found that there are various evolutionary classes of multiple planets in binaries compared to simple hierarchical triple systems containing only one planet. Using the Kozai mechanism and the Laplace-Lagrange secular theory, we also provide analytic criteria that can readily predict the secular evolutionary behavior of a pair of planetary orbits in binaries. In the last part of this thesis we discuss an alternative channel of planetary migration induced by a combined effect of dissipative tidal forces

  10. Correlated binary regression with covariates specific to each binary observation.

    PubMed

    Prentice, R L

    1988-12-01

    Regression methods are considered for the analysis of correlated binary data when each binary observation may have its own covariates. It is argued that binary response models that condition on some or all binary responses in a given "block" are useful for studying certain types of dependencies, but not for the estimation of marginal response probabilities or pairwise correlations. Fully parametric approaches to these latter problems appear to be unduly complicated except in such special cases as the analysis of paired binary data. Hence, a generalized estimating equation approach is advocated for inference on response probabilities and correlations. Illustrations involving both small and large block sizes are provided.

  11. Accreting Binary Populations in the Earlier Universe

    NASA Technical Reports Server (NTRS)

    Hornschemeier, Ann

    2010-01-01

    It is now understood that X-ray binaries dominate the hard X-ray emission from normal star-forming galaxies. Thanks to the deepest (2-4 Ms) Chandra surveys, such galaxies are now being studied in X-rays out to z approximates 4. Interesting X-ray stacking results (based on 30+ galaxies per redshift bin) suggest that the mean rest-frame 2-10 keV luminosity from z=3-4 Lyman break galaxies (LBGs), is comparable to the most powerful starburst galaxies in the local Universe. This result possibly indicates a similar production mechanism for accreting binaries over large cosmological timescales. To understand and constrain better the production of X-ray binaries in high-redshift LBGs, we have utilized XMM-Newton observations of a small sample of z approximates 0.1 GALEX-selected Ultraviolet-Luminous Galaxies (UVLGs); local analogs to high-redshift LBGs. Our observations enable us to study the X-ray emission from LBG-like galaxies on an individual basis, thus allowing us to constrain object-to-object variances in this population. We supplement these results with X-ray stacking constraints using the new 3.2 Ms Chandra Deep Field-South (completed spring 2010) and LBG candidates selected from HST, Swift UVOT, and ground-based data. These measurements provide new X-ray constraints that sample well the entire z=0-4 baseline

  12. Accreting Binary Populations in the Earlier Universe

    NASA Technical Reports Server (NTRS)

    Hornschemeier, Ann

    2010-01-01

    It is now understood that X-ray binaries dominate the hard X-ray emission from normal star-forming galaxies. Thanks to the deepest (2-4 Ms) Chandra surveys, such galaxies are now being studied in X-rays out to z approximates 4. Interesting X-ray stacking results (based on 30+ galaxies per redshift bin) suggest that the mean rest-frame 2-10 keV luminosity from z=3-4 Lyman break galaxies (LBGs), is comparable to the most powerful starburst galaxies in the local Universe. This result possibly indicates a similar production mechanism for accreting binaries over large cosmological timescales. To understand and constrain better the production of X-ray binaries in high-redshift LBGs, we have utilized XMM-Newton observations of a small sample of z approximates 0.1 GALEX-selected Ultraviolet-Luminous Galaxies (UVLGs); local analogs to high-redshift LBGs. Our observations enable us to study the X-ray emission from LBG-like galaxies on an individual basis, thus allowing us to constrain object-to-object variances in this population. We supplement these results with X-ray stacking constraints using the new 3.2 Ms Chandra Deep Field-South (completed spring 2010) and LBG candidates selected from HST, Swift UVOT, and ground-based data. These measurements provide new X-ray constraints that sample well the entire z=0-4 baseline

  13. Kepler as a Binary Star Mission

    NASA Astrophysics Data System (ADS)

    di Stefano, Rosanne

    2010-12-01

    The Kepler observatory was designed to discover transits by Earth-like planets orbiting Sun-like stars. Its first major discoveries, however, are hot objects in close orbits around main-sequence stars. These are likely to be white-dwarf remnants of stars that have transferred mass to the present-day main sequence stars. These particular main-sequence stars are among the Kepler targets because they are bright. The question is: how many of the other Kepler target stars are also orbited by white dwarfs? We have shown that several hundred white dwarfs are likely to transit the Kepler target stars during the mission. In some cases, the signature will be dominated by gravitational lensing, producing distinctive ``antitransits''. Neutron stars and black holes may also be discovered this way. The lensing signature provides a measurement of the gravitational mass of the compact object. Through the discovery of both transits and antitransits caused by white dwarfs, Kepler will discover and study binaries that have already experienced a phase of mass transfer or a common envelope phase. Thus, Kepler will become a premier tool for the study of interacting binaries. During the next phase of interaction, some of the Kepler binaries may become nuclear-burning white dwarfs, and may be candidates for Type Ia supernovae or accretion-induced collapse.

  14. Pulsar Candidate in Andromeda

    NASA Image and Video Library

    2017-03-23

    NASA's Nuclear Spectroscope Telescope Array, or NuSTAR, has identified a candidate pulsar in Andromeda -- the nearest large galaxy to the Milky Way. This likely pulsar is brighter at high energies than the Andromeda galaxy's entire black hole population. The inset image shows the pulsar candidate in blue, as seen in X-ray light by NuSTAR. The background image of Andromeda was taken by NASA's Galaxy Evolution Explorer in ultraviolet light. Andromeda is a spiral galaxy like our Milky Way but larger in size. It lies 2.5 million light-years away in the Andromeda constellation. http://photojournal.jpl.nasa.gov/catalog/PIA20970

  15. Learning to assign binary weights to binary descriptor

    NASA Astrophysics Data System (ADS)

    Huang, Zhoudi; Wei, Zhenzhong; Zhang, Guangjun

    2016-10-01

    Constructing robust binary local feature descriptors are receiving increasing interest due to their binary nature, which can enable fast processing while requiring significantly less memory than their floating-point competitors. To bridge the performance gap between the binary and floating-point descriptors without increasing the computational cost of computing and matching, optimal binary weights are learning to assign to binary descriptor for considering each bit might contribute differently to the distinctiveness and robustness. Technically, a large-scale regularized optimization method is applied to learn float weights for each bit of the binary descriptor. Furthermore, binary approximation for the float weights is performed by utilizing an efficient alternatively greedy strategy, which can significantly improve the discriminative power while preserve fast matching advantage. Extensive experimental results on two challenging datasets (Brown dataset and Oxford dataset) demonstrate the effectiveness and efficiency of the proposed method.

  16. ALMOST ALL OF KEPLER'S MULTIPLE-PLANET CANDIDATES ARE PLANETS

    SciTech Connect

    Lissauer, Jack J.; Rowe, Jason F.; Bryson, Stephen T.; Howell, Steve B.; Jenkins, Jon M.; Kinemuchi, Karen; Koch, David G.; Marcy, Geoffrey W.; Adams, Elisabeth; Fressin, Francois; Geary, John; Holman, Matthew J.; Ragozzine, Darin; Buchhave, Lars A.; Ciardi, David R.; Fabrycky, Daniel C.; Ford, Eric B.; Morehead, Robert C.; Gilliland, Ronald L.; and others

    2012-05-10

    We present a statistical analysis that demonstrates that the overwhelming majority of Kepler candidate multiple transiting systems (multis) indeed represent true, physically associated transiting planets. Binary stars provide the primary source of false positives among Kepler planet candidates, implying that false positives should be nearly randomly distributed among Kepler targets. In contrast, true transiting planets would appear clustered around a smaller number of Kepler targets if detectable planets tend to come in systems and/or if the orbital planes of planets encircling the same star are correlated. There are more than one hundred times as many Kepler planet candidates in multi-candidate systems as would be predicted from a random distribution of candidates, implying that the vast majority are true planets. Most of these multis are multiple-planet systems orbiting the Kepler target star, but there are likely cases where (1) the planetary system orbits a fainter star, and the planets are thus significantly larger than has been estimated, or (2) the planets orbit different stars within a binary/multiple star system. We use the low overall false-positive rate among Kepler multis, together with analysis of Kepler spacecraft and ground-based data, to validate the closely packed Kepler-33 planetary system, which orbits a star that has evolved somewhat off of the main sequence. Kepler-33 hosts five transiting planets, with periods ranging from 5.67 to 41 days.

  17. MICROLENSING BINARIES DISCOVERED THROUGH HIGH-MAGNIFICATION CHANNEL

    SciTech Connect

    Shin, I.-G.; Choi, J.-Y.; Park, S.-Y.; Han, C.; Gould, A.; Gaudi, B. S.; Sumi, T.; Udalski, A.; Beaulieu, J.-P.; Dominik, M.; Allen, W.; Bos, M.; Christie, G. W.; Depoy, D. L.; Dong, S.; Drummond, J.; Gal-Yam, A.; Hung, L.-W.; Janczak, J.; Kaspi, S.; Collaboration: muFUN Collaboration; MOA Collaboration; OGLE Collaboration; PLANET Collaboration; RoboNet Collaboration; MiNDSTEp Consortium; and others

    2012-02-20

    Microlensing can provide a useful tool to probe binary distributions down to low-mass limits of binary companions. In this paper, we analyze the light curves of eight binary-lensing events detected through the channel of high-magnification events during the seasons from 2007 to 2010. The perturbations, which are confined near the peak of the light curves, can be easily distinguished from the central perturbations caused by planets. However, the degeneracy between close and wide binary solutions cannot be resolved with a 3{sigma} confidence level for three events, implying that the degeneracy would be an important obstacle in studying binary distributions. The dependence of the degeneracy on the lensing parameters is consistent with a theoretical prediction that the degeneracy becomes severe as the binary separation and the mass ratio deviate from the values of resonant caustics. The measured mass ratio of the event OGLE-2008-BLG-510/MOA-2008-BLG-369 is q {approx} 0.1, making the companion of the lens a strong brown dwarf candidate.

  18. UNUSUALLY WIDE BINARIES: ARE THEY WIDE OR UNUSUAL?

    SciTech Connect

    Kraus, Adam L.; Hillenbrand, Lynne A. E-mail: lah@astro.caltech.ed

    2009-10-01

    We describe an astrometric and spectroscopic campaign to confirm the youth and association of a complete sample of candidate wide companions in Taurus and Upper Sco. Our survey found 15 new binary systems (three in Taurus and 12 in Upper Sco) with separations of 3''-30'' (500-5000 AU) among all of the known members with masses of 2.5-0.012 M {sub sun}. The total sample of 49 wide systems in these two regions conforms to only some expectations from field multiplicity surveys. Higher mass stars have a higher frequency of wide binary companions, and there is a marked paucity of wide binary systems near the substellar regime. However, the separation distribution appears to be log-flat, rather than declining as in the field, and the mass ratio distribution is more biased toward similar-mass companions than the initial mass function or the field G-dwarf distribution. The maximum separation also shows no evidence of a limit at approx<5000 AU until the abrupt cessation of any wide binary formation at system masses of approx0.3 M {sub sun}. We attribute this result to the post-natal dynamical sculpting that occurs for most field systems; our binary systems will escape to the field intact, but most field stars are formed in denser clusters and undergo significant dynamical evolution. In summary, only wide binary systems with total masses approx<0.3 M {sub sun} appear to be 'unusually wide'.

  19. 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.

  20. ALA Candidates: Presidential Timbre

    ERIC Educational Resources Information Center

    Berry, John N., III

    2010-01-01

    This article presents an interview with two effective spokespeople, notable school librarian Sara Kelly Johns and retired public library administrator Molly Raphael, who compete to be American Library Association (ALA) president. One of them will be elected president of ALA for a year's term beginning in July 2011. Each candidate comes from a…

  1. ALA Candidates: Presidential Timbre

    ERIC Educational Resources Information Center

    Berry, John N., III

    2010-01-01

    This article presents an interview with two effective spokespeople, notable school librarian Sara Kelly Johns and retired public library administrator Molly Raphael, who compete to be American Library Association (ALA) president. One of them will be elected president of ALA for a year's term beginning in July 2011. Each candidate comes from a…

  2. NEA rotations and binaries

    NASA Astrophysics Data System (ADS)

    Pravec, Petr; Harris, A. W.; Warner, B. D.

    2007-05-01

    Of nearly 3900 near-Earth asteroids known in June 2006, 325 have got estimated rotation periods. NEAs with sizes down to 10 meters have been sampled. Observed spin distribution shows a major changing point around D=200 m. Larger NEAs show a barrier against spin rates >11 d-1 (period P~2.2 h) that shifts to slower rates with increasing equatorial elongation. The spin barrier is interpreted as a critical spin rate for bodies held together by self-gravitation only, suggesting that NEAs larger than 200 m are mostly strenghtless bodies (i.e., with zero tensile strength), so called `rubble piles'. The barrier disappears at D<200 m where most objects rotate too fast to be held together by self-gravitation only, so a non-zero cohesion is implied in the smaller NEAs. The distribution of NEA spin rates in the `rubble pile' range (D>0.2 km) is non-Maxwellian, suggesting that other mechanisms than just collisions worked there. There is a pile up in front of the barrier (P of 2-3 h). It may be related to a spin up mechanism crowding asteroids to the barrier. An excess of slow rotators is seen at P>30 h. The spin-down mechanism has no clear lower limit on spin rate; periods as long as tens of days occur. Most NEAs appear to be in basic spin states with rotation around the principal axis. Excited rotations are present among and actually dominate in slow rotators with damping timescales >4.5 byr. A few tumblers observed among fast rotating coherent objects consistently appear to be more rigid or younger than the larger, rubble-pile tumblers. An abundant population of binary systems among NEAs has been found. The fraction of binaries among NEAs larger than 0.3 km has been estimated to be 15 +/-4%. Primaries of the binary systems concentrate at fast spin rates (periods 2-3 h) and low amplitudes, i.e., they lie just below the spin barrier. The total angular momentum content in the binary systems suggests that they formed at the critical spin rate, and that little or no angular

  3. Some (Apparently) Very Wide Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Warner, Brian D.; Harris, Alan W.; Stephens, Robert D.

    2016-10-01

    We present lightcurves for some of the approximately one dozen asteroids that appear to be very widely-separated binaries. Jacobsen et al. (2014, ApJ 780) attribute their formation to a somewhat complex series of events involving BYORP.The lightcurves consist of two components: Period 1 (P1) is very long, P1 = 50-600 h, with amplitudes of A1 = 0.23-1.0 mag. The second period and amplitudes are similar to the primaries of close binary systems, i.e., P2 = 2.2-3.6 h, A2 ~ 0.10 mag. Two candidates have secondary periods in the range of 5-7 hours. The most exceptional example is (19204) Joshuatree, which has values of P1 = 480 h, A1 = 0.25 mag and P2 = 21.25 h, A2 = 0.08 mag. Based on Jacobson et al. (2014, ApJ 780) and Pravec et al. (2016, Icarus 267), we suggest that P1 represents the primary (larger) body of the system and P2 represents the spin rate of the satellite.Supporting this supposition is that the large amplitude (A1) must be from the larger body, otherwise the dilution of amplitude would require the smaller body to be unreasonably elongate. The limiting size ratio for binaries is around 0.6 (see Pravec et al. 2010, Nature 466, Fig. 1), or a magnitude difference of about 1.0. For a secondary 1.0 mag fainter than the primary to produce a combined lightcurve amplitude of ~0.4 mag would require that the secondary undiluted amplitude to be several magnitudes (near-infinite elongation) and also a near equatorial aspect. This is not likely.Given the lack of mutual events, these can be considered to be only possible binaries. Since the orbital period is probably very long, it seems extremely unlikely that mutual events will ever be seen.The changing landscape of binary asteroid discoveries and theories calls for something beyond descriptive terms such as "suspicious", "possible", "likely", and "confirmed" in order to allow more accurate statistical studies. To this end, we are introducing a new "B" rating in the asteroid lightcurve database (Warner et al., 2009

  4. Binary AGB stars observed with Herschel

    NASA Astrophysics Data System (ADS)

    Kornfeld, Klaus

    2012-03-01

    Asymptotic Giant Branch stars are stars at the end of their lifetime with low to intermediate masses. They are important in the Galactic context, since they contribute a lot of dust to the interstellar medium (ISM) and influence the chemical evolution of the Galaxy. Many AGB stars show peculiar outflow morphologies depending on their mass-loss rates. The outflowing wind of these stars collides with the surrounding interstellar medium (ISM). The collisions with the ISM result in the formation of bow shocks or rings, well visible in the latest Herschel Space Observatory images made with the on-board PACS instrument. Kelvin-Helmholtz and Rayleight-Taylor instabilities were found in the bow shock regions. With the help of Herschel and within the framework of the MESS (Mass loss of Evolved StarS) Guaranteed Time Key Program it was tried to distinguish between the different morphologies. The outflow morphologies were categorized in 4 main classes: "fermata", "eye", "ring", and "irregular"; also point sources showing no resolved circumstellar envelopes (CSEs) were found. Some of the AGB stars in the MESS sample are known binary stars and the binary state of some other objects is still in discussion. A new attempt to clarify the binarity of the objects can be made by checking their outflow morphology and to compare the results with known morphological (a-)symmetries in binary systems. This Thesis discusses 14 binary AGB candidates from the MESS sample, the previous findings and the Herschel results. Herschel observes at infrared wavelengths. Light at this wavelengths can be seen through the dust, which is formed in the surrounding environment of these stars. For the unknown cases it is difficult to determine the binary state, because AGB stars can have very strong wind outflows, making the detection of a companion difficult. Photo- and spectroscopy, CO line outflow measurements or composite spectra can be used to identify features caused directly o! r indirectly by the

  5. Microfluidic binary phase flow

    NASA Astrophysics Data System (ADS)

    Angelescu, Dan; Menetrier, Laure; Wong, Joyce; Tabeling, Patrick; Salamitou, Philippe

    2004-03-01

    We present a novel binary phase flow regime where the two phases differ substantially in both their wetting and viscous properties. Optical tracking particles are used in order to investigate the details of such multiphase flow inside capillary channels. We also describe microfluidic filters we have developed, capable of separating the two phases based on capillary pressure. The performance of the filters in separating oil-water emulsions is discussed. Binary phase flow has been previously used in microchannels in applications such as emulsion generation, enhancement of mixing and assembly of custom colloidal paticles. Such microfluidic systems are increasingly used in a number of applications spanning a diverse range of industries, such as biotech, pharmaceuticals and more recently the oil industry.

  6. Binary Love relations

    NASA Astrophysics Data System (ADS)

    Yagi, Kent; Yunes, Nicolás

    2016-07-01

    When in a tight binary, the mutual tidal deformations of neutron stars get imprinted onto observables, encoding information about their internal structure at supranuclear densities and gravity in the extreme-gravity regime. Gravitational wave (GW) observations of their late binary inspiral may serve as a tool to extract the individual tidal deformabilities, but this is made difficult by degeneracies between them in the GW model. We here resolve this problem by discovering approximately equation-of-state (EoS)-insensitive relations between dimensionless combinations of the individual tidal deformabilities. We show that these relations break degeneracies in the GW model, allowing for the accurate extraction of both deformabilities. Such measurements can be used to better differentiate between EoS models, and improve tests of general relativity and cosmology.

  7. Parametric binary dissection

    NASA Technical Reports Server (NTRS)

    Bokhari, Shahid H.; Crockett, Thomas W.; Nicol, David M.

    1993-01-01

    Binary dissection is widely used to partition non-uniform domains over parallel computers. This algorithm does not consider the perimeter, surface area, or aspect ratio of the regions being generated and can yield decompositions that have poor communication to computation ratio. Parametric Binary Dissection (PBD) is a new algorithm in which each cut is chosen to minimize load + lambda x(shape). In a 2 (or 3) dimensional problem, load is the amount of computation to be performed in a subregion and shape could refer to the perimeter (respectively surface) of that subregion. Shape is a measure of communication overhead and the parameter permits us to trade off load imbalance against communication overhead. When A is zero, the algorithm reduces to plain binary dissection. This algorithm can be used to partition graphs embedded in 2 or 3-d. Load is the number of nodes in a subregion, shape the number of edges that leave that subregion, and lambda the ratio of time to communicate over an edge to the time to compute at a node. An algorithm is presented that finds the depth d parametric dissection of an embedded graph with n vertices and e edges in O(max(n log n, de)) time, which is an improvement over the O(dn log n) time of plain binary dissection. Parallel versions of this algorithm are also presented; the best of these requires O((n/p) log(sup 3)p) time on a p processor hypercube, assuming graphs of bounded degree. How PBD is applied to 3-d unstructured meshes and yields partitions that are better than those obtained by plain dissection is described. Its application to the color image quantization problem is also discussed, in which samples in a high-resolution color space are mapped onto a lower resolution space in a way that minimizes the color error.

  8. Binary Optics Toolkit

    SciTech Connect

    Neal, Daniel

    1996-04-02

    This software is a set of tools for the design and analysis of binary optics. It consists of a series of stand-alone programs written in C and some scripts written in an application-specific language interpreted by a CAD program called DW2000. This software can be used to optimize the design and placement of a complex lens array from input to output and produce contours, mask designs, and data exported for diffractive optic analysis.

  9. Processing Of Binary Images

    NASA Astrophysics Data System (ADS)

    Hou, H. S.

    1985-07-01

    An overview of the recent progress in the area of digital processing of binary images in the context of document processing is presented here. The topics covered include input scan, adaptive thresholding, halftoning, scaling and resolution conversion, data compression, character recognition, electronic mail, digital typography, and output scan. Emphasis has been placed on illustrating the basic principles rather than descriptions of a particular system. Recent technology advances and research in this field are also mentioned.

  10. 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.

  11. Electromagnetic and gravitational outputs from binary-neutron-star coalescence.

    PubMed

    Palenzuela, Carlos; Lehner, Luis; Ponce, Marcelo; Liebling, Steven L; Anderson, Matthew; Neilsen, David; Motl, Patrick

    2013-08-09

    The late stage of an inspiraling neutron-star binary gives rise to strong gravitational wave emission due to its highly dynamic, strong gravity. Moreover, interactions between the stellar magnetospheres can produce considerable electromagnetic radiation. We study this scenario using fully general relativistic, resistive magnetohydrodynamic simulations. We show that these interactions extract kinetic energy from the system, dissipate heat, and power radiative Poynting flux, as well as develop current sheets. Our results indicate that this power can (i) outshine pulsars in binaries, (ii) display a distinctive angular- and time-dependent pattern, and (iii) radiate within large opening angles. These properties suggest that some binary neutron-star mergers are ideal candidates for multimessenger astronomy.

  12. Superluminal Jets and Other Properties of Black Holes Binaries

    NASA Technical Reports Server (NTRS)

    Harmon, Alan

    1997-01-01

    Discoveries in the past few years of radio jets in Galactic black hole candidates have provided a link between active galactic nuclei (AGNS) and the compact stars in binary systems. The availability of binary systems relatively close by is an opportunity to learn about the jet production mechanism on a timescale a million times shorter than that of an AGN. Evidence is clearly seen of correlated high energy X-ray and gamma ray emission to radio emission from jets, linking the accretion and jet production mechanisms. objects such as GRS 1915+105, GRO J1655-40 and Cyg X-3 show striking properties which distinguish them from other black hole candidates. Our theoretical understanding of these systems is still in the formative stages. I review some of the most recent multiwavelength data and point out questions raised by these observations.

  13. Superluminal Jets and Other Properties of Black Holes Binaries

    NASA Technical Reports Server (NTRS)

    Harmon, Alan

    1997-01-01

    Discoveries in the past few years of radio jets in Galactic black hole candidates have provided a link between active galactic nuclei (AGNS) and the compact stars in binary systems. The availability of binary systems relatively close by is an opportunity to learn about the jet production mechanism on a timescale a million times shorter than that of an AGN. Evidence is clearly seen of correlated high energy X-ray and gamma ray emission to radio emission from jets, linking the accretion and jet production mechanisms. objects such as GRS 1915+105, GRO J1655-40 and Cyg X-3 show striking properties which distinguish them from other black hole candidates. Our theoretical understanding of these systems is still in the formative stages. I review some of the most recent multiwavelength data and point out questions raised by these observations.

  14. Binary-Signal Recovery

    NASA Technical Reports Server (NTRS)

    Griebeler, Elmer L.

    2011-01-01

    Binary communication through long cables, opto-isolators, isolating transformers, or repeaters can become distorted in characteristic ways. The usual solution is to slow the communication rate, change to a different method, or improve the communication media. It would help if the characteristic distortions could be accommodated at the receiving end to ease the communication problem. The distortions come from loss of the high-frequency content, which adds slopes to the transitions from ones to zeroes and zeroes to ones. This weakens the definition of the ones and zeroes in the time domain. The other major distortion is the reduction of low frequency, which causes the voltage that defines the ones or zeroes to drift out of recognizable range. This development describes a method for recovering a binary data stream from a signal that has been subjected to a loss of both higher-frequency content and low-frequency content that is essential to define the difference between ones and zeroes. The method makes use of the frequency structure of the waveform created by the data stream, and then enhances the characteristics related to the data to reconstruct the binary switching pattern. A major issue is simplicity. The approach taken here is to take the first derivative of the signal and then feed it to a hysteresis switch. This is equivalent in practice to using a non-resonant band pass filter feeding a Schmitt trigger. Obviously, the derivative signal needs to be offset to halfway between the thresholds of the hysteresis switch, and amplified so that the derivatives reliably exceed the thresholds. A transition from a zero to a one is the most substantial, fastest plus movement of voltage, and therefore will create the largest plus first derivative pulse. Since the quiet state of the derivative is sitting between the hysteresis thresholds, the plus pulse exceeds the plus threshold, switching the hysteresis switch plus, which re-establishes the data zero to one transition

  15. Dark matter candidates

    SciTech Connect

    Turner, M.S.

    1989-01-01

    One of the simplest, yet most profound, questions we can ask about the Universe is, how much stuff is in it, and further what is that stuff composed of. Needless to say, the answer to this question has very important implications for the evolution of the Universe, determining both the ultimate fate and the course of structure formation. Remarkably, at this late date in the history of the Universe we still do not have a definitive answer to this simplest of questions---although we have some very intriguing clues. It is known with certainty that most of the material in the Universe is dark, and we have the strong suspicion that the dominant component of material in the Cosmos is not baryons, but rather is exotic relic elementary particles left over from the earliest, very hot epoch of the Universe. If true, the Dark Matter question is a most fundamental one facing both particle physics and cosmology. The leading particle dark matter candidates are: the axion, the neutralino, and a light neutrino species. All three candidates are accessible to experimental tests, and experiments are now in progress. In addition, there are several dark horse, long shot, candidates, including the superheavy magnetic monopole and soliton stars. 13 refs.

  16. 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.

  17. Visual binary stars: data to investigate formation of binaries

    NASA Astrophysics Data System (ADS)

    Kovaleva,, D.; Malkov,, O.; Yungelson, L.; Chulkov, D.

    Statistics of orbital parameters of binary stars as well as statistics of their physical characteristics bear traces of star formation history. However, statistical investigations of binaries are complicated by incomplete or missing observational data and by a number of observational selection effects. Visual binaries are the most common type of observed binary stars, with the number of pairs exceeding 130 000. The most complete list of presently known visual binary stars was compiled by cross-matching objects and combining data of the three largest catalogues of visual binaries. This list was supplemented by the data on parallaxes, multicolor photometry, and spectral characteristics taken from other catalogues. This allowed us to compensate partly for the lack of observational data for these objects. The combined data allowed us to check the validity of observational values and to investigate statistics of the orbital and physical parameters of visual binaries. Corrections for incompleteness of observational data are discussed. The datasets obtained, together with modern distributions of binary parameters, will be used to reconstruct the initial distributions and parameters of the function of star formation for binary systems.

  18. Binary optics: Trends and limitations

    NASA Astrophysics Data System (ADS)

    Farn, Michael W.; Veldkamp, Wilfrid B.

    1993-08-01

    We describe the current state of binary optics, addressing both the technology and the industry (i.e., marketplace). With respect to the technology, the two dominant aspects are optical design methods and fabrication capabilities, with the optical design problem being limited by human innovation in the search for new applications and the fabrication issue being limited by the availability of resources required to improve fabrication capabilities. With respect to the industry, the current marketplace does not favor binary optics as a separate product line and so we expect that companies whose primary purpose is the production of binary optics will not represent the bulk of binary optics production. Rather, binary optics' more natural role is as an enabling technology - a technology which will directly result in a competitive advantage in a company's other business areas - and so we expect that the majority of binary optics will be produced for internal use.

  19. Binary optics: Trends and limitations

    NASA Technical Reports Server (NTRS)

    Farn, Michael W.; Veldkamp, Wilfrid B.

    1993-01-01

    We describe the current state of binary optics, addressing both the technology and the industry (i.e., marketplace). With respect to the technology, the two dominant aspects are optical design methods and fabrication capabilities, with the optical design problem being limited by human innovation in the search for new applications and the fabrication issue being limited by the availability of resources required to improve fabrication capabilities. With respect to the industry, the current marketplace does not favor binary optics as a separate product line and so we expect that companies whose primary purpose is the production of binary optics will not represent the bulk of binary optics production. Rather, binary optics' more natural role is as an enabling technology - a technology which will directly result in a competitive advantage in a company's other business areas - and so we expect that the majority of binary optics will be produced for internal use.

  20. The Search for Trojan Binaries

    NASA Astrophysics Data System (ADS)

    Merline, William J.; Tamblyn, P. M.; Dumas, C.; Close, L. M.; Chapman, C. R.; Durda, D. D.; Levison, H. F.; Hamilton, D. P.; Nesvorny, D.; Storrs, A.; Enke, B.; Menard, F.

    2007-10-01

    We report on observations of Jupiter Trojan asteroids in search of binaries. We made observations using HST/ACS of 35 small (V = 17.5-19.5) objects in Cycle 14, without detecting any binaires. We have also observed a few dozen Trojans in our ground-based study of larger Trojans, discovering only one binary. The result is that the frequency of moderately-separated binaries among the Trojans seem rather low, likely less than 5%. Although we have only statistics of small numbers, it appears that the binary frequencies are more akin to the larger Main-Belt asteroids, than to the frequency in the TNO region, which probably exceeds 10%. The low frequency is inconsistent with the projections based on Trojan contact binaries by Mann et al. (2006, BAAS 38, 6509), although our work cannot detect very close or contact binaries. We discovered and characterized the orbit and density of the first Trojan binary, (617) Patroclus using the Gemini AO system (Merline et al. 2001 IAUC 7741). A second binary, (624) Hecktor, has now been reported by Marchis et al. (2006, IAUC 8732). In a broad survey of Main Belt asteroids, we found that, among the larger objects, the binary fraction is about 2%, while we are finding that the fraction is significantly higher among smaller asteroids (and this is even more apparent from lightcurve discoveries). Further, characteristics of these smaller systems indicate a distinctly different formation mechanism the the larger MB binaries. Because the Trojans have compositions that are more like the KBOs, while they live in a collisional environment much more like the Main Belt than the KBOs, these objects should hold vital clues to binary formation mechanics. And because there seems to be a distinct difference in larger and smaller main-belt binaries, we sought to detect such differences among the Trojans as well.

  1. Radio emission from binary stars

    NASA Technical Reports Server (NTRS)

    Dulk, G. A.

    1986-01-01

    This paper reviews the radio emission from binary star systems - the emission processes that occur, the characteristics of the binary systems inferred from the radio observations, and the reasons for the activity. Several classes of binary stars are described including those with two main sequence stars, those with one normal star and a white dwarf, and those containing a neutron star or a black hole.

  2. Hunting for brown dwarf binaries and testing atmospheric models with X-Shooter

    NASA Astrophysics Data System (ADS)

    Manjavacas, E.; Goldman, B.; Alcalá, J. M.; Zapatero-Osorio, M. R.; Béjar, V. J. S.; Homeier, D.; Bonnefoy, M.; Smart, R. L.; Henning, T.; Allard, F.

    2016-01-01

    The determination of the brown dwarf binary fraction may contribute to the understanding of the substellar formation mechanisms. Unresolved brown dwarf binaries may be revealed through their peculiar spectra or the discrepancy between optical and near-infrared spectral-type classification. We obtained medium-resolution spectra of 22 brown dwarfs with these characteristics using the X-Shooter spectrograph at the Very Large Telescope. We aimed to identify brown dwarf binary candidates, and to test if the BT-Settl 2014 atmospheric models reproduce their observed spectra. To find binaries spanning the L-T boundary, we used spectral indices and compared the spectra of the selected candidates to single spectra and synthetic binary spectra. We used synthetic binary spectra with components of same spectral type to determine as well the sensitivity of the method to this class of binaries. We identified three candidates to be combination of L plus T brown dwarfs. We are not able to identify binaries with components of similar spectral type. In our sample, we measured minimum binary fraction of 9.1^{+9.9}_{-3.0} per cent. From the best fit of the BT-Settl models 2014 to the observed spectra, we derived the atmospheric parameters for the single objects. The BT-Settl models were able to reproduce the majority of the spectral energy distributions from our objects, and the variation of the equivalent width of the Rb I (794.8 nm) and Cs I (852.0 nm) lines with the spectral type. None the less, these models did not reproduce the evolution of the equivalent widths of the Na I (818.3 and 819.5 nm) and K I (1253 nm) lines with the spectral type.

  3. Teachers Candidates' Reviews on Teacher Candidate Training System

    ERIC Educational Resources Information Center

    Altintas, Sedat; Görgen, Izzet

    2017-01-01

    In our country, as a result of the appointment in some different disciplines, nearly 30000 teacher candidates could be a part of education system. Also, a new revision has been completed on teacher candidate training and it has been put into action. Teacher candidates have been trained for six months after they have been appointed. These teachers…

  4. FORMATION OF BLACK HOLE X-RAY BINARIES IN GLOBULAR CLUSTERS

    SciTech Connect

    Ivanova, N.; Heinke, C. O.; Woods, T. E.; Chaichenets, S.; Fregeau, J.; Lombardi, J. C.

    2010-07-10

    Inspired by the recent identification in extragalactic globular clusters of the first candidate black hole-white dwarf (BH-WD) X-ray binaries, where the compact accretors may be stellar-mass black holes (BHs), we explore how such binaries could be formed in a dynamical environment. We provide analyses of the formation rates via well-known formation channels like binary exchange and physical collisions and propose that the only possibility of forming BH-WD binaries is via coupling these usual formation channels with subsequent hardening and/or triple formation. In particular, we find that the most important mechanism for the creation of a BH-WD X-ray binary from an initially dynamically formed BH-WD binary is mass transfer induced in a triple system via the Kozai mechanism. Furthermore, we find that BH-WD binaries that evolve into X-ray sources can be formed by exchanges of a BH into a WD-WD binary or possibly by collisions of a BH and a giant star. If BHs undergo significant evaporation from the cluster or form a completely detached subcluster of BHs, then we cannot match the observationally inferred production rates even using the most optimistic estimates of formation rates. To explain the observations with stellar-mass BH-WD binaries, at least 1% of all formed BHs, or presumably 10% of the BHs present in the core now, must be involved in interactions with the rest of the core stellar population.

  5. Particle acceleration in binaries

    NASA Astrophysics Data System (ADS)

    Sinitsyna, V. G.; Sinitsyna, V. Y.

    2017-06-01

    Cygnus X-3 massive binary system is one of the powerful sources of radio and X-ray emission consisting of an accreting compact object, probably a black hole, with a Wolf-Rayet star companion. Based on the detections of ultra high energy gamma-rays by Kiel and Havera Park, Cygnus X-3 has been proposed to be one of the most powerful sources of charged cosmic ray particles in the Galaxy. The results of long-term observations of the Cyg X-3 binary at energies 800 GeV-85 TeV detected by SHALON in 1995 are presented with images, integral spectra and spectral energy distribution. The identification of source with Cygnus X-3 detected by SHALON was secured by the detection of its 4.8 hour orbital period in TeV gamma-rays. During the whole observation period of Cyg X-3 with SHALON significant flux increases were detected at energies above 0.8 TeV. These TeV flux increases are correlated with flaring activity at a lower energy range of X-ray and/or at observations of Fermi LAT as well as with radio emission from the relativistic jets of Cygnus X-3. The variability of very high-energy gamma-radiation and correlation of radiation activity in the wide energy range can provide essential information on particle mechanism production up to very high energies. Whereas, modulation of very high energy emission connected to the orbital motion of the binary system, provides an understanding of the emission processes, nature and location of particle acceleration.

  6. Evolution of Close Binary Systems

    SciTech Connect

    Yakut, K; Eggleton, P

    2005-01-24

    We collected data on the masses, radii, etc. of three classes of close binary stars: low-temperature contact binaries (LTCBs), near-contact binaries (NCBs), and detached close binaries (DCBs). They restrict themselves to systems where (1) both components are, at least arguably, near the Main Sequence, (2) the periods are less than a day, and (3) there is both spectroscopic and photometric analysis leading to reasonably reliable data. They discuss the possible evolutionary connections between these three classes, emphasizing the roles played by mass loss and angular momentum loss in rapidly-rotating cool stars.

  7. Gaia Assorted Mass Binaries Long Excluded from SLoWPoKES (GAMBLES): Identifying Ultra-wide Binary Pairs with Components of Diverse Mass

    NASA Astrophysics Data System (ADS)

    Oelkers, Ryan J.; Stassun, Keivan G.; Dhital, Saurav

    2017-06-01

    The formation and evolution of binary star systems are some of the remaining key questions in modern astronomy. Wide binary pairs (separations >103 au) are particularly intriguing because their low binding energies make it difficult for the stars to stay gravitationally bound over extended timescales, and thus to probe the dynamics of binary formation and dissolution. Our previous SLoWPoKES catalogs, I and II, provided the largest and most complete sample of wide-binary pairs of low masses. Here we present an extension of these catalogs to a broad range of stellar masses: the Gaia Assorted Mass Binaries Long Excluded from SloWPoKES (GAMBLES), comprising 8660 statistically significant wide pairs that we make available in a living online database. Within this catalog we identify a subset of 543 long-lived (dissipation timescale >1.5 Gyr) candidate binary pairs, of assorted mass, with typical separations between 103 and 105.5 au (0.002–1.5 pc), using the published distances and proper motions from the Tycho-Gaia Astrometric Solution and Sloan Digital Sky Survey photometry. Each pair has at most a false positive probability of 0.05; the total expectation is 2.44 false binaries in our sample. Among these, we find 22 systems with 3 components, 1 system with 4 components, and 15 pairs consisting of at least 1 possible red giant. We find the largest long-lived binary separation to be nearly 3.2 pc even so, >76% of GAMBLES long-lived binaries have large binding energies and dissipation lifetimes longer than 1.5 Gyr. Finally, we find that the distribution of binary separations is clearly bimodal, corroborating the findings from SloWPoKES and suggesting multiple pathways for the formation and dissipation of the widest binaries in the Galaxy.

  8. Ecospheres around binary stars

    NASA Astrophysics Data System (ADS)

    Deka, B.

    2011-01-01

    Scientific investigations concerning ecospheres of other stars are very important for understanding the posibilities of existence and evolution of extraterrestrial life. In several last years astronomers discovered hundreds of extrasolar planets. Identification of stars with ecospheres is the first step in selecting those planets which could be inhabited. Usually an ecosphere of a single star is considered but it may also exist in planetary systems with two suns. This possibility is very promising in search for life on other planets as more that 60 % of stars reside in binary or multiple systems.

  9. Low autocorrelation binary sequences

    NASA Astrophysics Data System (ADS)

    Packebusch, Tom; Mertens, Stephan

    2016-04-01

    Binary sequences with minimal autocorrelations have applications in communication engineering, mathematics and computer science. In statistical physics they appear as groundstates of the Bernasconi model. Finding these sequences is a notoriously hard problem, that so far can be solved only by exhaustive search. We review recent algorithms and present a new algorithm that finds optimal sequences of length N in time O(N {1.73}N). We computed all optimal sequences for N≤slant 66 and all optimal skewsymmetric sequences for N≤slant 119.

  10. BINARY STORAGE ELEMENT

    DOEpatents

    Chu, J.C.

    1958-06-10

    A binary storage device is described comprising a toggle provided with associsted improved driver circuits adapted to produce reliable action of the toggle during clearing of the toggle to one of its two states. or transferring information into and out of the toggle. The invention resides in the development of a self-regulating driver circuit to minimize the fluctuation of the driving voltages for the toggle. The disclosed driver circuit produces two pulses in response to an input pulse: a first or ''clear'' pulse beginning nt substantially the same time but endlrg slightly sooner than the second or ''transfer'' output pulse.

  11. Formation of the Wide Asynchronous Binary Asteroid Population

    NASA Astrophysics Data System (ADS)

    Jacobson, Seth A.; Scheeres, Daniel J.; McMahon, Jay

    2014-01-01

    We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semimajor axes relative to most near-Earth and main belt asteroid systems. Confirmed members have rapidly rotating primaries and satellites that are not tidally locked. Previously suggested formation mechanisms from impact ejecta, from planetary flybys, and directly from rotational fission events cannot satisfy all of the observations. The newly hypothesized mechanism works as follows: (1) these systems are formed from rotational fission, (2) their satellites are tidally locked, (3) their orbits are expanded by the binary Yarkovsky-O'Keefe-Radzievskii-Paddack (BYORP) effect, (4) their satellites desynchronize as a result of the adiabatic invariance between the libration of the secondary and the mutual orbit, and (5) the secondary avoids resynchronization because of the YORP effect. This seemingly complex chain of events is a natural pathway for binaries with satellites that have particular shapes, which define the BYORP effect torque that acts on the system. After detailing the theory, we analyze each of the wide asynchronous binary members and candidates to assess their most likely formation mechanism. Finally, we suggest possible future observations to check and constrain our hypothesis.

  12. Formation of the wide asynchronous binary asteroid population

    SciTech Connect

    Jacobson, Seth A.; Scheeres, Daniel J.; McMahon, Jay

    2014-01-01

    We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semimajor axes relative to most near-Earth and main belt asteroid systems. Confirmed members have rapidly rotating primaries and satellites that are not tidally locked. Previously suggested formation mechanisms from impact ejecta, from planetary flybys, and directly from rotational fission events cannot satisfy all of the observations. The newly hypothesized mechanism works as follows: (1) these systems are formed from rotational fission, (2) their satellites are tidally locked, (3) their orbits are expanded by the binary Yarkovsky-O'Keefe-Radzievskii-Paddack (BYORP) effect, (4) their satellites desynchronize as a result of the adiabatic invariance between the libration of the secondary and the mutual orbit, and (5) the secondary avoids resynchronization because of the YORP effect. This seemingly complex chain of events is a natural pathway for binaries with satellites that have particular shapes, which define the BYORP effect torque that acts on the system. After detailing the theory, we analyze each of the wide asynchronous binary members and candidates to assess their most likely formation mechanism. Finally, we suggest possible future observations to check and constrain our hypothesis.

  13. Analyzing Age-Rotation-Activity Relationships in Wide Binary Systems

    NASA Astrophysics Data System (ADS)

    Walton Clarke, Riley; Davenport, James R. A.

