- ID:
- ivo://CDS.VizieR/J/A+A/580/A21
- Title:
- BEER analysis of CoRoT light curves
- Short Name:
- J/A+A/580/A21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The BEER algorithm, introduced by Faigler & Mazeh (2011MNRAS.415.3921F), searches stellar lightcurves for the BEaming, Ellipsoidal, and Reflection (BEER) photometric modulations that are caused by a short-period companion. These three effects are typically of very low amplitude, and can mainly be detected in lightcurves from space-based photometers. Unlike eclipsing binaries, these effects are not limited to edge-on inclinations. Applying the algorithm to wide-field photometric surveys such as CoRoT and Kepler offers an opportunity to better understand the statistical properties of short-period binaries. It also widens the window for detecting intrinsically rare systems, like short-period brown-dwarf and massive- planetary companions to main-sequence stars. Applying the search to the first five long-run center CoRoT fields, we identified 481 non-eclipsing candidates with periodic flux amplitudes of 0.5-87mmag. Optimizing the Anglo-Australian-Telescope pointing coordinates and the AAOmega fiber-allocations with dedicated softwares, we acquired 6-7 medium-resolution spectra of 281 candidates in a seven-night campaign. Analysis of the red-arm AAOmega spectra, which covered the range of 8342-8842{AA}, yielded a radial-velocity precision of ~1 km/s. Spectra containing lines of more than one star were analyzed with the two- dimensional correlation algorithm TODCOR. The measured radial velocities confirmed the binarity of seventy of the BEER candidates, 45 single-line binaries, 18 double-line binaries, and 7 diluted binaries. We show that red giants introduce a major source of false candidates and demonstrate a way to improve BEER's performance in extracting higher fidelity samples from future searches of CoRoT lightcurves. The periods of the confirmed binaries span a range of 0.3-10days and show a rise in the number of binaries per logP bin toward longer periods. The estimated mass ratios of the double-line binaries and the mass ratios assigned to the single-line binaries, assuming an isotropic inclination distribution, span a range of 0.03-1. On the low-mass end we have detected two brown-dwarf candidates on a ~1day period orbit. This is the first time non-eclipsing beaming binaries are detected in CoRoT data, and we estimate that ~300 such binaries can be detected in the CoRoT long-run lightcurves.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/124/281
- Title:
- BH Vir BV light curves
- Short Name:
- J/A+AS/124/281
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Photoelectric observations of the short period eclipsing binary BH Vir in B and V bands are presented. Comparing with earlier published observations, we found that there were smaller variations in the light curve (outside eclipse) in 1991 than in the previous data.
- ID:
- ivo://CDS.VizieR/J/ApJ/521/682
- Title:
- Binaries in the Praesepe and Coma clusters
- Short Name:
- J/ApJ/521/682
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This completes a study of the evolution of binary systems in five open clusters of various ages. Among 21 stars observed in Praesepe, eight are found or confirmed to be spectroscopic binaries and orbital elements are derived, while one more shows long-term binary motion. Among 18 stars observed in the Coma Berenices cluster, five are found or confirmed to be spectroscopic binaries and orbital elements are derived, while a sixth has tentative elements.
- ID:
- ivo://CDS.VizieR/J/other/PNAOJ/2.561
- Title:
- Binaries speckle observations. IV.
- Short Name:
- J/other/PNAOJ/2.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the fourth paper of this series giving results of speckle observations for 22 visual and 161 spectroscopic binaries. The observation was carried out by using the 212 cm telescope of San Pedro Martir Observatory in Mexico at 7 nights from July 20 to July 26, 1991. We obtained fringes in power spectra of i 19 visual and 11 spectroscopic binaries (6 newly resolved ones) with angular separation larger than 0.06". We introduced a new ICCD TV camera in this observation, and were able to achieve the diffraction-limit resolution of the 212 cm telescope.
- ID:
- ivo://CDS.VizieR/J/A+A/315/384
- Title:
- Binarity among B-stars in NGC 6231
- Short Name:
- J/A+A/315/384
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured radial velocities for 53 B-type stars, between B1 and B9, in the young open cluster NGC 6231 through a cross-correlation technique with synthetic spectra. Two measurements for 36 stars of the sample were obtained with a time separation of about two years. We derived a minimum binary fraction of 52% in the considered population. The velocity determination precisions were simulated and we analysed their dependence upon the S/N ratios of the spectra and upon the stellar rotational velocities. We discuss the selection of the templates for the correlation.
