http://arxiv.org/abs/2206.00604
Objects from the Sixth catalog of orbits of visual binary stars (ORB6) are investigated to validate Gaia EDR3 parallaxes and provide mass estimates for the respected systems. We show that 2/3 of binaries with 0.2 — 0.5 arcsec separation are left without parallax solution in EDR3. A special attention is paid to 521 pairs with parallax known separately for both components. 16 entries are deemed optical pairs. At once we give examples of solid binary stars with large discrepancy of reported parallaxes, which are underestimated at least by a factor of 3 for stars with large RUWE. Parallaxes are needed to estimate stellar masses. Since nearly 30\% of ORB6 entries lack full 5 or 6-parameter solution in EDR3, we attempt to enrich the astrometric data. Distant companions of ORB6 entries are revealed in EDR3 by analysis of stellar proper motion and Hipparcos parallaxes. In certain cases intrinsic EDR3 parallaxes of binary components are less reliable than of the outer companions. Gaia DR2, TGAS and Hipparcos parallaxes are used when EDR3 data is unavailable. Synthetic mass-luminosity relation in G band for main sequence stars is obtained to provide mass estimates along with dynamical mass calculated via Kepler’s Third Law.
D. Chulkov and O. Malkov
Thu, 2 Jun 22
40/57
Comments: Submitted to MNRAS 31.05.2022