    2017-01-01

    We present an analysis of flare activity among equal mass wide binary pairs using a combination of value-added data sets from the NASA Kepler mission. Wide binary twins form from the same molecular cloud and are therefore coeval, making them ideal benchmarks for stellar evolution and formation studies. This implies that their magnetic activity should decay at the same rate, causing a similar decrease in flare activity over time. The first data set is the list of known wide binary candidates in the Kepler field, and contains pairs of stars that have similar proper motions. We then crossmatch these systems with data on relative flare luminosity for ~200,000 stars in the original Kepler field, provided by an automated flare-finding algorithm. This combined data set allows us to compare flare activity, mass, and pair separation between stars in binary pairs. We preliminarily find that the flare rates for these stars do not show strong correlation, indicating either a large intrinsic scatter in the flare rate as these stars age, or that the formation mechanism of wide binaries somehow affects their dynamo evolution. As a goal for future development of this work, we hope to compare flare rates with gyrochronology in these key systems.

  14. Formation of the first three gravitational-wave observations through isolated binary evolution

    NASA Astrophysics Data System (ADS)

    Stevenson, Simon; Vigna-Gómez, Alejandro; Mandel, Ilya; Barrett, Jim W.; Neijssel, Coenraad J.; Perkins, David; de Mink, Selma E.

    2017-04-01

    During its first four months of taking data, Advanced LIGO has detected gravitational waves from two binary black hole mergers, GW150914 and GW151226, along with the statistically less significant binary black hole merger candidate LVT151012. Here we use the rapid binary population synthesis code COMPAS to show that all three events can be explained by a single evolutionary channel--classical isolated binary evolution via mass transfer including a common envelope phase. We show all three events could have formed in low-metallicity environments (Z=0.001) from progenitor binaries with typical total masses >~160M\\xodot, >~60M\\xodot and >~90M\\xodot, for GW150914, GW151226 and LVT151012, respectively.

  15. Formation of the first three gravitational-wave observations through isolated binary evolution

    PubMed Central

    Stevenson, Simon; Vigna-Gómez, Alejandro; Mandel, Ilya; Barrett, Jim W.; Neijssel, Coenraad J.; Perkins, David; de Mink, Selma E.

    2017-01-01

    During its first four months of taking data, Advanced LIGO has detected gravitational waves from two binary black hole mergers, GW150914 and GW151226, along with the statistically less significant binary black hole merger candidate LVT151012. Here we use the rapid binary population synthesis code COMPAS to show that all three events can be explained by a single evolutionary channel—classical isolated binary evolution via mass transfer including a common envelope phase. We show all three events could have formed in low-metallicity environments (Z=0.001) from progenitor binaries with typical total masses ≳160M⊙, ≳60M⊙ and ≳90M⊙, for GW150914, GW151226 and LVT151012, respectively. PMID:28378739

  16. Formation of the first three gravitational-wave observations through isolated binary evolution.

    PubMed

    Stevenson, Simon; Vigna-Gómez, Alejandro; Mandel, Ilya; Barrett, Jim W; Neijssel, Coenraad J; Perkins, David; de Mink, Selma E

    2017-04-05

    During its first four months of taking data, Advanced LIGO has detected gravitational waves from two binary black hole mergers, GW150914 and GW151226, along with the statistically less significant binary black hole merger candidate LVT151012. Here we use the rapid binary population synthesis code COMPAS to show that all three events can be explained by a single evolutionary channel-classical isolated binary evolution via mass transfer including a common envelope phase. We show all three events could have formed in low-metallicity environments (Z=0.001) from progenitor binaries with typical total masses ≳160M⊙, ≳60M⊙ and ≳90M⊙, for GW150914, GW151226 and LVT151012, respectively.

  17. Radial-velocity measures and the existence of astrophysical binaries in late-type dwarf stars

    NASA Technical Reports Server (NTRS)

    Bopp, B. W.; Meredith, R.

    1986-01-01

    Radial velocities with errors of 1-2 km/s are presented based on CCD scans obtained with the Kitt Peak National Observatory coude feed telescope between 1982 and 1985 of 48 dK-M stars that lack Balmer emission. Comparison with Gliese's (1969) values shows only two stars to be spectroscopic binary candidates with small velocity amplitudes. No evidence for any short period (less than 10 days) binaries is found, supporting the conclusions of Young et al. (1986) that there are no astrophysical binaries among these chromosherically inactive dM stars.

  18. Solar Type Binary Systems with Impacting Gas Streams

    NASA Astrophysics Data System (ADS)

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

    2002-02-01

    Our quest is the discovery of near-contact solar type eclipsing binaries which show evidence of stream impacts. The existence of stream impacts would provide evidence of dynamic mass transfer possibly leading to coalescence into contact. This would lend strong support to the theoretical scenarios of 1) Angular Momentum Loss (AML) via magnetic breaking and 2) Thermal Relaxation Oscillations (TRO) ,ie., oscillations between a near-contact 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 such stream impacts when they are subjected to precision UBVRI multi-band photometry, since these fall in the pre-contact period range for F to K dwarf binaries. Modern light curve synthesis techniques will be used to simultaneously model the multi-band light curves. Impact spots will be adjusted numerically along with the stellar atmosphere parameters. Spectroscopic work will follow to verify stream activity in emission lines and to obtain radial velocity curves for calculating orbital parameters and fundamental physical characteristics. Our larger goal is to understand close binary evolution in general, in detached, semi-detached and contact modes. This study could supply an important piece to the puzzle. We now have found four stream system candidates: CN And, BE Cep, ZZ Eri and V343 Cen giving us an encouraging 40 % rate of recovery.

  19. 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.

  20. Observational Types of Binaries in the Binary Star Database

    NASA Astrophysics Data System (ADS)

    Malkov, O.; Kovaleva, D.; Kaygorodov, P.

    2017-06-01

    In the present paper we describe observational types of binaries, included in BDB, the Binary star database, which presently contains data on physical and positional parameters for about 260 000 components of 120 000 stellar systems of multiplicity 2 to more than 20, taken from a large variety of published catalogues and databases.

  1. The Internal-Candidate Syndrome

    ERIC Educational Resources Information Center

    Barden, Dennis M.

    2008-01-01

    In this article, the author explains the complications involved when an internal candidate is included in an open search for a leadership position in an academic institution. Internal-candidate syndrome is a dilemma faced by institutions when they have to choose between an internal candidate and an external one. There are two reasons why…

  2. Cepheid Binary Companions

    NASA Astrophysics Data System (ADS)

    Remage Evans, Nancy

    Blue main sequence companions of binary Cepheids can be used to determine Clio luminosity of the Cepheids. By matching the composite spectrum of the companion and the Cepheid with those of standard stars, the spectral type of the companion and the magnitude difference between the two stars can be determined. The main sequence absolute magnitude calibration of the companion then leads to the absolute magnitude of the Cepheid. The aim of this project is to obtain low dispersion SWP spectra of three Cepheids (T Vul, Y Lac, and RS Ori) for which the LWP spectra show excess flux at 2500 from the companion. In addition, we request LWP low dispersion spectra of five Cepheids to complete the survey of all Cepheids brighter than 8" magnitude to look for companions. Archival IUE spectra are non-existant or inadequate (no LWP or overexposed). The purpose of this survey is to accurately determine the percentage of Cepheids which are binaries, to compare with evolutionary predictions. This IUE survey will identify definitively Cepheids with blue companions, about which there is come confusion from groundbased photometric techniques, and hence prevent distortions to such parameters as luminosity, color and reddening. In addition, the distribution of mass ratios (from the spectral type of the main sequence mass and the evolutionary mass of the Cepheid (Evans and Bolton, 1989)), is basic information about star formation.

  3. Elemental abundances of solar sibling candidates

    SciTech Connect

    Ramírez, I.; Lambert, D. L.; Endl, M.; Cochran, W. D.; MacQueen, P. J.; Bajkova, A. T.; Bobylev, V. V.; Wittenmyer, R. A.

    2014-06-01

    Dynamical information along with survey data on metallicity and in some cases age have been used recently by some authors to search for candidates of stars that were born in the cluster where the Sun formed. We have acquired high-resolution, high signal-to-noise ratio spectra for 30 of these objects to determine, using detailed elemental abundance analysis, if they could be true solar siblings. Only two of the candidates are found to have solar chemical composition. Updated modeling of the stars' past orbits in a realistic Galactic potential reveals that one of them, HD 162826, satisfies both chemical and dynamical conditions for being a sibling of the Sun. Measurements of rare-element abundances for this star further confirm its solar composition, with the only possible exception of Sm. Analysis of long-term high-precision radial velocity data rules out the presence of hot Jupiters and confirms that this star is not in a binary system. We find that chemical tagging does not necessarily benefit from studying as many elements as possible but instead from identifying and carefully measuring the abundances of those elements that show large star-to-star scatter at a given metallicity. Future searches employing data products from ongoing massive astrometric and spectroscopic surveys can be optimized by acknowledging this fact.

  4. Elemental Abundances of Solar Sibling Candidates

    NASA Astrophysics Data System (ADS)

    Ramírez, I.; Bajkova, A. T.; Bobylev, V. V.; Roederer, I. U.; Lambert, D. L.; Endl, M.; Cochran, W. D.; MacQueen, P. J.; Wittenmyer, R. A.

    2014-06-01

    Dynamical information along with survey data on metallicity and in some cases age have been used recently by some authors to search for candidates of stars that were born in the cluster where the Sun formed. We have acquired high-resolution, high signal-to-noise ratio spectra for 30 of these objects to determine, using detailed elemental abundance analysis, if they could be true solar siblings. Only two of the candidates are found to have solar chemical composition. Updated modeling of the stars' past orbits in a realistic Galactic potential reveals that one of them, HD 162826, satisfies both chemical and dynamical conditions for being a sibling of the Sun. Measurements of rare-element abundances for this star further confirm its solar composition, with the only possible exception of Sm. Analysis of long-term high-precision radial velocity data rules out the presence of hot Jupiters and confirms that this star is not in a binary system. We find that chemical tagging does not necessarily benefit from studying as many elements as possible but instead from identifying and carefully measuring the abundances of those elements that show large star-to-star scatter at a given metallicity. Future searches employing data products from ongoing massive astrometric and spectroscopic surveys can be optimized by acknowledging this fact.

  5. On the Binary Fraction of Globular Cluster NGC 5053: the Method

    NASA Astrophysics Data System (ADS)

    Ji, Jun; Bregman, J. N.

    2010-01-01

    Binaries are thought to be the primary energy source in globular clusters, since they can heat the environmental stars in globular clusters by converting their binding energy to kinetic energy of the encounter stars through dynamical interactions. Even a small primordial binary fraction is sufficient to prevent globular clusters from core collapse for many relaxation times. So binary fraction is an essential parameter which can dramatically affect the evolution of globular clusters. Here we present a detailed analyzing method on the binary fraction of globular cluster NGC 5053, with the HST archival ACS data in the F606W and F814W bands. The PSF-fitting photometry is used with the DOLPHOT ACS module to obtain a high quality color-magnitude diagram. An aperture photometry is also performed for comparison. We find that both the PSF-fitting and aperture photometry obtain similar quality CMDs, but PSF photometry tends to recover more stars towards the cluster core. We also formulate the blending effect (or star superposition) to be the Poisson probability distribution function, which is confirmed by our Monte-Carlo simulations for blending. A minimum binary fraction is obtained by counting stars that are beyond 3-sigma photometric errors on the blue side. A global binary fraction is also obtained by comparing the residual color distribution profile of the Main Sequence stars to the one that is constructed by artificial stars with a known binary fraction. Chi-square test is then used to search the best-fit binary fraction value. We obtain a minimum binary fraction of 6.6% for NGC 5053, which does not depend on any assumption of the binary mass ratio distribution, and a model-dependent binary fraction range of 7% to 12%. Finally, we select 242 binary candidates that are beyond 3-sigma photometric errors, which could be later confirmed by spectroscopic observations from the ground.

  6. The Impact of Stellar Multiplicity on Planetary Systems. I. The Ruinous Influence of Close Binary Companions

    NASA Astrophysics Data System (ADS)

    Kraus, Adam L.; Ireland, Michael J.; Huber, Daniel; Mann, Andrew W.; Dupuy, Trent J.

    2016-07-01

    The dynamical influence of binary companions is expected to profoundly influence planetary systems. However, the difficulty of identifying planets in binary systems has left the magnitude of this effect uncertain; despite numerous theoretical hurdles to their formation and survival, at least some binary systems clearly host planets. We present high-resolution imaging of 382 Kepler Objects of Interest (KOIs) obtained using adaptive-optics imaging and nonredundant aperture-mask interferometry on the Keck II telescope. Among the full sample of 506 candidate binary companions to KOIs, we super-resolve some binary systems to projected separations of <5 au, showing that planets might form in these dynamically active environments. However, the full distribution of projected separations for our planet-host sample more broadly reveals a deep paucity of binary companions at solar-system scales. For a field binary population, we should have found 58 binary companions with projected separation ρ < 50 au and mass ratio q > 0.4 we instead only found 23 companions (a 4.6σ deficit), many of which must be wider pairs that are only close in projection. When the binary population is parametrized with a semimajor axis cutoff a cut and a suppression factor inside that cutoff S bin, we find with correlated uncertainties that inside {a}{cut}={47}-23+59 au, the planet occurrence rate in binary systems is only {S}{bin}={0.34}-0.15+0.14 times that of wider binaries or single stars. Our results demonstrate that a fifth of all solar-type stars in the Milky Way are disallowed from hosting planetary systems due to the influence of a binary companion.

  7. Conjugating binary systems for spacecraft thermal control

    NASA Technical Reports Server (NTRS)

    Grodzka, Philomena G.; Dean, William G.; Sisk, Lori A.; Karu, Zain S.

    1989-01-01

    The materials search was directed to liquid pairs which can form hydrogen bonds of just the right strength, i.e., strong enough to give a high heat of mixing, but weak enough to enable phase change to occur. The cursory studies performed in the area of additive effects indicate that Conjugating Binary (CB) performance can probably be fine-tuned by this means. The Fluid Loop Test Systems (FLTS) tests of candidate CBs indicate that the systems Triethylamine (TEA)/water and propionaldehyde/water show close to the ideal, reversible behavior, at least initially. The Quick Screening Tests QSTs and FLTS tests, however, both suffer from rather severe static due either to inadequate stirring or temperature control. Thus it is not possible to adequately evaluate less than ideal CB performers. Less than ideal performers, it should be noted, may have features that make them better practical CBs than ideal performers. Improvement of the evaluation instrumentation is thus indicated.

  8. Relativistic Binaries in Globular Clusters.

    PubMed

    Benacquista, Matthew J; Downing, Jonathan M B

    2013-01-01

    Galactic globular clusters are old, dense star systems typically containing 10(4)-10(6) stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution that leads to relativistic binaries, and current and possible future observational evidence for this population. Our discussion of globular cluster evolution will focus on the processes that boost the production of tight binary systems and the subsequent interaction of these binaries that can alter the properties of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker-Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.

  9. Multilevel Models for Binary Data

    ERIC Educational Resources Information Center

    Powers, Daniel A.

    2012-01-01

    The methods and models for categorical data analysis cover considerable ground, ranging from regression-type models for binary and binomial data, count data, to ordered and unordered polytomous variables, as well as regression models that mix qualitative and continuous data. This article focuses on methods for binary or binomial data, which are…

  10. Multilevel Models for Binary Data

    ERIC Educational Resources Information Center

    Powers, Daniel A.

    2012-01-01

    The methods and models for categorical data analysis cover considerable ground, ranging from regression-type models for binary and binomial data, count data, to ordered and unordered polytomous variables, as well as regression models that mix qualitative and continuous data. This article focuses on methods for binary or binomial data, which are…

  11. Generic Phase Diagram of Binary Superlattices

    NASA Astrophysics Data System (ADS)

    Tkachenko, Alexei

    Emergence of a large variety of self-assembled superlattices is a dramatic recent trend in the fields of nanoparticle and colloidal sciences. Motivated by this development, we propose a model that combines simplicity with a remarkably rich phase behavior, applicable to a wide range of such self-assembled systems. Those include nanoparticle and colloidal assemblies driven by DNA-mediated interactions, electrostatics, and possibly, by controlled drying. In our model, a binary system of Large and Small hard sphere (L and S)interact via selective short-range (''sticky'') attraction. In its simplest version, this Binary Sticky Sphere model features attraction only between 'S' and 'L' particles, respectively. We demonstrate that in the limit when this attraction is sufficiently strong compared to kT, the problem becomes purely geometrical: the thermodynamically preferred state should maximize the number of S-L contacts. A general procedure for constructing the phase diagram as a function of system composition f, and particle size ratio r, is outlined. In this way, the global phase behavior can be calculated very efficiently, for a given set of plausible candidate phases. Furthermore, the geometric nature of the problem enables us to generate those candidate phases through a well defined and intuitive construction. We calculate the phase diagrams both for 2D and 3D systems, and compare the results with existing experiments. Most of the 3D superlattices observed to date are featured in our phase diagram, while several more are yet to be discovered. The research was carried out at the CFN, DOE Office of Science Facility, at BNL, under Contract No. DE-SC0012704.

  12. Gravitational Wave Detection of Compact Binaries Through Multivariate Analysis

    NASA Astrophysics Data System (ADS)

    Atallah, Dany Victor; Dorrington, Iain; Sutton, Patrick

    2017-01-01

    The first detection of gravitational waves (GW), GW150914, as produced by a binary black hole merger, has ushered in the era of GW astronomy. The detection technique used to find GW150914 considered only a fraction of the information available describing the candidate event: mainly the detector signal to noise ratios and chi-squared values. In hopes of greatly increasing detection rates, we want to take advantage of all the information available about candidate events. We employ a technique called Multivariate Analysis (MVA) to improve LIGO sensitivity to GW signals. MVA techniques are efficient ways to scan high dimensional data spaces for signal/noise classification. Our goal is to use MVA to classify compact-object binary coalescence (CBC) events composed of any combination of black holes and neutron stars. CBC waveforms are modeled through numerical relativity. Templates of the modeled waveforms are used to search for CBCs and quantify candidate events. Different MVA pipelines are under investigation to look for CBC signals and un-modelled signals, with promising results. One such MVA pipeline used for the un-modelled search can theoretically analyze far more data than the MVA pipelines currently explored for CBCs, potentially making a more powerful classifier. In principle, this extra information could improve the sensitivity to GW signals. We will present the results from our efforts to adapt an MVA pipeline used in the un-modelled search to classify candidate events from the CBC search.

  13. Shuttle - Crew Candidates

    NASA Image and Video Library

    1979-03-01

    Astronaut -Candidate (ASCAN) Guion S. Bluford and Aviation Safety Officer Charles F. Hayes got a unique perspective of their environment during a zero- gravity flight. They are aboard a KC-135 Aircraft, which flies a special pattern repeatedly to afford a series of 30-seconds-of-weightlessness sessions. Astronauts Bluford and Hayes are being assisted by C. P. Stanley of the Photography Branch of the Photographic Technology Division (PTD) at Johnson Space Center (JSC). Some medical studies and a Motion Sickness Experiment were conducted on this particular flight. Astronaut Bluford is one of 20 Scientist/ASCAN's who began training at JSC, 07/1978. 1. Dr. Jeffrey A. Hoffman - Zero-G 2. ASCAN Shannon Lucid - Zero-G 3. ASCAN Guion Bluford - Zero-G

  14. Signature Visualization of Software Binaries

    SciTech Connect

    Panas, T

    2008-07-01

    In this paper we present work on the visualization of software binaries. In particular, we utilize ROSE, an open source compiler infrastructure, to pre-process software binaries, and we apply a landscape metaphor to visualize the signature of each binary (malware). We define the signature of a binary as a metric-based layout of the functions contained in the binary. In our initial experiment, we visualize the signatures of a series of computer worms that all originate from the same line. These visualizations are useful for a number of reasons. First, the images reveal how the archetype has evolved over a series of versions of one worm. Second, one can see the distinct changes between version. This allows the viewer to form conclusions about the development cycle of a particular worm.

  15. Magnetic activity of interacting binaries

    NASA Astrophysics Data System (ADS)

    Hill, Colin A.

    2017-10-01

    Interacting binaries provide unique parameter regimes, both rapid rotation and tidal distortion, in which to test stellar dynamo theories and study the resulting magnetic activity. Close binaries such as cataclysmic variables (CVs) have been found to differentially rotate, and so can provide testbeds for tidal dissipation efficiency in stellar convective envelopes, with implications for both CV and planet-star evolution. Furthermore, CVs show evidence of preferential emergence of magnetic flux tubes towards the companion star, as well as large, long-lived prominences that form preferentially within the binary geometry. Moreover, RS CVn binaries also show clear magnetic interactions between the two components in the form of coronal X-ray emission. Here, we review several examples of magnetic interactions in different types of close binaries.

  16. How do binary clusters form?

    NASA Astrophysics Data System (ADS)

    Arnold, Becky; Goodwin, Simon P.; Griffiths, D. W.; Parker, Richard. J.

    2017-10-01

    Approximately 10 per cent of star clusters are found in pairs, known as binary clusters. We propose a mechanism for binary cluster formation; we use N-body simulations to show that velocity substructure in a single (even fairly smooth) region can cause binary clusters to form. This process is highly stochastic and it is not obvious from a region's initial conditions whether a binary will form and, if it does, which stars will end up in which cluster. We find the probability that a region will divide is mainly determined by its virial ratio, and a virial ratio above 'equilibrium' is generally necessary for binary formation. We also find that the mass ratio of the two clusters is strongly influenced by the initial degree of spatial substructure in the region.

  17. BINARY ASTROMETRIC MICROLENSING WITH GAIA

    SciTech Connect

    Sajadian, Sedighe

    2015-04-15

    We investigate whether or not Gaia can specify the binary fractions of massive stellar populations in the Galactic disk through astrometric microlensing. Furthermore, we study whether or not some information about their mass distributions can be inferred via this method. In this regard, we simulate the binary astrometric microlensing events due to massive stellar populations according to the Gaia observing strategy by considering (i) stellar-mass black holes, (ii) neutron stars, (iii) white dwarfs, and (iv) main-sequence stars as microlenses. The Gaia efficiency for detecting the binary signatures in binary astrometric microlensing events is ∼10%–20%. By calculating the optical depth due to the mentioned stellar populations, the numbers of the binary astrometric microlensing events being observed with Gaia with detectable binary signatures, for the binary fraction of about 0.1, are estimated to be 6, 11, 77, and 1316, respectively. Consequently, Gaia can potentially specify the binary fractions of these massive stellar populations. However, the binary fraction of black holes measured with this method has a large uncertainty owing to a low number of the estimated events. Knowing the binary fractions in massive stellar populations helps with studying the gravitational waves. Moreover, we investigate the number of massive microlenses for which Gaia specifies masses through astrometric microlensing of single lenses toward the Galactic bulge. The resulting efficiencies of measuring the mass of mentioned populations are 9.8%, 2.9%, 1.2%, and 0.8%, respectively. The numbers of their astrometric microlensing events being observed in the Gaia era in which the lens mass can be inferred with the relative error less than 0.5 toward the Galactic bulge are estimated as 45, 34, 76, and 786, respectively. Hence, Gaia potentially gives us some information about the mass distribution of these massive stellar populations.

  18. Main Sequence Binary Fraction in Globular Cluster NGC 6397

    NASA Astrophysics Data System (ADS)

    Srinath, Srikar; Cool, A. M.; Anderson, J.

    2011-01-01

    We report preliminary results from a study of main-sequence binaries (MSBs) in the core-collapsed globular cluster NGC 6397 using the Hubble Space Telescope (HST) Advanced Camera for Surveys. We analyze images of the central regions of the cluster extending out to approximately one half-mass radius (rhm = 2.33') taken with the Wide Field Channel in the F435W and F625W filters. After removing non-members using proper motions, we construct a color-magnitude diagram (CMD) containing 15578 cluster stars. Model cluster CMDs indicate that in the range 16 < R < 22, MSBs with mass ratio (q=M2/M1) > 0.6 appear sufficiently far above and redward of the main sequence ridge line to be distinguishable from the single-star sequence. Out of 10835 stars in this magnitude range, we identify an initial set of 137 stars (with primary masses in the range 0.4-0.7 Msun) whose offset from the single-star sequence is statistically significant. A check of quality of fit to the PSF combined with close visual inspection of the images shows that 85 of these stars are well measured and unresolved and are thus good MSB candidates. The resulting upper limit on the fraction of MSBs with q > 0.6 and primaries in the range 0.4-0.7 Msun is 0.8%. We compare our measured fraction and the radial distribution of the MSB candidates to earlier findings based on HST/WFPC2 imaging and explore the significance of the results for the total binary population in NGC 6397. Keywords: binaries: general - globular clusters: individual(NGC 6397) - binary fraction - stars: main sequence binary

  19. Masses and Luminosities of X-Ray Binaries

    NASA Technical Reports Server (NTRS)

    Quirrenbach, Andreas; Frink, Sabine; Tomsick, John

    2004-01-01

    Using SIM, we will perform narrow-angle observations of several X-ray binaries to determine their orbits, and we will observe about 50 X-ray binary systems in wide-angle mode to measure their distances and proper motions. Sources with mass estimates for the compact component of greater than 3 solar masses are generally called black hole candidates since this mass is above the theoretical neutron star limit. Narrow-angle observations of these sources provide a direct test of the dynamical mass estimates on which the black hole evidence is based. Better measurements of the black hole masses will provide constraints on possible evolutionary paths that lead to black hole formation. When combined with X-ray data, mass measurements may provide additional constraints on the black hole spin. Precise mass determinations of neutron star systems can address the question of whether neutron stars can be significantly more massive than 1.4 solar masses, which would eliminate soft models of the neutron star equations of state. The wide-angle observations will probe the Galactic distribution of X-ray binaries through parallaxes and proper motions. They will also eliminate the uncertainties in the luminosities of individual sources, which is currently up to a full order of magnitude. This will enable more detailed comparisons of X-ray observations to physical models such as advection-dominated accretion flows (ADAFs). We intend to carry out the following measurements: 1) Determine the orbits of two black hole candidates to measure the black hole masses; 2) Obtain precise mass measurements for two neutron star systems to constrain neutron star equations of state; 3) Determine the distances and thus luminosities of selected representatives of various classes of X-ray binaries (black hole candidates, neutron stars, jet sources); 4) In the process of distance determination, proper motions will also be measured, from which the age of the population can be estimated.

  20. PLANET HUNTERS: NEW KEPLER PLANET CANDIDATES FROM ANALYSIS OF QUARTER 2

    SciTech Connect

    Lintott, Chris J.; Schwamb, Megan E.; Schwainski, Kevin; and others

    2013-06-15

    We present new planet candidates identified in NASA Kepler Quarter 2 public release data by volunteers engaged in the Planet Hunters citizen science project. The two candidates presented here survive checks for false positives, including examination of the pixel offset to constrain the possibility of a background eclipsing binary. The orbital periods of the planet candidates are 97.46 days (KIC 4552729) and 284.03 (KIC 10005758) days and the modeled planet radii are 5.3 and 3.8 R{sub Circled-Plus }. The latter star has an additional known planet candidate with a radius of 5.05 R{sub Circled-Plus} and a period of 134.49 days, which was detected by the Kepler pipeline. The discovery of these candidates illustrates the value of massively distributed volunteer review of the Kepler database to recover candidates which were otherwise uncataloged.

  1. Planet Hunters: New Kepler Planet Candidates from Analysis of Quarter 2

    NASA Astrophysics Data System (ADS)

    Lintott, Chris J.; Schwamb, Megan E.; Barclay, Thomas; Sharzer, Charlie; Fischer, Debra A.; Brewer, John; Giguere, Matthew; Lynn, Stuart; Parrish, Michael; Batalha, Natalie; Bryson, Steve; Jenkins, Jon; Ragozzine, Darin; Rowe, Jason F.; Schwainski, Kevin; Gagliano, Robert; Gilardi, Joe; Jek, Kian J.; Pääkkönen, Jari-Pekka; Smits, Tjapko

    2013-06-01

    We present new planet candidates identified in NASA Kepler Quarter 2 public release data by volunteers engaged in the Planet Hunters citizen science project. The two candidates presented here survive checks for false positives, including examination of the pixel offset to constrain the possibility of a background eclipsing binary. The orbital periods of the planet candidates are 97.46 days (KIC 4552729) and 284.03 (KIC 10005758) days and the modeled planet radii are 5.3 and 3.8 R ⊕. The latter star has an additional known planet candidate with a radius of 5.05 R ⊕ and a period of 134.49 days, which was detected by the Kepler pipeline. The discovery of these candidates illustrates the value of massively distributed volunteer review of the Kepler database to recover candidates which were otherwise uncataloged. .

  2. VLSI binary updown counter

    NASA Technical Reports Server (NTRS)

    Truong, Trieu-Kie (Inventor); Hsu, In-Shek (Inventor); Reed, Irving S. (Inventor)

    1989-01-01

    A pipeline binary updown counter is comprised of simple stages that may be readily replicated. Each stage is defined by the Boolean logic equation: A(sub n)(t) = A(sub n)(t - 1) exclusive OR (U AND P(sub n)) inclusive OR (D AND Q(sub n)), where A(sub n)(t) denotes the value of the nth bit at time t. The input to the counter has three values represented by two binary signals U and D such that if both are zero, the input is zero, if U = 0 and D = 1, the input is -1 and if U = 1 and D = 0, the input is +1. P(sub n) represents a product of A(sub k)'s for 1 is less than or equal to k is less than or equal to -1, while Q(sub n) represents the product of bar A's for 1 is less than or equal to K is less than or equal to n - 1, where bar A(sub k) is the complement of A(sub k) and P(sub n) and Q(sub n) are expressed as the following two equations: P(sub n) = A(sub n - 1) A(sub n - 2)...A(sub 1) and Q(sub n) = bar A(sub n - 1) bar A(sub n - 2)...bar A(sub 1), which can be written in recursive form as P(sub n) = P(sub n - 1) AND bar A(sub n - 1) and Q(sub n) = Q(sub n - 1) AND bar A(sub n - 1) with the initial values P(sub 1) = 1 and Q(sub 1) = 1.

  3. SLoWPoKES-II: 100,000 WIDE BINARIES IDENTIFIED IN SDSS WITHOUT PROPER MOTIONS

    SciTech Connect

    Dhital, Saurav; West, Andrew A.; Schluns, Kyle J.; Massey, Angela P.; Stassun, Keivan G.

    2015-08-15

    We present the Sloan Low-mass Wide Pairs of Kinematically Equivalent Stars (SLoWPoKES)-II catalog of low-mass visual binaries identified from the Sloan Digital Sky Survey (SDSS) by matching photometric distances. The candidate pairs are vetted by comparing the stellar information. The candidate pairs are vetted by comparing the stellar density at their respective Galactic positions to Monte Carlo realizations of a simulated Milky Way. In this way, we are able to identify large numbers of bona fide wide binaries without the need for proper motions. Here, 105,537 visual binaries with angular separations of ∼1–20″ were identified, each with a probability of chance alignment of ≤5%. This is the largest catalog of bona fide wide binaries to date, and it contains a diversity of systems—in mass, mass ratios, binary separations, metallicity, and evolutionary states—that should facilitate follow-up studies to characterize the properties of M dwarfs and white dwarfs. There is a subtle but definitive suggestion of multiple populations in the physical separation distribution, supporting earlier findings. We suggest that wide binaries are composed of multiple populations, most likely representing different formation modes. There are 141 M7 or later wide binary candidates, representing a seven-fold increase over the number currently known. These binaries are too wide to have been formed via the ejection mechanism. Finally, we found that 6% of spectroscopically confirmed M dwarfs are not included in the SDSS STAR catalog; they are misclassified as extended sources due to the presence of a nearby or partially resolved companion. The SLoWPoKES-II catalog is publicly available to the entire community on the World Wide Web via the Filtergraph data visualization portal.

  4. Contact binaries: I. An inspection of the HSB contact binary model by comparison of relationships obtained from theoretical light curves with that from astronomical observations

    NASA Astrophysics Data System (ADS)

    Luo, ChangQing; Huang, RunQian

    2012-03-01

    The light curve is one of the most important photometric characteristics of variable stars, which can supply physical information about many stars. So, light curves are the best candidate to inspect a theoretical model of binaries. One important feature of the light curve is the difference of two light minima of the light curve, namely the difference between the primary eclipse depth and the secondary eclipse depth ( DED). In this paper, the secondary eclipse depths of theoretical and observational light curves are studied. Firstly, a method to calculate the theoretical light curves of an eclipsing binary with non-spherical components is proposed, which can be put into the HSB contact binary model [Huang R Q, et al. Chin J Astron Astrophys, 2007, 7: 235-244; Song H F, et al. Chin J Astron Astrophys, 2007, 7: 539-550]. Theoretical light curves and the DED of the binary can be obtained at every evolutionary phase. The relationships of DED with mass and luminosity are presented and show special features for the contact binaries. Secondly, a large amount of observational data is collected, from which 11 massive, intermediate-mass contact binaries and 9 low-mass contact binaries are chosen and the two relationships are obtained using theoretical light curves. Finally, in order to check whether the HSB contact binary model can be used in contact binary systems with massive, intermediate-mass and low-mass components, a comparison is performed for the above mentioned relationships obtained from theoretical light curves with those from the astronomical observations. The results show a good agreement for contact binary systems with all different masses.

  5. The CoRoT transit candidate catalog

    NASA Astrophysics Data System (ADS)

    Aigrain, S.; Deleuil, M.

    2013-09-01

    We present a full catalog of all the candidate transiting planets identified by the CoRoT space mission during its first 5 years of operations, including homogeneously derived transit parameters, validation diagnostics and a summary of the outcome of follow-up observations, where available.The catalog includes confirmed planets, clear false alarms (mainly blended or grazing eclipsing binaries), but also dozens of unconfirmed cases, where the follow-up was either inconclusive (hot stars, fast rotators) or incomplete (owing to limited telescope time and the relatively faint nature of the CoRoT targets). The catalog is intended primarily as a resource for the community, for example as a starting point for completeness and population studies. The candidate detection and selection processes have evolved significantly over the course of the mission. Several teams independently analyse the light curves from each observing run, searching for transits and providing ranked candidate lists, which are subsequently merged and ranked manually. This enables the use of some specialist methods, which are better suited to the detection of only certain types of transits, but makes it difficult to provide an overall assessment of the sensitivity of the mission to transits of different depths and periods. However, we note the transit search methods used by the different teams have gradually converged since launch, and there are now fewer teams actively involved in the transit search, with more overlap between the resulting candidate lists. For each CoRoT observing run, one team member coordinates the selection of candidates for followup, with input from the other team members. The set of criteria used to perform this selection have also evolved over the years, becoming more homogeneous. In particular, the light curve fitting tools used to produce the transit parameters and other diagnostics, which are included in the present catalog, are now routinely used to validate candidates and

  6. Proper-motion binaries in the Hipparcos catalogue. Comparison with radial velocity data

    NASA Astrophysics Data System (ADS)

    Frankowski, A.; Jancart, S.; Jorissen, A.

    2007-03-01

    Context: This paper is the last in a series devoted to the analysis of the binary content of the Hipparcos Catalogue. Aims: The comparison of the proper motions constructed from positions spanning a short (Hipparcos) or long time (Tycho-2) makes it possible to uncover binaries with periods of the order of or somewhat larger than the short time span (in this case, the 3 yr duration of the Hipparcos mission), since the unrecognised orbital motion will then add to the proper motion. Methods: A list of candidate proper motion binaries is constructed from a carefully designed χ2 test evaluating the statistical significance of the difference between the Tycho-2 and Hipparcos proper motions for 103 134 stars in common between the two catalogues (excluding components of visual systems). Since similar lists of proper-motion binaries have already been constructed, the present paper focuses on the evaluation of the detection efficiency of proper-motion binaries, using different kinds of control data (mostly radial velocities). The detection rate for entries from the Ninth Catalogue of Spectroscopic Binary Orbits (S_B^9) is evaluated, as well as for stars like barium stars, which are known to be all binaries, and finally for spectroscopic binaries identified from radial velocity data in the Geneva-Copenhagen survey of F and G dwarfs in the solar neighbourhood. Results: Proper motion binaries are efficiently detected for systems with parallaxes in excess of ~20 mas, and periods in the range 1000-30 000 d. The shortest periods in this range (1000-2000 d, i.e., once to twice the duration of the Hipparcos mission) may appear only as DMSA/G binaries (accelerated proper motion in the Hipparcos Double and Multiple System Annex). Proper motion binaries detected among S_B9 systems having periods shorter than about 400 d hint at triple systems, the proper-motion binary involving a component with a longer orbital period. A list of 19 candidate triple systems is provided. Binaries

  7. Vetting Kepler Planet Candidates with Multi-Color Photometry from the Gran Telescopio Canarias

    NASA Astrophysics Data System (ADS)

    Colon, Knicole; Ford, E. B.

    2011-09-01

    We present multi-color observations of small (super-Earth to Neptune-size) planet candidates recently identified by the Kepler space mission. By applying the unique capabilities of OSIRIS (installed on the 10.4-meter Gran Telescopio Canarias) for near-simultaneous multi-color photometry, we use the color of Kepler candidates as measured during predicted transit events to reject candidates that are false positives (e.g., a blend with an eclipsing binary in the background or bound to the target star). Our results include the discovery of a background eclipsing binary star (KIC 7025851) near KOI-565 (KIC 7025846). Based on the location of the eclipsing binary ( 15 arcsec from KOI-565), we conclude that the eclipsing binary contaminated the light from KOI-565 to mimic the super-Earth-size transit signal that was detected by Kepler. We also compare the technique of measuring colors in two narrow (2 nm) bandpasses separated by only a few nanometers in wavelength ( 790-794 nm) with measuring colors in two wider (36-58 nm) bandpasses located at bluer ( 666 nm) and redder ( 858 nm) wavelengths. These observations are part of a program to statistically determine the likelihood that planet candidates (e.g., with a given size) ultimately end up being false positives and are complementary to a similar program using warm-Spitzer. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-0802270.

  8. Spectroscopy of Kepler Exo-planet Transit Candidate Stars

    NASA Astrophysics Data System (ADS)

    Howell, Steve B.; Everett, Mark; Silva, David; Rowe, Jason; Szkody, Paula; Mighell, Ken; Holberg, Jay

    2011-08-01

    We propose a long term spectroscopic follow-up program in support of the NASA Kepler exo-planet mission. The Kepler project is now focusing on exo-planet candidates which are smaller in radius (down to Earth- size), have longer period orbits, and exo-planet candidates in fainter stars and eclipsing binary stars. Our five scientific goals for our 4m program are to provide: 1) reconnaissance spectra of newly discovered exo-planet stars yielding model fits to T_eff and log g, 2) radial velocity solutions for eclipsing binary star systems in which a third body exo-planet candidate has been detected, 3) velocity or line asymmetry (bisector) measurements in order to provide a line of defense against unseen stellar mass companions, 4) good S/N spectroscopic observations of newly discovered white dwarfs to use as photometric calibrators for the Kepler focal plane, and 5) spectra of odd/interesting variable stars discovered by Kepler. All of these tasks can be accomplished using the Kitt Peak 4-m telescope and RCspec as shown by our previous time allocations.

  9. Spectroscopy of Kepler Exo-planet Transit Candidate Stars

    NASA Astrophysics Data System (ADS)

    Howell, Steve B.; Everett, Mark; Rowe, Jason; Silva, David; Szkody, Paula; Mighell, Ken; Holberg, Jay

    2011-02-01

    We propose a long term spectroscopic follow-up program in support of the NASA Kepler exo-planet mission. The Kepler project is now focusing on exo-planet candidates which are smaller in radius (down to Earth- size), have longer period orbits, and exo-planet candidates around fainter stars and eclipsing binary stars. We have five scientific goals for this project: 1) obtain reconnaissance type spectra for newly discovered exo-planet stars leading to model fits for Teff and log g, 2) provide radial velocity solutions for eclipsing binary star systems in which a third body exo-planet candidate has been detected, 3) Provide velocity or line asymmetry (bisector) measurements in order to provide a line of defense against unseen stellar mass companions, 4) obtain good S/N spectroscopic observations of new white dwarfs to use as photometric calibrators for the Kepler focal plane, and 5) obtain spectra of odd/interesting variable stars discovered by Kepler. All of these tasks can be accomplished using the Kitt Peak 4-m telescope and RCSPEC as shown by our previous time allocation.

  10. Likely Planet Candidates Identified by Machine Learning Applied to Four Years of Kepler Data

    NASA Astrophysics Data System (ADS)

    Jenkins, Jon M.; McCauliff, S. D.; Catanzarite, J. H.; Twicken, J. D.; Klaus, T. C.; SOC, Kepler; SO, Kepler

    2013-10-01

    Over 3,200 transiting planet candidates, 134 confirmed planets, and ~2,400 eclipsing binaries have been identified by the Kepler Science pipeline since launch in March 2009. Compiling the list of candidates is an intensive manual effort as over 18,000 transit-like signatures are identified for a run across 34 months. The vast majority are caused by artifacts that mimic transits. While the pipeline provides diagnostics that can reduce the initial list down to ~5,000 light curves, this effort can overlook valid planetary candidates. The large number of diagnostics 100) makes it difficult to examine all the information available in identifying planetary candidates. The effort required for vetting all threshold-crossing events (TCEs) takes several months by many individuals associated with the Kepler Threshold Crossing Event Review Team (TCERT). We have developed a random-forest classifier that decides whether a TCE should be called `planet candidate’, `astrophysical false positive’, or `non-transiting phenomena’. Ideally a machine learning algorithm will generate a list of candidates that approximates those generated by human review, thereby allowing the humans to focus on the most interesting cases. By using a machine learning-based auto-vetting process, we have the opportunity to identify the most important metrics and diagnostics for separating signatures of transiting planets and eclipsing binaries from instrument-induced features, thereby improving the efficiency of the manual effort. We report the results of a applying a random forest classifier to four years of Kepler data. We present characteristics of the likely planet candidates identified by the auto-vetter as well as those objects classified as astrophysical false positives (eclipsing binaries and background eclipsing binaries). We examine the auto-vetter's performance through receiver operating characteristic curves for each of three classes: planet candidate, astrophysical false positive, and

  11. BINARIES AMONG DEBRIS DISK STARS

    SciTech Connect

    Rodriguez, David R.; Zuckerman, B.

    2012-02-01

    We have gathered a sample of 112 main-sequence stars with known debris disks. We collected published information and performed adaptive optics observations at Lick Observatory to determine if these debris disks are associated with binary or multiple stars. We discovered a previously unknown M-star companion to HD 1051 at a projected separation of 628 AU. We found that 25% {+-} 4% of our debris disk systems are binary or triple star systems, substantially less than the expected {approx}50%. The period distribution for these suggests a relative lack of systems with 1-100 AU separations. Only a few systems have blackbody disk radii comparable to the binary/triple separation. Together, these two characteristics suggest that binaries with intermediate separations of 1-100 AU readily clear out their disks. We find that the fractional disk luminosity, as a proxy for disk mass, is generally lower for multiple systems than for single stars at any given age. Hence, for a binary to possess a disk (or form planets) it must either be a very widely separated binary with disk particles orbiting a single star or it must be a small separation binary with a circumbinary disk.

