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1471. Binary quasars from LQAC-2
ID:
ivo://CDS.VizieR/J/A+A/564/A117
Title:
Binary quasars from LQAC-2
Short Name:
J/A+A/564/A117
Date:
21 Oct 2021
Publisher:
CDS
Description:
Thanks to huge surveys, such as the Sloan Digital Sky Survey (SDSS), the last decade has shown a dramatic increase in the number of known quasars. In the second release of the general compiled catalogue Large Quasar Astrometric Catalogue (LQAC), 187504 objects are recorded. From this catalogue, we carry out statistical studies dealing with several topics: the astrometric accuracy of the quasars, their spatial location, the distribution of the distance to the closest neighbour, the identification of binary quasars, the completness of catalogues at a given magnitude and the estimation of the number of quasars expected to be detected by the astrometric space mission Gaia. We analyse the astrometric improvements brought by the LQAC-2 in terms of equatorial coordinates off-sets. We plot the bi-dimensional spatial distribution of the LQAC-2 quasars according to their equatorial, galactic, and ecliptic coordinates, thus exploring the anisotropy of the distribution. We compare the observed distribution of closest neighbours with the theoretical values based on a Poisson distribution. Moreover, we perform a comparison between two catalogues, the SDSS and the 2dF inside a huge common field. By extrapolating to the whole sky we deduce the number of quasars that will be detected by Gaia.
1472. Binary quasars in the SDSS
ID:
ivo://CDS.VizieR/J/AJ/131/1
Title:
Binary quasars in the SDSS
Short Name:
J/AJ/131/1
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a sample of 221 new quasar pairs with proper transverse separations R_prop_<1h^1^Mpc over the redshift range 0.5<z<3.0, discovered from an extensive follow-up campaign to find companions around the Sloan Digital Sky Survey (Cat. <VII/243>) and 2dF QSO Redshift Survey (Cat. <VII/241>) quasars. This sample includes 26 new binary quasars with separations R_prop_<50h^-1^kpc ({thetas}<10"), more than doubling the number of such systems known. We define a statistical sample of binaries selected with homogeneous criteria and compute its selection function, taking into account sources of incompleteness. The first measurement of the quasar correlation function on scales 10h^-1^kpc<R_prop_<400h^-1^kpc is presented.
1473. Binary red supergiants. II. B-type companions
ID:
ivo://CDS.VizieR/J/ApJ/875/124
Title:
Binary red supergiants. II. B-type companions
Short Name:
J/ApJ/875/124
Date:
20 Jan 2022 11:13:46
Publisher:
CDS
Description:
The percentage of massive main-sequence OB stars in binary systems is thought to be as high as 100%. However, very few Galactic binary red supergiants (RSGs) have been identified, despite the fact that these stars are the evolved descendants of OB stars. As shown in our recent paper, binary RSGs will likely have B-type companions, as dictated by stellar evolution considerations. Such a system will have a very unique photometric signature due to the shape of the spectral energy distribution. Using photometric cutoffs, it should therefore be possible to detect candidate RSG+B star binary systems. Here we present our spectroscopic follow-up observations of such candidates. Out of our initial list of 280 candidates in M31 and M33, we observed 149 and confirmed 63 as newly discovered RSG+B star binary systems. Additional spectra of four candidate systems in the Small Magellanic Cloud confirmed all of them as new RSG+B star binaries including the first known RSG+Be star system. By fitting BSTAR06 and MARCS model atmospheres to the newly obtained spectra, we place estimates on the temperatures and subtypes of both the B stars and RSGs. Overall, we have found 87 new RSG+B star binary systems in M31, M33 and the Small and Large Magellanic Clouds. Our future studies are aimed at determining the binary fraction of RSGs.
1474. Binary speckle measurements at Calar Alto
ID:
ivo://CDS.VizieR/J/AJ/127/1181
Title:
Binary speckle measurements at Calar Alto
Short Name:
J/AJ/127/1181
Date:
21 Oct 2021
Publisher:
CDS
Description:
Results of our second observational run of binary star interferometric measurements with an ICCD speckle camera attached to the 1.52m telescope of the Observatorio Astronomico Nacional at Calar Alto (Almeria, Spain) in 2000 June-July are presented. The measured angular separations range from 0.096" to 6.558". With the use of the new speckle data, the orbits of the visual binaries WDS 14369+4813 and WDS 21597+4908 are improved.
1475. Binary speckle measurements at Calar Alto. I.
ID:
ivo://CDS.VizieR/J/A+A/366/868
Title:
Binary speckle measurements at Calar Alto. I.
Short Name:
J/A+A/366/868
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first results of our speckle interferometric measurements of binary stars made with the ICCD speckle camera using the 1.52-m telescope of the Observatorio Astronomico Nacional at Calar Alto (Spain) in September, 1999. The data contain 123 observations of 83 systems. The measured angular separations range from 0.153" to 6.727". We have used there new speckle measurements to improve the orbital elements for the binaries COU 247 and BU 524 AB.
