Gaia Spectroscopic Orbits Validated with LAMOST and GALAH Radial Velocities
Abstract
The recently published Gaia DR3 catalog of 181 327 spectroscopic binaries (SB) includes the Keplerian elements of each orbit, but not the measured radial velocities (RVs) and their epochs themselves. Instead, the catalog lists a few parameters that characterize the robustness of each solution. In this work, we use two external sources to validate the orbits  17 563 LAMOST DR6 and 6 018 GALAH DR3 stars with measured RVs that have GaiaSB orbits. We compare the expected RVs, based on the Gaia orbits, with the LAMOST and GALAH measurements. Finding some orbits that are not consistent with these measurements, we constructed a function that estimates the probability of each of the Gaia orbits to be correct, using the published robust parameters. On this basis, we devise a clean but still very large Gaia SB1 sample of 91 740 orbits. The sample differs from the parent sample by the absence of  physically unlikely and hence presumably spurious  shortperiod binaries with high eccentricity. The clean SB1 sample offers the prospect of thorough statistical studies of the binary population, after careful modeling of the remaining selection effects. As a first step, we point to two possible emerging features  a circularized mainsequence subsample, and a paucity of shortperiod lowmass primary binaries
 Publication:

arXiv eprints
 Pub Date:
 July 2022
 arXiv:
 arXiv:2207.08832
 Bibcode:
 2022arXiv220708832B
 Keywords:

 Astrophysics  Solar and Stellar Astrophysics;
 Astrophysics  Earth and Planetary Astrophysics;
 Astrophysics  Astrophysics of Galaxies;
 Astrophysics  Instrumentation and Methods for Astrophysics
 EPrint:
 15 pages, 16 figures, submitted to MNRAS