  12. Binaries and Multiple Stellar Systems

    NASA Astrophysics Data System (ADS)

    Horch, Elliott

    Binary and multiple stellar systems have importance in three main areas of astronomy and astrophysics. First, because of the relatively simple gravitational interaction at work in the case of binary stars, these systems provide a basic check on stellar structure and evolution theory since the masses may be determined through observation. When these masses can be linked to other properties of the two stars, such as luminosity, color, and radius, they can provide very stringent constraints on stellar models. Second, the statistics of binary and multiple star systems provide clues to star formation mechanisms and environmental effects in the galactic gravitational potential and in clusters. Although a number of good results have been obtained in nearby star clusters and associations, knowledge of the field population has been somewhat limited until recently by a lack of large, complete samples of binaries. However, there appears to be a great deal of promise in this area for the coming decade in part due to astrometric satellites such as Hipparcos and Gaia. Third, the binary scenario is invoked to explain several important types of astrophysical phenomena such as Type Ia supernovae, cataclysmic variables, and stellar x-ray sources. Since the first of these mentioned is a standard candle for the extragalactic distance scale, it may even be said binary stars play a minor role in field of cosmology. However, in this chapter, the focus will mainly be on normal stars in binary and multiple-stellar systems. The basic physics of binaries will be reviewed, and the observational methods in use today will be discussed together with their limitations and prospects for the future. Finally, an overview of the current science in the three main areas mentioned where binaries have a significant impact will be given.

  13. CREW CANDIDATES - SHUTTLE - JSC

    NASA Image and Video Library

    1977-01-31

    S78-26569 (31 Jan. 1978) --- The 35 new astronaut candidates, presented Jan. 31, 1978, in the Building 2 auditorium at NASA's Johnson Space Center, pose for photographers. They are arranged in alphabetical order with top left as beginning point and bottom right as stopping point. They are Guion S. Bluford, Daniel C. Brandenstein, James F. Buchli, Michael L. Coats, Richard O. Covey, John O. Creighton, John M. Fabian, Anna L. Fisher, Dale A. Gardner, Robert L. Gibson, Frederick D. Gregory, S. David Griggs, Terry J. Hart, Frederick H. (Rick) Hauck, Steven A. Hawley, Jeffrey A. Hoffman, Shannon W. Lucid, Jon A. McBride, Ronald E. McNair, Richard M. (Mike) Mullane, Steven R. Nagel, George D. Nelson, Ellison S. Onizuka, Judith A. Resnik, Sally K. Ride, Francis R. (Dick) Scobee, Rhea Seddon, Brewster H. Shaw Jr., Loren J. Shriver, Robert L. Stewart, Kathryn D. Sullivan, Norman E. Thagard, James D. van Hoften, David M. Walker and Donald E. Williams. Photo credit: NASA or National Aeronautics and Space Administration

  14. Towards A Complete Census of the Solar-Type Binaries in the Young Open Cluster M37

    NASA Astrophysics Data System (ADS)

    Geller, Aaron M.; Meibom, Soren; Barnes, Sydney A.; Mathieu, Robert D.

    2012-08-01

    Binary stars govern the dynamical evolution of star clusters and determine the formation rates and mechanisms for exotic stars like blue stragglers and X-ray sources. Understanding the near-primordial (after removal of the natal gas) binary population of star clusters is of primary importance for dynamical models of star clusters, which have the potential to revolutionize our understanding of star cluster evolution. Yet the binary frequencies and distributions of binary orbital parameters (period, eccentricity, etc.) for young coeval stellar populations are poorly known, due to a lack of necessary observations. Time-series radial-velocity surveys are essential for identifying and characterizing binary populations. Using WIYN/Hydra data, we have already identified a nearly complete sample of 329 solar-type (1.5 <=M [M_⊙] <=1.0) candidate members in the young (~540 Myr) open cluster M37. Of these stars, 82 show significant radial-velocity variability, indicative of a binary companion. Kinematic orbital solutions are crucial to define the initial binary conditions critical for dynamical star cluster models, and to understand how binaries affects stellar rotational evolution. As we have already identified the binaries in M37, we have a unique opportunity to add significantly to our knowledge of young binaries with minimal additional telescope time. We propose to initiate a WIYN/Hydra multi-epoch radial-velocity survey of the 82 velocity variables in M37.

  15. Modified evolution of stellar binaries from supermassive black hole binaries

    NASA Astrophysics Data System (ADS)

    Liu, Bin; Wang, Yi-Han; Yuan, Ye-Fei

    2017-04-01

    The evolution of main-sequence binaries resided in the galactic centre is influenced a lot by the central supermassive black hole (SMBH). Due to this perturbation, the stars in a dense environment are likely to experience mergers or collisions through secular or non-secular interactions. In this work, we study the dynamics of the stellar binaries at galactic centre, perturbed by another distant SMBH. Geometrically, such a four-body system is supposed to be decomposed into the inner triple (SMBH-star-star) and the outer triple (SMBH-stellar binary-SMBH). We survey the parameter space and determine the criteria analytically for the stellar mergers and the tidal disruption events (TDEs). For a relative distant and equal masses SMBH binary, the stars have more opportunities to merge as a result from the Lidov-Kozai (LK) oscillations in the inner triple. With a sample of tight stellar binaries, our numerical experiments reveal that a significant fraction of the binaries, ˜70 per cent, experience merger eventually. Whereas the majority of the stellar TDEs are likely to occur at a close periapses to the SMBH, induced by the outer Kozai effect. The tidal disruptions are found numerically as many as ˜10 per cent for a close SMBH binary that is enhanced significantly than the one without the external SMBH. These effects require the outer perturber to have an inclined orbit (≥40°) relatively to the inner orbital plane and may lead to a burst of the extremely astronomical events associated with the detection of the SMBH binary.

  16. Binary Oscillatory Crossflow Electrophoresis

    NASA Technical Reports Server (NTRS)

    Molloy, Richard F.; Gallagher, Christopher T.; Leighton, David T., Jr.

    1997-01-01

    Electrophoresis has long been recognized as an effective analytic technique for the separation of proteins and other charged species, however attempts at scaling up to accommodate commercial volumes have met with limited success. In this report we describe a novel electrophoretic separation technique - Binary Oscillatory Crossflow Electrophoresis (BOCE). Numerical simulations indicate that the technique has the potential for preparative scale throughputs with high resolution, while simultaneously avoiding many problems common to conventional electrophoresis. The technique utilizes the interaction of an oscillatory electric field and a transverse oscillatory shear flow to create an active binary filter for the separation of charged protein species. An oscillatory electric field is applied across the narrow gap of a rectangular channel inducing a periodic motion of charged protein species. The amplitude of this motion depends on the dimensionless electrophoretic mobility, alpha = E(sub o)mu/(omega)d, where E(sub o) is the amplitude of the electric field oscillations, mu is the dimensional mobility, omega is the angular frequency of oscillation and d is the channel gap width. An oscillatory shear flow is induced along the length of the channel resulting in the separation of species with different mobilities. We present a model that predicts the oscillatory behavior of charged species and allows estimation of both the magnitude of the induced convective velocity and the effective diffusivity as a function of a in infinitely long channels. Numerical results indicate that in addition to the mobility dependence, the steady state behavior of solute species may be strongly affected by oscillating fluid into and out of the active electric field region at the ends of the cell. The effect is most pronounced using time dependent shear flows of the same frequency (cos((omega)t)) flow mode) as the electric field oscillations. Under such conditions, experiments indicate that

  17. Stability of binaries. Part II: Rubble-pile binaries

    NASA Astrophysics Data System (ADS)

    Sharma, Ishan

    2016-10-01

    We consider the stability of the binary asteroids whose members are granular aggregates held together by self-gravity alone. A binary is said to be stable whenever both its members are orbitally and structurally stable to both orbital and structural perturbations. To this end, we extend the stability analysis of Sharma (Sharma [2015] Icarus, 258, 438-453), that is applicable to binaries with rigid members, to the case of binary systems with rubble members. We employ volume averaging (Sharma et al. [2009] Icarus, 200, 304-322), which was inspired by past work on elastic/fluid, rotating and gravitating ellipsoids. This technique has shown promise when applied to rubble-pile ellipsoids, but requires further work to settle some of its underlying assumptions. The stability test is finally applied to some suspected binary systems, viz., 216 Kleopatra, 624 Hektor and 90 Antiope. We also see that equilibrated binaries that are close to mobilizing their maximum friction can sustain only a narrow range of shapes and, generally, congruent shapes are preferred.

  18. Binary star database: binaries discovered in non-optical bands

    NASA Astrophysics Data System (ADS)

    Malkov, Oleg Yu.; Tessema, Solomon B.; Kniazev, Alexei Yu.

    The Binary star Database (BDB) is the world's principal database of binary and multiple systems of all observational types. In particular, it should contain data on binaries discovered in non-optical bands, X-ray binaries (XRBs) and radio pulsars in binaries. The goal of the present study was to compile complete lists of such objects. Due to the lack of a unified identification system for XRBs, we had to select them from five principal catalogues of X-ray sources. After cross-identification and positional cross-matching, a general catalogue of 373 XRBs was constructed for the first time. It contains coordinates, indication of photometric and spectroscopic binarity, and extensive cross-identification. In the preparation of the catalogue, a number of XRB classification disagreements were resolved, some catalogued identifiers and coordinates were corrected, and duplicated entries in the original catalogues were found. We have also compiled a general list of 239 radio pulsars in binary systems. The list is supplied with indication of photometric, spectroscopic or X-ray binarity, and with cross-identification data.

  19. Binary black hole spectroscopy

    NASA Astrophysics Data System (ADS)

    Van Den Broeck, Chris; Sengupta, Anand S.

    2007-03-01

    We study parameter estimation with post-Newtonian (PN) gravitational waveforms for the quasi-circular, adiabatic inspiral of spinning binary compact objects. In particular, the performance of amplitude-corrected waveforms is compared with that of the more commonly used restricted waveforms, in Advanced LIGO and EGO. With restricted waveforms, the properties of the source can only be extracted from the phasing. In the case of amplitude-corrected waveforms, the spectrum encodes a wealth of additional information, which leads to dramatic improvements in parameter estimation. At distances of ~100 Mpc, the full PN waveforms allow for high-accuracy parameter extraction for total mass up to several hundred solar masses, while with the restricted ones the errors are steep functions of mass, and accurate parameter estimation is only possible for relatively light stellar mass binaries. At the low-mass end, the inclusion of amplitude corrections reduces the error on the time of coalescence by an order of magnitude in Advanced LIGO and a factor of 5 in EGO compared to the restricted waveforms; at higher masses these differences are much larger. The individual component masses, which are very poorly determined with restricted waveforms, become measurable with high accuracy if amplitude-corrected waveforms are used, with errors as low as a few per cent in Advanced LIGO and a few tenths of a per cent in EGO. The usual spin orbit parameter β is also poorly determined with restricted waveforms (except for low-mass systems in EGO), but the full waveforms give errors that are small compared to the largest possible value consistent with the Kerr bound. This suggests a way of finding out if one or both of the component objects violate this bound. On the other hand, we find that the spin spin parameter σ remains poorly determined even when the full waveform is used. Generally, all errors have but a weak dependence on the magnitudes and orientations of the spins. We also briefly

  20. Radio detection of the young binary HD 160934

    NASA Astrophysics Data System (ADS)

    Azulay, R.; Guirado, J. C.; Marcaide, J. M.; Martí-Vidal, I.; Arroyo-Torres, B.

    2014-01-01

    Context. Precise determination of dynamical masses of pre-main-sequence (PMS) stars is essential to calibrate stellar evolution models that are widely used to derive theoretical masses of young low-mass objects. Binary stars in young, nearby loose associations are particularly good candidates for this calibration since all members share a common age. Interestingly, some of these young binaries present a persistent and compact radio emission, which makes them excellent targets for astrometric VLBI studies. Aims: We aim to monitor the orbital motion of the binary system HD 160934, a member of the AB Doradus moving group. Methods: We observed HD 160934 with the Very Large Array and the European VLBI Network at 8.4 and 5 GHz, respectively. The orbital information derived from these observations was analyzed along with previously reported orbital measurements. Results: We show that the two components of the binary, HD 160934 A and HD 160934 c, display compact radio emission at VLBI scales, providing precise information on the relative orbit. Revised orbital elements were estimated. Conclusions: Future VLBI monitoring of this pair should determine precise model-independent mass estimates for the A and c components, which will serve as calibration tests for PMS evolutionary models.

  1. EXPLORING A 'FLOW' OF HIGHLY ECCENTRIC BINARIES WITH KEPLER

    SciTech Connect

    Dong Subo; Katz, Boaz; Socrates, Aristotle

    2013-01-20

    With 16-month of Kepler data, 15 long-period (40-265 days) eclipsing binaries on highly eccentric orbits (minimum e between 0.5 and 0.85) are identified from their closely separated primary and secondary eclipses ({Delta}t{sub I,II} = 3-10 days). These systems confirm the existence of a previously hinted binary population situated near a constant angular momentum track at P(1 - e {sup 2}){sup 3/2} {approx} 15 days, close to the tidal circularization period P{sub circ}. They may be presently migrating due to tidal dissipation and form a steady-state 'flow' ({approx}1% of stars) feeding the close-binary population (few % of stars). If so, future Kepler data releases will reveal a growing number (dozens) of systems at longer periods, following dN/dlgP {proportional_to} P {sup 1/3} with increasing eccentricities reaching e {yields} 0.98 for P {yields} 1000 days. Radial-velocity follow-up of long-period eclipsing binaries with no secondary eclipses could offer a significantly larger sample. Orders of magnitude more (hundreds) may reveal their presence from periodic 'eccentricity pulses', such as tidal ellipsoidal variations near pericenter passages. Several new few-day-long eccentricity-pulse candidates with long periods (P = 25-80 days) are reported.

  2. The ELM Survey: Finding the Shortest Period Binary White Dwarfs

    NASA Astrophysics Data System (ADS)

    Canton, Paul; Gianninas, Alexandros; Kilic, Mukremin; Brown, Warren; Kenyon, Scott

    2014-08-01

    A new discovery space for short period binary white dwarfs has opened up with the availability of 14,600 deg^2 of SDSS Data Release 9 photometry. The Extremely Low-Mass (ELM) Survey takes advantage of this photometry and SDSS spectroscopy to identify compact systems with 1 hour or shorter orbital periods. To significantly increase the number of merging white dwarf systems known, we have proposed to obtain follow- up spectroscopic observations of all candidates with g ≤ 19 mag and photometric colors consistent with extremely low-mass (≤ 0.3 M_⊙) white dwarfs. Most of our 2012A Hale and 2012B KP 4m observing runs were lost to weather, yet we managed to identify at least one new short period binary. Our 2013A run on the KP 4m was successful in identifying many new ELM white dwarfs, and in our 2013B follow-up run we observed two new 3 hour binaries while also obtaining further data on a number of other merging systems. Here we propose to continue our program by observing our fall targets on the KP 4m telescope to constrain their binary orbital periods. Our two major science goals are to discover detached gravitational wave sources for fundamental tests of general relativity, and to constrain the formation rate and space density of merging white dwarfs. The latter is important for constraining the contribution of double degenerates to Type Ia and underluminous supernovae.

  3. Determination of the Period of Binary Asteroid Systems

    NASA Astrophysics Data System (ADS)

    Lust, Nathaniel B.; Britt, D. T.

    2008-09-01

    In the study of asteroids, binary pairs offer a unique window of study. By observing these systems and determining the period of the secondary, it is possible to determine system mass (e.g. Pravec and Hahn 1997; Ryan et al., 2004). With mass and volume, properties such as bulk density and porosity can be derived. At the University of Central Florida we have begun a binary asteroid hunt, in conjunction with the Prague consortium, in order to identify new binary candidates and to better constrain data on known pairs. All of the observations are collected on campus using a 0.5meter f/8.1 Ritchey-Chretien telescope with a SBIG STL-6303E detector. For our first test target we observed the known binary asteroid 107 Camila over a period of six days for approximately six to eight hours a night. The data is then processed using an open source python algorithm developed by Nate Lust. The data is read in, reduced, and compared to a standard star. Once the light curve was generated we make use of the CLEAN algorithm, originally developed by Hogbom (1974), to extract meaningful periods from the light curve.

  4. Mesoscopic model for binary fluids

    NASA Astrophysics Data System (ADS)

    Echeverria, C.; Tucci, K.; Alvarez-Llamoza, O.; Orozco-Guillén, E. E.; Morales, M.; Cosenza, M. G.

    2017-10-01

    We propose a model for studying binary fluids based on the mesoscopic molecular simulation technique known as multiparticle collision, where the space and state variables are continuous, and time is discrete. We include a repulsion rule to simulate segregation processes that does not require calculation of the interaction forces between particles, so binary fluids can be described on a mesoscopic scale. The model is conceptually simple and computationally efficient; it maintains Galilean invariance and conserves the mass and energy in the system at the micro- and macro-scale, whereas momentum is conserved globally. For a wide range of temperatures and densities, the model yields results in good agreement with the known properties of binary fluids, such as the density profile, interface width, phase separation, and phase growth. We also apply the model to the study of binary fluids in crowded environments with consistent results.

  5. An adaptable binary entropy coder

    NASA Technical Reports Server (NTRS)

    Kiely, A.; Klimesh, M.

    2001-01-01

    We present a novel entropy coding technique which is based on recursive interleaving of variable-to-variable length binary source codes. We discuss code design and performance estimation methods, as well as practical encoding and decoding algorithms.

  6. Cryptography with DNA binary strands.

    PubMed

    Leier, A; Richter, C; Banzhaf, W; Rauhe, H

    2000-06-01

    Biotechnological methods can be used for cryptography. Here two different cryptographic approaches based on DNA binary strands are shown. The first approach shows how DNA binary strands can be used for steganography, a technique of encryption by information hiding, to provide rapid encryption and decryption. It is shown that DNA steganography based on DNA binary strands is secure under the assumption that an interceptor has the same technological capabilities as sender and receiver of encrypted messages. The second approach shown here is based on steganography and a method of graphical subtraction of binary gel-images. It can be used to constitute a molecular checksum and can be combined with the first approach to support encryption. DNA cryptography might become of practical relevance in the context of labelling organic and inorganic materials with DNA 'barcodes'.

  7. CHAOTIC ZONES AROUND GRAVITATING BINARIES

    SciTech Connect

    Shevchenko, Ivan I.

    2015-01-20

    The extent of the continuous zone of chaotic orbits of a small-mass tertiary around a system of two gravitationally bound primaries of comparable masses (a binary star, a binary black hole, a binary asteroid, etc.) is estimated analytically, as a function of the tertiary's orbital eccentricity. The separatrix map theory is used to demonstrate that the central continuous chaos zone emerges (above a threshold in the primaries' mass ratio) due to overlapping of the orbital resonances corresponding to the integer ratios p:1 between the tertiary and the central binary periods. In this zone, the unlimited chaotic orbital diffusion of the tertiary takes place, up to its ejection from the system. The primaries' mass ratio, above which such a chaotic zone is universally present at all initial eccentricities of the tertiary, is estimated. The diversity of the observed orbital configurations of biplanetary and circumbinary exosystems is shown to be in accord with the existence of the primaries' mass parameter threshold.

  8. Separation in 5 Msun Binaries

    NASA Astrophysics Data System (ADS)

    Evans, Nancy R.; Bond, H. E.; Schaefer, G.; Mason, B. D.; Karovska, M.; Tingle, E.

    2013-01-01

    Cepheids (5 Msun stars) provide an excellent sample for determining the binary properties of fairly massive stars. International Ultraviolet Explorer (IUE) observations of Cepheids brighter than 8th magnitude resulted in a list of ALL companions more massive than 2.0 Msun uniformly sensitive to all separations. Hubble Space Telescope Wide Field Camera 3 (WFC3) has resolved three of these binaries (Eta Aql, S Nor, and V659 Cen). Combining these separations with orbital data in the literature, we derive an unbiased distribution of binary separations for a sample of 18 Cepheids, and also a distribution of mass ratios. The distribution of orbital periods shows that the 5 Msun binaries prefer shorter periods than 1 Msun stars, reflecting differences in star formation processes.

  9. Radio emission from binary stars

    NASA Technical Reports Server (NTRS)

    Dulk, George A.

    1986-01-01

    Radio emission from binary star systems; characteristics of the binary systems inferred from the radio observations; and the reasons for the activity are reviewed. Binary stars with two main sequence stars, with one normal star and a white dwarf, and those containing a neutron star or a black hole are described. Energy may be directly available as matter falls into the potential well of a compact object. Electromagnetic induction effects may occur due to relative motions of magnetic fields and matter. By enforcing rapid rotation, binaries can induce strong dynamo action and hence generate free energy in the form of intense, complex, evolving magnetic fields. Whatever the source of energy, the observations at radio and X-ray wavelengths demonstrate that electrons are accelerated to high energies (mildly relativistic and, ultrarelativistic). Observed or inferred radio brightness temperatures range up to 10 to the 15th power K or more, implying coherent emission for sources brighter than 10 billion K.

  10. Post-common envelope binaries from SDSS - VII. A catalogue of white dwarf-main sequence binaries

    NASA Astrophysics Data System (ADS)

    Rebassa-Mansergas, A.; Gänsicke, B. T.; Schreiber, M. R.; Koester, D.; Rodríguez-Gil, P.

    2010-02-01

    We present a catalogue of 1602 white-dwarf-main-sequence (WDMS) binaries from the spectroscopic Sloan Digital Sky Survey Data Release 6 (SDSS DR6). Among these, we identify 440 as new WDMS binaries. We select WDMS binary candidates by template fitting all 1.27 million DR6 spectra, using combined constraints in both χ2 and signal-to-noise ratio. In addition, we use Galaxy Evolution Explorer (GALEX) and UKIRT Infrared Sky Survey (UKIDSS) magnitudes to search for objects in which one of the two components dominates the SDSS spectrum. We use a decomposition/fitting technique to measure the effective temperatures, surface gravities, masses and distances to the white dwarfs, as well as the spectral types and distances to the companions in our catalogue. Distributions and density maps obtained from these stellar parameters are then used to study both the general properties and the selection effects of WDMS binaries in the SDSS. A comparison between the distances measured to the white dwarfs and the main-sequence companions shows dsec > dwd for approximately one-fifth of the systems, a tendency already found in our previous work. The hypothesis that magnetic activity raises the temperature of the inter-spot regions in active stars that are heavily covered by cool spots, leading to a bluer optical colour compared to inactive stars, remains the best explanation for this behaviour. We also make use of SDSS-GALEX-UKIDSS magnitudes to investigate the distribution of WDMS binaries, as well as their white-dwarf effective temperatures and companion star spectral types, in ultraviolet to infrared colour space. We show that WDMS binaries can be very efficiently separated from single main-sequence stars and white dwarfs when using a combined ultraviolet, optical and infrared colour selection. Finally, we also provide radial velocities for 1068 systems measured from the NaI λλ8183.27, 8194.81 absorption doublet and/or the Hα emission line. Among the systems with multiple SDSS

  11. SOPHIE velocimetry of Kepler transit candidates. VII. A false-positive rate of 35% for Kepler close-in giant candidates

    NASA Astrophysics Data System (ADS)

    Santerne, A.; Díaz, R. F.; Moutou, C.; Bouchy, F.; Hébrard, G.; Almenara, J.-M.; Bonomo, A. S.; Deleuil, M.; Santos, N. C.

    2012-09-01

    The false-positive probability (FPP) of Kepler transiting candidates is a key value for statistical studies of candidate properties. A previous investigation of the stellar population in the Kepler field has provided an estimate for the FPP of less than 5% for most of the candidates. We report here the results of our radial velocity observations on a sample of 46 Kepler candidates with a transit depth greater than 0.4%, orbital period less than 25 days and host star brighter than Kepler magnitude 14.7. We used the SOPHIE spectrograph mounted on the 1.93-m telescope at the Observatoire de Haute-Provence to establish the nature of the transiting candidates. In this sample, we found five undiluted eclipsing binaries, two brown dwarfs, six diluted eclipsing binaries, and nine new transiting planets that complement the 11 already published planets. The remaining 13 candidates were not followed-up or remain unsolved due to photon noise limitation or lack of observations. From these results we computed the FPP for Kepler close-in giant candidates to be 34.8% ± 6.5%. We aimed to investigate the variation of the FPP for giant candidates with the longer orbital periods and found that it should be constant for orbital periods between 10 and 200 days. This significantly disagrees with the previous estimates. We discuss the reasons for this discrepancy and the possible extension of this work toward smaller planet candidates. Finally, taking the false-positive rate into account, we refined the occurrence rate of hot Jupiters from the Kepler data. Based on observations made with SOPHIE on the 1.93-m telescope at Observatoire de Haute-Provence (CNRS), France.Figures 7, 8, and Tables 2-19 are available in electronic form at http://www.aanda.org

  12. Quick matching of binary images

    NASA Astrophysics Data System (ADS)

    Mustafa, Adnan A. Y.

    2015-09-01

    Matching images is a fundamental problem in image processing. The most common technique used to compare binary images is to calculate the correlation between two images or simply to subtract them. Both of these methods -as well as other matching methods- require some type of similarity operation to be applied to the whole image, and hence they are image size dependent. This implies that as image size increases, more processing time is required. However, with image sizes already exceeding 20 mega-pixels and standard image sizes doubling approximately every five years, the need to find a size invariant image matching method is becoming crucial. In this paper, we present a quick way to compare and match binary images based on the Probabilistic Matching Model (PMM). We present two simple image size invariant methods based on PMM: one for fast detection of dissimilar binary images and another for matching binary images. For detecting dissimilar binary images we introduce the Dissimilar Detection via Mapping method (DDM). We compare DDM to other popular matching methods used in the image processing arena and show that DDM is magnitudes faster than any other method. For binary image matching, we use DDM as a preprocessor for other popular methods to speed up their matching speed. In particular, we use DDM with cross correlation to speed it up. Test results are presented for real images varying in size from 16 kilo-pixel images to 10 mega-pixel images to show the method's size invariance.

  13. 2009 Elections: The Candidates Statements

    ERIC Educational Resources Information Center

    TechTrends: Linking Research and Practice to Improve Learning, 2009

    2009-01-01

    This article presents the candidates for the 2009 Association for Educational Communications and Technology (AECT) election and their statements. The candidates are: (1) Andy Gibbons (President-Elect); (2) Barbara B. Lockee (President-Elect); (3) Mary Jean Bishop (At-Large Representative); and (4) Deepak Subramony (At-Large Representative). In…

  14. 2009 Elections: The Candidates Statements

    ERIC Educational Resources Information Center

    TechTrends: Linking Research and Practice to Improve Learning, 2009

    2009-01-01

    This article presents the candidates for the 2009 Association for Educational Communications and Technology (AECT) election and their statements. The candidates are: (1) Andy Gibbons (President-Elect); (2) Barbara B. Lockee (President-Elect); (3) Mary Jean Bishop (At-Large Representative); and (4) Deepak Subramony (At-Large Representative). In…

  15. Coincidence probabilities for spacecraft gravitational wave experiments - Massive coalescing binaries

    NASA Technical Reports Server (NTRS)

    Tinto, Massimo; Armstrong, J. W.

    1991-01-01

    Massive coalescing binary systems are candidate sources of gravitational radiation in the millihertz frequency band accessible to spacecraft Doppler tracking experiments. This paper discusses signal processing and detection probability for waves from coalescing binaries in the regime where the signal frequency increases linearly with time, i.e., 'chirp' signals. Using known noise statistics, thresholds with given false alarm probabilities are established for one- and two-spacecraft experiments. Given the threshold, the detection probability is calculated as a function of gravitational wave amplitude for both one- and two-spacecraft experiments, assuming random polarization states and under various assumptions about wave directions. This allows quantitative statements about the detection efficiency of these experiments and the utility of coincidence experiments. In particular, coincidence probabilities for two-spacecraft experiments are insensitive to the angle between the directions to the two spacecraft, indicating that near-optical experiments can be done without constraints on spacecraft trajectories.

  16. Binary nanoparticle superlattices of soft-particle systems

    PubMed Central

    Travesset, Alex

    2015-01-01

    The solid-phase diagram of binary systems consisting of particles of diameter σA=σ and σB=γσ (γ≤1) interacting with an inverse p = 12 power law is investigated as a paradigm of a soft potential. In addition to the diameter ratio γ that characterizes hard-sphere models, the phase diagram is a function of an additional parameter that controls the relative interaction strength between the different particle types. Phase diagrams are determined from extremes of thermodynamic functions by considering 15 candidate lattices. In general, it is shown that the phase diagram of a soft repulsive potential leads to the morphological diversity observed in experiments with binary nanoparticles, thus providing a general framework to understand their phase diagrams. Particular emphasis is given to the two most successful crystallization strategies so far: evaporation of solvent from nanoparticles with grafted hydrocarbon ligands and DNA programmable self-assembly. PMID:26195799

  17. Binary nanoparticle superlattices of soft-particle systems

    DOE PAGES

    Travesset, Alex

    2015-08-04

    The solid-phase diagram of binary systems consisting of particles of diameter σA=σ and σB=γσ (γ≤1) interacting with an inverse p = 12 power law is investigated as a paradigm of a soft potential. In addition to the diameter ratio γ that characterizes hard-sphere models, the phase diagram is a function of an additional parameter that controls the relative interaction strength between the different particle types. Phase diagrams are determined from extremes of thermodynamic functions by considering 15 candidate lattices. In general, it is shown that the phase diagram of a soft repulsive potential leads to the morphological diversity observed inmore » experiments with binary nanoparticles, thus providing a general framework to understand their phase diagrams. In addition, particular emphasis is shown to the two most successful crystallization strategies so far: evaporation of solvent from nanoparticles with grafted hydrocarbon ligands and DNA programmable self-assembly.« less

  18. Merger of binary neutron stars in numerical relativity

    NASA Astrophysics Data System (ADS)

    Shibata, Masaru

    2014-09-01

    The merger of binary neutron stars is one of most promising sources of gravitational waves. It is also a promising candidate for the central engine of short-hard gamma-ray bursts and a source of the strong transient electromagnetic signal that could be the counterpart of gravitational-wave signals. Numerical relativity is probably the unique tool for theoretically exploring the merger process, and now, it is powerful enough to provide us a wide variety of aspects of the binary-neutron-star merger. In this talk, I will summarize our current understanding of the entire merger event that is obtained by a large-scale numerical-relativity simulations. In particular, I focus on the relation between the neutron-star equation of state and gravitational waves emitted during the late inspiral and merger phase, and observable electromagnetic signal that is likely to be emitted by the dynamical ejecta through r-process nucleosynthesis.

  19. Likely Planet Candidates Identified by Machine Learning Applied to Four Years of Kepler Data

    NASA Astrophysics Data System (ADS)

    Jenkins, Jon M.; McCauliff, S. D.; Catanzarite, J.; Twicken, J. D.; Burke, C. J.; Campbell, J.; Seader, S.

    2014-01-01

    Over 3200 transiting planet candidates, 134 confirmed planets, and ~2,400 eclipsing binaries have been identified by the Kepler Science pipeline since launch in March 2009. Compiling the list of candidates is an intensive manual effort as over 18,000 transit-like signatures are identified for a run across 34 months. The vast majority are caused by artifacts that mimic transits. While the pipeline provides diagnostics that can reduce the initial list down to ~5,000 light curves, this effort can overlook valid planetary candidates. The large number of diagnostics 100) makes it difficult to examine all the information available. The effort required for vetting all threshold-crossing events (TCEs) takes several months by many individuals associated with the Kepler Threshold Crossing Event Review Team (TCERT). We have developed a random-forest classifier that classifies each TCE as `planet candidate’, `astrophysical false positive’, or `non-transiting phenomena’. Ideally the algorithm will generate a list of candidates that approximates those generated by human review, thereby allowing the humans to focus on the most interesting cases. By using a machine learning-based auto-vetting process, we have the opportunity to identify the most important metrics and diagnostics for separating signatures of transiting planets and eclipsing binaries from instrument-induced features, thereby improving the efficiency of the manual effort. We report the results of applying a random forest classifier to four years of Kepler data. We present characteristics of the likely planet candidates identified by the auto-vetter as well as those objects classified as astrophysical false positives (eclipsing binaries and background eclipsing binaries). We examine the auto-vetter's performance through receiver operating characteristic curves for each of three classes: planet candidate, astrophysical false positive, and non-transiting phenomena. Funding for this mission is provided by NASA

  20. Planets in Wide Binaries from Kepler: Ages, Stability and Evolution of Planetary Systems

    NASA Astrophysics Data System (ADS)

    Weisenburger, Kolby L.; West, Andrew A.; Janes, Kenneth; Dhital, Saurav

    2014-06-01

    Using the Kepler Input Catalog and the fourth U.S. Naval Observatory CCD Astrograph Catalog, we have identified 1509 common proper motion (CPM) binaries in the Kepler field of view, of which a small subset host planet candidates, or Kepler Objects of Interest (KOIs). We have verified the fidelity of the CPM pairs using a Galactic model and follow-up astrometric observations. We present 73 KOIs distributed over 58 CPM pairs and highlight the first wide binary system (separation > 1000 AU) where both stellar components host at least one KOI. Because our binary sample was initially targeted for a gyrochronology analysis, we also present measurements of stellar rotation periods and preliminary estimates of stellar (and planetary) ages. We use these extrapolated planetary ages to investigate longterm planet stability in wide binaries and test potential formation and evolution scenarios of these dynamically complex systems.

  1. Discovery of ZZ Cetis in detached white dwarf plus main-sequence binaries

    NASA Astrophysics Data System (ADS)

    Pyrzas, S.; Gänsicke, B. T.; Hermes, J. J.; Copperwheat, C. M.; Rebassa-Mansergas, A.; Dhillon, V. S.; Littlefair, S. P.; Marsh, T. R.; Parsons, S. G.; Savoury, C. D. J.; Schreiber, M. R.; Barros, S. C. C.; Bento, J.; Breedt, E.; Kerry, P.

    2015-02-01

    We present the first results of a dedicated search for pulsating white dwarfs (WDs) in detached WD plus main-sequence (MS) binaries. Candidate systems were selected from a catalogue of WD+MS binaries, based on the surface gravities and effective temperatures of the WDs. We observed a total of 26 systems using ULTRACAM mounted on ESO's 3.5 m New Technology Telescope at La Silla. Our photometric observations reveal pulsations in seven WDs of our sample, including the first pulsating WD with an MS companion in a post-common envelope (CE) binary, SDSS J1136+0409. Asteroseismology of these new pulsating systems will provide crucial insight into how binary interactions, particularly the CE phase, affect the internal structure and evolution of WDs. In addition, our observations have revealed the partially eclipsing nature of one of our targets, SDSS J1223-0056.

  2. The ELM Survey. VII. Orbital Properties of Low-Mass White Dwarf Binaries

    NASA Astrophysics Data System (ADS)

    Brown, Warren R.; Gianninas, A.; Kilic, Mukremin; Kenyon, Scott J.; Allende Prieto, Carlos

    2016-02-01

    We present the discovery of 15 extremely low-mass (5\\lt {log}g\\lt 7) white dwarf (WD) candidates, 9 of which are in ultra-compact double-degenerate binaries. Our targeted extremely low-mass Survey sample now includes 76 binaries. The sample has a lognormal distribution of orbital periods with a median period of 5.4 hr. The velocity amplitudes imply that the binary companions have a normal distribution of mass with 0.76 M⊙ mean and 0.25 M⊙ dispersion. Thus extremely low-mass WDs are found in binaries with a typical mass ratio of 1:4. Statistically speaking, 95% of the WD binaries have a total mass below the Chandrasekhar mass, and thus are not type Ia supernova progenitors. Yet half of the observed binaries will merge in less than 6 Gyr due to gravitational wave radiation; probable outcomes include single massive WDs and stable mass transfer AM CVn binaries. Based on observations obtained at the MMT Observatory, a joint facility of the Smithsonian Institution and the University of Arizona.

  3. New Constraints on the False Positive Rate for Short-Period Kepler Planet Candidates

    NASA Astrophysics Data System (ADS)

    Colón, Knicole D.; Morehead, Robert C.; Ford, Eric B.

    2015-01-01

    The Kepler space mission has discovered thousands of potential planets orbiting other stars, thereby setting the stage for in-depth studies of different populations of planets. We present new multi-wavelength transit photometry of small (Rp < 6 Earth radii), short-period (P < 6 days) Kepler planet candidates acquired with the Gran Telescopio Canarias. Multi-wavelength transit photometry allows us to search for wavelength-dependent transit depths and subsequently identify eclipsing binary false positives (which are especially prevalent at the shortest orbital periods). We combine these new observations of three candidates with previous results for five other candidates (Colón & Ford 2011 and Colón, Ford, & Morehead 2012) to provide new constraints on the false positive rate for small, close-in candidates. In our full sample, we identify four candidates as viable planets and four as eclipsing binary false positives. We therefore find a higher false positive rate for small, close-in candidates compared to the lower false positive rate of ~10% determined by other studies for the full sample of Kepler planet candidates (e.g. Fressin et al. 2013). We also discuss the dearth of known planets with periods less than ~2.5 days and radii between ~3 and 11 Earth radii (the so-called 'sub-Jovian desert'), since the majority of the candidates in our study are located in or around this 'desert.' The lack of planets with these orbital and physical properties is not expected to be due to observational bias, as short-period planets are generally easier to detect (especially if they are larger or more massive than Earth). We consider the implications of our results for the other ~20 Kepler planet candidates located in this desert. Characterizing these candidates will allow us to better understand the formation processes of this apparently rare class of planets.

  4. VizieR Online Data Catalog: HIP binaries with radial velocities (Frankowski+, 2007)

    NASA Astrophysics Data System (ADS)

    Frankowski, A.; Jancart, S.; Jorissen, A.

    2006-11-01

    The comparison of the proper motions constructed from positions spanning a short (Hipparcos) or long time (Tycho-2) makes it possible to uncover binaries with periods of the order of or somewhat larger than the short time span (in this case, the 3 yr duration of the Hipparcos mission), since the unrecognised orbital motion will then add to the proper motion. A list of candidate proper motion binaries is constructed from a chi-square test evaluating the statistical significance of the difference between the Tycho-2 and Hipparcos proper motions for 103134 stars in common between the two catalogues (excluding components of visual systems). The present paper focuses on the evaluation of the detection efficiency of proper-motion binaries, using different kinds of control data (mostly radial velocities). The detection rate for entries from the Ninth Catalogue of Spectroscopic Binary Orbits (SB9) is evaluated, as well as for stars like barium stars, which are known to be all binaries, and finally for spectroscopic binaries identified from radial velocity data in the Geneva-Copenhagen survey of F and G dwarfs in the solar neighbourhood. Proper motion binaries are efficiently detected for systems with parallaxes in excess of 20mas, and periods in the range 1000-30000d. The shortest periods in this range (1000-2000d, i.e., once to twice the duration of the Hipparcos mission) may appear only as DMSA/G binaries (accelerated proper motion in the Hipparcos Double and Multiple System Annex). Proper motion binaries detected among SB9 systems having periods shorter than about 400d hint at triple systems, the proper-motion binary involving a component with a longer orbital period. A list of 19 candidate triple systems is provided. Binaries suspected of having low-mass (brown-dwarf-like) companions are listed as well. Among the 37 barium stars with parallaxes larger than 5mas, only 7 exhibit no evidence for duplicity whatsoever (be it spectroscopic or astrometric). Finally, the

  5. The FK Comae candidate UX Librae

    NASA Technical Reports Server (NTRS)

    Bopp, B. W.; Goodrich, B. D.; Africano, J. L.; Noah, P. V.; Meredith, R. J.; Palmer, L. H.; Quigley, R. J.

    1984-01-01

    New optical spectroscopic and photometric data are presented for the active chromosphere FK Com candidate UZ Lib. The star is shown to have an extremely large photometric amplitude in V of 0.35 mag, and its rotation period is established as 4.75 + or - 0.01 days. The optical spectrum is that of an early K giant, broadened by a rotation velocity of approximately 65 km/s. H-alpha is visible as a very broad emission feature, with a profile resembling that seen in FK Com. The emission intensity and profile are variable over the rotation period, with the strongest emission present at photometric minimum, in accord with dark starspot models. The photospheric absorption line profiles show variable asymmetries and distortions which are interpreted as due to the effects of the dark starspot rotating across the line of sight. New radial velocity measures are combined with published data to demonstrate the UZ Lib is a member of a binary system in synchronous rotation with a secondary of mass approximately 0.5 solar masses. This information is considered in light of the conflicting models for the origin of the optical and spectral variability of the FK Com stars, as well as their uncertain evolutionary status.

  6. The FK Comae candidate UX Librae

    NASA Technical Reports Server (NTRS)

    Bopp, B. W.; Goodrich, B. D.; Africano, J. L.; Noah, P. V.; Meredith, R. J.; Palmer, L. H.; Quigley, R. J.

    1984-01-01

    New optical spectroscopic and photometric data are presented for the active chromosphere FK Com candidate UZ Lib. The star is shown to have an extremely large photometric amplitude in V of 0.35 mag, and its rotation period is established as 4.75 + or - 0.01 days. The optical spectrum is that of an early K giant, broadened by a rotation velocity of approximately 65 km/s. H-alpha is visible as a very broad emission feature, with a profile resembling that seen in FK Com. The emission intensity and profile are variable over the rotation period, with the strongest emission present at photometric minimum, in accord with dark starspot models. The photospheric absorption line profiles show variable asymmetries and distortions which are interpreted as due to the effects of the dark starspot rotating across the line of sight. New radial velocity measures are combined with published data to demonstrate the UZ Lib is a member of a binary system in synchronous rotation with a secondary of mass approximately 0.5 solar masses. This information is considered in light of the conflicting models for the origin of the optical and spectral variability of the FK Com stars, as well as their uncertain evolutionary status.

  7. High Resolution Imaging of Very Low Mass Spectral Binaries: Three Resolved Systems and Detection of Orbital Motion in an L/T Transition Binary

    NASA Astrophysics Data System (ADS)

    Bardalez Gagliuffi, Daniella C.; Gelino, Christopher R.; Burgasser, Adam J.

    2015-11-01

    We present high resolution Laser Guide Star Adaptive Optics imaging of 43 late-M, L and T dwarf systems with Keck/NIRC2. These include 17 spectral binary candidates, systems whose spectra suggest the presence of a T dwarf secondary. We resolve three systems: 2MASS J1341-3052, SDSS J1511+0607 and SDSS J2052-1609 the first two are resolved for the first time. All three have projected separations <8 AU and estimated periods of 14-80 years. We also report a preliminary orbit determination for SDSS J2052-1609 based on six epochs of resolved astrometry between 2005 and 2010. Among the 14 unresolved spectral binaries, 5 systems were confirmed binaries but remained unresolved, implying a minimum binary fraction of {47}-11+12% for this sample. Our inability to resolve most of the spectral binaries, including the confirmed binaries, supports the hypothesis that a large fraction of very low mass systems have relatively small separations and are missed with direct imaging. Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.

