CALIBRATING GAIA DR3 UNCERTAINTIES BASED ON DATA FOR WIDE BINARY STARS OF THE FIELD OF GALAXY

Abstract

We use the catalog of wide binary stars [1], created on the basis of Gaia EDR3 and including more than a million pairs, to analyze Gaia DR3 data independently obtained for the components of the pairs. It is shown that the spatial heterogeneity of the catalog reflects the Gaia scanning law. The change in the spatial density of binary stars of the catalog with increasing distance from the Sun is investigated. By comparison with the model distribution, it is shown that the catalog contains approximately 2.5 times fewer binary stars than would be expected without spatial incompleteness. It is confirmed that the radius of spatial completeness of the catalog is on average close to 200 pc and depends on the absolute magnitude of the main component. The spatial density of binary stars in the catalog mildly depends on the difference in the stellar magnitudes of the components, and significantly depends on the physical distance between the components. The incompleteness of the catalog in relation to pairs with a distance between components less than 100 AU occurs already at a distance of 25 pc from the Sun. A comparison of the characteristics of components of the same pair independently determined within the Gaia DR3 catalog allows us to investigate how the probability of a non-random combination of components is related to the proximity of their characteristics. A high degree of correlation of the degree of agreement of the characteristics with the reliability of the pair is found for radial velocities. Qualitative agreement is observed for the metallicity estimates of [Fe/H] and, to a lesser extent, for the absorption estimates of \({{A}_{G}}\). No agreement was found for the ages of the stars, which indicates their significant uncertainty in the dataset consisting mainly of main sequence stars. At the same time, age estimates for pairs with evolved components show noticeably better agreement than for the dataset as a whole. Using the parameters of the components of pairs from Gaia DR3, an independent estimation of the uncertainties of the values of radial velocities and metallicities depending on the apparent magnitude G of the sources was performed. Estimates of probable median values of radial velocity errors and metallicity of Gaia DR3 sources are proposed. Depending on the apparent magnitude, they exceed the median values of errors given in the catalog: for radial velocities by 1.5–3 times, for metallicity [Fe/H] by 7–25 times. The paper is based on a talk presented at the astrophysical memorial seminar “Novelties in Understanding the Evolution of Binary Stars”, dedicated to the 90th anniversary of Professor M.A. Svechnikov.