1476. Binary star orbits
ID:
ivo://CDS.VizieR/J/AJ/123/1023
Title:
Binary star orbits
Short Name:
J/AJ/123/1023
Date:
21 Oct 2021
Publisher:
CDS
Description:
Orbital elements are presented for 117 binary systems with no previous orbit calculation. For nearly all of these systems, these elements must be regarded as preliminary, but the ephemerides presented here should be relatively accurate over the next several decades. Further, the analysis of these systems should highlight the need for their continued observation by dedicated programs to improve the veracity of these elements.
1477. Binary Star Pop. with Common Proper Motion
ID:
ivo://CDS.VizieR/J/AZh/97/733
Title:
Binary Star Pop. with Common Proper Motion
Short Name:
J/AZh/97/733
Date:
22 Feb 2022
Publisher:
CDS
Description:
We describe a homogeneous catalog compilation of common proper motion stars based on GaiaDR2. A preliminary list of all pairs of stars within the radius of 100pc around the Sun with a separation less than a parsec was compiled. Also, a subset of comoving pairs, wide binary stars, was selected. The clusters and systems with multiplicity larger than 2 were excluded from consideration. The resulting catalog contains 10358 pairs of stars. The catalog selectivity function was estimated by comparison with a set of randomly selected field stars and with a model sample obtained by population synthesis. The estimates of the star masses in the catalogued objects, both components of which belong to the main-sequence, show an excess of ''twins'', composed by stars with similar masses. This excess decreases with increasing separation between components. It is shown that such an effect cannot be a consequence of the selectivity function only and does not appear in the model where star formation of similar masses is not artificially preferred. The article is based on the talk presented at the conference ''Astrometry yesterday, today, tomorrow'' (Sternberg Astronomical Institute of the Moscow State University, October 14 - 16, 2019).
1478. Binary stars astrom. and photom. measurements
ID:
ivo://CDS.VizieR/J/MNRAS/473/4497
Title:
Binary stars astrom. and photom. measurements
Short Name:
J/MNRAS/473/4497
Date:
21 Oct 2021
Publisher:
CDS
Description:
The adaptive optics system at the 3.6m Advanced Electro-Optical System telescope was used to measure the astrometry and differential magnitude in I band of binary star systems between 2002 and 2006. We report 413 astrometric and photometric measurements of 373 stellar pairs. The astrometric measurements will be of use for future orbital determination, and the photometric measurements will be of use in estimating the spectral types of the component stars. For 21 binaries that had not been observed in decades, we are able to confirm that the systems share common proper motion. Candidate new companions were detected in 24 systems; for these we show the discovery images. Follow-up observations should be able to determine if these systems share common proper motion and are gravitationally bound objects. We computed orbits for nine binaries. Of these, the orbits of five systems are improved compared to prior orbits and four systems have their orbits computed for the first time. In addition, 315 stars were unresolved and the full-width half maxima of the images are presented.
1479. 2590 binary stars in Hipparcos and Gaia DR2
ID:
ivo://CDS.VizieR/J/AJ/160/284
Title:
2590 binary stars in Hipparcos and Gaia DR2
Short Name:
J/AJ/160/284
Date:
09 Mar 2022 22:00:00
Publisher:
CDS
Description:
The Hipparcos catalog and its Double and Multiple System Annex (DMSA) lists 4099 components with individual proper motions and coordinates on the epoch 1991.25. Many of these long-period binary stars are also present in Gaia Data Release 2 (DR2). Using the available relative positions and proper motions separated by 24.25yr, the equations of relative orbital motion can be solved for the two epoch eccentric anomalies, orbital period, and eccentricity. This method employs elimination of the linear Thiele-Innes unknowns and nonlinear optimization of the remaining condition equations. The quality of these solutions is compromised by the insufficient condition and modest precision of the Hipparcos astrometric data, as revealed by Monte Carlo simulations with artificially perturbed data points. The presence of multiple systems and optical pairs can also perturb the results. Limited experiments with artificial data indicate that useful estimates can be obtained with a 25yr epoch difference for wide binaries with orbital periods up to ~500yr. The prospects of this method dramatically improve with the proposed next-generation space astrometry missions such as Gaia-NIR and Theia, especially when additional conditions are included from astrometric or spectroscopic measurements. An ancillary catalog of cross-identification and astrometric information for 1295 double-star pairs cross-matched in Gaia DR2 and Hipparcos is also published.
1480. Binary stars in the Orion Nebula Cluster
ID:
ivo://CDS.VizieR/J/A+A/458/461
Title:
Binary stars in the Orion Nebula Cluster
Short Name:
J/A+A/458/461
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on a high-spatial-resolution survey for binary stars in the periphery of the Orion Nebula Cluster, at 5-15arcmin (0.65-2pc) from the cluster center. We observed 228 stars with adaptive optics systems, in order to find companions at separations of 0.13"-1.12" (60-500AU), and detected 13 new binaries. Combined with the results of Petr (1998, Ph.D. Thesis, University of Heidelberg), we have a sample of 275 objects, about half of which have masses from the literature and high probabilities to be cluster members.

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