  8. Coordinated observations of interacting peculiar red giant binaries, 1

    NASA Technical Reports Server (NTRS)

    Ake, T.

    1995-01-01

    IUE Observations were begun for a two-year program to monitor the UV variability of three interacting peculiar red giant (PRG) binaries, HD 59643 (C6,s) HD 35155 (S3/2), and HR 1105 (S3.5/2.5). All of these systems were suspected to involve accretion of material from the PRG to a white-dwarf secondary, based mainly on previous IUE investigations. From our earlier surveys of PRG's, they were primary candidates to test the hypothesis that Tc-poor PRG's are formed as a result of mass transfer from a secondary component rather than from internal thermal pulsing while on the asymptotic red giant branch.

  9. The Michigan Binary Star Program

    NASA Astrophysics Data System (ADS)

    Lindner, Rudi P.

    2007-07-01

    At the end of the nineteenth century, William J. Hussey and Robert G. Aitken, both at Lick Observatory, began a systematic search for unrecorded binary stars with the aid of the 12" and 36" refracting telescopes at Lick Observatory. Aitken's work (and book on binary stars) are well known, Hussey's contributions less so. In 1905 Hussey, a Michigan engineering graduate, returned to direct the Ann Arbor astronomy program, and immediately he began to design new instrumentation for the study of binary stars and to train potential observers. For a time, he spent six months a year at the La Plata Observatory, where he discovered a number of new pairs and decided upon a major southern hemisphere campaign. He spent a decade obtaining the lenses for a large refractor, through the vicissitudes of war and depression. Finally, he obtained a site in South Africa, a 26" refractor, and a small corps of observers, but he died in London en route to fulfill his dream. His right hand man, Richard Rossiter, established the observatory and spent the next thirty years discovering and measuring binary stars: his personal total is a record for the field. This talk is an account of the methods, results, and utility of the extraordinary binary star factory in the veldt.

  10. Commission 42: Close Binary Stars

    NASA Astrophysics Data System (ADS)

    Ribas, Ignasi; Richards, Mercedes T.; Rucinski, Slavek; Bradstreet, David H.; Harmanec, Petr; Kaluzny, Janusz; Mikolajewska, Joanna; Munari, Ulisse; Niarchos, Panagiotis; Olah, Katalin; Pribulla, Theodor; Scarfe, Colin D.; Torres, Guillermo

    2012-04-01

    The present report covers the main developments in the field of close binaries during the triennium 2009-2012. In addition to scientific publications, there have been several opportunities for direct interaction of researchers working on close binaries. A number of meetings focused on more or less specific topics have taken place during this past years but the highlight for Commission 42 is arguably IAU Symposium 282 held in 2011 in Slovakia. The meeting exploited a strong connection in the methodology and tools used by close binary studies and the rapidly advancing field of exoplanet research. After all, exoplanetary systems are mostly discovered and studied using techniques employed by analyses of close binaries for decades. Modelling of exoplanet radial velocity curves and transiting planet light curves are just particular cases of single-lined and eclipsing binary systems, respectively, with very unequal component properties. As shown by IAU Symposium 282, the synergies between the two fields are strong and potentially very useful. Found below is a summary of the main scientific topics and conclusions from this very successful Symposium.

  11. A Speeding Binary in the Galactic Halo

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-04-01

    The recent discovery of a hyper-velocity binary star system in the halo of the Milky Way poses a mystery: how was this system accelerated to its high speed?Accelerating StarsUnlike the uniform motion in the Galactic disk, stars in the Milky Ways halo exhibit a huge diversity of orbits that are usually tilted relative to the disk and have a variety of speeds. One type of halo star, so-called hyper-velocity stars, travel with speeds that can approach the escape velocity of the Galaxy.How do these hyper-velocity stars come about? Assuming they form in the Galactic disk, there are multiple proposed scenarios through which they could be accelerated and injected into the halo, such as:Ejection after a close encounter with the supermassive black hole at the Galactic centerEjection due to a nearby supernova explosionEjection as the result of a dynamical interaction in a dense stellar population.Further observations of hyper-velocity stars are necessary to identify the mechanism responsible for their acceleration.J1211s SurpriseModels of J1211s orbit show it did not originate from the Galactic center (black dot). The solar symbol shows the position of the Sun and the star shows the current position of J1211. The bottom two panels show two depictions(x-y plane and r-z plane) of estimated orbits of J1211 over the past 10 Gyr. [Nmeth et al. 2016]To this end, a team of scientists led by Pter Nmeth (Friedrich Alexander University, Erlangen-Nrnberg) recently studied the candidate halo hyper-velocity star SDSS J121150.27+143716.2. The scientists obtained spectroscopy of J1211 using spectrographs at the Keck Telescope in Hawaii and ESOs Very Large Telescope in Chile. To their surprise, they discovered the signature of a companion in the spectra: J1211 is actually a binary!Nmeth and collaborators found that J1211, located roughly 18,000 light-years away, is moving at a rapid ~570 km/s relative to the galactic rest frame. The binary system consists of a hot (30,600 K) subdwarf and a

  12. Single transit candidates from K2: detection and period estimation

    NASA Astrophysics Data System (ADS)

    Osborn, H. P.; Armstrong, D. J.; Brown, D. J. A.; McCormac, J.; Doyle, A. P.; Louden, T. M.; Kirk, J.; Spake, J. J.; Lam, K. W. F.; Walker, S. R.; Faedi, F.; Pollacco, D. L.

    2016-04-01

    Photometric surveys such as Kepler have the precision to identify exoplanet and eclipsing binary candidates from only a single transit. K2, with its 75 d campaign duration, is ideally suited to detect significant numbers of single-eclipsing objects. Here we develop a Bayesian transit-fitting tool (`Namaste: An Mcmc Analysis of Single Transit Exoplanets') to extract orbital information from single transit events. We achieve favourable results testing this technique on known Kepler planets, and apply the technique to seven candidates identified from a targeted search of K2 campaigns 1, 2 and 3. We find EPIC203311200 to host an excellent exoplanet candidate with a period, assuming zero eccentricity, of 540 ^{+410}_{-230} d and a radius of 0.51 ± 0.05RJup. We also find six further transit candidates for which more follow-up is required to determine a planetary origin. Such a technique could be used in the future with TESS, PLATO and ground-based photometric surveys such as NGTS, potentially allowing the detection of planets in reach of confirmation by Gaia.

  13. Validation and characterization of Kepler exoplanet candidates with Warm Spitzer

    NASA Astrophysics Data System (ADS)

    Desert, Jean-Michel; Charbonneau, D.; Kepler Science Team

    2011-05-01

    I present the status and results from an ongoing project that uses 800 hours of the Spitzer Space Telescope to gather near-infrared photometric measurements of transiting extrasolar planet candidates detected by the Kepler Mission. The main purposes of this project is to validate planetary candidates, and to characterize confirmed planets. By comparing the light curves spanning times of primary transit for candidates observed with Kepler and Spitzer, we can exclude significant sources of astrophysical false positives resulting from blends (e.g. background eclipsing binaries) that mimic an exoplanetary signature in the Kepler bandpass. I show how our infrared observations can help to validate the planetary nature of several candidates with small radii, which could be rocky in composition. By combining occultation measurements of the reflected starlight in the optical with estimates of the thermal emission in the near-infrared, we are able to constrain the energy budget of a handful of hot-Jupiters and compare such constraints to those for other giant planets.

  14. A Systematic Search for Exoplanet Candidates in K2 Data

    NASA Astrophysics Data System (ADS)

    Kahre, Tarryn; Karnes, Katherine L.; Caldwell, Douglas A.; Smith, Jeffrey C.

    2016-01-01

    We present a catalog of 41 promising exoplanet candidates in 33 stellar systems from the K2 Campaign 3 data. The K2 Mission was developed upon the mechanical failure of the second of four reaction wheels, as the Kepler Spacecraft could not continue the original Kepler Mission. The Kepler Mission was a 4-year mission designed to determine the prevalence of exoplanets in our galaxy, and the configuration and diversity of those planetary systems discovered. The K2 Mission has a similar goal, though the spacecraft now points at fields along the ecliptic in ~75 day campaigns (Howell et al. 2014). Although the light curves in K2 data are noisier and have significant motion-induced systematics, it has been shown that there is success in finding exoplanets and exoplanet candidates (Foreman-Mackey et al. 2015; Montet et al. 2015). Utilizing the Transiting Planet Search and Data Validation from the Kepler Processing Pipeline, we systematically search K2 Campaign 3 for potential exoplanet candidates. Setting a 7.1s maximum folded statistic threshold minimum for a minimum of three transit events, we define our initial candidate list. Our list is further narrowed by the results from Data Validation, as it allows us to statistically identify false positives, such as eclipsing binaries or uncorrected roll-drift, in our sample. We further draw parallels between our results and other transit-searching pipeline results published for Campaign 3.

  15. Undercover Stars Among Exoplanet Candidates

    NASA Astrophysics Data System (ADS)

    2005-03-01

    events by monitoring the brightness of a very large number of stars over extended time intervals. During the past years, it has also included a search for periodic, very shallow "dips" in the brightness of stars, caused by the regular transit of small orbiting objects (small stars, brown dwarfs [2] or Jupiter-size planets). The OGLE team has since announced 177 "planetary transit candidates" from their survey of several hundred thousand stars in three southern sky fields, one in the direction of the Galactic Centre, another within the Carina constellation and the third within the Centaurus/Musca constellations. The nature of the transiting object can however only be established by subsequent radial-velocity observations of the parent star. The size of the velocity variations (the amplitude) is directly related to the mass of the companion object and therefore allows discrimination between stars and planets as the cause of the observed brightness "dip". A Bonanza of Low-Mass Stars An international team of astronomers [3] has made use of the 8.2-m VLT Kueyen telescope for this work. Profiting from the multiplex capacity of the FLAMES/UVES facility that permits to obtain high-resolution spectra of up to 8 objects simultaneously, they have looked at 60 OGLE transit candidate stars, measuring their radial velocities with an accuracy of about 50 m/s [4]. This ambitious programme has so far resulted in the discovery of five new transiting exoplanets (see, e.g., ESO PR 11/04 for the announcement of two of those). Most of the other transit candidates identified by OGLE have turned out to be eclipsing binaries, that is, in most cases common, small and low-mass stars passing in front of a solar-like star. This additional wealth of data on small and light stars is a real bonanza for the astronomers. Constraining the Relation Between Mass and Radius Low-mass stars are exceptionally interesting objects, also because the physical conditions in their interiors have much in common with

  16. CNO Processing in Massive Algol Binaries

    NASA Technical Reports Server (NTRS)

    Wade, Richard A.

    1998-01-01

    This program, used ultraviolet observations by the IUE Observatory along with other tools to search for abundance anomalies indicative of CNO processing in the secondary (mass-donating) stars of six interacting binary systems. Related IUE-based activities were also undertaken under this grant. Two Supplements to the grant were awarded. Supplement No. 1 was in connection with the NASA Grant Supplements for Education program, for a workshop for elementary school science teachers. The two sessions of the workshop were held October 24 and November 14, 1992. Eighteen school teachers from central Pennsylvania, grades 1-7, participated in the workshop, for which they received one unit of in-service training credit from their Intermediate Unit. Supplement No. 2 was awarded for additional IUE observations of the Algol stars V342 Aql and TU Mon. Observations of all six candidate stars were made with IUE, and attention was narrowed to TU Mon in particular, for which further IUE observations were made using Director's discretionary time. Observations of TU Mon were also carried out with the Voyager UV spectrometers, and optical spectroscopy was obtained on several occasions at Penn State's Black Moshannon Observatory. Photometric data on TU Mon were acquired by Dr. Paul Etzel at Mt. Laguna Observatory (MLO). McGouldrick was employed part-time during the Fall academic semester to assist in accessing the IUE Archive, and to correlate data on some cataclysmic variables and related objects that were observed with both IUE and the Voyager Far Ultraviolet Spectrometers. Approximately 21 relevant binary systems were observed with the Voyager UVS over the past decade, and a paper is being prepared for eventual publication that will serve as an index to the UVS data archive on these stars, providing observation dates, mean count rates in far and extreme UV bands, and a discussion of the relevant literature concerning the far UV behavior (including correlative IUE information from the

  17. Binaries with a δ Scuti Component: Results from a Long-Term Observational Survey, Updated Catalog, and Future Prospects

    NASA Astrophysics Data System (ADS)

    Liakos, A.; Niarchos, P.

    2015-07-01

    Results are presented from a six-year systematic observational survey of candidate eclipsing binaries with a δ Sct component. More than one hundred systems with component(s) of spectral type A-F were observed in order to check for possible pulsational behavior. Some ˜14% (13 cases) among the currently known systems of this class were confirmed. We present an updated list of all currently known δ Sct systems in eclipsing binaries based on all available information from the literature. Possible correlations between their pulsational and binary properties are discussed.

  18. Size of Kepler Planet Candidates

    NASA Image and Video Library

    2013-01-07

    Kepler data has increased by 20 percent and now totals 2,740 potential planets orbiting 2,036 stars; dramatic increases are seen in the number of Earth-size and super Earth-size candidates discovered.

  19. Black Hole Binaries in Quiescence

    NASA Astrophysics Data System (ADS)

    Bailyn, Charles D.

    I discuss some of what is known and unknown about the behavior of black hole binary systems in the quiescent accretion state. Quiescence is important for several reasons: 1) the dominance of the companion star in optical and IR wavelengths allows the binary parameters to be robustly determined - as an example, we argue that the longer proposed distance to the X-ray source GRO J1655-40 is correct; 2) quiescence represents the limiting case of an extremely low accretion rate, in which both accretion and jets can be observed; 3) understanding the evolution and duration of the quiescent state is a key factor in determining the overall demographics of X-ray binaries, which has taken on a new importance in the era of gravitational wave astronomy.

  20. Experience with parametric binary dissection

    NASA Technical Reports Server (NTRS)

    Bokhari, Shahid H.

    1993-01-01

    Parametric Binary Dissection (PBD) is a new algorithm that can be used for partitioning graphs embedded in 2- or 3-dimensional space. It partitions explicitly on the basis of nodes + (lambda)x(edges cut), where lambda is the ratio of time to communicate over an edge to the time to compute at a node. The new algorithm is faster than the original binary dissection algorithm and attempts to obtain better partitions than the older algorithm, which only takes nodes into account. The performance of parametric dissection with plain binary dissection on 3 large unstructured 3-d meshes obtained from computational fluid dynamics and on 2 random graphs were compared. It was showm that the new algorithm can usually yield partitions that are substantially superior, but that its performance is heavily dependent on the input data.

  1. Statistical study of visual binaries

    NASA Astrophysics Data System (ADS)

    Abdel-Rahman, H. I.; Nouh, M. I.; Elsanhoury, W. H.

    2017-04-01

    In this paper, some statistical distributions of wide pairs included in Double Star Catalogue are investigated. Frequency distributions and testing hypothesis are derived for some basic parameters of visual binaries. The results reached indicate that, it was found that the magnitude difference is distributed exponentially, which means that the majority of the component of the selected systems is of the same spectral type. The distribution of the mass ratios is concentrated about 0.7 which agree with Salpeter mass function. The distribution of the linear separation appears to be exponentially, which contradict with previous studies for close binaries.

  2. Protocols for quantum binary voting

    NASA Astrophysics Data System (ADS)

    Thapliyal, Kishore; Sharma, Rishi Dutt; Pathak, Anirban

    Two new protocols for quantum binary voting are proposed. One of the proposed protocols is designed using a standard scheme for controlled deterministic secure quantum communication (CDSQC), and the other one is designed using the idea of quantum cryptographic switch, which uses a technique known as permutation of particles. A few possible alternative approaches to accomplish the same task (quantum binary voting) have also been discussed. Security of the proposed protocols is analyzed. Further, the efficiencies of the proposed protocols are computed, and are compared with that of the existing protocols. The comparison has established that the proposed protocols are more efficient than the existing protocols.

  3. Speckle Imaging and Spectroscopy of Kepler Exo-planet Transit Candidate Stars

    NASA Astrophysics Data System (ADS)

    Howell, Steve B.; Sherry, William; Horch, Elliott; Doyle, Laurance

    2010-02-01

    The NASA Kepler mission was successfully launched on 6 March 2009 and has begun science operations. Commissioning tests done early on in the mission have shown that for the bright sources, 10-15 ppm relative photometry can be achieved. This level assures we will detect Earth- like transits if they are present. ``Hot Jupiter" and similar large planet candidates have already been discovered and will be discussed at the Jan. AAS meeting as well as in a special issue of Science magazine to appear near years end. The plethora of variability observed is astounding and includes a number of eclipsing binaries which appear to have Jupiter and smaller size objects as an orbiting their body. Our proposal consists of three highly related objectives: 1) To continue our highly successful speckle imaging program which is a major component of defense to weed out false positive candidate transiting planets found by Kepler and move the rest to probable or certain exo-planet detections; 2) To obtain low resolution ``discovery" type spectra for planet candidate stars in order to provide spectral type and luminosity class indicators as well as a first look triage to eliminate binaries and rapid rotators; and 3) to obtain ~1Aresolution time ordered spectra of eclipsing binaries that are exo-planet candidates in order to obtain the velocity solution for the binary star, allowing its signal to be modeled and removed from the Keck or HET exo-planet velocity search. As of this writing, Kepler has produced a list of 227 exo-planet candidates which require false positive decision tree observations. Our proposed effort performs much of the first line of defense for the mission.

  4. Mental Effort in Binary Categorization Aided by Binary Cues

    ERIC Educational Resources Information Center

    Botzer, Assaf; Meyer, Joachim; Parmet, Yisrael

    2013-01-01

    Binary cueing systems assist in many tasks, often alerting people about potential hazards (such as alarms and alerts). We investigate whether cues, besides possibly improving decision accuracy, also affect the effort users invest in tasks and whether the required effort in tasks affects the responses to cues. We developed a novel experimental tool…

  5. The luminous red nova M101-OT2015-1: a candidate for common envelope ejection

    NASA Astrophysics Data System (ADS)

    Blagorodnova, Nadejda; Kasliwal, Mansi M.; Kotak, Rubina

    2017-01-01

    Binary interaction is an important phase in the study of stellar evolution. Approximately 50% of O star population live in close binary systems as to allow interaction with the companion. Although massive binary progenitors have been associated with thermonuclear supernovae, stripped core collapse supernovae, cataclysmic variables, X-ray binaries, or the mind blowing massive binary black holes recently detected by LIGO, the exact evolutionary path followed by the system is still under debate. One of the critical phases is the common envelope (CE) phase, required to bring a long period binary into a much shorter orbit. Currently, this phase also represents a challenge for the current stellar evolution models. Given the uncertainty, observational constraints are valuable input to advance in this field. One particular class of transient objects, called Luminous Red Novae (LRNe), has been associated with the termination of the CE phase, when a total or partial ejection of the least bound layers of the primary star are expelled at the expense of decreasing the orbital energy of the system. In my talk I will discuss the results of 16 years of observations of M101-OT2015-1, a LRN in M101 galaxy. I will describe the progenitor star (system) and the main characteristics of the outburst. Finally, I will present the results of the evolution of its remnant in infrared wavelengths. Given the long time span of our observations, this event represents one of the best studied CE ejection candidate at extragalactic distances.

  6. Double-lined Spectroscopic Binary Stars in the Radial Velocity Experiment Survey

    NASA Astrophysics Data System (ADS)

    Matijevič, G.; Zwitter, T.; Munari, U.; Bienaymé, O.; Binney, J.; Bland-Hawthorn, J.; Boeche, C.; Campbell, R.; Freeman, K. C.; Gibson, B.; Gilmore, G.; Grebel, E. K.; Helmi, A.; Navarro, J. F.; Parker, Q. A.; Seabroke, G. M.; Siebert, A.; Siviero, A.; Steinmetz, M.; Watson, F. G.; Williams, M.; Wyse, R. F. G.

    2010-07-01

    We devise a new method for the detection of double-lined binary stars in a sample of the Radial Velocity Experiment (RAVE) survey spectra. The method is both tested against extensive simulations based on synthetic spectra and compared to direct visual inspection of all RAVE spectra. It is based on the properties and shape of the cross-correlation function, and is able to recover ~80% of all binaries with an orbital period of order 1 day. Systems with periods up to 1 yr are still within the detection reach. We have applied the method to 25,850 spectra of the RAVE second data release and found 123 double-lined binary candidates, only eight of which are already marked as binaries in the SIMBAD database. Among the candidates, there are seven that show spectral features consistent with the RS CVn type (solar type with active chromosphere) and seven that might be of W UMa type (over-contact binaries). One star, HD 101167, seems to be a triple system composed of three nearly identical G-type dwarfs. The tested classification method could also be applicable to the data of the upcoming Gaia mission.

  7. A Study of Planetary Nebulae Possessing Binary Central Stars

    NASA Astrophysics Data System (ADS)

    Tyndall, Amy A.

    2014-01-01

    shown to have a rotation period of 6.4 d which is most likely a sign of mass accretion. Such a system represents a rare opportunity to further the investigation into the formation of barium stars and intermediate period, post-asymptotic giant branch (AGB) systems. Finally, the first analysis of an object from the new POPIPlaN catalogue of PNe is presented. Photometry of the central star system of PN G033.8+01.5 showed it to be a compact binary of P = 0.1268 d, consisting of a cool M2 V main sequence star and a hot WD surrounded by a very asymmetric PN. The very short orbital period leads to the possibility of PN G033.8+01.5 being a cataclysmic variable candidate, which in turn leads to the question of whether the visible nebulous material is that of a true PN or if it is the remnant of an outburst.

  8. Binary YORP Effect and Evolution of Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Steinberg, Elad; Sari, Re'em

    2011-02-01

    The rotation states of kilometer-sized near-Earth asteroids are known to be affected by the Yarkevsky O'Keefe-Radzievskii-Paddack (YORP) effect. In a related effect, binary YORP (BYORP), the orbital properties of a binary asteroid evolve under a radiation effect mostly acting on a tidally locked secondary. The BYORP effect can alter the orbital elements over ~104-105 years for a Dp = 2 km primary with a Ds = 0.4 km secondary at 1 AU. It can either separate the binary components or cause them to collide. In this paper, we devise a simple approach to calculate the YORP effect on asteroids and the BYORP effect on binaries including J 2 effects due to primary oblateness and the Sun. We apply this to asteroids with known shapes as well as a set of randomly generated bodies with various degrees of smoothness. We find a strong correlation between the strengths of an asteroid's YORP and BYORP effects. Therefore, statistical knowledge of one could be used to estimate the effect of the other. We show that the action of BYORP preferentially shrinks rather than expands the binary orbit and that YORP preferentially slows down asteroids. This conclusion holds for the two extremes of thermal conductivities studied in this work and the assumption that the asteroid reaches a stable point, but may break down for moderate thermal conductivity. The YORP and BYORP effects are shown to be smaller than could be naively expected due to near cancellation of the effects at small scales. Taking this near cancellation into account, a simple order-of-magnitude estimate of the YORP and BYORP effects as a function of the sizes and smoothness of the bodies is calculated. Finally, we provide a simple proof showing that there is no secular effect due to absorption of radiation in BYORP.

  9. BINARY YORP EFFECT AND EVOLUTION OF BINARY ASTEROIDS

    SciTech Connect

    Steinberg, Elad; Sari, Re'em

    2011-02-15

    The rotation states of kilometer-sized near-Earth asteroids are known to be affected by the Yarkevsky O'Keefe-Radzievskii-Paddack (YORP) effect. In a related effect, binary YORP (BYORP), the orbital properties of a binary asteroid evolve under a radiation effect mostly acting on a tidally locked secondary. The BYORP effect can alter the orbital elements over {approx}10{sup 4}-10{sup 5} years for a D{sub p} = 2 km primary with a D{sub s} = 0.4 km secondary at 1 AU. It can either separate the binary components or cause them to collide. In this paper, we devise a simple approach to calculate the YORP effect on asteroids and the BYORP effect on binaries including J{sub 2} effects due to primary oblateness and the Sun. We apply this to asteroids with known shapes as well as a set of randomly generated bodies with various degrees of smoothness. We find a strong correlation between the strengths of an asteroid's YORP and BYORP effects. Therefore, statistical knowledge of one could be used to estimate the effect of the other. We show that the action of BYORP preferentially shrinks rather than expands the binary orbit and that YORP preferentially slows down asteroids. This conclusion holds for the two extremes of thermal conductivities studied in this work and the assumption that the asteroid reaches a stable point, but may break down for moderate thermal conductivity. The YORP and BYORP effects are shown to be smaller than could be naively expected due to near cancellation of the effects at small scales. Taking this near cancellation into account, a simple order-of-magnitude estimate of the YORP and BYORP effects as a function of the sizes and smoothness of the bodies is calculated. Finally, we provide a simple proof showing that there is no secular effect due to absorption of radiation in BYORP.

  10. 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.

  11. 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.

  12. 76 FR 4896 - Call for Candidates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-27

    ... From the Federal Register Online via the Government Publishing Office FEDERAL ACCOUNTING STANDARDS ADVISORY BOARD Call for Candidates AGENCY: Federal Accounting Standards Advisory Board. ACTION: Notice... Federal Accounting Standards Advisory Board (FASAB) is currently seeking candidates (candidates must not...

  13. 11 CFR 9002.4 - Eligible candidates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... FINANCING DEFINITIONS § 9002.4 Eligible candidates. Eligible candidates means those Presidential and Vice Presidential candidates who have met all applicable conditions for eligibility to receive payments from...

  14. Generating Constant Weight Binary Codes

    ERIC Educational Resources Information Center

    Knight, D.G.

    2008-01-01

    The determination of bounds for A(n, d, w), the maximum possible number of binary vectors of length n, weight w, and pairwise Hamming distance no less than d, is a classic problem in coding theory. Such sets of vectors have many applications. A description is given of how the problem can be used in a first-year undergraduate computational…

  15. Generating Constant Weight Binary Codes

    ERIC Educational Resources Information Center

    Knight, D.G.

    2008-01-01

    The determination of bounds for A(n, d, w), the maximum possible number of binary vectors of length n, weight w, and pairwise Hamming distance no less than d, is a classic problem in coding theory. Such sets of vectors have many applications. A description is given of how the problem can be used in a first-year undergraduate computational…

  16. Clostridium difficile binary toxin CDT

    PubMed Central

    Gerding, Dale N; Johnson, Stuart; Rupnik, Maja; Aktories, Klaus

    2014-01-01

    Binary toxin (CDT) is frequently observed in Clostridium difficile strains associated with increased severity of C. difficile infection (CDI). CDT belongs to the family of binary ADP-ribosylating toxins consisting of two separate toxin components: CDTa, the enzymatic ADP-ribosyltransferase which modifies actin, and CDTb which binds to host cells and translocates CDTa into the cytosol. CDTb is activated by serine proteases and binds to lipolysis stimulated lipoprotein receptor. ADP-ribosylation induces depolymerization of the actin cytoskeleton. Toxin-induced actin depolymerization also produces microtubule-based membrane protrusions which form a network on epithelial cells and increase bacterial adherence. Multiple clinical studies indicate an association between binary toxin genes in C. difficile and increased 30-d CDI mortality independent of PCR ribotype. Further studies including measures of binary toxin in stool, analyses of CDI mortality caused by CDT-producing strains, and examination of the relationship of CDT expression to TcdA and TcdB toxin variants and PCR ribotypes are needed. PMID:24253566

  17. A Galactic Binary Detection Pipeline

    NASA Technical Reports Server (NTRS)

    Littenberg, Tyson B.

    2011-01-01

    The Galaxy is suspected to contain hundreds of millions of binary white dwarf systems, a large fraction of which will have sufficiently small orbital period to emit gravitational radiation in band for space-based gravitational wave detectors such as the Laser Interferometer Space Antenna (LISA). LISA's main science goal is the detection of cosmological events (supermassive black hole mergers, etc.) however the gravitational signal from the galaxy will be the dominant contribution to the data - including instrumental noise over approximately two decades in frequency. The catalogue of detectable binary systems will serve as an unparalleled means of studying the Galaxy. Furthermore, to maximize the scientific return from the mission, the data must be "cleansed" of the galactic foreground. We will present an algorithm that can accurately resolve and subtract 2:: 10000 of these sources from simulated data supplied by the Mock LISA Data Challenge Task Force. Using the time evolution of the gravitational wave frequency, we will reconstruct the position of the recovered binaries and show how LISA will sample the entire compact binary population in the Galaxy.

  18. 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.

  19. Sequential binary collision ionization mechanisms

    NASA Astrophysics Data System (ADS)

    van Boeyen, R. W.; Watanabe, N.; Doering, J. P.; Moore, J. H.; Coplan, M. A.; Cooper, J. W.

    2004-03-01

    Fully differential cross sections for the electron-impact ionization of the magnesium 3s orbital have been measured in a high-momentum-transfer regime wherein the ionization mechanisms can be accurately described by simple binary collision models. Measurements where performed at incident-electron energies from 400 to 3000 eV, ejected-electron energies of 62 eV, scattering angle of 20 °, and momentum transfers of 2 to 5 a.u. In the out-of-plane geometry of the experiment the cross section is observed far off the Bethe ridge. Both first- and second-order processes can be clearly distinguished as previously observed by Murray et al [Ref. 1] and Schulz et al [Ref. 2]. Owing to the relatively large momentum of the ejected electron, the second order processes can be modeled as sequential binary collisions involving a binary elastic collision between the incident electron and ionic core and a binary knock-out collision between the incident electron and target electron. At low incident-electron energies the cross section for both first and second order processes are comparable, while at high incident energies second-order processes dominate. *Supported by NSF under grant PHY-99-87870. [1] A. J. Murray, M. B. J. Woolf, and F. H. Read J. Phys. B 25, 3021 (1992). [2] M. Schulz, R. Moshammer, D. Fischer, H. Kollmus, D. H. Madison. S. Jones and J. Ullrich, Nature 422, 48 (2003).

  20. Binary logic is rich enough

    SciTech Connect

    Zapatrin, R.R.

    1992-02-01

    Given a finite ortholattice L, the *-semigroup is explicitly built whose annihilator ortholattice is isomorphic to L. Thus, it is shown that any finite quantum logic is the additive part of a binary logic. Some areas of possible applications are outlined. 7 refs.

  1. Consolidated RXTE Observing Grants on Observation of Neutron Stars and Black Holes in Binaries

    NASA Technical Reports Server (NTRS)

    Prince, Thomas A.; Vaughan, Brian A.

    1998-01-01

    This final report is a study of neutron stars and black holes in binaries. The activities focused on observation made with the Rossi X-ray Timing Explorer. The following areas were covered: long term observations of accreting binary pulsars with the All-Sky Monitor (ASM); observations of Centaurus X-3 with the Proportional Counter Array (PCA) and the High-Energy X-ray Timing Experiment (HEXTE); observations of accreting pulsars with the PCA and HEXTE; studies of quasi-periodic oscillations (QPO); and investigations of accreting black-hole candidates.

  2. Hunting stellar-mass black holes in X-ray binaries

    NASA Astrophysics Data System (ADS)

    Corral-Santana, J. M.

    2017-07-01

    In the last 50 years of X-ray astronomy we have detected nearly 60 Galactic stellar-mass black hole (BH) candidates in transient X-ray binaries, i.e. systems with low-mass companions and sporadic outburst episodes. In addition, we have detected 2 more systems with high-mass companion stars. Only 17 out of the ˜60 transients have been dynamically confirmed although we have established strong constrains in two more systems. In this contribution, we will introduce the X-ray binaries, summarise their status and present the latest advances in the field.

  3. Consolidated RXTE Observing Grants on Observation of Neutron Stars and Black Holes in Binaries

    NASA Technical Reports Server (NTRS)

    Prince, Thomas A.; Vaughan, Brian A.

    1998-01-01

    This final report is a study of neutron stars and black holes in binaries. The activities focused on observation made with the Rossi X-ray Timing Explorer. The following areas were covered: long term observations of accreting binary pulsars with the All-Sky Monitor (ASM); observations of Centaurus X-3 with the Proportional Counter Array (PCA) and the High-Energy X-ray Timing Experiment (HEXTE); observations of accreting pulsars with the PCA and HEXTE; studies of quasi-periodic oscillations (QPO); and investigations of accreting black-hole candidates.

  4. A zoo of computable binary normal sequences

    PubMed Central

    Pincus, Steve; Singer, Burton H.

    2012-01-01

    Historically there has been a virtual absence of constructive methods to produce broad classes of “certifiably random” infinite sequences, despite considerable interest in this endeavor. Previously, we proved a theorem that yielded explicit algorithms to produce diverse sets of normal numbers, reasonable candidates for random sequences, given their limiting equidistribution of subblocks of all lengths. Herein, we develop this algorithmic approach much further, systematizing the normal number generation process in several ways. We construct delineated, distinct sets of normal numbers (classified by the extent to which initial segments deviate from maximal irregularity), with virtually any allowable specified rate of convergence to 0 of this deviation, encompassing arbitrarily fast and slow rates, and accommodating asymmetric behavior above or below a centered median. As a corollary, we provide an explicit construction of a normal number that satisfies the Law of the Iterated Logarithm. We also produce distinct families of “biased” normal numbers, with virtually any specified rate of convergence of the bias (to 0). This latter theory is in part motivated by the remarkable observation that the binary version of Champernowne’s number, which is also normal, is biased—any initial segment has more 1s than 0s. Finally, we construct an interesting normal sequence with arbitrarily fast convergence to equidistribution of singleton blocks, yet arbitrarily slow convergence of pairs, which has profound implications both for probability theory, and for metrics to evaluate the “near-randomness” of sequences. PMID:23125196

  5. 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.

  6. 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.

  7. Coevolution of binaries and circumbinary gaseous discs

    NASA Astrophysics Data System (ADS)

    Fleming, David P.; Quinn, Thomas R.

    2017-01-01

    The recent discoveries of circumbinary planets by Kepler raise questions for contemporary planet formation models. Understanding how these planets form requires characterizing their formation environment, the circumbinary protoplanetary disc and how the disc and binary interact and change as a result. The central binary excites resonances in the surrounding protoplanetary disc which drive evolution in both the binary orbital elements and in the disc. To probe how these interactions impact binary eccentricity and disc structure evolution, N-body smooth particle hydrodynamics simulations of gaseous protoplanetary discs surrounding binaries based on Kepler 38 were run for 104 binary periods for several initial binary eccentricities. We find that nearly circular binaries weakly couple to the disc via a parametric instability and excite disc eccentricity growth. Eccentric binaries strongly couple to the disc causing eccentricity growth for both the disc and binary. Discs around sufficiently eccentric binaries which strongly couple to the disc develop an m = 1 spiral wave launched from the 1:3 eccentric outer Lindblad resonance which corresponds to an alignment of gas particle longitude of periastrons. All systems display binary semimajor axis decay due to dissipation from the viscous disc.

  8. Learning Rotation-Invariant Local Binary Descriptor.

    PubMed

    Duan, Yueqi; Lu, Jiwen; Feng, Jianjiang; Zhou, Jie

    2017-08-01

    In this paper, we propose a rotation-invariant local binary descriptor (RI-LBD) learning method for visual recognition. Compared with hand-crafted local binary descriptors, such as local binary pattern and its variants, which require strong prior knowledge, local binary feature learning methods are more efficient and data-adaptive. Unlike existing learning-based local binary descriptors, such as compact binary face descriptor and simultaneous local binary feature learning and encoding, which are susceptible to rotations, our RI-LBD first categorizes each local patch into a rotational binary pattern (RBP), and then jointly learns the orientation for each pattern and the projection matrix to obtain RI-LBDs. As all the rotation variants of a patch belong to the same RBP, they are rotated into the same orientation and projected into the same binary descriptor. Then, we construct a codebook by a clustering method on the learned binary codes, and obtain a histogram feature for each image as the final representation. In order to exploit higher order statistical information, we extend our RI-LBD to the triple rotation-invariant co-occurrence local binary descriptor (TRICo-LBD) learning method, which learns a triple co-occurrence binary code for each local patch. Extensive experimental results on four different visual recognition tasks, including image patch matching, texture classification, face recognition, and scene classification, show that our RI-LBD and TRICo-LBD outperform most existing local descriptors.

  9. Δ μ binaries among stars with large proper motions

    NASA Astrophysics Data System (ADS)

    Khovritchev, M. Yu.; Kulikova, A. M.

    2015-12-01

    Based on observations performed with the Pulkovo normal astrograph in 2008-2015 and data from sky surveys (DSS, 2MASS, SDSS DR12, WISE), we have investigated the motions of 1308 stars with proper motions larger than 300 mas yr-1 down to magnitude 17. The main idea of our search for binary stars based on this material is reduced to comparing the quasi-mean (POSS2-POSS1; an epoch difference of ≈50 yr) and quasi-instantaneous (2МASS, SDSS, WISE, Pulkovo; an epoch difference of ≈10 yr) proper motions. If the difference is statistically significant compared to the proper motion errors, then the object may be considered as a Δ μ-binary candidate. One hundred and twenty one stars from among those included in the observational program satisfy this requirement. Additional confirmations of binarity for a number of stars have been obtained by comparing the calculated proper motions with the data from several programs of stellar trigonometric parallax determinations and by analyzing the asymmetry of stellar images on sky-survey CCD frames. Analysis of the highly accurate SDSS photometric data for four stars (J0656+3827, J0838+3940, J1229+5332, J2330+4639) allows us to reach a conclusion about the probability that these Δ μ binaries are white dwarf +Mdwarf pairs.

  10. Simulating binary inspirals in a corotating spherical coordinate system

    NASA Astrophysics Data System (ADS)

    Garrett, Travis Marshall

    The gravitational waves produced by the inspiral and merger of two black holes are expected to be the first detected by the newly constructed gravitational wave observatories. Accurate theoretical models that describe the generation and shape of these gravitational waves need to be constructed. These theoretical waveforms will aid in the detection of astrophysical wave sources, and will allow us to test general relativity in the strong field regime. Numerical relativity is the leading candidate for constructing accurate waveforms, and in this thesis we develop methods to help advance the field. In particular we use a corotating spherical coordinate system to simulate the evolution of a compact binary system as it produces gravitational radiation. We combine this method with both the Weak Radiation Reaction and Hydro-without- Hydro approximations to produce stable dynamical evolutions. We also utilize Nordström's conformally flat theory of gravitation as a relativistic laboratory during the development process. Additionally we perform semi-analytic calculations to determine the approximate way in which binaries decay in Nordström's theory. We find an excellent agreement between our semi-analytic calculations and the orbital evolutions produced by the code, and thus conclude that these methods form a solid basis for simulating binary inspirals and the gravitational waves they produce in general relativity.

  11. A corrosion investigation of solder candidates for high-temperature applications

    NASA Astrophysics Data System (ADS)

    Chidambaram, Vivek; Hald, John; Ambat, Rajan; Hattel, Jesper

    2009-06-01

    The step-soldering approach is being employed in the multi-chip module technology. High-lead-containing alloys are among the solders currently being used in this approach. Au-Sn and Au-Ge based candidate alloys have been proposed as alternative solders for this application. In this work, a corrosion investigation was carried out on potential ternary lead-free candidate alloys based on these binary alloys for high-temperature applications. These promising ternary candidate alloys were determined by the CALPHAD approach based on the solidification criterion and the nature of the phases predicted in the bulk solder. This work reveals that the Au-Sn-based candidate alloys close to the eutectic composition (20 wt.% Sn) are more corrosion resistant than the Au-Ge-based ones.

  12. New prospects for observing and cataloguing exoplanets in well-detached binaries

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

    This paper is devoted to study the circumstances favourable to detect circumstellar and circumbinary planets in well-detached binary-star systems using eclipse timing variations (ETVs). We investigated the dynamics of well-detached binary star systems with a star separation from 0.5 to 3 au, 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 Plato, Tess and Cheops). For the chosen star separations both dynamical configurations (circumstellar and circumbinary) may be observable. We performed numerical simulations by using the full three-body problem as dynamical model. The dynamical stability and the ETVs are investigated by computing ETV maps for different masses of the secondary star and the exoplanet (Earth, Neptune and Jupiter size). In addition we changed the planet's and binary's eccentricities. We conclude that many amplitudes of ETVs are large enough to detect exoplanets in binary-star systems. As an application, we prepared statistics of the catalogue of exoplanets in binary star systems which we introduce in this article and compared the statistics with our parameter-space which we used for our calculations. In addition to these statistics of the catalogue we enlarged them by the investigation of well-detached binary star systems from several catalogues and discussed the possibility of further candidates.

  13. 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.

  14. A Catalog of Automatically Detected Ring Galaxy Candidates in PanSTARRS

    NASA Astrophysics Data System (ADS)

    Timmis, Ian; Shamir, Lior

    2017-07-01

    We developed and applied a computer analysis method to detect ring galaxy candidates in the first data release of the Panoramic Survey Telescope and Rapid Response System (PanSTARRS). The method works by applying a low-pass filter, followed by dynamic global thresholding, to search for closed regions in the binary mask of each galaxy image. Applying the method to ∼3 × 106 PanSTARRS galaxy images produced a catalog of 185 ring galaxy candidates based on their visual appearance.

  15. Binary companions of nearby supernova remnants found with Gaia

    NASA Astrophysics Data System (ADS)

    Boubert, D.; Fraser, M.; Evans, N. W.; Green, D. A.; Izzard, R. G.

    2017-09-01

    Aims: We search for runaway former companions of the progenitors of nearby Galactic core-collapse supernova remnants (SNRs) in the Tycho-Gaia astrometric solution (TGAS). Methods: We look for candidates among a sample of ten SNRs with distances ≲2kpc, taking astrometry and G magnitude from TGAS and B,V magnitudes from the AAVSO Photometric All-Sky Survey (APASS). A simple method of tracking back stars and finding the closest point to the SNR centre is shown to have several failings when ranking candidates. In particular, it neglects our expectation that massive stars preferentially have massive companions. We evolve a grid of binary stars to exploit these covariances in the distribution of runaway star properties in colour - magnitude - ejection velocity space. We construct an analytic model which predicts the properties of a runaway star, in which the model parameters are the location in the grid of progenitor binaries and the properties of the SNR. Using nested sampling we calculate the Bayesian evidence for each candidate to be the runaway and simultaneously constrain the properties of that runaway and of the SNR itself. Results: We identify four likely runaway companions of the Cygnus Loop (G074.0-08.5), HB 21 (G089.0+ 04.7), S147 (G180.0+ 01.7) and the Monoceros Loop (G205.5+ 00.5). HD 37424 has previously been suggested as the companion of S147, however the other three stars are new candidates. The favoured companion of HB 21 is the Be star BD+50 3188 whose emission-line features could be explained by pre-supernova mass transfer from the primary. There is a small probability that the 2M⊙ candidate runaway TYC 2688-1556-1 associated with the Cygnus Loop is a hypervelocity star. If the Monoceros Loop is related to the on-going star formation in the Mon OB2 association, the progenitor of the Monoceros Loop is required to be more massive than 40M⊙ which is in tension with the posterior for our candidate runaway star HD 261393.