- ID:
- ivo://CDS.VizieR/J/A+A/620/A85
- Title:
- Binary post-AGB stars radial velocities
- Short Name:
- J/A+A/620/A85
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Binary post-asymptotic giant branch (post-AGB) stars are thought to be the products of a strong but poorly-understood interaction during the AGB phase. The aim of this contribution is to update the orbital elements of a sample of galactic post-AGB binaries observed in a long-term radial-velocity monitoring campaign, by analysing these systems in a homogeneous way. Radial velocities are computed from high signal-to-noise spectra by use of a cross-correlation method. The radial-velocity curves are fitted by using both a least-squares algorithm and a Nelder-Mead simplex algorithm. We use a Monte Carlo method to compute uncertainties on the orbital elements. The resulting mass functions are used to derive a companion mass distribution by optimising the predicted to the observed cumulative mass-function distributions, after correcting for observational bias. As a result, we derive and update orbital elements for 33 galactic post-AGB binaries, among which 3 are new orbits. The orbital periods of the systems range from 100 to about 3000 days. Over 70 percent (23 out of 33) of our binaries have significant non-zero eccentricities ranging over all periods. Their orbits are non-circular despite the fact that the Roche-lobe radii are smaller than the maximum size of a typical AGB star and tidal circularisation should have been strong when the objects were on the AGB. We derive a distribution of companion masses that is peaked around 1.09M_{sun}_ with a standard deviation of 0.62M_{sun}_. The large spread in companion masses highlights the diversity of post-AGB binary systems. Post-AGB binaries are often chemically peculiar, showing in their photospheres the result of an accretion process of circumstellar gas devoid of refractory elements. We find that only post-AGB stars with high effective temperatures (>5500K) in wide orbits are depleted in refractory elements, suggesting that re-accretion of material from a circumbinary disc is an ongoing process. It appears, however, that depletion is inefficient for the closest orbits irrespective of the actual surface temperature.
- ID:
- ivo://CDS.VizieR/J/MNRAS/430/2018
- Title:
- 6 bright Galactic Cepheids data
- Short Name:
- J/MNRAS/430/2018
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the analysis of photometric and spectroscopic data of six bright Galactic Cepheids: GH Carinae, V419 Centauri, V898 Centauri, AD Puppis, AY Sagittarii and ST Velorum. Based on new radial velocity data (in some cases supplemented with earlier data available in the literature), these Cepheids have been found to be members in spectroscopic binary systems. V898 Cen turned out to have one of the largest orbital radial velocity amplitude (>40km/s) among the known binary Cepheids. The data are insufficient to determine the orbital periods nor other orbital elements for these new spectroscopic binaries. These discoveries corroborate the statement on the high frequency of occurrence of binaries among the classical Cepheids, a fact to be taken into account when calibrating the period-luminosity relationship for Cepheids. We have also compiled all available photometric data that revealed that the pulsation period of AD Pup, the longest period Cepheid in this sample, is continuously increasing with {Delta}P=0.004567d/century, likely to be caused by stellar evolution. The wave-like pattern superimposed on the parabolic O-C graph of AD Pup may well be caused by the light-time effect in the binary system. ST Vel also pulsates with a continuously increasing period. The other four Cepheids are characterized with stable pulsation periods in the last half century.
- ID:
- ivo://CDS.VizieR/J/MNRAS/472/4173
- Title:
- Bright white dwarfs for high-speed photometry
- Short Name:
- J/MNRAS/472/4173
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The upcoming NASA Transiting Exoplanet Survey Satellite (TESS) will obtain space-based uninterrupted light curves for a large sample of bright white dwarfs distributed across the entire sky, providing a very rich resource for asteroseismological studies and the search for transits from planetary debris. We have compiled an all-sky catalogue of ultraviolet, optical and infrared photometry as well as proper motions, which we propose as an essential tool for the preliminary identification and characterization of potential targets. We present data for 1864 known white dwarfs and 305 high-probability white dwarf candidates brighter than 17mag. We describe the spectroscopic follow-up of 135 stars, of which 82 are white dwarfs and 25 are hot subdwarfs. The new confirmed stars include six pulsating white dwarf candidates (ZZ Cetis), and nine white dwarf binaries with a cool main- sequence companion. We identify one star with a spectroscopic distance of only 25pc from the Sun. Around the time TESS is launched, we foresee that all white dwarfs in this sample will have trigonometric parallaxes measured by the ESA Gaia mission next year.
- ID:
- ivo://CDS.VizieR/J/AJ/141/195
- Title:
- BV light curves of FT Ori
- Short Name:
- J/AJ/141/195
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate absolute properties are determined for the first time for the 3.15 day period eccentric eclipsing binary star FT Ori based on new absolute photometry, five differential light curves, and a radial velocity curve. The stars appear to be normal for their spectral types, A0+A2. The orbit is highly eccentric (e=0.409) and shows apsidal motion with a period of 536-years. The absolute properties and the degree of central mass concentration of the stars are consistent with current theoretical models at an age of 190Myr.
- ID:
- ivo://CDS.VizieR/J/AJ/129/1669
- Title:
- BV photometry of HD 37824, HD 181809, and HD 217188
- Short Name:
- J/AJ/129/1669
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained spectroscopy and photometry of three chromospherically active, single-lined spectroscopic binaries: HD 37824 (V1149 Ori), HD 181809 (V4138 Sgr), and HD 217188 (AZ Psc). * HD 37824 has a circular orbit with a period of 53.57 days. Its primary is a K0 III star, while the secondary is likely a G or K dwarf. * HD 181809 has an orbit with a period of 13.04667 days and a low eccentricity of 0.040. The primary has a spectral type of K0 IIIIV, and its secondary is probably an M dwarf. * The orbit of HD 217188 has a period of 47.1209 days and a moderately high eccentricity of 0.470. The spectral type of the primary is K0III, while the secondary is likely an M dwarf. All three systems are estimated to have near solar iron abundances. Photometric observations spanning 15-16 years for all three stars yield mean photometric periods of 53.12, 59.85, and 90.89 days for HD 37824, HD 181809, and HD 217188, respectively.
