Calibration of Uncertainties of the Gaia DR3 Catalog Based on Data on Wide Binary Stars of the Galaxy Field

TL;DR

This study uses wide binary stars from Gaia DR3 to calibrate and analyze the catalog's completeness, uncertainties, and reliability, revealing significant underestimation of binary counts and providing improved error estimates for radial velocities and metallicities.

Contribution

It introduces a method to calibrate Gaia DR3 uncertainties using wide binary stars and assesses catalog completeness and reliability with new error estimates.

Findings

Gaia DR3 contains about 2.5 times fewer binaries than expected.

Spatial completeness radius is about 200 pc, varying with star brightness.

Radial velocity and metallicity errors are underestimated in the catalog.

Abstract

The catalog of wide binary stars by El-Badry et al. (2021) [arXiv:2101.05282], created on the basis of Gaia EDR3 data and including more than a million pairs, was used to analyze Gaia DR3 data obtained independently for their components. By comparison with the model distribution, it is shown that the catalog contains approximately 2.5 times fewer binary stars than would be expected in the absence of 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 depends weakly on the difference in the magnitudes of the components, and significantly depends on the physical distance between the components. A high correlation between the degree of agreement between the characteristics and the reliability of the pair was found for radial velocities. Qualitative agreement is observed for metallicity [Fe/H] estimates and, to a lesser extent, for absorption A_G estimates. No agreement was found for the ages of the stars, which indicates their great uncertainty in the ensemble, consisting mainly of main sequence stars. Age estimates for pairs with evolved components show significantly better agreement than for the dataset as a whole. Using the parameters of the components of the pairs from Gaia DR3, an independent estimate of the uncertainties in the radial velocities and metallicities depending on the apparent magnitude of the sources was performed. Estimates of the probable median values of errors in the radial velocities and metallicities of Gaia DR3 sources are proposed. Depending on the apparent magnitude, they exceed the median error values given in the catalog: for radial velocities by 1.5-3 times, for metallicities [Fe/H] by 7-25 times.