  16. SAO RAS SN candidates classifications

    NASA Astrophysics Data System (ADS)

    Fatkhullin, T. A.; Moskvitin, A. S.

    2016-08-01

    We observed SN candidates (AT 2016eow, AT 2016enu and AT 2016enf) with the BTA/Scorpio-I on August, 4. Direct images in the R band and long-slit spectra in the range of 3600-7600AA (resolution FWHM = 10A) were obtained.

  17. Candidate Exercise Technologies and Prescriptions

    NASA Technical Reports Server (NTRS)

    Loerch, Linda H.

    2010-01-01

    This slide presentation reviews potential exercise technologies to counter the effects of space flight. It includes a overview of the exercise countermeasures project, a review of some of the candidate exercise technologies being considered and a few of the analog exercise hardware devices, and a review of new studies that are designed to optimize the current and future exercise protocols.

  18. Interviewing Teacher-Librarian Candidates

    ERIC Educational Resources Information Center

    Yucht, Alice

    2004-01-01

    When recently asked by an administrator for some realistic questions and "recommended" responses to expect while interviewing candidates for school library positions, the author grouped the questions into three categories: library management, information skills and teaching skills. In this article are the questions she suggested, along with topics…

  19. Teacher Candidate Applications of Telecommunications.

    ERIC Educational Resources Information Center

    Crawford, Caroline M.; Hilburn, Sue; Willis, Jana

    Telecommunications offers teacher candidates an environment through which to delve into higher order thinking skills within the methods coursework, student teaching internship experience, as well as within the PreK-12 classroom environment. Modeling of appropriate uses of technology within the learning environment as the teacher candidate…

  20. Email Journaling for Teacher Candidates

    ERIC Educational Resources Information Center

    Jenny, Geraldine Covert

    2005-01-01

    This paper discusses email journaling for those hoping to become a teacher. The author discusses an innovative format she designed for journal entries that revolutionized her field experience supervision practices and those of other supervisors with whom she has shared this format. It has vastly improved the quality of the teacher-candidate's…

  1. Candidate Cave Entrances on Mars

    NASA Astrophysics Data System (ADS)

    Cushing, Glen

    2012-04-01

    This paper presents newly discovered candidate cave entrances into Martian near-surface lava tubes, volcano-tectonic fracture systems, and pit craters and describes their characteristics and exploration possibilities. These candidates are all collapse features that occur either intermittently along laterally continuous trench-like depressions or in the floors of sheer-walled atypical pit craters. As viewed from orbit, locations of most candidates are visibly consistent with known terrestrial features such as tube-fed lava flows, volcano-tectonic fractures, and pit craters, each of which forms by mechanisms that can produce caves. Although we cannot determine subsurface extents of the Martian features discussed here, some may continue unimpeded for many kilometers if terrestrial examples are indeed analogous. The features presented here were identified in images acquired by the Mars Odyssey's Thermal Emission Imaging System visiblewavelength camera, and by the Mars Reconnaissance Orbiter's Context Camera. Select candidates have since been targeted by the High-Resolution Imaging Science Experiment. Martian caves are promising potential sites for future human habitation and astrobiology investigations; understanding their characteristics is critical for long-term mission planning and for developing the necessary exploration technologies.

  2. Candidate cave entrances on Mars

    USGS Publications Warehouse

    Cushing, Glen E.

    2012-01-01

    This paper presents newly discovered candidate cave entrances into Martian near-surface lava tubes, volcano-tectonic fracture systems, and pit craters and describes their characteristics and exploration possibilities. These candidates are all collapse features that occur either intermittently along laterally continuous trench-like depressions or in the floors of sheer-walled atypical pit craters. As viewed from orbit, locations of most candidates are visibly consistent with known terrestrial features such as tube-fed lava flows, volcano-tectonic fractures, and pit craters, each of which forms by mechanisms that can produce caves. Although we cannot determine subsurface extents of the Martian features discussed here, some may continue unimpeded for many kilometers if terrestrial examples are indeed analogous. The features presented here were identified in images acquired by the Mars Odyssey's Thermal Emission Imaging System visible-wavelength camera, and by the Mars Reconnaissance Orbiter's Context Camera. Select candidates have since been targeted by the High-Resolution Imaging Science Experiment. Martian caves are promising potential sites for future human habitation and astrobiology investigations; understanding their characteristics is critical for long-term mission planning and for developing the necessary exploration technologies.

  3. Candidate gene prioritization with Endeavour.

    PubMed

    Tranchevent, Léon-Charles; Ardeshirdavani, Amin; ElShal, Sarah; Alcaide, Daniel; Aerts, Jan; Auboeuf, Didier; Moreau, Yves

    2016-07-08

    Genomic studies and high-throughput experiments often produce large lists of candidate genes among which only a small fraction are truly relevant to the disease, phenotype or biological process of interest. Gene prioritization tackles this problem by ranking candidate genes by profiling candidates across multiple genomic data sources and integrating this heterogeneous information into a global ranking. We describe an extended version of our gene prioritization method, Endeavour, now available for six species and integrating 75 data sources. The performance (Area Under the Curve) of Endeavour on cross-validation benchmarks using 'gold standard' gene sets varies from 88% (for human phenotypes) to 95% (for worm gene function). In addition, we have also validated our approach using a time-stamped benchmark derived from the Human Phenotype Ontology, which provides a setting close to prospective validation. With this benchmark, using 3854 novel gene-phenotype associations, we observe a performance of 82%. Altogether, our results indicate that this extended version of Endeavour efficiently prioritizes candidate genes. The Endeavour web server is freely available at https://endeavour.esat.kuleuven.be/.

  4. Searching for twins of the V1309 Sco progenitor system: a selection of long-period contact binaries

    NASA Astrophysics Data System (ADS)

    Kurtenkov, Alexander

    2017-01-01

    The only well-studied red nova progenitor (V1309 Sco) was a contact binary with a 1.4-day period. The prospects for searching for similar systems, as well as stellar merger candidates in general, are explored in this work. The photospheric temperatures of 128 variables with periods P=1.1-1.8 d classified as W UMa-type binaries are calculated using their colors listed in the SDSS catalog. A selection of 15 contact binaries with similar temperatures and periods as the V1309 Sco progenitor is compiled. The Kepler Eclipsing Binary Catalog is used to analyse systems with eclipse timing variations (ETV) possibly caused by changes of the orbital period. Out of the 31 systems with parabolic ETV curves listed by Conroy et al. (2014, AJ, 147, 45) two could be contact binaries with a decreasing period and, therefore, potential stellar merger candidates. Out of the 569 contact binaries in the OGLE field analysed by Kubiak et al. (2006, AcA, 56, 253) 14 systems have periods longer than 0.8 d and a statistically significant period decrease.

  5. Binary nucleation at low temperatures

    NASA Technical Reports Server (NTRS)

    Zahoransky, R. A.; Peters, F.

    1985-01-01

    The onset of homogeneous condensation of binary vapors in the supersaturated state is studied in ethanol/n-propanol and water/ethanol via their unsteady expansion in a shock tube at temperatures below 273 K. Ethanol/n-propanol forms a nearly ideal solution, whereas water/ethanol is an example of a strongly nonideal mixture. Vapor mixtures of various compositions are diluted in dry air at small mole fractions and expanded in the driver section from room temperature. The onset of homogeneous condensation is detected optically and the corresponding thermodynamic state is evaluated. The experimental results are compared with the binary nucleation theory, and the particular problems of theoretical evaluation at low temperatures are discussed.

  6. Mass transfer between binary stars

    NASA Technical Reports Server (NTRS)

    Modisette, J. L.; Kondo, Y.

    1980-01-01

    The transfer of mass from one component of a binary system to another by mass ejection is analyzed through a stellar wind mechanism, using a model which integrates the equations of motion, including the energy equation, with an initial static atmosphere and various temperature fluctuations imposed at the base of the star's corona. The model is applied to several situations and the energy flow is calculated along the line of centers between the two binary components, in the rotating frame of the system, thereby incorporating the centrifugal force. It is shown that relatively small disturbances in the lower chromosphere or photosphere can produce mass loss through a stellar wind mechanism, due to the amplification of the disturbance propagating into the thinner atmosphere. Since there are many possible sources of the disturbance, the model can be used to explain many mass ejection phenomena.

  7. Binary Stars in SBS Survey

    NASA Astrophysics Data System (ADS)

    Erastova, L. K.

    2016-06-01

    Thirty spectroscopic binary stars were found in the Second Byurakan Survey (SBS). They show composite spectra - WD(DA)+dM or dC (for example Liebert et al. 1994). They may have red color, if the radiation of the red star dominates, and blue one, if the blue star is brighter and have peculiar spectrum in our survey plate. We obtained slit spectra for most of such objects. But we often see the spectrum of one component, because our slit spectra did not cover all optical range. We examine by eye the slit spectra of all SBS stellar objects (˜700) in SDSS DR7, DR8 or DR9 independent on our observations. We confirmed or discovered the duplicity of 30 stars. Usually they are spectroscopic binaries, where one component is WD (DA) and the second one is a red star with or without emission. There also are other components combinations. Sometimes there are emission lines, probably, indicating variable ones.

  8. Binary Inspiral in Quadratic Gravity

    NASA Astrophysics Data System (ADS)

    Yagi, Kent

    2015-01-01

    Quadratic gravity is a general class of quantum-gravity-inspired theories, where the Einstein-Hilbert action is extended through the addition of all terms quadratic in the curvature tensor coupled to a scalar field. In this article, we focus on the scalar Gauss- Bonnet (sGB) theory and consider the black hole binary inspiral in this theory. By applying the post-Newtonian (PN) formalism, we found that there is a scalar dipole radiation which leads to -1PN correction in the energy flux relative to gravitational radiation in general relativity. From the orbital decay rate of a low-mass X-ray binary A0600-20, we obtain the bound that is six orders of magnitude stronger than the current solar system bound. Furthermore, we show that the excess in the orbital decay rate of XTE J1118+480 can be explained by the scalar radiation in sGB theory.

  9. Close supermassive binary black holes.

    PubMed

    Gaskell, C Martin

    2010-01-07

    It has been proposed that when the peaks of the broad emission lines in active galactic nuclei (AGNs) are significantly blueshifted or redshifted from the systemic velocity of the host galaxy, this could be a consequence of orbital motion of a supermassive black-hole binary (SMBB). The AGN J1536+0441 ( = SDSS J153636.22+044127.0) has recently been proposed as an example of this phenomenon. It is proposed here instead that J1536+0441 is an example of line emission from a disk. If this is correct, the lack of clear optical spectral evidence for close SMBBs is significant, and argues either that the merging of close SMBBs is much faster than has generally been hitherto thought, or if the approach is slow, that when the separation of the binary is comparable to the size of the torus and broad-line region, the feeding of the black holes is disrupted.

  10. Information graphs for binary predictors.

    PubMed

    Hughes, G; McRoberts, N; Burnett, F J

    2015-01-01

    Binary predictors are used in a wide range of crop protection decision-making applications. Such predictors provide a simple analytical apparatus for the formulation of evidence related to risk factors, for use in the process of Bayesian updating of probabilities of crop disease. For diagrammatic interpretation of diagnostic probabilities, the receiver operating characteristic is available. Here, we view binary predictors from the perspective of diagnostic information. After a brief introduction to the basic information theoretic concepts of entropy and expected mutual information, we use an example data set to provide diagrammatic interpretations of expected mutual information, relative entropy, information inaccuracy, information updating, and specific information. Our information graphs also illustrate correspondences between diagnostic information and diagnostic probabilities.

  11. Cool Star Binaries with ALEXIS

    NASA Technical Reports Server (NTRS)

    Stern, Robert A.

    1998-01-01

    We proposed to search for high-temperature, flare-produced Fe XXIII line emission from active cool star binary systems using the ALEXIS all-sky survey. Previous X-ray transient searches with ARIEL V and HEAO-1, and subsequent shorter duration monitoring with the GINGA and EXOSAT satellites demonstrated that active binaries can produce large (EM approximately equals 10(exp 55-56/cu cm) X-ray flares lasting several hours or longer. Hot plasma from these flares at temperatures of 10(exp 7)K or more should produce Fe XXIII line emission at lambda = 132.8 A, very near the peak response of ALEXIS telescopes 1A and 2A. Our primary goals were to estimate flare frequency for the largest flares in the active binary systems, and, if the data permitted, to derive a distribution of flare energy vs. frequency for the sample as a whole. After a long delay due to the initial problems with the ALEXIS attitude control, the heroic efforts on the part of the ALEXIS satellite team enabled us to carry out this survey. However, the combination of the higher than expected and variable background in the ALEXIS detectors, and the lower throughput of the ALEXIS telescopes resulted in no convincing detections of large flares from the active binary systems. In addition, vignetting-corrected effective exposure times from the ALEXIS aspect solution were not available prior to the end of this contract; therefore, we were unable to convert upper limits measured in ALEXIS counts to the equivalent L(sub EUV).

  12. A Wide Angle Search for Hot Jupiters and 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.; Colazo, Carlos; Guzzo, Pablo; Lambas, Diego G.; Quiñones, Ceci; Stringer, Katelyn; Tapia, Luis; Wisdom, Colin

    2016-01-01

    The past two decades have seen a significant advancement in the detection, classification and understanding of exoplanets and binary star systems. The vast majority of these systems consist of stars on the main sequence or on the giant branch, leading to a dearth of knowledge of properties at early times (<50 Myr). Only one transiting planet candidate and a dozen eclipsing binaries are known among pre-main sequence objects, yet these are the systems that can provide the best constraints on stellar and planetary formation models. We have recently completed a photometric survey of 3 young (<50 Myr), nearby (D<150 pc) moving groups with a small-aperture instrument, nicknamed ``AggieCam''. We detected 7 candidate Hot Jupiters and over 200 likely pre-main sequence binaries, which are now being followed up photometrically and spectroscopically.

  13. Optical BVRI photometry of common proper motion F/G/K+M wide separation binaries

    SciTech Connect

    Li, Ting; Marshall, Jennifer L.; Williams, Patrick; Chavez, Joy; Lépine, Sébastien

    2014-10-01

    We present optical (BVRI) photometric measurements of a sample of 76 common proper motion wide separation main-sequence binary pairs. The pairs are composed of a F-, G-, or K-type primary star and an M-type secondary. The sample is selected from the revised NLTT catalog and the LSPM catalog. The photometry is generally precise to 0.03 mag in all bands. We separate our sample into two groups, dwarf candidates and subdwarf candidates, using the reduced proper motion diagram constructed with our improved photometry. The M subdwarf candidates in general have larger V – R colors than the M dwarf candidates at a given V – I color. This is consistent with an average metallicity difference between the two groups, as predicted by the PHOENIX/BT-Settl models. The improved photometry will be used as input into a technique to determine the metallicities of the M-type stars.

  14. 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.

  15. Marangoni convection in binary mixtures.

    PubMed

    Zhang, Jie; Behringer, Robert P; Oron, Alexander

    2007-07-01

    Marangoni instabilities in binary mixtures in the presence of the Soret effect and evaporation are different from those in pure liquids. In contrast to a large amount of experimental work on Marangoni convection in pure liquids, such experiments in binary mixtures are not available in the literature, to our knowledge. Using binary mixtures of NaCl/water in an open system, evaporation of water molecules at the liquid-vapor interface is inevitable. We have systematically investigated the pattern formation for a set of substrate temperatures and solute concentrations in an open system. The flow patterns evolve with time, driven by surface-tension fluctuations due to evaporation and the Soret effect, while the air-liquid interface does not deform. A shadow-graph method is used to follow the pattern formation in time. The patterns are mainly composed of polygons and rolls. The mean pattern size first decreases slightly, and then gradually increases during the evolution. Evaporation affects the pattern formation mainly at the early stages and the local evaporation rate tends to become spatially uniform at the film surface. The Soret effect becomes important at the later stages and affects the mixture for a large mean solute concentration where the Soret number is significantly above zero. The strength of convection increases with the initial solute concentration and the substrate temperature. Our findings differ from the theoretical predictions in which evaporation is neglected.

  16. Binary stars in loose associations: AB Dor B and HD 160934

    NASA Astrophysics Data System (ADS)

    Azulay, R.; Guirado, J. C.; Marcaide, J. M.; Martí-Vidal, I.; Ros, E.

    2015-05-01

    Precise determination of dynamical masses of pre-main- sequence (PMS) stars is necessary to calibrate PMS stellar evolutionary models, whose predictions are in disagreement with measurements for masses below 1.2 M_{⊙}. Binary stars in young, nearby loose associations are particularly good candidates, since all members share a common age. We present phase-reference VLBI observations of two binary systems that belong to the AB Doradus moving, HD 160934 A/c and AB Dor Ba/Bb, from which we have measured both the relative and absolute orbital motion. Accordingly, we obtained precise estimates of the mass of the components of these binaries (ranging from 0.25 to 0.7 M_{⊙}). We will show how these measurements provide precise calibration points for testing PMS models of low-mass stars.

  17. Computational identification of promising thermoelectric materials among known quasi-2D binary compounds

    SciTech Connect

    Gorai, Prashun; Toberer, Eric S.; Stevanović, Vladan

    2016-01-01

    Quasi low-dimensional structures are abundant among known thermoelectric materials, primarily because of their low lattice thermal conductivities. In this work, we have computationally assessed the potential of 427 known binary quasi-2D structures in 272 different chemistries for thermoelectric performance. To assess the thermoelectric performance, we employ an improved version of our previously developed descriptor for thermoelectric performance [Yan et al., Energy Environ. Sci., 2015, 8, 983]. The improvement is in the explicit treatment of van der Waals interactions in quasi-2D materials, which leads to significantly better predictions of their crystal structures and lattice thermal conductivities. The improved methodology correctly identifies known binary quasi-2D thermoelectric materials such as Sb2Te3, Bi2Te3, SnSe, SnS, InSe, and In2Se3. As a result, we propose candidate quasi-2D binary materials, a number of which have not been previously considered for thermoelectric applications.

  18. On the Evolution, Numbers, and Characteristics of Close-Binary Supersoft Sources

    NASA Technical Reports Server (NTRS)

    DiStefano, R.; Nelson, L. A.

    1996-01-01

    The ability to perform detailed evolutionary calculations is essential to the development of a well-defined and testable binary model. Unfortunately, traditional evolutionary calculations cannot be used to follow a significant fraction of possible close-binary supersoft sources (CBSS's). It is therefore important to examine the in-put physics carefully, to be sure that all relevant and potentially important physical processes are included. In this paper we continue a line of research begun last year, and explore the role that winds are expected to play in the evolution of CBSS's. We find that at least a subset of the systems that seemed to be candidates for common envelope evolution may survive, if radiation emitted by the white dwarf drives winds from the system. We study the effects of winds on the binary evolution of CBSS's, and compute the number and characteristics of CBSS's expected to be presently active in galaxies such as our own or M31.

  19. Revisiting the Influence of Unidentified Binaries on Velocity Dispersion Measurements in Ultra-faint Stellar Systems

    NASA Astrophysics Data System (ADS)

    McConnachie, Alan W.; Côté, Patrick

    2010-10-01

    Velocity dispersion measurements of recently discovered Milky Way satellites with MV >~ -7 imply that they posses high mass-to-light ratios. The expected velocity dispersions due to their baryonic mass are ~0.2 km s-1, but values gsim3 km s-1 are measured. We perform Monte Carlo simulations of mock radial velocity measurements of these systems assuming that they have mass-to-light ratios similar to globular clusters and posses an unidentified binary star population, to determine if these stars could boost the velocity dispersion to the observed values. We find that this hypothesis is unlikely to produce dispersions much in excess of ~4.5 km s-1, in agreement with previous work. However, for the systems with the potentially smallest velocity dispersions, values consistent with observations are produced in 5%-40% of our simulations for binary fractions in excess of f bin(P <= 10 yr)~ 5%. This sample includes the dwarf galaxy candidates that lie closest to classical globular clusters in MV - rh space. Considered as a population, it is unlikely that all of these dwarf galaxy candidates have mass-to-light ratios typical of globular clusters, but boosting of the observed dispersion by binaries from near-zero values cannot be ruled out at high confidence for several individual dwarf galaxy candidates. Given the importance of obtaining accurate velocity dispersions and dynamical masses for the faintest satellites, it is clearly desirable to directly exclude the possible effect of binaries on these systems. This requires multi-epoch radial velocity measurements with individual uncertainties of lsim1 km s-1 to identify spectroscopic binaries with orbital velocities of the order of the observed velocity dispersion.

  20. The Phases Differential Astrometry Data Archive. 5. Candidate Substellar Companions to Binary Systems

    DTIC Science & Technology

    2010-12-01

    Mathematics and Astronomy, 105-24, California Institute of Technology, Pasadena, CA 91125, USA 5 Nicolaus Copernicus Astronomical Center, Polish Academy...they are the reverses of Nicolaus and Venator, the Latinized versions of Cacciatore’s own names (Allen 1963). Table 9 Orbit Model for HD 171779 Parameter

  1. On the Binary Origin of FS CMa Stars: Young Massive Clusters as Test Beds

    NASA Astrophysics Data System (ADS)

    de la Fuente, D.; Najarro, F.; Garcia, M.

    2017-02-01

    FS CMa stars are low-luminosity objects showing the B[e] phenomenon whose evolutionary origin is yet to be unraveled. Various binary-related hypotheses have been recently proposed, two of them involving a spiral-in evolution of the binary orbit. The latter occurs more often in dense stellar environments, such as young massive clusters (YMCs). Hence, a systematic study of FS CMa stars in YMCs would be crucial to find out how these objects are created. Two FS CMa stars have been confirmed and three candidates have been found in YMCs through a search method based on narrow-band photometry at Paschen-α and the neighboring continuum. We apply this method to archival data from the Paschen-α survey of the Galactic Center region, yielding a new candidate in the Quintuplet cluster. Limitations of this method and other alternatives are briefly discussed.

  2. Neutrino-driven explosions of ultra-stripped Type Ic supernovae generating binary neutron stars

    NASA Astrophysics Data System (ADS)

    Suwa, Yudai; Yoshida, Takashi; Shibata, Masaru; Umeda, Hideyuki; Takahashi, Koh

    2015-12-01

    We study explosion characteristics of ultra-stripped supernovae (SNe), which are candidates of SNe generating binary neutron stars (NSs). As a first step, we perform stellar evolutionary simulations of bare carbon-oxygen cores of mass from 1.45 to 2.0 M⊙ until the iron cores become unstable and start collapsing. We then perform axisymmetric hydrodynamics simulations with spectral neutrino transport using these stellar evolution outcomes as initial conditions. All models exhibit successful explosions driven by neutrino heating. The diagnostic explosion energy, ejecta mass, Ni mass, and NS mass are typically ˜1050 erg, ˜0.1 M⊙, ˜0.01 M⊙, and ≈1.3 M⊙, which are compatible with observations of rapidly evolving and luminous transient such as SN 2005ek. We also find that the ultra-stripped SN is a candidate for producing the secondary low-mass NS in the observed compact binary NSs like PSR J0737-3039.

  3. Pulsed Accretion onto Eccentric and Circular Binaries

    NASA Astrophysics Data System (ADS)

    Muñoz, Diego J.; Lai, Dong

    2016-08-01

    We present numerical simulations of circumbinary accretion onto eccentric and circular binaries using the moving-mesh code AREPO. This is the first set of simulations to tackle the problem of binary accretion using a finite-volume scheme on a freely moving mesh, which allows for accurate measurements of accretion onto individual stars for arbitrary binary eccentricity. While accretion onto a circular binary shows bursts with period of ˜ 5 times the binary period P b, accretion onto an eccentric binary is predominantly modulated at the period ˜ 1{P}{{b}}. For an equal-mass circular binary, the accretion rates onto individual stars are quite similar to each other, following the same variable pattern in time. By contrast, for eccentric binaries, one of the stars can accrete at a rate 10-20 times larger than its companion. This “symmetry breaking” between the stars, however, alternates over timescales of order 200P b and can be attributed to a slowly precessing, eccentric circumbinary disk. Over longer timescales, the net accretion rates onto individual stars are the same, reaching a quasi-steady state with the circumbinary disk. These results have important implications for the accretion behavior of binary T Tauri stars and supermassive binary black holes.

  4. GALAXY ROTATION AND RAPID SUPERMASSIVE BINARY COALESCENCE

    SciTech Connect

    Holley-Bockelmann, Kelly; Khan, Fazeel Mahmood

    2015-09-10

    Galaxy mergers usher the supermassive black hole (SMBH) in each galaxy to the center of the potential, where they form an SMBH binary. The binary orbit shrinks by ejecting stars via three-body scattering, but ample work has shown that in spherical galaxy models, the binary separation stalls after ejecting all the stars in its loss cone—this is the well-known final parsec problem. However, it has been shown that SMBH binaries in non-spherical galactic nuclei harden at a nearly constant rate until reaching the gravitational wave regime. Here we use a suite of direct N-body simulations to follow SMBH binary evolution in both corotating and counterrotating flattened galaxy models. For N > 500 K, we find that the evolution of the SMBH binary is convergent and is independent of the particle number. Rotation in general increases the hardening rate of SMBH binaries even more effectively than galaxy geometry alone. SMBH binary hardening rates are similar for co- and counterrotating galaxies. In the corotating case, the center of mass of the SMBH binary settles into an orbit that is in corotation resonance with the background rotating model, and the coalescence time is roughly a few 100 Myr faster than a non-rotating flattened model. We find that counterrotation drives SMBHs to coalesce on a nearly radial orbit promptly after forming a hard binary. We discuss the implications for gravitational wave astronomy, hypervelocity star production, and the effect on the structure of the host galaxy.

  5. All Bright Cold Classical KBOs are Binary

    NASA Astrophysics Data System (ADS)

    Noll, Keith S.; Parker, Alex H.; Grundy, William M.

    2014-11-01

    When sorted by absolute magnitude as seen in ground based observations, an extremely high fraction of the brightest Cold Classical (CC) Kuiper Belt objects (KBO) are, in fact resolved as binaries when observed at higher angular resolution. Of the 22 CCs brighter than H=6.1 observed by HST, 16 have been found to be binary yielding a binary fraction of 73±10%. When low inclination interlopers from the hot population and close binaries are considered, this very high fraction is consistent with 100% of bright CCs being binary. At fainter absolute magnitudes, this fraction drops to ~20%. Such a situation is a natural outcome of a broken size distribution with a steep drop-off in the number of CCs with individual component diameters larger than 150 km (for an assumed albedo of 0.15). A sharp cutoff in the size distribution for CCs is consistent with formation models that suggest that most planetesimals form at a preferred modal size of order 100 km.The very high fraction of binaries among the largest CCs also serves to limit the separation distribution of KBO binaries. At most, 27% of the brightest CCs are possible unresolved binaries. The apparent power law distribution of binary separation must cut off near the current observational limits of HST ( 1800 km at 43 AU). It is worth noting, however, that this observation does not constrain how many components of resolved binaries may themselves be unresolved multiples like 47171 1999 TC36. Finally, it is important to point out that, when sorted by the size of the primary rather than absolute magnitude of the unresolved pair, the fraction of binaries is relatively constant with size (Nesvorny et al. 2011, AJ 141, 159) eliminating observational bias as cause of the pile up of binaries among the brightest Cold Classical Kuiper Belt objects.The very high fraction of binaries among the brightest CCs appears to be an effect of the underlying CC size distribution.

  6. Leishmaniasis: vaccine candidates and perspectives.

    PubMed

    Singh, Bhawana; Sundar, Shyam

    2012-06-06

    Leishmania is a protozoan parasite and a causative agent of the various clinical forms of leishmaniasis. High cost, resistance and toxic side effects of traditional drugs entail identification and development of therapeutic alternatives. The sound understanding of parasite biology is key for identifying novel drug targets, that can induce the cell mediated immunity (mainly CD4+ and CD8+ IFN-gamma mediated responses) polarized towards a Th1 response. These aspects are important in designing a new vaccine along with the consideration of the candidates with respect to their ability to raise memory response in order to improve the vaccine performance. This review is an effort to identify molecules according to their homology with the host and their ability to be used as potent vaccine candidates.

  7. Enthalpy screen of drug candidates.

    PubMed

    Schön, Arne; Freire, Ernesto

    2016-11-15

    The enthalpic and entropic contributions to the binding affinity of drug candidates have been acknowledged to be important determinants of the quality of a drug molecule. These quantities, usually summarized in the thermodynamic signature, provide a rapid assessment of the forces that drive the binding of a ligand. Having access to the thermodynamic signature in the early stages of the drug discovery process will provide critical information towards the selection of the best drug candidates for development. In this paper, the Enthalpy Screen technique is presented. The enthalpy screen allows fast and accurate determination of the binding enthalpy for hundreds of ligands. As such, it appears to be ideally suited to aid in the ranking of the hundreds of hits that are usually identified after standard high throughput screening. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. OPTOPUS observations of quasar candidates.

    NASA Astrophysics Data System (ADS)

    Cristiani, S.

    1987-06-01

    OPTOPUS is a fiber-optic instrument for multiple-object spectroscopy with the Boiler & Chivens spectrograph and a CCD detector at the 3.6-m telescope. The system has been described in detail by the Optical Instrumentation Group (1985, The Messenger 41,25). Its application for observing Halley's comet has been reported by Lund and Surdej (1986, The Messenger 43, 1). Here another "classical" use of multiple-object spectroscopy is presented: followup observations of quasar candidates.

  9. Candidate Hα emission and absorption line sources in the Galactic Bulge Survey

    NASA Astrophysics Data System (ADS)

    Wevers, T.; Jonker, P. G.; Nelemans, G.; Torres, M. A. P.; Groot, P. J.; Steeghs, D.; Maccarone, T. J.; Hynes, R. I.; Heinke, C.; Britt, C.

    2017-04-01

    We present a catalogue of candidate Hα emission and absorption line sources and blue objects in the Galactic Bulge Survey (GBS) region. We use a point source catalogue of the GBS fields (two strips of (l × b) = (6° × 1°) centred at b = 1.5° above and below the Galactic Centre), covering the magnitude range 16 ≤ r΄ ≤ 22.5. We utilize (r΄ - i΄, r΄ - Hα) colour-colour diagrams to select Hα emission and absorption line candidates, and also identify blue objects (compared to field stars) using the r΄ - i΄ colour index. We identify 1337 Hα emission line candidates and 336 Hα absorption line candidates. These catalogues likely contain a plethora of sources, ranging from active (binary) stars, early-type emission line objects, cataclysmic variables (CVs) and low-mass X-ray binaries (LMXBs) to background active galactic nuclei (AGN). The 389 blue objects we identify are likely systems containing a compact object, such as CVs, planetary nebulae and LMXBs. Hot subluminous dwarfs (sdO/B stars) are also expected to be found as blue outliers. Cross-matching our outliers with the GBS X-ray catalogue yields 16 sources, including 7 (magnetic) CVs and 1 qLMXB candidate among the emission line candidates and 1 background AGN for the absorption line candidates. One of the blue outliers is a high-state AM CVn system. Spectroscopic observations combined with the multiwavelength coverage of this area, including X-ray, ultraviolet and (time-resolved) optical and infrared observations, can be used to further constrain the nature of individual sources.

  10. 1998 astronaut candidates tour KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At the Apollo/Saturn V Center, some of the 1998 astronaut candidate class (group 17) take a close look at the Saturn V rocket on display. The U.S. candidates include Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and international candidates Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes. The class is at KSC for training activities, including fire training and a flight awareness program, plus touring the OPF, SSME Processing Facility, VAB, SSPF, launch pads, SLF, Apollo/Saturn V Center and the crew headquarters.

  11. 1998 astronaut candidates tour KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Some of the 1998 astronaut candidate class (group 17) take a close look at displays in the Apollo/Saturn V Center at KSC. The U.S. candidates include Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and international candidates Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes. The class is at KSC for training activities, including fire training and a flight awareness program, plus touring the OPF, SSME Processing Facility, VAB, SSPF, launch pads, SLF, Apollo/Saturn V Center and the crew headquarters.

  12. 1998 astronaut candidates tour KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At the Apollo/Saturn V Center, some of the 1998 astronaut candidate class (group 17) line up for a photo while standing under the engines of the Saturn V rocket on display. The U.S. candidates include Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and international candidates Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes. The class is at KSC for training activities, including fire training and a flight awareness program, plus touring the OPF, SSME Processing Facility, VAB, SSPF, launch pads, SLF, Apollo/Saturn V Center and the crew headquarters.

  13. 1998 astronaut candidates tour KSC

    NASA Technical Reports Server (NTRS)

    1999-01-01

    At the Apollo/Saturn V Center, some of the 1998 astronaut candidate class (group 17) line up for a photo during a tour of facilities at KSC. The U.S. candidates include Clayton C. Anderson, Lee J. Archambault, Tracy E. Caldwell (Ph.D.), Gregory E. Chamitoff (Ph.D.), Timothy J. Creamer, Christopher J. Ferguson, Michael J. Foreman, Michael E. Fossum, Kenneth T. Ham, Patricia C. Hilliard (M.D.), Gregory C. Johnson, Gregory H. Johnson, Stanley G. Love (Ph.D.), Leland D. Melvin, Barbara R. Morgan, William A. Oefelein, John D. Olivas (Ph.D.), Nicholas J.M. Patrick (Ph.D.), Alan G. Poindexter, Garrett E. Reisman (Ph.D.), Steven R. Swanson, Douglas H. Wheelock, Sunita L. Williams, Neil W. Woodward III, George D. Zamka; and international candidates Leopold Eyharts, Paolo Nespoli, Hans Schlegel, Roberto Vittori, Bjarni V. Tryggvason, and Marcos Pontes. The class is at KSC for training activities, including fire training and a flight awareness program, plus touring the OPF, SSME Processing Facility, VAB, SSPF, launch pads, SLF and the crew headquarters.

  14. SPECTRA OF TYPE II CEPHEID CANDIDATES AND RELATED STARS

    SciTech Connect

    Schmidt, E. G.; Rogalla, Danielle; Thacker-Lynn, Lauren E-mail: drogall1@bigred.unl.edu

    2011-02-15

    We present low-resolution spectra for variable stars in the Cepheid period range from the ROTSE-I Demonstration Project and the All Sky Automated Survey, some of which were previously identified as type II Cepheid candidates. We have derived effective temperatures, gravities, and metallicities from the spectra. Based on this, three types of variables were identified: Cepheid strip stars, cool stars that lie along the red subgiant and giant branch, and cool main-sequence stars. Many fewer type II Cepheids were found than expected and most have amplitudes less than 0.4 mag. The cool variables include many likely binaries as well as intrinsic variables. Variation among the main-sequence stars is likely to be mostly due to binarity or stellar activity.

  15. Searching for Coincident Electromagnetic Signals from Advanced LIGO Gravitational-Wave Candidates Using the Fermi Gamma-Ray Burst Monitor

    NASA Astrophysics Data System (ADS)

    Littenberg, Tyson; Fermi GBM Team; LIGO; Virgo Collaboration

    2017-01-01

    With the dawn of gravitational-wave (GW) astronomy, multimessenger observations combining the electromagnetic and GW sky are eagerly anticipated. During Advanced LIGO's first observing run (O1), data from the Fermi Gamma-ray Burst Monitor (GBM) were analyzed in search of electromagnetic transients coincident with GW candidates. The GBM search employs a coherent analysis over all GBM detectors using the full sky-location-dependent instrument response, and ranks candidate events by a Bayesian likelihood statistic. The GBM analysis was performed on candidate events from a search of LIGO data for merging compact binaries of total mass between 2 and 100 solar masses. The gravitational-wave candidate arrival time and its reconstructed source position were used as priors for the search of GBM data. We describe the GBM search for counterparts of the O1 candidates, and highlight improvements to the analysis made in preparation for future LIGO/Virgo observations.

  16. PLANETARY CANDIDATES OBSERVED BY KEPLER. III. ANALYSIS OF THE FIRST 16 MONTHS OF DATA

    SciTech Connect

    Batalha, Natalie M.; Rowe, Jason F.; Burke, Christopher J.; Caldwell, Douglas A.; Mullally, Fergal; Thompson, Susan E.; Barclay, Thomas; Dupree, Andrea K.; Latham, David W.; Quinn, Samuel N.; Ragozzine, Darin; Fabrycky, Daniel C.; Fortney, Jonathan J.; Ford, Eric B.; Gilliland, Ronald L.; Isaacson, Howard; Marcy, Geoffrey W.; and others

    2013-02-15

    New transiting planet candidates are identified in 16 months (2009 May-2010 September) of data from the Kepler spacecraft. Nearly 5000 periodic transit-like signals are vetted against astrophysical and instrumental false positives yielding 1108 viable new planet candidates, bringing the total count up to over 2300. Improved vetting metrics are employed, contributing to higher catalog reliability. Most notable is the noise-weighted robust averaging of multi-quarter photo-center offsets derived from difference image analysis that identifies likely background eclipsing binaries. Twenty-two months of photometry are used for the purpose of characterizing each of the candidates. Ephemerides (transit epoch, T {sub 0}, and orbital period, P) are tabulated as well as the products of light curve modeling: reduced radius (R {sub P}/R {sub *}), reduced semimajor axis (d/R {sub *}), and impact parameter (b). The largest fractional increases are seen for the smallest planet candidates (201% for candidates smaller than 2 R {sub Circled-Plus} compared to 53% for candidates larger than 2 R {sub Circled-Plus }) and those at longer orbital periods (124% for candidates outside of 50 day orbits versus 86% for candidates inside of 50 day orbits). The gains are larger than expected from increasing the observing window from 13 months (Quarters 1-5) to 16 months (Quarters 1-6) even in regions of parameter space where one would have expected the previous catalogs to be complete. Analyses of planet frequencies based on previous catalogs will be affected by such incompleteness. The fraction of all planet candidate host stars with multiple candidates has grown from 17% to 20%, and the paucity of short-period giant planets in multiple systems is still evident. The progression toward smaller planets at longer orbital periods with each new catalog release suggests that Earth-size planets in the habitable zone are forthcoming if, indeed, such planets are abundant.

  17. Binary Black Holes from Dense Star Clusters

    NASA Astrophysics Data System (ADS)

    Rodriguez, Carl

    2017-01-01

    The recent detections of gravitational waves from merging binary black holes have the potential to revolutionize our understanding of compact object astrophysics. But to fully utilize this new window into the universe, we must compare these observations to detailed models of binary black hole formation throughout cosmic time. In this talk, I will review our current understanding of cluster dynamics, describing how binary black holes can be formed through gravitational interactions in dense stellar environments, such as globular clusters and galactic nuclei. I will review the properties and merger rates of binary black holes from the dynamical formation channel. Finally, I will describe how the spins of a binary black hole are determined by its formation history, and how we can use this to discriminate between dynamically-formed binaries and those formed from isolated evolution in galactic fields.

  18. WISE detection of the galactic low-mass X-ray binaries

    SciTech Connect

    Wang, Xuebing; Wang, Zhongxiang

    2014-06-20

    We report on the results from our search for the Wide-field Infrared Survey Explorer (WISE) detection of the Galactic low-mass X-ray binaries (LMXBs). Among 187 binaries cataloged in Liu et al., we find 13 counterparts and 2 candidate counterparts. For the 13 counterparts, 2 (4U 0614+091 and GX 339–4) have already been confirmed by previous studies to have a jet and 1 (GRS 1915+105) to have a candidate circumbinary disk, from which the detected infrared emission arose. Having collected the broadband optical and near-infrared data in the literature and constructed flux density spectra for the other 10 binaries, we identify that 3 (A0620–00, XTE J1118+480, and GX 1+4) are candidate circumbinary disk systems, 4 (Cen X-4, 4U 1700+24, 3A 1954+319, and Cyg X-2) had thermal emission from their companion stars, and 3 (Sco X-1, Her X-1, and Swift J1753.5–0127) are peculiar systems with the origin of their infrared emission rather uncertain. We discuss the results and WISE counterparts' brightness distribution among the known LMXBs, and suggest that more than half of the LMXBs would have a jet, a circumbinary disk, or both.

  19. Planetesimal Accretion in Binary Star Systems

    NASA Astrophysics Data System (ADS)

    Marzari, F.; Scholl, H.

    2000-11-01

    Planetesimal accretion in close binary systems is a complex process for the gravitational perturbations of the companion star on the planetesimal orbits. These perturbations excite high eccentricities that can halt the accumulation process of planetesimals into planets also in those regions around the star where stable planetary orbits would eventually be possible. However, the evolution of a planetesimal swarm is also affected by collisions and gas drag. In particular, gas drag combined with the secular perturbations of the secondary star forces a strong alignment of all the planetesimal periastra. Since periastra are also coupled to eccentricities via the secular perturbations of the companion, the orbits of the planetesimals, besides all being aligned, also have very close values of eccentricity. This orbital ``phasing'' strongly reduces the contribution of the eccentricity to the relative velocities between planetesimals, and the impact speeds are dominated by the Keplerian shear: accretion becomes possible. This behavior is not limited to small planetesimals but also affects bodies as large as 100 km in diameter. The effects of gas drag are in fact enhanced by the presence of the constant forced component in the orbital eccentricity of the planetesimals. We describe analytically the periastron alignment by using the secular equations developed by Heppenheimer, and we test the prediction of the theory with a numerical code that integrates the orbits of a swarm of planetesimals perturbed by gas drag and collisions. The gas density is assumed to decrease outward, and the collisions are modeled as inelastic. Our computations are focused on the α Centauri system, which is a good candidate for terrestrial planets as we will show. The impact velocities between planetesimals of different sizes are computed at progressively increasing distances from the primary star and are compared with estimates for the maximum velocity for accretion. According to our simulations in

  20. Measuring Close Binary Stars with Speckle Interferometry

    DTIC Science & Technology

    2014-09-01

    Measuring Close Binary Stars with Speckle Interferometry Keith T. Knox Air Force Research Laboratory ABSTRACT Speckle interferometry...Labeyrie, 1970) is a well-tested and still used method for detecting and measuring binary stars that are closer together than the width of the...orientation of the binary star system (Horch, 1996, Tokovinin, 2010). In this talk, a method for analyzing the fringes in the power spectrum will be

  1. Speckle Imaging of Kepler and CoRoT Exo-planet Transit Candidate Stars

    NASA Astrophysics Data System (ADS)

    Howell, Steve B.; Horch, Elliott; Sherry, William; Ciardi, David

    2010-08-01

    Kepler and CoRoT are complementary space missions dedicated to the detection of exoplanets. The primary science goal of CoRoT is to find Neptune-sized (>3 Earth radii) planets in intermediate orbits, while the prime science goal of Kepler is to find Earth-sized planets (<3 Earth radii) in year-long orbits. Both missions employ the photometric transit method and both spacecraft are performing well with nominal operation of the spacecraft, telescopes, electronics, and instruments. As with ground-based surveys, Kepler and CoRoT candidates need to be screened for background eclipsing binary stars which, when photometrically blended with the primary target, can mimic exo-planetary transits. The list of candidate transiting planets found by Kepler/CoRoT requires follow-up to ascertain probable or certain exo- planet detection. While Earth-sized (and Neptune-sized in long orbital periods) exo-planets can not currently (easily) be confirmed from the ground, many of the false positive eliminations steps can be performed by ground-based observations. Follow-up for Kepler exo-planet candidates is now aimed at Neptune-size and smaller planets in longer period orbits. This proposal aims to obtain high resolution speckle imaging to observe Kepler/CoRoT exo-planet transit candidates in order to eliminate the largest false positive contributor in any transit search - background eclipsing binary stars or faint companion stars.

  2. Survival of planets around shrinking stellar binaries

    PubMed Central

    Muñoz, Diego J.; Lai, Dong

    2015-01-01

    The discovery of transiting circumbinary planets by the Kepler mission suggests that planets can form efficiently around binary stars. None of the stellar binaries currently known to host planets has a period shorter than 7 d, despite the large number of eclipsing binaries found in the Kepler target list with periods shorter than a few days. These compact binaries are believed to have evolved from wider orbits into their current configurations via the so-called Lidov–Kozai migration mechanism, in which gravitational perturbations from a distant tertiary companion induce large-amplitude eccentricity oscillations in the binary, followed by orbital decay and circularization due to tidal dissipation in the stars. Here we explore the orbital evolution of planets around binaries undergoing orbital decay by this mechanism. We show that planets may survive and become misaligned from their host binary, or may develop erratic behavior in eccentricity, resulting in their consumption by the stars or ejection from the system as the binary decays. Our results suggest that circumbinary planets around compact binaries could still exist, and we offer predictions as to what their orbital configurations should be like. PMID:26159412

  3. Survival of planets around shrinking stellar binaries

    NASA Astrophysics Data System (ADS)

    Munoz, Diego Jose; Lai, Dong

    2015-12-01

    The discovery of transiting circumbinary planets by the Kepler mission suggests that planets can form efficiently around binary stars. None of the stellar binaries currently known to host planets has a period shorter than 7 days, despite the large number of eclipsing binaries found in the Kepler target list with periods shorter than a few days. These compact binaries are believed to have evolved from wider orbits into their current configurations via the so-called Lidov-Kozai migration mechanism, in which gravitational perturbations from a distant tertiary companion induce large-amplitude eccentricity oscillations in the binary, followed by orbital decay and circularization due to tidal dissipation in the stars. We present new results (PNAS 112, 30, p 9264) on the orbital evolution of planets around binaries undergoing orbital decay by this "LK+tide" mechanism. From secular and N-body calculations, we show how planets may survive and become misaligned from their host binary, or may develop erratic behavior in eccentricity, resulting in their consumption by the stars or ejection from the system as the binary decays. Either outcome can explain these planets' elusiveness to detection. Our results suggest that circumbinary planets around compact binaries could still exist, and we offer specific predictions as to what their orbital configurations should be like.

  4. Survival of planets around shrinking stellar binaries.

    PubMed

    Muñoz, Diego J; Lai, Dong

    2015-07-28

    The discovery of transiting circumbinary planets by the Kepler mission suggests that planets can form efficiently around binary stars. None of the stellar binaries currently known to host planets has a period shorter than 7 d, despite the large number of eclipsing binaries found in the Kepler target list with periods shorter than a few days. These compact binaries are believed to have evolved from wider orbits into their current configurations via the so-called Lidov-Kozai migration mechanism, in which gravitational perturbations from a distant tertiary companion induce large-amplitude eccentricity oscillations in the binary, followed by orbital decay and circularization due to tidal dissipation in the stars. Here we explore the orbital evolution of planets around binaries undergoing orbital decay by this mechanism. We show that planets may survive and become misaligned from their host binary, or may develop erratic behavior in eccentricity, resulting in their consumption by the stars or ejection from the system as the binary decays. Our results suggest that circumbinary planets around compact binaries could still exist, and we offer predictions as to what their orbital configurations should be like.

  5. Young and Waltzing Binary Stars

    NASA Astrophysics Data System (ADS)

    2001-10-01

    ADONIS Observes Low-mass Eclipsing System in Orion Summary A series of very detailed images of a binary system of two young stars have been combined into a movie . In merely 3 days, the stars swing around each other. As seen from the earth, they pass in front of each other twice during a full revolution, producing eclipses during which their combined brightness diminishes . A careful analysis of the orbital motions has now made it possible to deduce the masses of the two dancing stars . Both turn out to be about as heavy as our Sun. But while the Sun is about 4500 million years old, these two stars are still in their infancy. They are located some 1500 light-years away in the Orion star-forming region and they probably formed just 10 million years ago . This is the first time such an accurate determination of the stellar masses could be achieved for a young binary system of low-mass stars . The new result provides an important piece of information for our current understanding of how young stars evolve. The observations were obtained by a team of astronomers from Italy and ESO [1] using the ADaptive Optics Near Infrared System (ADONIS) on the 3.6-m telescope at the ESO La Silla Observatory. PR Photo 29a/01 : The RXJ 0529.4+0041 system before primary eclipse PR Photo 29b/01 : The RXJ 0529.4+0041 system at mid-primary eclipse PR Photo 29c/01 : The RXJ 0529.4+0041 system after primary eclipse PR Photo 29d/01 : The RXJ 0529.4+0041 system before secondary eclipse PR Photo 29e/01 : The RXJ 0529.4+0041 system at mid-secondary eclipse PR Photo 29f/01 : The RXJ 0529.4+0041 system after secondary eclipse PR Video Clip 06/01 : Video of the RXJ 0529.4+0041 system Binary stars and stellar masses Since some time, astronomers have noted that most stars seem to form in binary or multiple systems. This is quite fortunate, as the study of binary stars is the only way in which it is possible to measure directly one of the most fundamental quantities of a star, its mass. The mass of a

  6. Crustal Failure during Binary Inspiral

    NASA Astrophysics Data System (ADS)

    Penner, A. J.; Andersson, N.; Jones, D. I.; Samuelsson, L.; Hawke, I.

    2012-04-01

    We present the first fully relativistic calculations of the crustal strain induced in a neutron star by a binary companion at the late stages of inspiral, employing realistic equations of state for the fluid core and the solid crust. We show that while the deep crust is likely to fail only shortly before coalescence, there is a large variation in elastic strain, with the outermost layers failing relatively early on in the inspiral. We discuss the significance of the results for both electromagnetic and gravitational-wave astronomy.

  7. Spectroscopic Orbits of Three Binaries

    NASA Astrophysics Data System (ADS)

    Scarfe, C. D.

    2017-10-01

    This paper presents new spectroscopic orbits of three binaries with evolved primaries and periods of the order of a few years, two of them very eccentric. All the orbits were determined primarily from observations made with the DAO 1.2-m telescope and coudé spectrograph. Observations were obtained using the radial velocity spectrometer until it was decommissioned in 2004, and since then using a CCD detector, and cross-correlating the spectra with those of standard stars. It will be evident that the latter procedure leads to smaller observational scatter than the former did.

  8. CRUSTAL FAILURE DURING BINARY INSPIRAL

    SciTech Connect

    Penner, A. J.; Andersson, N.; Jones, D. I.; Hawke, I.; Samuelsson, L.

    2012-04-20

    We present the first fully relativistic calculations of the crustal strain induced in a neutron star by a binary companion at the late stages of inspiral, employing realistic equations of state for the fluid core and the solid crust. We show that while the deep crust is likely to fail only shortly before coalescence, there is a large variation in elastic strain, with the outermost layers failing relatively early on in the inspiral. We discuss the significance of the results for both electromagnetic and gravitational-wave astronomy.

  9. SYSTEMATICALLY MISCLASSIFIED BINARY DEPENDENT VARIABLES

    PubMed Central

    TENNEKOON, VIDHURA; ROSENMAN, ROBERT

    2014-01-01

    When a binary dependent variable is misclassified, that is, recorded in the category other than where it really belongs, probit and logit estimates are biased and inconsistent. In some cases the probability of misclassification may vary systematically with covariates, and thus be endogenous. In this paper we develop an estimation approach that corrects for endogenous misclassification, validate our approach using a simulation study, and apply it to the analysis of a treatment program designed to improve family dynamics. Our results show that endogenous misclassification could lead to potentially incorrect conclusions unless corrected using an appropriate technique. PMID:27293307

  10. Constraining the Orbits of the Supermassive Binary Blackhole Pair 0402+379

    NASA Astrophysics Data System (ADS)

    Holland, Ben; Peck, Alison B.; Taylor, Gregory B.; Zavala, Robert T.; Romani, Roger W.

    2015-01-01

    Galaxy mergers are a relatively common occurrence in the Universe. Given that most large galaxies harbor supermassive black holes in their centers, it should follow that two supermassive black holes could be found in the centers of galaxies that have recently undergone a merger event. Supermassive black hole binaries (SMBHB) with small separation (referred to as "tight binaries"), however, are quite rare, implying that the mergers happen less often than we think, or that the binary black hole merger happens much more quickly than expected from simulations. We present observations of one of the best candidates for a tight SMBHB, 0402+379, made in 2003, 2005, and 2009 using the VLBA at 3 frequencies, and report on their apparent relative component motions over this time frame. Additionally, these results are compared to earlier observations of 0402+379 which can help establish a long time baseline. This information, although still preliminary, can be used to provide constraints on the orbits of this binary system which in turn may yield insight as to why these binary systems are not significantly more commonly detected in, for example, ULIRGs in the late stages of merger.

  11. THE DISTRIBUTION OF COALESCING COMPACT BINARIES IN THE LOCAL UNIVERSE: PROSPECTS FOR GRAVITATIONAL-WAVE OBSERVATIONS

    SciTech Connect

    Kelley, Luke Zoltan; Ramirez-Ruiz, Enrico; Zemp, Marcel; Diemand, Juerg; Mandel, Ilya

    2010-12-10

    Merging compact binaries are the most viable and best-studied candidates for gravitational-wave (GW) detection by the fully operational network of ground-based observatories. In anticipation of the first detections, the expected distribution of GW sources in the local universe is of considerable interest. Here we investigate the full phase-space distribution of coalescing compact binaries at z = 0 using dark matter simulations of structure formation. The fact that these binary systems acquire large barycentric velocities at birth ('kicks') results in merger site distributions that are more diffusely distributed with respect to their putative hosts, with mergers occurring out to distances of a few Mpc from the host halo. Redshift estimates based solely on the nearest galaxy in projection can, as a result, be inaccurate. On the other hand, large offsets from the host galaxy could aid the detection of faint optical counterparts and should be considered when designing strategies for follow-up observations. The degree of isotropy in the projected sky distributions of GW sources is found to be augmented with increasing kick velocity and to be severely enhanced if progenitor systems possess large kicks as inferred from the known population of pulsars and double compact binaries. Even in the absence of observed electromagnetic counterparts, the differences in sky distributions of binaries produced by disparate kick-velocity models could be discerned by GW observatories, within the expected accuracies and detection rates of advanced LIGO-in particular with the addition of more interferometers.

  12. The accretion flow in the ultra-compact binary ES Cet

    NASA Astrophysics Data System (ADS)

    Steeghs, D.

    Recently, three variable stars have been identified as likely accreting binary systems with ultra-short orbital periods. Optical and X-ray observations have revealed periodicities of 5-10 minutes, making them the closest binaries known as well as strong sources of gravitational wave emission. Such short-period accreting binaries form the cornerstone to our understanding of binary formation and evolution, in particular of the large double white dwarf population in our galaxy, a candidate progenitor population for Type Ia supernovae. We propose to obtain the first phase-resolved UV observations of the brightest of these three, ES Cet. With the FUSE observations, we will (i) determine the temperature of the primary and the composition of their donor stars, (ii) correlate the UV variability with other wavebands and determine if the periods are indeed orbital, (iii) look for dynamical signatures of direct-impact accretion that is expected to govern the survival rate of double white dwarfs. These UV observations are essential in order to unequivocally determine whether these are indeed the most compact binaries known.

  13. WIYN open cluster study. LX. Spectroscopic binary orbits in NGC 6819

    SciTech Connect

    Milliman, Katelyn E.; Mathieu, Robert D.; Gosnell, Natalie M.; Geller, Aaron M.; Meibom, Søren; Platais, Imants

    2014-08-01

    We present the current state of the WOCS radial-velocity (RV) survey for the rich open cluster NGC 6819 (2.5 Gyr) including 93 spectroscopic binary orbits with periods ranging from 1.5 to 8000 days. These results are the product of our ongoing RV survey of NGC 6819 using the Hydra Multi-Object Spectrograph on the WIYN 3.5 m telescope. We also include a detailed analysis of multiple prior sets of optical photometry for NGC 6819. Within a 1° field of view, our stellar sample includes the giant branch, the red clump, and blue straggler candidates, and extends to almost 2 mag below the main sequence (MS) turnoff. For each star observed in our survey we present all RV measurements, the average RV, and velocity variability information. Additionally, we discuss notable binaries from our sample, including eclipsing binaries (WOCS 23009, WOCS 24009, and WOCS 40007), stars noted in Kepler asteroseismology studies (WOCS 4008, WOCS 7009, and WOCS 8007), and potential descendants of past blue stragglers (WOCS 1006 and WOCS 6002). We find the incompleteness-corrected binary fraction for all MS binaries with periods less than 10{sup 4} days to be 22% ± 3% and a tidal circularization period of 6.2{sub −1.1}{sup +1.1} days for NGC 6819.

  14. BINARY QUASARS AT HIGH REDSHIFT. I. 24 NEW QUASAR PAIRS AT z {approx} 3-4

    SciTech Connect

    Hennawi, Joseph F.; Myers, Adam D.; Shen, Yue; Strauss, Michael A.; Djorgovski, S. G.; Glikman, Eilat; Mahabal, Ashish; Fan Xiaohui; Martin, Crystal L.; Richards, Gordon T.; Schneider, Donald P.; Shankar, Francesco

    2010-08-20

    The clustering of quasars on small scales yields fundamental constraints on models of quasar evolution and the buildup of supermassive black holes. This paper describes the first systematic survey to discover high-redshift binary quasars. Using color-selection and photometric redshift techniques, we searched 8142 deg{sup 2} of Sloan Digital Sky Survey imaging data for binary quasar candidates, and confirmed them with follow-up spectroscopy. Our sample of 27 high-redshift binaries (24 of them new discoveries) at redshifts 2.9 < z < 4.3 with proper transverse separations 10 kpc < R{sub perpendicular} < 650 kpc increases the number of such objects known by an order of magnitude. Eight members of this sample are very close pairs with R{sub perpendicular} < 100 kpc, and of these close systems four are at z>3.5. The completeness and efficiency of our well-defined selection algorithm are quantified using simulated photometry and we find that our sample is {approx}50% complete. Our companion paper uses this knowledge to make the first measurement of the small-scale clustering (R < 1 h {sup -1} Mpc comoving) of high-redshift quasars. High-redshift binaries constitute exponentially rare coincidences of two extreme (M {approx}> 10{sup 9} M {sub sun}) supermassive black holes. At z {approx} 4, there is about one close binary per 10 Gpc{sup 3}, thus these could be the highest sigma peaks, the analogs of superclusters, in the early universe.

  15. Outflows Driven by a Potential Proto-Brown Dwarf Binary System IRAS 16253-2429

    NASA Astrophysics Data System (ADS)

    Hsieh, Tien-Hao; Lai, Shih-Ping; Belloche, Arnaud; Wyrowski, Friedrich

    2015-08-01

    We have studied the molecular outflows driven by a potential proto-brown dwarf candidate IRAS 16253-2429 (hereafter IRAS 16253) with CO (2—1) using SMA and IRAM 30m telescope and CO (6—5) using APEX. Our SMA observations suggest that IRAS 16253 is hosting a binary system. The low mass of its envelope suggests that the central objects may eventually accrete only ~0.14 Msun of material (assuming the star formation efficiency is at most 0.3), which makes IRAS 16253 a potential proto brown dwarf binary system since the maximum mass of a brown dwarf is 0.08 Msun; one or two brown dwarfs may form depending on the current mass of the protostars and the future accretion process. The Position-Velocity diagrams of the outflows show sinusoidal structures which may be related to the outflow wiggling from the binary rotation. This allowed us to estimate the orbital period of the binary system. On the basis of Kepler's third law, we suggest that IRAS 16253 is very likely to contain at least one proto brown dwarf if the binary separation is less than ~0.5 arcsec. The large-scale outflows are further mapped with IRAM 30m telescope and APEX Champ+. We found that CO (6—5) traces high-excited gas around the precessing H2 jets and CO (2—1) likely probes the cold swept-up gas or entrained gas with cone-like structure.

  16. Accurate and fast 3D surface measurement with temporal-spatial binary encoding structured illumination.

    PubMed

    Zhu, Jiangping; Zhou, Pei; Su, Xianyu; You, Zhisheng

    2016-12-12

    Balancing the accuracy and speed for 3D surface measurement of object is crucial in many important applications. Binary encoding pattern utilizing the high-speed image switching rate of digital mirror device (DMD)-based projector could be used as the candidate for fast even high-speed 3D measurement, but current most schemes only enable the measurement speed, which limit their application scopes. In this paper, we present a binary encoding method and develop an experimental system aiming to solve such a situation. Our approach encodes one computer-generated standard 8 bit sinusoidal fringe pattern into multiple binary patterns (sequence) with designed temporal-spatial binary encoding tactics. The binary pattern sequence is then high-speed and in-focus projected onto the surface of tested object, and then captured by means of temporal-integration imaging to form one sinusoidal fringe image. Further the combination of phase-shifting technique and temporal phase unwrapping algorithm leads to fast and accurate 3D measurement. The systematic accuracy better than 0.08mm is achievable. The measurement results with mask and palm are given to confirm the feasibility.

  17. P/2013 P5 PANSTARRS --- a rubbing binary?

    NASA Astrophysics Data System (ADS)

    Hainaut, O.; Snodgrass, C.

    2014-07-01

    P/2013 P5 PANSTARRS (hereafter P5) was discovered [1] on a Main Belt orbit, with a cometary appearance, thereby joining the small but growing collection of objects with such characteristics, loosely called the Main Belt Comets. The dust-lifting process at play on these bodies is not known, although several hypotheses are considered. Furthermore, it is likely that different objects are associated with different processes. For instance, 133P [2,3] and 238P [4] were active for extended periods of time on consecutive passage through perihelion; traditional cometary activity, i.e. caused by the sublimation of volatile ice, is the most likely candidate. In other cases, e.g. (596) Scheila [5,6], P/2012 F5 [7,8] or P/2010 A2 [9-11], the morphology of the dust cloud was compatible with a short, impulsive dust release; they are interpreted as the result of an impact with a smaller body. Finally, in some cases, rotational disruption was proposed as the process causing the activity: a gentle centrifugal lift (proposed by Agarwal et al. [12] for A2) or a complete disruption for P/2013 R3 [13]. Other additional processes were proposed by Jewitt [14], but they do not apply in the case of P5. P5 displayed a dust pattern [15-17] that had not been observed before in other objects. The dust cloud appeared as a series of radial fans and streaks, including some extremely narrow ones. The straight streaks matched synchrones, i.e. loci of dust particles emitted at a given time, and spread radially by the radiation pressure acting differently over a broad range of particle sizes. The narrowness of these lines, especially as observed with HST [15], indicated that the emission episodes were very short. Through a Finson-Probstein [18] analysis, it was shown that the dust release started at least 8 months before the observations, and had a series of very short episodes of dust releases. Because of the location of P5 in the inner Main Belt, sublimation-driven activity is unlikely. Rotational

  18. A multiwavelength investigation of candidate millisecond pulsars in unassociated γ-ray sources

    NASA Astrophysics Data System (ADS)

    Salvetti, D.; Mignani, R. P.; De Luca, A.; Marelli, M.; Pallanca, C.; Breeveld, A. A.; Hüsemann, P.; Belfiore, A.; Becker, W.; Greiner, J.

    2017-09-01

    About one-third of the 3033 γ-ray sources in the Third Fermi-LAT Gamma-ray Source Catalogue (3FGL) are unidentified and do not have even a tentative association with a known object; hence, they are defined as unassociated. Among Galactic γ-ray sources, pulsars represent the largest class, with over 200 identifications to date. About one-third of them are millisecond pulsars (MSPs) in binary systems. Therefore, it is plausible that a sizeable fraction of the unassociated Galactic γ-ray sources belong to this class. We collected X-ray and optical observations of the fields of 12 unassociated Fermi sources that have been classified as likely MSPs according to statistical classification techniques. To find observational support for the proposed classification, we looked for periodic modulations of the X-ray and optical flux of these sources, which could be associated with the orbital period of an MSP in a tight binary system. Four of the observed sources were identified as binary MSPs, or proposed as high-confidence candidates, while this work was in progress. For these sources, we present the results of our follow-up investigations, whereas for the others we present possible evidence of new MSP identifications. In particular, we discuss the case of 3FGL J0744.1-2523 that we proposed as a possible binary MSP based upon the preliminary detection of a 0.115 d periodicity in the flux of its candidate optical counterpart. We also found very marginal evidence of periodicity in the candidate optical counterpart to 3FGL J0802.3-5610, at a period of 0.4159 d, which needs to be confirmed by further observations.

  19. Testing Models of Circum-Binary-AGN Accretion for PSO J334.2028+01.4075

    NASA Astrophysics Data System (ADS)

    Foord, Adi; Gultekin, Kayhan; Reynolds, Mark

    2017-08-01

    We present analysis of new Chandra data of PSO J334.2028+01.4075 (PSO J334 hereafter), a strong binary AGN candidate discovered by Liu et al. (2015) based on periodic variation of the optical flux. Recent radio coverage presented in Mooley et al. (2017) further supports that PSO J334 is a binary black hole system, as the quasar was found to be lobe-dominated with a twisted radio structure, possibly due to a precessing jet. With no prior X-ray coverage for PSO J334, our new 50 ksec Chandra observation allows for the unique opportunity to differentiate between a single or binary-AGN system, and if a binary, can characterize the mode of accretion. The two most basic sets of predictions via simulations of circum-binary accretion model are a “cavity”, where the inner region of the accretion disk is mostly empty and emission is truncated blueward of the wavelength associated with the temperature of the innermost ring, or “minidisks”, where there is substantial accretion onto one or both of the members of the binary, each with their own shock-heated thin-disk accretion system. We find the X-ray emission to be well-fit with a heavily absorbed power-law, incompatible with the cavity scenario. Further, we construct an SED of PSO J334 by combining radio through X-ray observations and compare it to standard QSO SEDs. We discuss the implications of the comparison between the SED of PSO J334 and that of a single AGN, and assess the likelihood of the binary model for PSO J334.

  20. Environmentally friendly lubricating oil candidate.

    PubMed

    Ozgülsün, A; Karaosmanoğlu, F

    1999-01-01

    Synthetic lubricating oils based on renewable sources, excluding petroleum, have a great importance among all of the lubricating oil alternatives that are included in the research field about clean and environmentally friendly lubricating oil technologies. One of the environmentally friendly lubricating oils is a vegetable oil-based product. In this study, the esterification product of oleic acid with a fraction of molasses fusel oil as a lubricating oil candidate was determined according to the American Society for Testing and Materials (ASTM) standard tests. The results indicate that the ester product can be used as an environmental friendly lubricating oil or lubricating oil additive.

  1. A Search for Isolated Stellar-Mass Black Hole Candidates Based on Pulsar Kinematics

    NASA Astrophysics Data System (ADS)

    Chmyreva, E.; Beskin, G.; Dyachenko, V.

    2017-06-01

    We propose searching for isolated stellar-mass black hole (BH) candidates based on the fact that more than 50% of radio pulsars have originated in binary systems, now disrupted, where the other component could have evolved into a BH prior to the second supernova event of the system, which caused its disruption. We selected isolated radio pulsars with known parallaxes and relatively small characteristic ages that fit our criteria and traced their trajectories back to their presumed birth locations. These locations were then analyzed for possible BH candidates based on positional, photometric, and spectral data available in the online catalogs. We use the example of 4 pulsars from our sample, J0139+5814, J0922+0638, J0358+5413, and J1935+1616, to demonstrate the proposed method, and present the first results: 22 candidates were selected for further analysis.

  2. 11 CFR 9032.2 - Candidate.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... FUND DEFINITIONS § 9032.2 Candidate. Candidate means an individual who seeks nomination for election to the office of President of the United States. An individual is considered to seek nomination for...

  3. Kepler Discovers Earth-size Planet Candidates

    NASA Image and Video Library

    NASA's Kepler mission has discovered its first Earth-size planet candidates and its first candidates in the habitable zone, a region where liquid water could exist on a planet's surface. Five of th...

  4. Four Republican Presidential Candidates Debate Educational Issues.

    ERIC Educational Resources Information Center

    Equity and Excellence, 1988

    1988-01-01

    Provides the transcript of a September 1987 debate on educational issues between Republican presidential candidates Jack Kemp and Pierre du Pont. Interspersed throughout the transcript are written responses to questions submitted to additional candidates Robert Dole and George Bush. (BJV)

  5. The Young Visual Binary Database

    NASA Astrophysics Data System (ADS)

    Prato, Lisa A.; Avilez, Ian; Allen, Thomas; Zoonematkermani, Saeid; Biddle, Lauren; Muzzio, Ryan; Wittal, Matthew; Schaefer, Gail; Simon, Michal

    2017-01-01

    We have obtained adaptive optics imaging and high-resolution H-band and in some cases K-band spectra of each component in close to 100 young multiple systems in the nearby star forming regions of Taurus, Ophiuchus, TW Hya, and Orion. The binary separations for the pairs in our sample range from 30 mas to 3 arcseconds. The imaging and most of our spectra were obtained with instruments behind adaptive optics systems in order to resolve even the closest companions. We are in the process of determining fundamental stellar and circumstellar properties, such as effective temperature, Vsin(i), veiling, and radial velocity, for each component in the entire sample. The beta version of our database includes systems in the Taurus region and provides plots, downloadable ascii spectra, and values of the stellar and circumstellar properties for both stars in each system. This resource is openly available to the community at http://jumar.lowell.edu/BinaryStars/. In this poster we describe initial results from our analysis of the survey data. Support for this research was provided in part by NSF award AST-1313399 and by NASA Keck KPDA funding.

  6. Interacting jets from binary protostars

    NASA Astrophysics Data System (ADS)

    Murphy, G. C.; Lery, T.; O'Sullivan, S.; Spicer, D.; Bacciotti, F.; Rosen, A.

    2008-02-01

    Aims: We investigate potential models that could explain why multiple proto-stellar systems predominantly show single jets. During their formation, stars most frequently produce energetic outflows and jets. However, binary jets have only been observed in a very small number of systems. Methods: We model numerically 3D binary jets for various outflow parameters. We also model the propagation of jets from a specific source, namely L1551 IRS 5, known to have two jets, using recent observations as constraints for simulations with a new MHD code. We examine their morphology and dynamics, and produce synthetic emission maps. Results: We find that the two jets interfere up to the stage where one of them is almost destroyed or engulfed into the second one. We are able to reproduce some of the observational features of L1551 such as the bending of the secondary jet. Conclusions: While the effects of orbital motion are negligible over the jets dynamical timeline, their interaction has significant impact on their morphology. If the jets are not strictly parallel, as in most observed cases, we show that the magnetic field can help the collimation and refocusing of both of the two jets.

  7. Close binary neutron star systems

    NASA Astrophysics Data System (ADS)

    Marronetti, Pedro

    1999-12-01

    We present a method to calculate solutions to the initial value problem in (3 + 1) general relativity corresponding to binary neutron-star systems (BNS) in irrotational quasi-equilibrium orbits. The initial value equations are solved using a conformally flat spatial metric tensor. The stellar fluid dynamics corresponds to that of systems with zero vorticity in the inertial reference frame. Irrotational systems like the ones analyzed in the present work are likely to resemble the final stages of the evolution of neutron-star binaries, thus providing insights on the inspiral process. The fluid velocity is derived from the gradient of a scalar potential. A numerical program was developed to solve the elliptic equations for the metric fields and the fluid velocity potential. We discuss the different numerical techniques employed to achieve high resolution across the stellar volume, as well as the methods used to find solutions to the Poisson-like equations with their corresponding boundary conditions. We present sequences of quasi-stable circular orbits which conserve baryonic mass. These sequences mimic the time evolution of the inspiral and are obtained without solving the complex evolution equations. They also provide sets of initial value data for future time evolution codes, which should be valid very close to the final merger. We evaluate the emission of gravitational radiation during the evolution through multipole expansions methods.

  8. 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.

  9. Method of all-optical frequency encoded decimal to binary and binary coded decimal, binary to gray, and gray to binary data conversion using semiconductor optical amplifiers

    NASA Astrophysics Data System (ADS)

    Garai, Sisir Kumar

    2011-07-01

    Conversion of optical data from decimal to binary format is very important in optical computing and optical signal processing. There are many binary code systems to represent decimal numbers, the most common being the binary coded decimal (BCD) and gray code system. There are a wide choice of BCD codes, one of which is a natural BCD having a weighted code of 8421, by means of which it is possible to represent a decimal number from 0 to 9 with a combination of 4bit binary digits. The reflected binary code, also known as the Gray code, is a binary numeral system where two successive values differ in only 1bit. The Gray code is very important in digital optical communication as it is used to prevent spurious output from optical switches as well as to facilitate error correction in digital communications in an optical domain. Here in this communication, the author proposes an all-optical frequency encoded method of ``:decimal to binary, BCD,'' ``binary to gray,'' and ``gray to binary'' data conversion using the high-speed switching actions of semiconductor optical amplifiers. To convert decimal numbers to a binary form, a frequency encoding technique is adopted to represent two binary bits, 0 and 1. The frequency encoding technique offers advantages over conventional encoding techniques in terms of less probability of bit errors and greater reliability. Here the author has exploited the polarization switch made of a semiconductor optical amplifier (SOA) and a property of nonlinear rotation of the state of polarization of the probe beam in SOA for frequency conversion to develop the method of frequency encoded data conversion.

  10. Coordinated observations of interacting peculiar red giant binaries, 2

    NASA Technical Reports Server (NTRS)

    Ake, T.

    1995-01-01

    IUE and H alpha observations continued on a two-year program to monitor the UV variability of three interacting peculiar red giant (PRG) binaries, HD 59643 (C6,s), HD 35155 (S3/2), and HR 1105 (S3.5/2.5). All of these systems were suspected to involve accretion of material from the PRG to a white-dwarf secondary, based mainly on previous IUE investigations. They were primary candidates from earlier surveys of PRG's to test the hypothesis that the Tc-poor PRG's are formed as a result of mass transfer from a secondary component rather than from internal thermal pulsing while on the asymptotic red giant branch.

  11. Teacher Candidate Dispositions: Perspectives of Professional Expectations

    ERIC Educational Resources Information Center

    Wake, Donna; Bunn, Gary

    2016-01-01

    This study describes a programmatic effort to examine dispositions perceptions of teacher candidates entering the profession. Study participants included 114 master's level teaching candidates in their first semester of a nontraditional teacher education program. Teacher candidates scored themselves on a department disposition rubric designed to…

  12. 11 CFR 100.154 - Candidate debates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 11 Federal Elections 1 2010-01-01 2010-01-01 false Candidate debates. 100.154 Section 100.154 Federal Elections FEDERAL ELECTION COMMISSION GENERAL SCOPE AND DEFINITIONS (2 U.S.C. 431) Exceptions to Expenditures § 100.154 Candidate debates. Funds used to defray costs incurred in staging candidate debates...

  13. 11 CFR 100.92 - Candidate debates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 11 Federal Elections 1 2010-01-01 2010-01-01 false Candidate debates. 100.92 Section 100.92 Federal Elections FEDERAL ELECTION COMMISSION GENERAL SCOPE AND DEFINITIONS (2 U.S.C. 431) Exceptions to Contributions § 100.92 Candidate debates. Funds provided to defray costs incurred in staging candidate...

  14. Teacher Candidate Dispositions: Perspectives of Professional Expectations

    ERIC Educational Resources Information Center

    Wake, Donna; Bunn, Gary

    2016-01-01

    This study describes a programmatic effort to examine dispositions perceptions of teacher candidates entering the profession. Study participants included 114 master's level teaching candidates in their first semester of a nontraditional teacher education program. Teacher candidates scored themselves on a department disposition rubric designed to…

  15. Planetary Candidates Observed by Kepler, III: Analysis of the First 16 Months of Data

    SciTech Connect

    Batalha, Natalie M.; Rowe, Jason F.; Bryson, Stephen T.; Barclay, Thomas; Burke, Christopher J.; Caldwell, Douglas A.; Christiansen, Jessie L.; Mullally, Fergal; Thompson, Susan E.; Brown, Timothy M.; Dupree, Andrea K.; /Harvard-Smithsonian Ctr. Astrophys. /UC, Santa Cruz

    2012-02-01

    New transiting planet candidates are identified in sixteen months (May 2009 - September 2010) of data from the Kepler spacecraft. Nearly five thousand periodic transit-like signals are vetted against astrophysical and instrumental false positives yielding 1091 viable new planet candidates, bringing the total count up to over 2,300. Improved vetting metrics are employed, contributing to higher catalog reliability. Most notable is the noise-weighted robust averaging of multiquarter photo-center offsets derived from difference image analysis which identifies likely background eclipsing binaries. Twenty-two months of photometry are used for the purpose of characterizing each of the new candidates. Ephemerides (transit epoch, T{sub 0}, and orbital period, P) are tabulated as well as the products of light curve modeling: reduced radius (R{sub P}/R{sub {star}}), reduced semi-major axis (d/R{sub {star}}), and impact parameter (b). The largest fractional increases are seen for the smallest planet candidates (197% for candidates smaller than 2R{sub {circle_plus}} compared to 52% for candidates larger than 2R{sub {circle_plus}}) and those at longer orbital periods (123% for candidates outside of 50 day orbits versus 85% for candidates inside of 50 day orbits). The gains are larger than expected from increasing the observing window from thirteen months (Quarter 1 - Quarter 5) to sixteen months (Quarter 1 - Quarter 6). This demonstrates the benefit of continued development of pipeline analysis software. The fraction of all host stars with multiple candidates has grown from 17% to 20%, and the paucity of short-period giant planets in multiple systems is still evident. The progression toward smaller planets at longer orbital periods with each new catalog release suggests that Earth-size planets in the Habitable Zone are forthcoming if, indeed, such planets are abundant.

  16. Speckle Imaging of Kepler Exo-planet Transit Candidate Stars

    NASA Astrophysics Data System (ADS)

    Howell, Steve B.; Horch, Elliott; Sherry, William

    2009-08-01

    The NASA Kepler mission was successfully launched on 6 March 2009 and will begin science operations near 1 May. At the present time, commissioning tests are being performed and all spacecraft and science instruments are nominal. Kepler's main science focus is to discover Earth-like exo-planets via photometric transit detection. ``Hot Jupiters" will be found by the hundreds (using current ground-based statistics) but Earth-sized planets (up to 2.5 Earth radii) will be more difficult, yet are the holy grail of the mission. To take the list of candidate transiting planets found by Kepler and move them to probable or certain exo-planet detections, a decision tree of false positive elimination will occur. While earth-sized exo-planets can not currently be confirmed from the ground, many of the false positive eliminations steps can be performed. This proposal aims to obtain high resolution speckle imaging to 1) finish the characterization of ~500 comparison sample stars in the Kepler field of view prior to any transit information as a sample to place planet host stars in context with and to 2) observe Kepler exo-planet transit candidates in order to eliminate the largest false positive contributor in any transit search - background eclipsing binary stars or faint companion stars.

  17. Optical spectroscopy of candidate Alpha Persei white dwarfs

    NASA Astrophysics Data System (ADS)

    Casewell, S. L.; Dobbie, P. D.; Geier, S.; Lodieu, N.; Hambly, N. C.

    2015-08-01

    As part of an investigation into the high-mass end of the initial mass-final mass relation we performed a search for new white dwarf members of the nearby (172.4 pc), young (80-90 Myr) α Persei open star cluster. The photometric and astrometric search using the United Kingdom InfraRed Telescope (UKIRT) Infrared Deep Sky Survey and SuperCOSMOS sky surveys discovered 14 new white dwarf candidates. We have obtained medium resolution optical spectra of the brightest 11 candidates using the William Herschel Telescope and confirmed that while 7 are DA white dwarfs, 3 are DB white dwarfs and 1 is an sdOB star, only three have cooling ages within the cluster age, and from their position on the initial mass-final mass relation, it is likely none are cluster members. This result is disappointing, as recent work on the cluster mass function suggests that there should be at least one white dwarf member, even at this young age. It may be that any white dwarf members of α Per are hidden within binary systems, as is the case in the Hyades cluster, however the lack of high-mass stars within the cluster also makes this seem unlikely. One alternative is that a significant level of detection incompleteness in the legacy optical image survey data at this Galactic latitude has caused some white dwarf members to be overlooked. If this is the case, Gaia will find them.

  18. SDSS-III MARVELS Planet Candidate RV Follow-up

    NASA Astrophysics Data System (ADS)

    Ge, Jian; Thomas, Neil; Ma, Bo; Li, Rui; SIthajan, Sirinrat

    2014-02-01

    Planetary systems, discovered by the radial velocity (RV) surveys, reveal strong correlations between the planet frequency and stellar properties, such as metallicity and mass, and a greater diversity in planets than found in the solar system. However, due to the sample sizes of extant surveys (~100 to a few hundreds of stars) and their heterogeneity, many key questions remained to be addressed: Do metal poor stars obey the same trends for planet occurrence as metal rich stars? What is the distribution of giant planets around intermediate- mass stars and binaries? Is the ``planet desert'' within 0.6 AU in the planet orbital distribution of intermediate-mass stars real? The MARVELS survey has produced the largest homogeneous RV measurements of 3300 V=7.6-12 FGK stars. The latest data pipeline effort at UF has been able to remove long term systematic errors suffered in the earlier data pipeline. 18 high confident giant planet candidates have been identified among newly processed data. We propose to follow up these giant planet candidates with the KPNO EXPERT instrument to confirm the detection and also characterize their orbits. The confirmed planets will be used to measure occurrence rates, distributions and multiplicity of giants planets around F,G,K stars with a broad range of mass (~0.6-2.5 M_⊙) and metallicity ([Fe/H]~-1.5-0.5). The well defined MARVELS survey cadence allows robust determinations of completeness limits for rigorously testing giant planet formation theories and constraining models.

  19. Fabricating binary optics: An overview of binary optics process technology

    NASA Technical Reports Server (NTRS)

    Stern, Margaret B.

    1993-01-01

    A review of binary optics processing technology is presented. Pattern replication techniques have been optimized to generate high-quality efficient microoptics in visible and infrared materials. High resolution optical photolithography and precision alignment is used to fabricate maximally efficient fused silica diffractive microlenses at lambda = 633 nm. The degradation in optical efficiency of four-phase-level fused silica microlenses resulting from an intentional 0.35 micron translational error has been systematically measured as a function of lens speed (F/2 - F/60). Novel processes necessary for high sag refractive IR microoptics arrays, including deep anisotropic Si-etching, planarization of deep topography and multilayer resist techniques, are described. Initial results are presented for monolithic integration of photonic and microoptic systems.

  20. A FIRST COMPARISON OF KEPLER PLANET CANDIDATES IN SINGLE AND MULTIPLE SYSTEMS

    SciTech Connect

    Latham, David W.; Quinn, Samuel N.; Carter, Joshua A.; Holman, Matthew J.; Rowe, Jason F.; Borucki, William J.; Bryson, Stephen T.; Howell, Steve B.; Batalha, Natalie M.; Brown, Timothy M.; Buchhave, Lars A.; Caldwell, Douglas A.; Christiansen, Jessie L.; Dunham, Edward W.; Fabrycky, Daniel C.; Ford, Eric B.; Gautier, Thomas N. III

    2011-05-10

    In this Letter, we present an overview of the rich population of systems with multiple candidate transiting planets found in the first four months of Kepler data. The census of multiples includes 115 targets that show two candidate planets, 45 with three, eight with four, and one each with five and six, for a total of 170 systems with 408 candidates. When compared to the 827 systems with only one candidate, the multiples account for 17% of the total number of systems, and one-third of all the planet candidates. We compare the characteristics of candidates found in multiples with those found in singles. False positives due to eclipsing binaries are much less common for the multiples, as expected. Singles and multiples are both dominated by planets smaller than Neptune; 69{sup +2}{sub -3}% for singles and 86{sup +2}{sub -5}% for multiples. This result, that systems with multiple transiting planets are less likely to include a transiting giant planet, suggests that close-in giant planets tend to disrupt the orbital inclinations of small planets in flat systems, or maybe even prevent the formation of such systems in the first place.

  1. Planetary Candidates Observed by Kepler IV: Planet Sample from Q1-Q8 (22 Months)

    NASA Astrophysics Data System (ADS)

    Burke, Christopher J.; Bryson, Stephen T.; Mullally, F.; Rowe, Jason F.; Christiansen, Jessie L.; Thompson, Susan E.; Coughlin, Jeffrey L.; Haas, Michael R.; Batalha, Natalie M.; Caldwell, Douglas A.; Jenkins, Jon M.; Still, Martin; Barclay, Thomas; Borucki, William J.; Chaplin, William J.; Ciardi, David R.; Clarke, Bruce D.; Cochran, William D.; Demory, Brice-Olivier; Esquerdo, Gilbert A.; Gautier, Thomas N., III; Gilliland, Ronald L.; Girouard, Forrest R.; Havel, Mathieu; Henze, Christopher E.; Howell, Steve B.; Huber, Daniel; Latham, David W.; Li, Jie; Morehead, Robert C.; Morton, Timothy D.; Pepper, Joshua; Quintana, Elisa; Ragozzine, Darin; Seader, Shawn E.; Shah, Yash; Shporer, Avi; Tenenbaum, Peter; Twicken, Joseph D.; Wolfgang, Angie

    2014-02-01

    We provide updates to the Kepler planet candidate sample based upon nearly two years of high-precision photometry (i.e., Q1-Q8). From an initial list of nearly 13,400 threshold crossing events, 480 new host stars are identified from their flux time series as consistent with hosting transiting planets. Potential transit signals are subjected to further analysis using the pixel-level data, which allows background eclipsing binaries to be identified through small image position shifts during transit. We also re-evaluate Kepler Objects of Interest (KOIs) 1-1609, which were identified early in the mission, using substantially more data to test for background false positives and to find additional multiple systems. Combining the new and previous KOI samples, we provide updated parameters for 2738 Kepler planet candidates distributed across 2017 host stars. From the combined Kepler planet candidates, 472 are new from the Q1-Q8 data examined in this study. The new Kepler planet candidates represent ~40% of the sample with R P ~ 1 R ⊕ and represent ~40% of the low equilibrium temperature (T eq < 300 K) sample. We review the known biases in the current sample of Kepler planet candidates relevant to evaluating planet population statistics with the current Kepler planet candidate sample.

  2. Fill-in binary loop pulse-torque quantizer

    NASA Technical Reports Server (NTRS)

    Lory, C. B.

    1975-01-01

    Fill-in binary (FIB) loop provides constant heating of torque generator, an advantage of binary current switching. At the same time, it avoids mode-related dead zone and data delay of binary, an advantage of ternary quantization.

  3. New systemic radial velocities of suspected RR Lyrae binary stars

    NASA Astrophysics Data System (ADS)

    Guggenberger, E.; Barnes, T. G.; Kolenberg, K.

    2016-05-01

    Among the tens of thousands of known RR Lyrae stars there are only a handful that show indications of possible binarity. The question why this is the case is still unsolved, and has recently sparked several studies dedicated to the search for additional RR Lyraes in binary systems. Such systems are particularly valuable because they might allow to constrain the stellar mass. Most of the recent studies, however, are based on photometry by finding a light time effect in the timings of maximum light. This approach is a very promising and successful one, but it has a major drawback: by itself, it cannot serve as a definite proof of binarity, because other phenomena such as the Blazhko effect or intrinsic period changes could lead to similar results. Spectroscopic radial velocity measurements, on the other hand, can serve as definite proof of binarity. We have therefore started a project to study spectroscopically RR Lyrae stars that are suspected to be binaries. We have obtained radial velocity (RV) curves with the 2.1m telescope at McDonald observatory. From these we derive systemic RVs which we will compare to previous measurements in order to find changes induced by orbital motions. We also construct templates of the RV curves that can facilitate future studies. We also observed the most promising RR Lyrae binary candidate, TU UMa, as no recent spectroscopic measurements were available. We present a densely covered pulsational RV curve, which will be used to test the predictions of the orbit models that are based on the O - C variations.

  4. The Evolution of Compact Binary Star Systems.

    PubMed

    Postnov, Konstantin A; Yungelson, Lev R

    2006-01-01

    We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Binary NSs and BHs are thought to be the primary astrophysical sources of gravitational waves (GWs) within the frequency band of ground-based detectors, while compact binaries of WDs are important sources of GWs at lower frequencies to be covered by space interferometers (LISA). Major uncertainties in the current understanding of properties of NSs and BHs most relevant to the GW studies are discussed, including the treatment of the natal kicks which compact stellar remnants acquire during the core collapse of massive stars and the common envelope phase of binary evolution. We discuss the coalescence rates of binary NSs and BHs and prospects for their detections, the formation and evolution of binary WDs and their observational manifestations. Special attention is given to AM CVn-stars - compact binaries in which the Roche lobe is filled by another WD or a low-mass partially degenerate helium-star, as these stars are thought to be the best LISA verification binary GW sources.

  5. Gravitational radiation, inspiraling binaries, and cosmology

    NASA Technical Reports Server (NTRS)

    Chernoff, David F.; Finn, Lee S.

    1993-01-01

    We show how to measure cosmological parameters using observations of inspiraling binary neutron star or black hole systems in one or more gravitational wave detectors. To illustrate, we focus on the case of fixed mass binary systems observed in a single Laser Interferometer Gravitational-wave Observatory (LIGO)-like detector. Using realistic detector noise estimates, we characterize the rate of detections as a function of a threshold SNR Rho(0), H0, and the binary 'chirp' mass. For Rho(0) = 8, H0 = 100 km/s/Mpc, and 1.4 solar mass neutron star binaries, the sample has a median redshift of 0.22. Under the same assumptions but independent of H0, a conservative rate density of coalescing binaries implies LIGO will observe about 50/yr binary inspiral events. The precision with which H0 and the deceleration parameter q0 may be determined depends on the number of observed inspirals. For fixed mass binary systems, about 100 observations with Rho(0) = 10 in the LIGO will give H0 to 10 percent in an Einstein-DeSitter cosmology, and 3000 will give q0 to 20 percent. For the conservative rate density of coalescing binaries, 100 detections with Rho(0) = 10 will require about 4 yrs.

  6. An Acidity Scale for Binary Oxides.

    ERIC Educational Resources Information Center

    Smith, Derek W.

    1987-01-01

    Discusses the classification of binary oxides as acidic, basic, or amphoteric. Demonstrates how a numerical scale for acidity/basicity of binary oxides can be constructed using thermochemical data for oxoacid salts. Presents the calculations derived from the data that provide the numeric scale values. (TW)

  7. The Evolution of Compact Binary Star Systems.

    PubMed

    Postnov, Konstantin A; Yungelson, Lev R

    2014-01-01

    We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Mergings of compact-star binaries are expected to be the most important sources for forthcoming gravitational-wave (GW) astronomy. In the first part of the review, we discuss observational manifestations of close binaries with NS and/or BH components and their merger rate, crucial points in the formation and evolution of compact stars in binary systems, including the treatment of the natal kicks, which NSs and BHs acquire during the core collapse of massive stars and the common envelope phase of binary evolution, which are most relevant to the merging rates of NS-NS, NS-BH and BH-BH binaries. The second part of the review is devoted mainly to the formation and evolution of binary WDs and their observational manifestations, including their role as progenitors of cosmologically-important thermonuclear SN Ia. We also consider AM CVn-stars, which are thought to be the best verification binary GW sources for future low-frequency GW space interferometers.

  8. Gravitational radiation, inspiraling binaries, and cosmology

    NASA Technical Reports Server (NTRS)

    Chernoff, David F.; Finn, Lee S.

    1993-01-01

    We show how to measure cosmological parameters using observations of inspiraling binary neutron star or black hole systems in one or more gravitational wave detectors. To illustrate, we focus on the case of fixed mass binary systems observed in a single Laser Interferometer Gravitational-wave Observatory (LIGO)-like detector. Using realistic detector noise estimates, we characterize the rate of detections as a function of a threshold SNR Rho(0), H0, and the binary 'chirp' mass. For Rho(0) = 8, H0 = 100 km/s/Mpc, and 1.4 solar mass neutron star binaries, the sample has a median redshift of 0.22. Under the same assumptions but independent of H0, a conservative rate density of coalescing binaries implies LIGO will observe about 50/yr binary inspiral events. The precision with which H0 and the deceleration parameter q0 may be determined depends on the number of observed inspirals. For fixed mass binary systems, about 100 observations with Rho(0) = 10 in the LIGO will give H0 to 10 percent in an Einstein-DeSitter cosmology, and 3000 will give q0 to 20 percent. For the conservative rate density of coalescing binaries, 100 detections with Rho(0) = 10 will require about 4 yrs.

  9. ECCENTRIC EVOLUTION OF SUPERMASSIVE BLACK HOLE BINARIES

    SciTech Connect

    Iwasawa, Masaki; An, Sangyong; Matsubayashi, Tatsushi; Funato, Yoko; Makino, Junichiro

    2011-04-10

    In recent numerical simulations, it has been found that the eccentricity of supermassive black hole (SMBH)-intermediate black hole (IMBH) binaries grows toward unity through interactions with the stellar background. This increase of eccentricity reduces the merging timescale of the binary through the gravitational radiation to a value well below the Hubble time. It also gives a theoretical explanation of the existence of eccentric binaries such as that in OJ287. In self-consistent N-body simulations, this increase of eccentricity is always observed. On the other hand, the result of the scattering experiment between SMBH binaries and field stars indicated that the eccentricity dose not change significantly. This discrepancy leaves the high eccentricity of the SMBH binaries in N-body simulations unexplained. Here, we present a stellar-dynamical mechanism that drives the increase of the eccentricity of an SMBH binary with a large mass ratio. There are two key processes involved. The first one is the Kozai mechanism under a non-axisymmetric potential, which effectively randomizes the angular momenta of surrounding stars. The other is the selective ejection of stars with prograde orbits. Through these two mechanisms, field stars extract the orbital angular momentum of the SMBH binary. Our proposed mechanism causes the increase in the eccentricity of most of SMBH binaries, resulting in the rapid merger through gravitational wave radiation. Our result has given a definite solution to the 'last-parsec problem'.

  10. An Acidity Scale for Binary Oxides.

    ERIC Educational Resources Information Center

    Smith, Derek W.

    1987-01-01

    Discusses the classification of binary oxides as acidic, basic, or amphoteric. Demonstrates how a numerical scale for acidity/basicity of binary oxides can be constructed using thermochemical data for oxoacid salts. Presents the calculations derived from the data that provide the numeric scale values. (TW)

  11. Evidence for a binary origin of a central compact object

    NASA Astrophysics Data System (ADS)

    Doroshenko, Victor; Pühlhofer, Gerd; Kavanagh, Patrick; Santangelo, Andrea; Suleimanov, Valery; Klochkov, Dmitry

    2016-05-01

    Central compact objects (CCOs) are thought to be young thermally emitting isolated neutron stars that were born during the preceding core-collapse supernova explosion. Here, we present evidence that at least in one case the CCO could have been formed within a binary system. We show that the highly reddened optical source IRAS 17287-3443, located 25 arcsec away from the CCO candidate XMMUJ173203.3-344518 and classified previously as a post asymptotic giant branch star, is indeed surrounded by a dust shell. This shell is heated by the central star to temperatures of ˜90 K and observed as extended infrared emission in 8-160 μm band. The dust temperature also increases in the vicinity of the CCO which implies that it likely resides within the shell. We estimate the total dust mass to be ˜0.4-1.5 M⊙ which significantly exceeds expected dust yields by normal stars and thus likely condensed from supernova ejecta. Taking into account that both the age of the supernova remnant and the duration of active mass-loss phase by the optical star are much shorter than the total lifetime of either object, the supernova and the onset of the active mass-loss phase of the companion have likely occurred approximately simultaneously. This is most easily explained if the evolution of both objects is interconnected. We conclude, therefore, that both stars were likely members of the same binary system disrupted by a supernova.

  12. Infrared Spectroscopy of Low-mass X-ray Binaries

    NASA Astrophysics Data System (ADS)

    Bandyopadhyay, R. M.; Shahbaz, T.; Charles, P. A.; Naylor, T.

    1999-04-01

    Using CGS4 on UKIRT, we have obtained 2.00--2.45 mu m infrared spectra of a number of low-mass X-ray binaries including Sco X-1, Sco X-2, and GX13+1. Sco X-1 shows emission lines only, supporting our previous conclusion that the spectral type of the evolved secondary must be earlier than G5. Emission lines are also seen in the spectrum of Sco X-2, confirming the identity of the IR counterpart. We report the detection of CO bands in GX13+1 and estimate the most likely spectral type of the secondary to be K5 sc iii. We also find P Cygni type profiles in the Brackett gamma lines of Sco X-1 and GX13+1, indicating the presence of high velocity outflows in these systems. We present spectra of candidate IR counterparts to several other elusive X-ray binaries. Finally, implications for the nature and classification of these systems are discussed.

  13. Near-Infrared Observations of Compact Binary Systems

    NASA Astrophysics Data System (ADS)

    Khargharia, Juthika

    Low mass X-ray binaries (LMXBs) are a subset of compact binary systems in which a main-sequence or slightly evolved star fills its Roche lobe and donates mass to a neutron star or a black hole (BH) via an accretion disk. Robust estimates of compact object masses in these systems are required to enhance our current understanding of the physics of compact object formation, accretion disks and jets. Compact object masses are typically determined at near-infrared (NIR) wavelengths when the system is in quiescence and the donor star is the dominant source of flux. Previous studies have assumed that any non-stellar contribution at these wavelengths is minimal. However, this assumption is rarely true. By performing NIR spectroscopy, we determined the fractional donor star contribution to the NIR flux and the compact object masses in two LMXBs: V404 Cyg and Cen X-4. In our analysis, it was assumed that the light curve morphology remains consistent throughout quiescence. It has now been shown in several systems that veiling measurements from non-stellar sources are meaningful only if acquired contemporaneously with light curve measurements. We accounted for this in the measurement of the BH mass in the LMXB, XTE J1118+480. LMXBs are also considered to be the most likely candidates responsible for the formation of milli-second pulsars (MSP). Here, I present the unique case of PSR J1903+0327 that challenges this currently accepted theory of MSP formation and is a potential candidate for testing General Relativity. Observations in the NIR come with their own set of challenges. NIR detector arrays used in these observations generally have high dark current and readout noise. In an effort to lower the read noise in NICFPS at APO, we present a study done on the Hawaii-1RG engineering grade chip that served as a test bed for reducing the read noise in NICFPS.

  14. Binary optics in the '90s

    NASA Astrophysics Data System (ADS)

    Gallagher, Neal C., Jr.

    1991-03-01

    The term binary optics was first employed to the best of my knowledge by Wilfred Veldkamp of MIT Lincoln Laboratory; although, these devices have been in existence prior to this of this term. Generally the term refers to optical components whose transmittance or reflectance occurs in binary steps. Usually fabricated by use of one or more binary masks. Other than simple diffraction gratings the earliest examples of binary optics would be computer generated holograms. Computer generated holograms, or more generally digital holograms, have been used since the middle 1960's, and like holography in general, digital holograms have found a few, but very few, useful applications. It has not been until thinking began to focus on more general diffractive optical concepts, and less on the principles of holography, that new applications began to materialize in the area of binary optics. Two exampies would be compact disc technology and the correction for chromatic aberation in refractive lenses.

  15. The Fraction of KBO Contact Binaries

    NASA Astrophysics Data System (ADS)

    Lacerda, Pedro

    2007-05-01

    We use Roche binary models to improve previous estimates of the contact binariy fraction within the Kuiper Belt object (KBO) population (Sheppard & Jewitt 2004). Our simulations can be used to determine the lightcurve range of Roche binaries at arbitrary observing geometries, and for different surface types. This allows us to better correct the apparent fraction for observing geometry effects. We find that at least 9% of KBOs are contact binaries. Such high incidence of KBOs contact binaries has important implications to binary formation and collisional evolution scenarios. PL is grateful to the Portuguese Fundacao para a Ciencia e a Tecnologia (BPD/SPFH/18828/2004) for financial support. This work was supported, in part, by a grant from the NSF to David C. Jewitt.

  16. Asteroid Systems: Binaries, Triples, and Pairs

    NASA Astrophysics Data System (ADS)

    Margot, J.-L.; Pravec, P.; Taylor, P.; Carry, B.; Jacobson, S.

    In the past decade, the number of known binary near-Earth asteroids has more than quadrupled and the number of known large main-belt asteroids with satellites has doubled. Half a dozen triple asteroids have been discovered, and the previously unrecognized populations of asteroid pairs and small main-belt binaries have been identified. The current observational evidence confirms that small (≲20 km) binaries form by rotational fission and establishes that the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect powers the spin-up process. A unifying paradigm based on rotational fission and post-fission dynamics can explain the formation of small binaries, triples, and pairs. Large (>~20 km) binaries with small satellites are most likely created during large collisions.

  17. Terrestrial Planet Formation in Binary Star Systems

    NASA Astrophysics Data System (ADS)

    Quintana, Elisa V.; Lissauer, Jack J.

    More than half of all main sequence stars, and an even larger fraction of pre-main sequence stars, reside in binary or multiple systems (Duquennoy and Mayor 1991; Mathieu et al. 2000). The presence of planet-forming material has been indirectly observed around one or both components of some young binaries, and (Mathieu et al. 2000) numerical simulations of the formation of binary stars suggest that disks form within these systems, as well (Bodenheimer et al. 2000). Terrestrial planets and the cores of giant planets are thought to form by an accretion process within a disk of dust and gas (Safronov 1969; Lissauer 1993), and therefore may be common in binary star systems. In this chapter, we present the results from numerical simulations of the final stages of terrestrial planet formation around one or both stars of a binary.

  18. Neutron Star Mass Distribution in Binaries

    NASA Astrophysics Data System (ADS)

    Lee, Chang-Hwan; Kim, Young-Min

    2016-05-01

    Massive neutron stars with ∼ 2Mʘ have been observed in neutron star-white dwarf binaries. On the other hand, well-measured neutron star masses in double-neutron-star binaries are still consistent with the limit of 1.5Mʘ. These observations raised questions on the neutron star equations of state and the neutron star binary evolution processes. In this presentation, a hypothesis of super-Eddington accretion and its implications are discussed. We argue that a 2Mʘ neutron star is an outcome of the super-Eddington accretion during the evolution of neutron star-white dwarf binary progenitors. We also suggest the possibility of the existence of new type of neutron star binary which consists of a typical neutron star and a massive compact companion (high-mass neutron star or black hole) with M ≥ 2Mʘ.

  19. Terrestrial Planet Formation in Binary Star Systems

    NASA Technical Reports Server (NTRS)

    Lissauer, J. J.; Quintana, E. V.; Adams, F. C.; Chambers, J. E.

    2006-01-01

    Most stars reside in binary/multiple star systems; however, previous models of planet formation have studied growth of bodies orbiting an isolated single star. Disk material has been observed around one or both components of various young close binary star systems. If planets form at the right places within such disks, they can remain dynamically stable for very long times. We have simulated the late stages of growth of terrestrial planets in both circumbinary disks around 'close' binary star systems with stellar separations ($a_B$) in the range 0.05 AU $\\le a_B \\le$ 0.4 AU and binary eccentricities in the range $0 \\le e \\le 0.8$ and circumstellar disks around individual stars with binary separations of tens of AU. The initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet growth within our Solar System and around individual stars in the Alpha Centauri system (Quintana et al. 2002, A.J., 576, 982); giant planets analogous to Jupiter and Saturn are included if their orbits are stable. The planetary systems formed around close binaries with stellar apastron distances less than or equal to 0.2 AU with small stellar eccentricities are very similar to those formed in the Sun-Jupiter-Saturn, whereas planetary systems formed around binaries with larger maximum separations tend to be sparser, with fewer planets, especially interior to 1 AU. Likewise, when the binary periastron exceeds 10 AU, terrestrial planets can form over essentially the entire range of orbits allowed for single stars with Jupiter-like planets, although fewer terrestrial planets tend to form within high eccentricity binary systems. As the binary periastron decreases, the radial extent of the terrestrial planet systems is reduced accordingly. When the periastron is 5 AU, the formation of Earth-like planets near 1 AU is compromised.

  20. Constraining Accreting Binary Populations in Normal Galaxies

    NASA Astrophysics Data System (ADS)

    Lehmer, Bret; Hornschemeier, A.; Basu-Zych, A.; Fragos, T.; Jenkins, L.; Kalogera, V.; Ptak, A.; Tzanavaris, P.; Zezas, A.

    2011-01-01

    X-ray emission from accreting binary systems (X-ray binaries) uniquely probe the binary phase of stellar evolution and the formation of compact objects such as neutron stars and black holes. A detailed understanding of X-ray binary systems is needed to provide physical insight into the formation and evolution of the stars involved, as well as the demographics of interesting binary remnants, such as millisecond pulsars and gravitational wave sources. Our program makes wide use of Chandra observations and complementary multiwavelength data sets (through, e.g., the Spitzer Infrared Nearby Galaxies Survey [SINGS] and the Great Observatories Origins Deep Survey [GOODS]), as well as super-computing facilities, to provide: (1) improved calibrations for correlations between X-ray binary emission and physical properties (e.g., star-formation rate and stellar mass) for galaxies in the local Universe; (2) new physical constraints on accreting binary processes (e.g., common-envelope phase and mass transfer) through the fitting of X-ray binary synthesis models to observed local galaxy X-ray binary luminosity functions; (3) observational and model constraints on the X-ray evolution of normal galaxies over the last 90% of cosmic history (since z 4) from the Chandra Deep Field surveys and accreting binary synthesis models; and (4) predictions for deeper observations from forthcoming generations of X-ray telesopes (e.g., IXO, WFXT, and Gen-X) to provide a science driver for these missions. In this talk, we highlight the details of our program and discuss recent results.

  1. Terrestrial Planet Formation in Binary Star Systems

    NASA Technical Reports Server (NTRS)

    Lissauer, J. J.; Quintana, E. V.; Adams, F. C.; Chambers, J. E.

    2006-01-01

    Most stars reside in binary/multiple star systems; however, previous models of planet formation have studied growth of bodies orbiting an isolated single star. Disk material has been observed around one or both components of various young close binary star systems. If planets form at the right places within such disks, they can remain dynamically stable for very long times. We have simulated the late stages of growth of terrestrial planets in both circumbinary disks around 'close' binary star systems with stellar separations ($a_B$) in the range 0.05 AU $\\le a_B \\le$ 0.4 AU and binary eccentricities in the range $0 \\le e \\le 0.8$ and circumstellar disks around individual stars with binary separations of tens of AU. The initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet growth within our Solar System and around individual stars in the Alpha Centauri system (Quintana et al. 2002, A.J., 576, 982); giant planets analogous to Jupiter and Saturn are included if their orbits are stable. The planetary systems formed around close binaries with stellar apastron distances less than or equal to 0.2 AU with small stellar eccentricities are very similar to those formed in the Sun-Jupiter-Saturn, whereas planetary systems formed around binaries with larger maximum separations tend to be sparser, with fewer planets, especially interior to 1 AU. Likewise, when the binary periastron exceeds 10 AU, terrestrial planets can form over essentially the entire range of orbits allowed for single stars with Jupiter-like planets, although fewer terrestrial planets tend to form within high eccentricity binary systems. As the binary periastron decreases, the radial extent of the terrestrial planet systems is reduced accordingly. When the periastron is 5 AU, the formation of Earth-like planets near 1 AU is compromised.

  2. SN candidate in NGC 3106

    NASA Astrophysics Data System (ADS)

    Drake, A. J.; Djorgovski, S. G.; Mahabal, A. A.; Graham, M. J.; Williams, R.; Catelan, M.; Beshore, E. C.; Larson, S. M.; Gibbs, A.; Christensen, E.

    2009-06-01

    We report the discovery of a SN candidate found by the Catalina Real-time Transient Survey (CRTS) in NGC 3106.

    IDDateRADecMagMag hostz host
    CSS090625:100407+311229 2009-06-25 UT 04:03:46 10:04:06.78 31:12:29.0 16.1 12.7 0.021
    For finding charts, discovery images, lightcurves, etc., please see: http://voeventnet.cacr.caltech.edu/feeds/ATEL/CRTS.

  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. White Dwarfs in Astrometric Binaries?

    NASA Astrophysics Data System (ADS)

    Oliversen, N. A.; Evans, N. R.; Feibelman, W. A.; Kamper, K. W.

    1993-12-01

    Lippincott (1978, Space Sci Rev, 22, 153) compiled a list of astrometric binaries with unseen companions typically within 20 pc of the sun. Red companions have been observed in a number of these systems (e.g. McCarthy, D. W. 1983, IAU Coll. # 76, p. 107). Unseen, low mass companions could also be white dwarfs. We have obtained IUE observations of stars on the list which have primaries with spectral types M1 or earlier (white dwarf companions of cooler primaries could be detected from the ground), and are brighter than 10 mag, which do not have known red companions. Preliminary reductions (comparison with standard stars of appropriate spectral types) indicate that there are no white dwarfs in the sample. Further processing is being done to determine limits on possible white dwarf temperatures.

  6. 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

  7. Morphological Moments of Binary Images

    NASA Astrophysics Data System (ADS)

    Lomov, N.; Sidyakin, S.

    2017-05-01

    The concept of morphological moments of binary images is introduced. Morphological moments can be used as a shape descriptor combining an integral width description of an object with a description of its spatial distribution. The relationship between the proposed descriptor and the disc cover of the figure is discussed and an exact analytical method for descriptor calculation is proposed within the continuous morphology framework. The approach is based on the approximation of the shape by a polygonal figure and the extraction of its medial representation in the form of the continuous skeleton and the radial function. The proposed method for calculation of morphological moments achieves high accuracy and it is computationally efficient. Experimentations have been conducted. Obtained results indicate that the morphological moments are a more informative and rich shape descriptor than the area of the disc cover. Application of morphological moments to the font recognition task improves the recognition quality.

  8. Interdiffusion in binary ionic mixtures

    SciTech Connect

    Boercker, D.B.; Pollock, E.L.

    1987-08-15

    In this paper we present molecular-dynamics and kinetic-theory calculations of the interdiffusion coefficients in dense binary ionic mixtures for conditions appropriate to both astrophysical and inertial-confinement fusion (ICF) plasmas. The diffusion coefficient is the product of a Green-Kubo integral and a thermodynamic prefactor. The molecular-dynamics and kinetic-theory estimates of the Green-Kubo portion agree very well, and it is found that this integral may also be well represented by the usual concentration-weighted sum of self-diffusion coefficients. In addition, the low-density limit of the thermodynamic prefactor is shown to represent an enhancement of the diffusion by the ''ambipolar'' electric field.

  9. Advising Doctorate Candidates and Candidates' Views during the Dissertation Process

    ERIC Educational Resources Information Center

    Hilliard, Ann T.

    2013-01-01

    In order to provide candidates with effective advisement, it is important for the advisor to continue to practice positive professional relationships and provide relevant academic support to candidates. The advisor should work closely with other faculty members and need to listen to the voices of candidates to ensure candidates' success. What…

  10. Stability of multiplanet systems in binaries

    NASA Astrophysics Data System (ADS)

    Marzari, F.; Gallina, G.

    2016-10-01

    Context. When exploring the stability of multiplanet systems in binaries, two parameters are normally exploited: the critical semimajor axis ac computed by Holman & Wiegert (1999, AJ, 117, 621) within which planets are stable against the binary perturbations, and the Hill stability limit Δ determining the minimum separation beyond which two planets will avoid mutual close encounters. Both these parameters are derived in different contexts, i.e. Δ is usually adopted for computing the stability limit of two planets around a single star while ac is computed for a single planet in a binary system. Aims: Our aim is to test whether these two parameters can be safely applied in multiplanet systems in binaries or if their predictions fail for particular binary orbital configurations. Methods: We have used the frequency map analysis (FMA) to measure the diffusion of orbits in the phase space as an indicator of chaotic behaviour. Results: First we revisited the reliability of the empirical formula computing ac in the case of single planets in binaries and we find that, in some cases, it underestimates by 10-20% the real outer limit of stability and it does not account for planets trapped in resonance with the companion star well beyond ac. For two-planet systems, the value of Δ is close to that computed for planets around single stars, but the level of chaoticity close to it substantially increases for smaller semimajor axes and higher eccentricities of the binary orbit. In these configurations ac also begins to be unreliable and non-linear secular resonances with the stellar companion lead to chaotic behaviour well within ac, even for single planet systems. For two planet systems, the superposition of mean motion resonances, either mutual or with the binary companion, and non-linear secular resonances may lead to chaotic behaviour in all cases. We have developed a parametric semi-empirical formula determining the minimum value of the binary semimajor axis, for a given

  11. Application of SKIPSM to binary correlation

    NASA Astrophysics Data System (ADS)

    Waltz, Frederick M.

    1995-10-01

    Binary correlation is often used for finding specified patterns in complex binary images, especially in industrial inspection tasks such as locating the corners and/or edges of parts. As such, it is an important tool for higher-level 'intelligent' vision systems. Binary correlation is a form of binary template matching which provides a numerical value corresponding to 'degree of fit' rather than an 'all or nothing' answer. Commercially available high-speed image processing systems can readily perform this operation using linear convolvers, but such convolvers are very expensive except for very small kernels. Furthermore, linear convolvers constitute a gross 'overkill' for the relatively simple operation of binary correlation. Specialized binary convolvers have been built, but are not part of standard commercial systems. This paper describes a new pipelined implementation of binary correlation which fits into the standard SKIPSM (separated-kernel image processing using finite state machines) architecture and which can be built using standard ICs costing less than $500 total. The same approach can also be implemented in software, providing an order-of-magnitude increase in speed at no extra cost. Furthermore, this same SKIPSM architecture is highly versatile and programmable, allowing it to be software-reconfigured to perform hundreds of other pipelined image processing operations.

  12. Terrestrial Planet Formation in Binary Star Systems

    NASA Technical Reports Server (NTRS)

    Lissauer, Jack J.; Quintana, Elisa V.; Chambers, John; Duncan, Martin J.; Adams, Fred

    2003-01-01

    Most stars reside in multiple star systems; however, virtually all models of planetary growth have assumed an isolated single star. Numerical simulations of the collapse of molecular cloud cores to form binary stars suggest that disks will form within such systems. Observations indirectly suggest disk material around one or both components within young binary star systems. If planets form at the right places within such circumstellar disks, they can remain in stable orbits within the binary star systems for eons. We are simulating the late stages of growth of terrestrial planets within binary star systems, using a new, ultrafast, symplectic integrator that we have developed for this purpose. We show that the late stages of terrestrial planet formation can indeed take place in a wide variety of binary systems and we have begun to delineate the range of parameter space for which this statement is true. Results of our initial simulations of planetary growth around each star in the alpha Centauri system and other 'wide' binary systems, as well as around both stars in very close binary systems, will be presented.

  13. PERIODIC SIGNALS IN BINARY MICROLENSING EVENTS

    SciTech Connect

    Guo, Xinyi; Stefano, Rosanne Di; Esin, Ann; Taylor, Jeffrey

    2015-08-20

    Gravitational microlensing events are powerful tools for the study of stellar populations. In particular, they can be used to discover and study a variety of binary systems. A large number of binary lenses have already been found through microlensing surveys and a few of these systems show strong evidence of orbital motion on the timescale of the lensing event. We expect that more binary lenses of this kind will be detected in the future. For binaries whose orbital period is comparable to the event duration, the orbital motion can cause the lensing signal to deviate drastically from that of a static binary lens. The most striking property of such light curves is the presence of quasi-periodic features, which are produced as the source traverses the same regions in the rotating lens plane. These repeating features contain information about the orbital period of the lens. If this period can be extracted, then much can be learned about the lensing system even without performing time-consuming, detailed light-curve modeling. However, the relative transverse motion between the source and the lens significantly complicates the problem of period extraction. To resolve this difficulty, we present a modification of the standard Lomb–Scargle periodogram analysis. We test our method for four representative binary lens systems and demonstrate its efficiency in correctly extracting binary orbital periods.

  14. Formation of wide binaries by turbulent fragmentation

    NASA Astrophysics Data System (ADS)

    Lee, Jeong-Eun; Lee, Seokho; Dunham, Michael M.; Tatematsu, Ken'ichi; Choi, Minho; Bergin, Edwin A.; Evans, Neal J.

    2017-08-01

    Understanding the formation of wide-binary systems of very low-mass stars (M ≤ 0.1 solar masses, M⊙) is challenging 1,2,3 . The most obvious route is through widely separated low-mass collapsing fragments produced by turbulent fragmentation of a molecular core4,5. However, close binaries or multiples from disk fragmentation can also evolve to wide binaries over a few initial crossing times of the stellar cluster through tidal evolution6. Finding an isolated low-mass wide-binary system in the earliest stage of formation, before tidal evolution could occur, would prove that turbulent fragmentation is a viable mechanism for (very) low-mass wide binaries. Here we report high-resolution ALMA observations of a known wide-separation protostellar binary, showing that each component has a circumstellar disk. The system is too young7 to have evolved from a close binary, and the disk axes are misaligned, providing strong support for the turbulent fragmentation model. Masses of both stars are derived from the Keplerian rotation of the disks; both are very low-mass stars.

  15. Planet Formation in Binary Star Systems

    NASA Astrophysics Data System (ADS)

    Martin, Rebecca

    About half of observed exoplanets are estimated to be in binary systems. Understanding planet formation and evolution in binaries is therefore essential for explaining observed exoplanet properties. Recently, we discovered that a highly misaligned circumstellar disk in a binary system can undergo global Kozai-Lidov (KL) oscillations of the disk inclination and eccentricity. These oscillations likely have a significant impact on the formation and orbital evolution of planets in binary star systems. Planet formation by core accretion cannot operate during KL oscillations of the disk. First, we propose to consider the process of disk mass transfer between the binary members. Secondly, we will investigate the possibility of planet formation by disk fragmentation. Disk self gravity can weaken or suppress the oscillations during the early disk evolution when the disk mass is relatively high for a narrow range of parameters. Thirdly, we will investigate the evolution of a planet whose orbit is initially aligned with respect to the disk, but misaligned with respect to the orbit of the binary. We will study how these processes relate to observations of star-spin and planet orbit misalignment and to observations of planets that appear to be undergoing KL oscillations. Finally, we will analyze the evolution of misaligned multi-planet systems. This theoretical work will involve a combination of analytic and numerical techniques. The aim of this research is to shed some light on the formation of planets in binary star systems and to contribute to NASA's goal of understanding of the origins of exoplanetary systems.

  16. Radio detections of the brightening black hole candidate Swift J1753.5-0127 made with the Arcminute Microkelvin Imager Large Array

    NASA Astrophysics Data System (ADS)

    Bright, J.; Staley, T.; Fender, R.; Motta, S.; Cantwell, T.

    2017-02-01

    We report the first new radio detections of the re-brightening black hole X-ray binary candidate Swift J1753.5-0127, obtained on 15 February and 19 February 2017 with the Arcminute Microkelvin Imager Large Array (AMI-LA) interferometer.

  17. Interrupted Binary Mass Transfer in Star Clusters

    NASA Astrophysics Data System (ADS)

    Leigh, Nathan W. C.; Geller, Aaron M.; Toonen, Silvia

    2016-02-01

    Binary mass transfer (MT) is at the forefront of some of the most exciting puzzles of modern astrophysics, including SNe Ia, gamma-ray bursts, and the formation of most observed exotic stellar populations. Typically, the evolution is assumed to proceed in isolation, even in dense stellar environments such as star clusters. In this paper, we test the validity of this assumption via the analysis of a large grid of binary evolution models simulated with the SeBa code. For every binary, we calculate analytically the mean time until another single or binary star comes within the mean separation of the mass-transferring binary, and compare this timescale to the mean time for stable MT to occur. We then derive the probability for each respective binary to experience a direct dynamical interruption. The resulting probability distribution can be integrated to give an estimate for the fraction of binaries undergoing MT that are expected to be disrupted as a function of the host cluster properties. We find that for lower-mass clusters (≲ {10}4 {M}⊙ ), on the order of a few to a few tens of percent of binaries undergoing MT are expected to be interrupted by an interloping single, or more often binary, star, over the course of the cluster lifetime, whereas in more massive globular clusters we expect \\ll 1% to be interrupted. Furthermore, using numerical scattering experiments performed with the FEWBODY code, we show that the probability of interruption increases if perturbative fly-bys are considered as well, by a factor ˜2.

  18. Embedded binaries and their dense cores

    NASA Astrophysics Data System (ADS)

    Sadavoy, Sarah I.; Stahler, Steven W.

    2017-08-01

    We explore the relationship between young, embedded binaries and their parent cores, using observations within the Perseus Molecular Cloud. We combine recently published Very Large Array observations of young stars with core properties obtained from Submillimetre Common-User Bolometer Array 2 observations at 850 μm. Most embedded binary systems are found towards the centres of their parent cores, although several systems have components closer to the core edge. Wide binaries, defined as those systems with physical separations greater than 500 au, show a tendency to be aligned with the long axes of their parent cores, whereas tight binaries show no preferred orientation. We test a number of simple, evolutionary models to account for the observed populations of Class 0 and I sources, both single and binary. In the model that best explains the observations, all stars form initially as wide binaries. These binaries either break up into separate stars or else shrink into tighter orbits. Under the assumption that both stars remain embedded following binary break-up, we find a total star formation rate of 168 Myr-1. Alternatively, one star may be ejected from the dense core due to binary break-up. This latter assumption results in a star formation rate of 247 Myr-1. Both production rates are in satisfactory agreement with current estimates from other studies of Perseus. Future observations should be able to distinguish between these two possibilities. If our model continues to provide a good fit to other star-forming regions, then the mass fraction of dense cores that becomes stars is double what is currently believed.

  19. Photometric Survey for Asynchronous Binary Asteroids

    NASA Astrophysics Data System (ADS)

    Pravec, P.

    2005-05-01

    Asynchronous binary asteroids have been found to be abundant among fast- spinning near-Earth asteroids (NEAs) smaller than 2 km in diameter; Pravec et al. (2005, Icarus, submitted) derived that 15 +/- 4 % of NEAs in the size range 0.3 to 2 km are binary with the secondary-to-primary mean diameter ratio >=0.18. The early re-sults from the surveys of the Vesta family and the Hungaria group (Ryan et al., 2004, Planet. Space Sci. 42, 1093; 2004, Bull. Amer. Astron. Society 36, 1181; Warner et al., 2005, IAU Circ. 8511) suggest that the popula-tion extends beyond the region of terrestrial planets, but with characteristics shifted to larger sizes and longer periods; the four known binaries in the Vesta family/Hungaria group are 3 to 6 km large and they have primary rotation periods in a range of 3 to ~4 h, i.e., on the tail of the distribution of primary rotation periods of NEAs. The comparison suggests that formation and evolution mechanisms of asynchronous NEA and main-belt binaries may be similar and are related to their fast spins and rubble-pile structure. None of the current theories of their formation of evolution, however, explains the observed properties of both NEA and main- belt asynchronous bina-ries in full. We have established a collaborative observational program, called "Photometric Survey for Asynchro-nous Binary Asteroids" to discover and describe asynchronous binaries over a range of heliocentric distances from NEAs through Mars-crossers to inner main-belt asteroids. One new binary Amor asteroid, 2005 AB has been found during the first few months of the survey operation (Reddy et al., 2005, IAU Circ. 8483), and we have obtained follow-up data for two other binary systems. I outline the motivations, the technique, and the strategy of the Survey.

  20. A PSF-based approach to Kepler/K2 data - II. Exoplanet candidates in Praesepe (M 44)

    NASA Astrophysics Data System (ADS)

    Libralato, M.; Nardiello, D.; Bedin, L. R.; Borsato, L.; Granata, V.; Malavolta, L.; Piotto, G.; Ochner, P.; Cunial, A.; Nascimbeni, V.

    2016-12-01

    In this work, we keep pushing K2 data to a high photometric precision, close to that of the Kepler main mission, using a point-spread function (PSF)-based, neighbour-subtraction technique, which also overcome the dilution effects in crowded environments. We analyse the open cluster M 44 (NGC 2632), observed during the K2 Campaign 5, and extract light curves of stars imaged on module 14, where most of the cluster lies. We present two candidate exoplanets hosted by cluster members and five by field stars. As a by-product of our investigation, we find 1680 eclipsing binaries and variable stars, 1071 of which are new discoveries. Among them, we report the presence of a heartbeat binary star. Together with this work, we release to the community a catalogue with the variable stars and the candidate exoplanets found, as well as all our raw and detrended light curves.

  1. Dynamical mass transfer in cataclysmic binaries

    NASA Technical Reports Server (NTRS)

    Melia, Fulvio; Lamb, D. Q.

    1987-01-01

    When a binary comes into contact and mass transfer begins, orbital angular momentum is stored in the accretion disk until the disk couples tidally to the binary system. Taam and McDermott (1987) have suggested that this leads to unstable dynamical mass transfer in many cataclysmic variables in which mass transfer would otherwise be stable, and that it explains the gap between 2 and 3 h in the orbital period distribution of these systems. Here the consequences of this hypothesis for the evolution of cataclysmic binaries are explored. It is found that systems coming into contact longward of the period gap undergo one or more episodes of dynamical mass transfer.

  2. Gravitational waves from neutron star binaries

    NASA Astrophysics Data System (ADS)

    Lee, Chang-Hwan

    With H. A. Bethe, G. E. Brown worked on the merger rate of neutron star binaries for the gravitational wave detection. Their prediction has to be modified significantly due to the observations of 2M⊙ neutron stars and the detection of gravitational waves. There still, however, remains a possibility that neutron star-low mass black hole binaries are significant sources of gravitational waves for the ground-based detectors. In this paper, I review the evolution of neutron star binaries with super-Eddington accretion and discuss the future prospect.

  3. Proposed experiment to test fundamentally binary theories

    NASA Astrophysics Data System (ADS)

    Kleinmann, Matthias; Vértesi, Tamás; Cabello, Adán

    2017-09-01

    Fundamentally binary theories are nonsignaling theories in which measurements of many outcomes are constructed by selecting from binary measurements. They constitute a sensible alternative to quantum theory and have never been directly falsified by any experiment. Here we show that fundamentally binary theories are experimentally testable with current technology. For that, we identify a feasible Bell-type experiment on pairs of entangled qutrits. In addition, we prove that, for any n , quantum n -ary correlations are not fundamentally (n -1 ) -ary. For that, we introduce a family of inequalities that hold for fundamentally (n -1 ) -ary theories but are violated by quantum n -ary correlations.

  4. Calibration Binaries Observed at the SOR

    DTIC Science & Technology

    2012-09-01

    Kirtland AFB, NM 87117-5776 ABSTRACT In reviewing observations of binary stars taken with adaptive optics on the 3.5 m Starfire Optical Range telescope ...observations of 62 binaries from these two lists were obtained with Adaptive Optics (AO) on the 3.5 m telescope at the Starfire Optical Range (SOR), where all...adaptive optics on the 3.5 m Starfire Optical Range telescope over the past two years, a quarter of these calibration binaries, taken from two Excel

  5. Variance in binary stellar population synthesis

    NASA Astrophysics Data System (ADS)

    Breivik, Katelyn; Larson, Shane L.

    2016-03-01

    In the years preceding LISA, Milky Way compact binary population simulations can be used to inform the science capabilities of the mission. Galactic population simulation efforts generally focus on high fidelity models that require extensive computational power to produce a single simulated population for each model. Each simulated population represents an incomplete sample of the functions governing compact binary evolution, thus introducing variance from one simulation to another. We present a rapid Monte Carlo population simulation technique that can simulate thousands of populations in less than a week, thus allowing a full exploration of the variance associated with a binary stellar evolution model.

  6. 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

  7. 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

  8. RESOLVED COMPANIONS OF CEPHEIDS: TESTING THE CANDIDATES WITH X-RAY OBSERVATIONS

    SciTech Connect

    Evans, Nancy Remage; Pillitteri, Ignazio; Wolk, Scott; Karovska, Margarita; Tingle, Evan; Guinan, Edward; Engle, Scott; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D. E-mail: heb11@psu.edu

    2016-04-15

    We have made XMM-Newton observations of 14 Galactic Cepheids that have candidate resolved (≥5″) companion stars based on our earlier HST Wide Field Camera 3 (WFC3) imaging survey. Main-sequence stars that are young enough to be physical companions of Cepheids are expected to be strong X-ray producers in contrast to field stars. XMM-Newton exposures were set to detect essentially all companions hotter than spectral type M0 (corresponding to 0.5 M{sub ⊙}). The large majority of our candidate companions were not detected in X-rays, and hence are not confirmed as young companions. One resolved candidate (S Nor #4) was unambiguously detected, but the Cepheid is a member of a populous cluster. For this reason, it is likely that S Nor #4 is a cluster member rather than a gravitationally bound companion. Two further Cepheids (S Mus and R Cru) have X-ray emission that might be produced by either the Cepheid or the candidate resolved companion. A subsequent Chandra observation of S Mus shows that the X-rays are at the location of the Cepheid/spectroscopic binary. R Cru and also V659 Cen (also X-ray bright) have possible companions closer than 5″ (the limit for this study) which are the likely sources of X-rays. One final X-ray detection (V473 Lyr) has no known optical companion, so the prime suspect is the Cepheid itself. It is a unique Cepheid with a variable amplitude. The 14 stars that we observed with XMM constitute 36% of the 39 Cepheids found to have candidate companions in our HST/WFC3 optical survey. No young probable binary companions were found with separations of ≥5″ or 4000 au.

  9. Resolved Companions of Cepheids: Testing the Candidates with X-Ray Observations

    NASA Astrophysics Data System (ADS)

    Evans, Nancy Remage; Pillitteri, Ignazio; Wolk, Scott; Karovska, Margarita; Tingle, Evan; Guinan, Edward; Engle, Scott; Bond, Howard E.; Schaefer, Gail H.; Mason, Brian D.

    2016-04-01

    We have made XMM-Newton observations of 14 Galactic Cepheids that have candidate resolved (≥5″) companion stars based on our earlier HST Wide Field Camera 3 (WFC3) imaging survey. Main-sequence stars that are young enough to be physical companions of Cepheids are expected to be strong X-ray producers in contrast to field stars. XMM-Newton exposures were set to detect essentially all companions hotter than spectral type M0 (corresponding to 0.5 M⊙). The large majority of our candidate companions were not detected in X-rays, and hence are not confirmed as young companions. One resolved candidate (S Nor #4) was unambiguously detected, but the Cepheid is a member of a populous cluster. For this reason, it is likely that S Nor #4 is a cluster member rather than a gravitationally bound companion. Two further Cepheids (S Mus and R Cru) have X-ray emission that might be produced by either the Cepheid or the candidate resolved companion. A subsequent Chandra observation of S Mus shows that the X-rays are at the location of the Cepheid/spectroscopic binary. R Cru and also V659 Cen (also X-ray bright) have possible companions closer than 5″ (the limit for this study) which are the likely sources of X-rays. One final X-ray detection (V473 Lyr) has no known optical companion, so the prime suspect is the Cepheid itself. It is a unique Cepheid with a variable amplitude. The 14 stars that we observed with XMM constitute 36% of the 39 Cepheids found to have candidate companions in our HST/WFC3 optical survey. No young probable binary companions were found with separations of ≥5″ or 4000 au. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and the USA (NASA).

  10. SNPing away at candidate genes.

    PubMed

    Suchard, M A; Bailey, J N; Elashoff, D A; Sinsheimer, J S

    2001-01-01

    We develop regression methodology to identify subsets of single nucleotide polymorphisms (SNPs) within candidate genes related to quantitative traits and apply our methods to the simulated Genetic Analysis Workshop (GAW) 12 data set. In the data set we find 694 SNP loci with minimum allele frequencies of at least 0.01. We assume an additive casual model between these SNPs and all five quantitative traits. After initial screening using one-way analysis of variance, we employ a computationally efficient, simulated annealing algorithm to select among all possible subsets of SNP loci, using a generalization of Mallows' Cp as our optimality criterion. The simple transition kernel we develop evaluates new subsets in O(1), by requiring just three arithmetic operations to calculate the proposed RSS based on the Gauss-Jordan pivot. We identify an SNP loci located at 6-5782 related to traits 2 and 3 and several sites on gene 2 related to trait 5 using a subsample of 1,000 individuals and the full data set (n = 8,250) for comparison.

  11. 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

  12. Instabilities in Interacting Binary Stars

    NASA Astrophysics Data System (ADS)

    Andronov, I. L.; Andrych, K. D.; Antoniuk, K. A.; Baklanov, A. V.; Beringer, P.; Breus, V. V.; Burwitz, V.; Chinarova, L. L.; Chochol, D.; Cook, L. M.; Cook, M.; Dubovský, P.; Godlowski, W.; Hegedüs, T.; Hoňková, K.; Hric, L.; Jeon, Y.-B.; Juryšek, J.; Kim, C.-H.; Kim, Y.; Kim, Y.-H.; Kolesnikov, S. V.; Kudashkina, L. S.; Kusakin, A. V.; Marsakova, V. I.; Mason, P. A.; Mašek, M.; Mishevskiy, N.; Nelson, R. H.; Oksanen, A.; Parimucha, S.; Park, J.-W.; Petrík, K.; Quiñones, C.; Reinsch, K.; Robertson, J. W.; Sergey, I. M.; Szpanko, M.; Tkachenko, M. G.; Tkachuk, L. G.; Traulsen, I.; Tremko, J.; Tsehmeystrenko, V. S.; Yoon, J.-N.; Zola, S.; Shakhovskoy, N. M.

    2017-07-01

    The types of instability in the interacting binary stars are briefly reviewed. The project “Inter-Longitude Astronomy” is a series of smaller projects on concrete stars or groups of stars. It has no special funds, and is supported from resources and grants of participating organizations, when informal working groups are created. This “ILA” project is in some kind similar and complementary to other projects like WET, CBA, UkrVO, VSOLJ, BRNO, MEDUZA, AstroStatistics, where many of us collaborate. Totally we studied 1900+ variable stars of different types, including newly discovered variables. The characteristic timescale is from seconds to decades and (extrapolating) even more. The monitoring of the first star of our sample AM Her was initiated by Prof. V.P. Tsesevich (1907-1983). Since more than 358 ADS papers were published. In this short review, we present some highlights of our photometric and photo-polarimetric monitoring and mathematical modeling of interacting binary stars of different types: classical (AM Her, QQ Vul, V808 Aur = CSS 081231:071126+440405, FL Cet), asynchronous (BY Cam, V1432 Aql), intermediate (V405 Aql, BG CMi, MU Cam, V1343 Her, FO Aqr, AO Psc, RXJ 2123, 2133, 0636, 0704) polars and magnetic dwarf novae (DO Dra) with 25 timescales corresponding to different physical mechanisms and their combinations (part “Polar”); negative and positive superhumpers in nova-like (TT Ari, MV Lyr, V603 Aql, V795 Her) and many dwarf novae stars (“Superhumper”); eclipsing “non-magnetic” cataclysmic variables(BH Lyn, DW UMa, EM Cyg; PX And); symbiotic systems (“Symbiosis”); super-soft sources (SSS, QR And); spotted (and not spotted) eclipsing variables with (and without) evidence for a current mass transfer (“Eclipser”) with a special emphasis on systems with a direct impact of the stream into the gainer star's atmosphere, which we propose to call “Impactor” (short from “Extreme Direct Impactor”), or V361 Lyr-type stars. Other

  13. Calibrating binary lumped parameter models

    NASA Astrophysics Data System (ADS)

    Morgenstern, Uwe; Stewart, Mike

    2017-04-01

    Groundwater at its discharge point is a mixture of water from short and long flowlines, and therefore has a distribution of ages rather than a single age. Various transfer functions describe the distribution of ages within the water sample. Lumped parameter models (LPMs), which are mathematical models of water transport based on simplified aquifer geometry and flow configuration can account for such mixing of groundwater of different age, usually representing the age distribution with two parameters, the mean residence time, and the mixing parameter. Simple lumped parameter models can often match well the measured time varying age tracer concentrations, and therefore are a good representation of the groundwater mixing at these sites. Usually a few tracer data (time series and/or multi-tracer) can constrain both parameters. With the building of larger data sets of age tracer data throughout New Zealand, including tritium, SF6, CFCs, and recently Halon-1301, and time series of these tracers, we realised that for a number of wells the groundwater ages using a simple lumped parameter model were inconsistent between the different tracer methods. Contamination or degradation of individual tracers is unlikely because the different tracers show consistent trends over years and decades. This points toward a more complex mixing of groundwaters with different ages for such wells than represented by the simple lumped parameter models. Binary (or compound) mixing models are able to represent a more complex mixing, with mixing of water of two different age distributions. The problem related to these models is that they usually have 5 parameters which makes them data-hungry and therefore difficult to constrain all parameters. Two or more age tracers with different input functions, with multiple measurements over time, can provide the required information to constrain the parameters of the binary mixing model. We obtained excellent results using tritium time series encompassing

  14. CALCULATING THE HABITABLE ZONE OF BINARY STAR SYSTEMS. II. P-TYPE BINARIES

    SciTech Connect

    Haghighipour, Nader; Kaltenegger, Lisa

    2013-11-10

    We have developed a comprehensive methodology for calculating the circumbinary habitable zone (HZ) in planet-hosting P-type binary star systems. We present a general formalism for determining the contribution of each star of the binary to the total flux received at the top of the atmosphere of an Earth-like planet and use the Sun's HZ to calculate the inner and outer boundaries of the HZ around a binary star system. We apply our calculations to the Kepler's currently known circumbinary planetary systems and show the combined stellar flux that determines the boundaries of their HZs. We also show that the HZ in P-type systems is dynamic and, depending on the luminosity of the binary stars, their spectral types, and the binary eccentricity, its boundaries vary as the stars of the binary undergo their orbital motion. We present the details of our calculations and discuss the implications of the results.

  15. Pulsars in binary systems: probing binary stellar evolution and general relativity.

    PubMed

    Stairs, Ingrid H

    2004-04-23

    Radio pulsars in binary orbits often have short millisecond spin periods as a result of mass transfer from their companion stars. They therefore act as very precise, stable, moving clocks that allow us to investigate a large set of otherwise inaccessible astrophysical problems. The orbital parameters derived from high-precision binary pulsar timing provide constraints on binary evolution, characteristics of the binary pulsar population, and the masses of neutron stars with different mass-transfer histories. These binary systems also test gravitational theories, setting strong limits on deviations from general relativity. Surveys for new pulsars yield new binary systems that increase our understanding of all these fields and may open up whole new areas of physics, as most spectacularly evidenced by the recent discovery of an extremely relativistic double-pulsar system.

  16. Newly identified YSO candidates towards LDN 1188

    NASA Astrophysics Data System (ADS)

    Marton , G.; Verebélyi, E.; Kiss, Cs.; Smidla, J.

    2013-11-01

    We present an analysis of young stellar object (YSO) candidates towards the LDN 1188 molecular cloud. The YSO candidates were selected from the WISE all-sky catalogue, based on a statistical method. We found 601 candidates in the region, and classified them as Class I, Flat, and Class II YSOs. Groups were identified and described with the Minimal Spanning Tree (MST) method. Previously identified molecular cores show evidence of ongoing star formation at different stages throughout the cloud complex.

  17. Identifying Candidate Chemical-Disease Linkages ...

    EPA Pesticide Factsheets

    Presentation at meeting on Environmental and Epigenetic Determinants of IBD in New York, NY on identifying candidate chemical-disease linkages by using AOPs to identify molecular initiating events and using relevant high throughput assays to screen for candidate chemicals. This hazard information is combined with exposure models to inform risk assessment. Presentation at meeting on Environmental and Epigenetic Determinants of IBD in New York, NY on identifying candidate chemical-disease linkages by using AOPs to identify molecular initiating events and using relevant high throughput assays to screen for candidate chemicals. This hazard information is combined with exposure models to inform risk assessment.

  18. Improving enzymatic production of diglycerides by engineering binary ionic liquid medium system.

    PubMed

    Guo, Zheng; Kahveci, Derya; Ozçelik, Beraat; Xu, Xuebing

    2009-10-01

    The tunable property of ionic liquids (ILs) offers tremendous opportunity to rethink the strategy of current efforts to resolve technical challenges that occurred in many production approaches. To establish an efficient glycerolysis approach for enzymatic production of diglycerides (DG), this work reported a novel concept to improve DG yield by applying a binary IL system that consisted of one IL with better DG production selectivity and another IL being able to achieve higher conversion of triglycerides (TG). The candidates for combination were determined by individually examining lipase-catalyzed glycerolysis in different ILs, as a result, promising ones are divided into two groups based on their reaction specificities. The effects of parametric variables were then preliminarily evaluated, following a further investigation of the reaction performance in different binary IL systems from cross-group combinations. The combination of TOMA.Tf(2)N/Ammoeng 102 was employed for optimization by Response Surface Methodology. Eighty to eighty-five percent (mol%) of oil conversion and up to 90% (mol%) of total DG yield (73%, wt%) were obtained, which are markedly higher than those previously reported. This work demonstrated the practical feasibility to couple the technical advantage (high TG conversion and high DG production selective in this work) of individual ILs into a binary system to over-perform the reaction. It is believed that binary IL system could be also applicable to other enzymatic reaction systems for establishment of more efficient reaction protocols.

  19. A luminous gamma-ray binary in the large magellanic cloud

    SciTech Connect

    Corbet, R. H. D.; Chomiuk, L.; Coe, M. J.; Coley, J. B.; Dubus, G.; Edwards, P. G.; Martin, P.; McBride, V. A.; Stevens, J.; Strader, J.; Townsend, L. J.; Udalski, A.

    2016-09-27

    Gamma-ray binaries consist of a neutron star or a black hole interacting with a normal star to produce gamma-ray emission that dominates the radiative output of the system. Previously, only a handful of such systems have been discovered, all within our Galaxy. We report the discovery of a luminous gamma-ray binary in the Large Magellanic Cloud, found with the Fermi Large Area Telescope (LAT), from a search for periodic modulation in all sources in the third Fermi LAT catalog. This is the first such system to be found outside the Milky Way. Furthermore, the system has an orbital period of 10.3 days, and is associated with a massive O5III star located in the supernova remnant DEM L241, previously identified as the candidate high-mass X-ray binary (HMXB) CXOU J053600.0–673507. X-ray and radio emission are also modulated on the 10.3 day period, but are in anti-phase with the gamma-ray modulation. Optical radial velocity measurements suggest that the system contains a neutron star. The source is significantly more luminous than similar sources in the Milky Way, at radio, optical, X-ray, and gamma-ray wavelengths. The detection of this extra-galactic system, but no new Galactic systems, raises the possibility that the predicted number of gamma-ray binaries in our Galaxy has been overestimated, and that HMXBs may be born containing relatively slowly rotating neutron stars.

  20. The PyCBC search for gravitational waves from compact binary coalescence

    NASA Astrophysics Data System (ADS)

    Usman, Samantha A.; Nitz, Alexander H.; Harry, Ian W.; Biwer, Christopher M.; Brown, Duncan A.; Cabero, Miriam; Capano, Collin D.; Dal Canton, Tito; Dent, Thomas; Fairhurst, Stephen; Kehl, Marcel S.; Keppel, Drew; Krishnan, Badri; Lenon, Amber; Lundgren, Andrew; Nielsen, Alex B.; Pekowsky, Larne P.; Pfeiffer, Harald P.; Saulson, Peter R.; West, Matthew; Willis, Joshua L.

    2016-11-01

    We describe the PyCBC search for gravitational waves from compact-object binary coalescences in advanced gravitational-wave detector data. The search was used in the first Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) observing run and unambiguously identified two black hole binary mergers, GW150914 and GW151226. At its core, the PyCBC search performs a matched-filter search for binary merger signals using a bank of gravitational-wave template waveforms. We provide a complete description of the search pipeline including the steps used to mitigate the effects of noise transients in the data, identify candidate events and measure their statistical significance. The analysis is able to measure false-alarm rates as low as one per million years, required for confident detection of signals. Using data from initial LIGO's sixth science run, we show that the new analysis reduces the background noise in the search, giving a 30 % increase in sensitive volume for binary neutron star systems over previous searches.

  1. First all-sky search for continuous gravitational waves from unknown sources in binary systems

    NASA Astrophysics Data System (ADS)

    Aasi, J.; Abbott, B. P.; Abbott, R.; Abbott, T.; Abernathy, M. R.; Accadia, T.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Affeldt, C.; Agathos, M.; Aggarwal, N.; Aguiar, O. D.; Ain, A.; Ajith, P.; Alemic, A.; Allen, B.; Allocca, A.; Amariutei, D.; Andersen, M.; Anderson, R.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C.; Areeda, J.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Austin, L.; Aylott, B. E.; Babak, S.; Baker, P. T.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barbet, M.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Bauchrowitz, J.; Bauer, Th. S.; Behnke, B.; Bejger, M.; Beker, M. G.; Belczynski, C.; Bell, A. S.; Bell, C.; Bergmann, G.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Beyersdorf, P. T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biscans, S.; Bitossi, M.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bloemen, S.; Blom, M.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bond, C.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Boschi, V.; Bose, Sukanta; Bosi, L.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brückner, F.; Buchman, S.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burman, R.; Buskulic, D.; Buy, C.; Cadonati, L.; Cagnoli, G.; Calderón Bustillo, J.; Calloni, E.; Camp, J. B.; Campsie, P.; Cannon, K. C.; Canuel, B.; Cao, J.; Capano, C. D.; Carbognani, F.; Carbone, L.; Caride, S.; Castiglia, A.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Celerier, C.; Cella, G.; Cepeda, C.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, X.; Chen, Y.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Chow, J.; Christensen, N.; Chu, Q.; Chua, S. S. Y.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C.; Colombini, M.; Cominsky, L.; Constancio, M.; Conte, A.; Cook, D.; Corbitt, T. R.; Cordier, M.; Cornish, N.; Corpuz, A.; Corsi, A.; Costa, C. A.; Coughlin, M. W.; Coughlin, S.; Coulon, J.-P.; Countryman, S.; Couvares, P.; Coward, D. M.; Cowart, M.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Creighton, T. D.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dahl, K.; Dal Canton, T.; Damjanic, M.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Dattilo, V.; Daveloza, H.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; Dayanga, T.; Debreczeni, G.; Degallaix, J.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Dhurandhar, S.; Díaz, M.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Di Virgilio, A.; Donath, A.; Donovan, F.; Dooley, K. L.; Doravari, S.; Dossa, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Dwyer, S.; Eberle, T.; Edo, T.; Edwards, M.; Effler, A.; Eggenstein, H.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Endrőczi, G.; Essick, R.; Etzel, T.; Evans, M.; Evans, T.; Factourovich, M.; Fafone, V.; Fairhurst, S.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fehrmann, H.; Fejer, M. M.; Feldbaum, D.; Feroz, F.; Ferrante, I.; Ferrini, F.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Fisher, R. P.; Flaminio, R.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gair, J.; Gammaitoni, L.; Gaonkar, S.; Garufi, F.; Gehrels, N.; Gemme, G.; Genin, E.; Gennai, A.; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, C.; Gleason, J.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gordon, N.; Gorodetsky, M. L.; Gossan, S.; Goßler, S.; Gouaty, R.; Gräf, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Groot, P.; Grote, H.; Grover, K.; Grunewald, S.; Guidi, G. M.; Guido, C.; Gushwa, K.; Gustafson, E. K.; Gustafson, R.; Hammer, D.; Hammond, G.; Hanke, M.; Hanks, J.; Hanna, C.; Hanson, J.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Hart, M.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Heidmann, A.; Heintze, M.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Heptonstall, A. W.; Heurs, M.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Holt, K.; Hooper, S.; Hopkins, P.; Hosken, D. J.; Hough, J.; Howell, E. J.; Hu, Y.; Huerta, E.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh, M.; Huynh-Dinh, T.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Iyer, B. R.; Izumi, K.; Jacobson, M.; James, E.; Jang, H.; Jaranowski, P.; Ji, Y.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; K, Haris; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karlen, J.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, H.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Keiser, G. M.; Keitel, D.; Kelley, D. B.; Kells, W.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, C.; Kim, K.; Kim, N.; Kim, N. G.; Kim, Y.-M.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kline, J.; Koehlenbeck, S.; Kokeyama, K.; Kondrashov, V.; Koranda, S.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kremin, A.; Kringel, V.; Krishnan, B.; Królak, A.; Kuehn, G.; Kumar, A.; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Kwee, P.; Landry, M.; Lantz, B.; Larson, S.; Lasky, P. D.; Lawrie, C.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C.-H.; Lee, H. K.; Lee, H. M.; Lee, J.; Leonardi, M.; Leong, J. R.; Le Roux, A.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B.; Lewis, J.; Li, T. G. F.; Libbrecht, K.; Libson, A.; Lin, A. C.; Littenberg, T. B.; Litvine, V.; Lockerbie, N. A.; Lockett, V.; Lodhia, D.; Loew, K.; Logue, J.; Lombardi, A. L.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J.; Lubinski, M. J.; Lück, H.; Luijten, E.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Macarthur, J.; Macdonald, E. P.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magana-Sandoval, F.; Mageswaran, M.; Maglione, C.; Mailand, K.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Manca, G. M.; Mandel, I.; Mandic, V.; Mangano, V.; Mangini, N.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A.; Maros, E.; Marque, J.; Martelli, F.; Martin, I. W.; Martin, R. M.; Martinelli, L.; Martynov, D.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIver, J.; McLin, K.; Meacher, D.; Meadors, G. D.; Mehmet, M.; Meidam, J.; Meinders, M.; Melatos, A.; Mendell, G.; Mercer, R. A.; Meshkov, S.; Messenger, C.; Meyers, P.; Miao, H.; Michel, C.; Mikhailov, E. E.; Milano, L.; Milde, S.; Miller, J.; Minenkov, Y.; Mingarelli, C. M. F.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moe, B.; Moesta, P.; Mohan, M.; Mohapatra, S. R. P.; Moraru, D.; Moreno, G.; Morgado, N.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Munch, J.; Murphy, D.; Murray, P. G.; Mytidis, A.; Nagy, M. F.; Nanda Kumar, D.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nelemans, G.; Neri, I.; Neri, M.; Newton, G.; Nguyen, T.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Ochsner, E.; O'Dell, J.; Oelker, E.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oppermann, P.; O'Reilly, B.; O'Shaughnessy, R.; Osthelder, C.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Padilla, C.; Pai, A.; Palashov, O.; Palomba, C.; Pan, H.; Pan, Y.; Pankow, C.; Paoletti, F.; Paoletti, R.; Papa, M. A.; Paris, H.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Pedraza, M.; Penn, S.; Perreca, A.; Phelps, M.; Pichot, M.; Pickenpack, M.; Piergiovanni, F.; Pierro, V.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poeld, J.; Poggiani, R.; Poteomkin, A.; Powell, J.; Prasad, J.; Premachandra, S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Qin, J.; Quetschke, V.; Quintero, E.; Quiroga, G.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Rácz, I.; Radkins, H.; Raffai, P.; Raja, S.; Rajalakshmi, G.; Rakhmanov, M.; Ramet, C.; Ramirez, K.; Rapagnani, P.; Raymond, V.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Reid, S.; Reitze, D. H.; Rhoades, E.; Ricci, F.; Riles, K.; Robertson, N. A.; Robinet, F.; Rocchi, A.; Rodruck, M.; Rolland, L.; Rollins, J. G.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Salemi, F.; Sammut, L.; Sandberg, V.; Sanders, J. R.; Sannibale, V.; Santiago-Prieto, I.; Saracco, E.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Savage, R.; Scheuer, J.; Schilling, R.; Schnabel, R.; Schofield, R. M. S.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Shaddock, D.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sidery, T. L.; Siellez, K.; Siemens, X.; Sigg, D.; Simakov, D.; Singer, A.; Singer, L.; Singh, R.; Sintes, A. M.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M.; Smith, R. J. E.; Smith-Lefebvre, N. D.; Son, E. J.; Sorazu, B.; Souradeep, T.; Sperandio, L.; Staley, A.; Stebbins, J.; Steinlechner, J.; Steinlechner, S.; Stephens, B. C.; Steplewski, S.; Stevenson, S.; Stone, R.; Stops, D.; Strain, K. A.; Straniero, N.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Susmithan, S.; Sutton, P. J.; Swinkels, B.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tarabrin, S. P.; Taylor, R.; ter Braack, A. P. M.; Thirugnanasambandam, M. P.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Toncelli, A.; Tonelli, M.; Torre, O.; Torres, C. V.; Torrie, C. I.; Travasso, F.; Traylor, G.; Tse, M.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Urbanek, K.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vallisneri, M.; van den Brand, J. F. J.; Van Den Broeck, C.; van der Putten, S.; van der Sluys, M. V.; van Heijningen, J.; van Veggel, A. A.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Verma, S. S.; Vetrano, F.; Viceré, A.; Vincent-Finley, R.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Vousden, W. D.; Vyachanin, S. P.; Wade, A.; Wade, L.; Wade, M.; Walker, M.; Wallace, L.; Wang, M.; Wang, X.; Ward, R. L.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; White, D. J.; Whiting, B. F.; Wiesner, K.; Wilkinson, C.; Williams, K.; Williams, L.; Williams, R.; Williams, T.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Wittel, H.; Woan, G.; Worden, J.; Yablon, J.; Yakushin, I.; Yamamoto, H.; Yancey, C. C.; Yang, H.; Yang, Z.; Yoshida, S.; Yvert, M.; ZadroŻny, A.; Zanolin, M.; Zendri, J.-P.; Zhang, Fan; Zhang, L.; Zhao, C.; Zhu, X. J.; Zucker, M. E.; Zuraw, S.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

    2014-09-01

    We present the first results of an all-sky search for continuous gravitational waves from unknown spinning neutron stars in binary systems using LIGO and Virgo data. Using a specially developed analysis program, the TwoSpect algorithm, the search was carried out on data from the sixth LIGO science run and the second and third Virgo science runs. The search covers a range of frequencies from 20 Hz to 520 Hz, a range of orbital periods from 2 to ˜2,254 h and a frequency- and period-dependent range of frequency modulation depths from 0.277 to 100 mHz. This corresponds to a range of projected semimajor axes of the orbit from ˜0.6×10-3 ls to ˜6,500 ls assuming the orbit of the binary is circular. While no plausible candidate gravitational wave events survive the pipeline, upper limits are set on the analyzed data. The most sensitive 95% confidence upper limit obtained on gravitational wave strain is 2.3×10-24 at 217 Hz, assuming the source waves are circularly polarized. Although this search has been optimized for circular binary orbits, the upper limits obtained remain valid for orbital eccentricities as large as 0.9. In addition, upper limits are placed on continuous gravitational wave emission from the low-mass x-ray binary Scorpius X-1 between 20 Hz and 57.25 Hz.

  2. A massive binary black-hole system in OJ 287 and a test of general relativity.

    PubMed

    Valtonen, M J; Lehto, H J; Nilsson, K; Heidt, J; Takalo, L O; Sillanpää, A; Villforth, C; Kidger, M; Poyner, G; Pursimo, T; Zola, S; Wu, J-H; Zhou, X; Sadakane, K; Drozdz, M; Koziel, D; Marchev, D; Ogloza, W; Porowski, C; Siwak, M; Stachowski, G; Winiarski, M; Hentunen, V-P; Nissinen, M; Liakos, A; Dogru, S

    2008-04-17

    Tests of Einstein's general theory of relativity have mostly been carried out in weak gravitational fields where the space-time curvature effects are first-order deviations from Newton's theory. Binary pulsars provide a means of probing the strong gravitational field around a neutron star, but strong-field effects may be best tested in systems containing black holes. Here we report such a test in a close binary system of two candidate black holes in the quasar OJ 287. This quasar shows quasi-periodic optical outbursts at 12-year intervals, with two outburst peaks per interval. The latest outburst occurred in September 2007, within a day of the time predicted by the binary black-hole model and general relativity. The observations confirm the binary nature of the system and also provide evidence for the loss of orbital energy in agreement (within 10 per cent) with the emission of gravitational waves from the system. In the absence of gravitational wave emission the outburst would have happened 20 days later.

  3. A SYSTEMATIC SEARCH FOR MASSIVE BLACK HOLE BINARIES IN THE SLOAN DIGITAL SKY SURVEY SPECTROSCOPIC SAMPLE

    SciTech Connect

    Tsalmantza, P.; Decarli, R.; Hogg, David W.; Dotti, M. E-mail: decarli@mpia.de

    2011-09-01

    We present the results of a systematic search for massive black hole binaries in the Sloan Digital Sky Survey (SDSS) spectroscopic database. We focus on bound binaries, under the assumption that one of the black holes is active. In this framework, the broad lines associated with the accreting black hole are expected to show systematic velocity shifts with respect to the narrow lines, which trace the rest frame of the galaxy. For a sample of 54,586 quasars and 3929 galaxies at redshifts 0.1 < z < 1.5, we brute-force model each spectrum as a mixture of two quasars at two different redshifts. The spectral model is a data-driven dimensionality reduction of the SDSS quasar spectra based on a matrix factorization. We identified 32 objects with peculiar spectra. Nine of them can be interpreted as black hole binaries. This doubles the number of known black hole binary candidates. We also report on the discovery of a new class of extreme double-peaked emitters with exceptionally broad and faint Balmer lines. For all the interesting sources, we present detailed analysis of the spectra and discuss possible interpretations.

  4. A Luminous Gamma-ray Binary in the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Corbet, R. H. D.; Chomiuk, L.; Coe, M. J.; Coley, J. B.; Dubus, G.; Edwards, P. G.; Martin, P.; McBride, V. A.; Stevens, J.; Strader, J.; Townsend, L. J.; Udalski, A.

    2016-10-01

    Gamma-ray binaries consist of a neutron star or a black hole interacting with a normal star to produce gamma-ray emission that dominates the radiative output of the system. Only a handful of such systems have been previously discovered, all within our Galaxy. Here, we report the discovery of a luminous gamma-ray binary in the Large Magellanic Cloud, found with the Fermi Large Area Telescope (LAT), from a search for periodic modulation in all sources in the third Fermi LAT catalog. This is the first such system to be found outside the Milky Way. The system has an orbital period of 10.3 days, and is associated with a massive O5III star located in the supernova remnant DEM L241, previously identified as the candidate high-mass X-ray binary (HMXB) CXOU J053600.0-673507. X-ray and radio emission are also modulated on the 10.3 day period, but are in anti-phase with the gamma-ray modulation. Optical radial velocity measurements suggest that the system contains a neutron star. The source is significantly more luminous than similar sources in the Milky Way, at radio, optical, X-ray, and gamma-ray wavelengths. The detection of this extra-galactic system, but no new Galactic systems, raises the possibility that the predicted number of gamma-ray binaries in our Galaxy has been overestimated, and that HMXBs may be born containing relatively slowly rotating neutron stars.

  5. General simulation algorithm for autocorrelated binary processes

    NASA Astrophysics Data System (ADS)

    Serinaldi, Francesco; Lombardo, Federico

    2017-02-01

    The apparent ubiquity of binary random processes in physics and many other fields has attracted considerable attention from the modeling community. However, generation of binary sequences with prescribed autocorrelation is a challenging task owing to the discrete nature of the marginal distributions, which makes the application of classical spectral techniques problematic. We show that such methods can effectively be used if we focus on the parent continuous process of beta distributed transition probabilities rather than on the target binary process. This change of paradigm results in a simulation procedure effectively embedding a spectrum-based iterative amplitude-adjusted Fourier transform method devised for continuous processes. The proposed algorithm is fully general, requires minimal assumptions, and can easily simulate binary signals with power-law and exponentially decaying autocorrelation functions corresponding, for instance, to Hurst-Kolmogorov and Markov processes. An application to rainfall intermittency shows that the proposed algorithm can also simulate surrogate data preserving the empirical autocorrelation.

  6. 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.

  7. High-spin binary black hole mergers

    NASA Astrophysics Data System (ADS)

    Marronetti, Pedro; Tichy, Wolfgang; Brügmann, Bernd; Sperhake, Ulrich; González, José

    2008-04-01

    We study identical mass black hole binaries with spins perpendicular to the binary's orbital plane. These binaries have individual spins ranging from s/m^2=-0.90 to 0.90, (s1= s2 in all cases) which is near the limit possible with standard Bowen-York puncture initial data. The extreme cases correspond to the largest initial spin simulations to date. Our results expand the parameter space covered by Rezzolla et al. and, when combining both data sets, we obtain estimations for the minimum and maximum values for the intrinsic angular momenta of the remnant of binary black hole mergers of J/M^2=0.341(4) and 0.951(4) respectively.

  8. X-ray reprocessing in binaries

    NASA Astrophysics Data System (ADS)

    Paul, Biswajit

    2016-07-01

    We will discuss several aspects of X-ray reprocessing into X-rays or longer wavelength radiation in different kinds of binary systems. In high mass X-ray binaries, reprocessing of hard X-rays into emission lines or lower temperature black body emission is a useful tool to investigate the reprocessing media like the stellar wind, clumpy structures in the wind, accretion disk or accretion stream. In low mass X-ray binaries, reprocessing from the surface of the companion star, the accretion disk, warps and other structures in the accretion disk produce signatures in longer wavelength radiation. X-ray sources with temporal structures like the X-ray pulsars and thermonuclear burst sources are key in such studies. We will discuss results from several new investigations of X-ray reprocessing phenomena in X-ray binaries.

  9. Mass flow in close binary systems

    NASA Technical Reports Server (NTRS)

    Kondo, Y.; Mccluskey, G. E.

    1976-01-01

    The manner of mass flow in close binary systems is examined with a special view to the role of the so-called critical Roche (or Jacobian) lobe, taking into consideration relevant physical conditions such as radiation pressure that may affect the restricted three-body problem treatment. The mass does not necessarily flow from component one to component two through the L1 point to form a gaseous ring surrounding the latter. These considerations are applied to X-ray binaries with early-type optical components, such as Cyg X-1 (HDE 226868) and 3U 1700 - 37 (HD 153919). In the two bright close binary systems Beta Lyr and UW CMa, which are believed to be undergoing dynamic mass transfer, recent Copernicus observations show that the gas giving rise to the prominent ultraviolet emission lines surrounds the entire binary system rather than merely component two. Implications of these observations are also discussed.

  10. Classification of close binary systems by Svechnikov

    NASA Astrophysics Data System (ADS)

    Dryomova, G. N.

    The paper presents the historical overview of classification schemes of eclipsing variable stars with the foreground of advantages of the classification scheme by Svechnikov being widely appreciated for Close Binary Systems due to simplicity of classification criteria and brevity.

  11. Trompe L'Oeil 'binary' pulsars

    NASA Astrophysics Data System (ADS)

    Nelson, Robert W.; Finn, Lee S.; Wasserman, Ira

    1990-01-01

    A freely precessing pulsar produces pulse phase residuals which can mimic those of a pulsar in a binary orbit. In particular, discrete sets of phase residuals due to precessional motion of an isolated pulsar are sampled; it is shown that this data is well fit by residuals from a binary pulsar in a sufficiently tight orbit. Analytic and numerical relationships between the projected orbital size, a(p) sin i, and the orbital eccentricity, e, of a misidentified binary pulsar; are found the observations that would distinguish between these models are discussed. Regardless of the mechanism that causes the precession, the maximum amplitude of the phase residual is pi/2: consequently, a(p)sin i is (approximately) bounded by cP(puls)/4. The newly discovered 'binary' millisecond pulsars in the globular cluster 47 Tuc is discussed, and it is shown that the periodic frequency modulation reported cannot be explained by free precession.

  12. TOPICAL REVIEW: Coalescing binary neutron stars

    NASA Astrophysics Data System (ADS)

    Rasio, Frederic A.; Shapiro, Stuart L.

    1999-06-01

    Coalescing compact binaries with neutron star or black hole components provide the most promising sources of gravitational radiation for detection by the LIGO/VIRGO/GEO/TAMA laser interferometers now under construction. This fact has motivated several different theoretical studies of the inspiral and hydrodynamic merging of compact binaries. Analytic analyses of the inspiral waveforms have been performed in the post-Newtonian approximation. Analytic and numerical treatments of the coalescence waveforms from binary neutron stars have been performed using Newtonian hydrodynamics and the quadrupole radiation approximation. Numerical simulations of coalescing black hole and neutron star binaries are also underway in full general relativity. Recent results from each of these approaches will be described and their virtues and limitations summarized.

  13. 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.

  14. Composition formulas of binary eutectics

    PubMed Central

    Ma, Y. P.; Dong, D. D.; Dong, C.; Luo, L. J.; Wang, Q.; Qiang, J. B.; Wang, Y. M.

    2015-01-01

    The present paper addresses the long-standing composition puzzle of eutectic points by introducing a new structural tool for the description of short-range-order structural unit, the cluster-plus-glue-atom model. In this model, any structure is dissociated into a 1st-neighbor cluster and a few glue atoms between the clusters, expressed by a cluster formula [cluster]gluex. This model is applied here to establish the structural model for eutectic liquids, assuming that a eutectic liquid consist of two subunits issued from the relevant eutectic phases, each being expressed by the cluster formula for ideal metallic glasses, i.e., [cluster](glue atom)1 or 3. A structural unit is then composed of two clusters from the relevant eutectic phases plus 2, 4, or 6 glue atoms. Such a dual cluster formulism is well validated in all boron-containing (except those located by the extreme phase diagram ends) and in some commonly-encountered binary eutectics, within accuracies below 1 at.%. The dual cluster formulas vary extensively and are rarely identical even for eutectics of close compositions. They are generally formed with two distinctly different cluster types, with special cluster matching rules such as cuboctahedron plus capped trigonal prism and rhombidodecahedron plus octahedral antiprism. PMID:26658618

  15. Composition formulas of binary eutectics.

    PubMed

    Ma, Y P; Dong, D D; Dong, C; Luo, L J; Wang, Q; Qiang, J B; Wang, Y M

    2015-12-14

    The present paper addresses the long-standing composition puzzle of eutectic points by introducing a new structural tool for the description of short-range-order structural unit, the cluster-plus-glue-atom model. In this model, any structure is dissociated into a 1(st)-neighbor cluster and a few glue atoms between the clusters, expressed by a cluster formula [cluster]gluex. This model is applied here to establish the structural model for eutectic liquids, assuming that a eutectic liquid consist of two subunits issued from the relevant eutectic phases, each being expressed by the cluster formula for ideal metallic glasses, i.e., [cluster](glue atom)(1 or 3). A structural unit is then composed of two clusters from the relevant eutectic phases plus 2, 4, or 6 glue atoms. Such a dual cluster formulism is well validated in all boron-containing (except those located by the extreme phase diagram ends) and in some commonly-encountered binary eutectics, within accuracies below 1 at.%. The dual cluster formulas vary extensively and are rarely identical even for eutectics of close compositions. They are generally formed with two distinctly different cluster types, with special cluster matching rules such as cuboctahedron plus capped trigonal prism and rhombidodecahedron plus octahedral antiprism.

  16. Black hole binaries and microquasars

    NASA Astrophysics Data System (ADS)

    Zhang, Shuang-Nan

    2013-12-01

    This is a general review on the observations and physics of black hole X-ray binaries and microquasars, with the emphasize on recent developments in the high energy regime. The focus is put on understanding the accretion flows and measuring the parameters of black holes in them. It includes mainly two parts: i) Brief review of several recent review article on this subject; ii) Further development on several topics, including black hole spin measurements, hot accretion flows, corona formation, state transitions and thermal stability of standard think disk. This is thus not a regular bottom-up approach, which I feel not necessary at this stage. Major effort is made in making and incorporating from many sources useful plots and illustrations, in order to make this article more comprehensible to non-expert readers. In the end I attempt to make a unification scheme on the accretion-outflow (wind/jet) connections of all types of accreting BHs of all accretion rates and all BH mass scales, and finally provide a brief outlook.

  17. Composition formulas of binary eutectics

    NASA Astrophysics Data System (ADS)

    Ma, Y. P.; Dong, D. D.; Dong, C.; Luo, L. J.; Wang, Q.; Qiang, J. B.; Wang, Y. M.

    2015-12-01

    The present paper addresses the long-standing composition puzzle of eutectic points by introducing a new structural tool for the description of short-range-order structural unit, the cluster-plus-glue-atom model. In this model, any structure is dissociated into a 1st-neighbor cluster and a few glue atoms between the clusters, expressed by a cluster formula [cluster]gluex. This model is applied here to establish the structural model for eutectic liquids, assuming that a eutectic liquid consist of two subunits issued from the relevant eutectic phases, each being expressed by the cluster formula for ideal metallic glasses, i.e., [cluster](glue atom)1 or 3. A structural unit is then composed of two clusters from the relevant eutectic phases plus 2, 4, or 6 glue atoms. Such a dual cluster formulism is well validated in all boron-containing (except those located by the extreme phase diagram ends) and in some commonly-encountered binary eutectics, within accuracies below 1 at.%. The dual cluster formulas vary extensively and are rarely identical even for eutectics of close compositions. They are generally formed with two distinctly different cluster types, with special cluster matching rules such as cuboctahedron plus capped trigonal prism and rhombidodecahedron plus octahedral antiprism.

  18. Binary module test. Final report

    SciTech Connect

    Schilling, J.R.; Colley, T.C.; Pundyk, J.

    1980-12-01

    The objective of this project was to design and test a binary loop module representative of and scaleable to commercial size units. The design was based on state-of-the-art heat exchanger technology, and the purpose of the tests was to confirm performance of a supercritical boiling cycle using isobutane and a mixture of isobutane and isopentane as the secondary working fluid. The module was designed as one percent of a 50 MW unit. It was installed at Magma Power's East Mesa geothermal field and tested over a period of approximately 4 months. Most of the test runs were with isobutane but some data were collected for hydrocarbon mixtures. The results of the field tests are reported. In general these results indicate reasonably good heat balances and agreement with overall heat transfer coefficients calculated by current stream analysis methods and available fluid property data; however, measured pressure drops across the heat exchangers were 20 percent higher than estimated. System operation was stable under all conditions tested.

  19. Binary Outputs from Unitary Networks

    PubMed Central

    Crews, David

    2013-01-01

    When considering sex ratios, we have to first define the nature of the question. Are we referring to the gonads, secondary and accessory sex structures, physiology, brain, behavior, or to all of the above elements. If these elements are not concordant, the exceptions can prove illustrative of underlying processes at both the proximate and ultimate levels. At each of these levels, “sex” is the binary outcome resulting from the modulation of conserved networks of genes, proteins, cells, organs, and, in the case of the brain, discrete nuclei. These networks operate at multiple and sequential levels that usually are linear during the lifespan, but in some instances reversals are possible. For example, the gonads arise from a single “anlagen” and, in most instances, ovaries or testes result, although ovotestes are the norm in some species and gonadal reversal a property of other species. Other sexually dimorphic structures differentiate from multiple “anlaga” by reciprocal and sex-specific atrophy/hypertrophy, typically in an exaggerated manner, although the capacity to develop structures characteristic of the opposite gonadal sex remains inherent and intact. A perspective that integrates these different properties are presented here. PMID:23559320

  20. Dixie Valley Bottoming Binary Unit

    SciTech Connect

    McDonald, Dale

    2014-12-21

    This binary plant is the first air cooled, high-output refrigeration based waste heat recovery cycle in the industry. Its working fluid is environmentally friendly and as such, the permits that would be required with a hydrocarbon based cycle are not necessary. The unit is largely modularized, meaning that the unit’s individual skids were assembled in another location and were shipped via truck to the plant site. The Air Cooled Condensers (ACC), equipment piping, and Balance of Plant (BOP) piping were constructed at site. This project further demonstrates the technical feasibility of using low temperature brine for geothermal power utilization. The development of the unit led to the realization of low temperature, high output, and environmentally friendly heat recovery systems through domestic research and engineering. The project generates additional renewable energy, resulting in cleaner air and reduced carbon dioxide emissions. Royalty and tax payments to governmental agencies will increase, resulting in reduced financial pressure on local entities. The major components of the unit were sourced from American companies, resulting in increased economic activity throughout the country.