Binary masses and luminosities with Gaia DR3

Abstract

Context. The recent third data release (DR3) of Gaia has brought some new exciting data about stellar binaries. It provides new opportunities to fully characterize more stellar systems and contributes to enriching our global knowledge of stellar behaviour. Aims. By combining the new Gaia non-single stars catalogue with double-lined spectroscopic binaries (SB2), we can determine the individual masses and luminosities of the components. To fit an empirical mass-luminosity relation in the Gaia G band, lower-mass stars must be added. These masses can be derived using Gaia-resolved wide binaries combined with literature data. Methods. Using the BINARYS tool, we combined the astrometric non-single star solutions in the Gaia DR3 with SB2 data from two other catalogues: the 9th Catalogue of Spectroscopic Binary orbits (SB9), and APOGEE. We also searched for low-mass stars that are resolved in Gaia with direct imaging and HIPPARCOS data or with a literature mass fraction. Results. The combination of Gaia astrometric non-single star solutions with double-lined spectroscopic data enabled us to characterize 43 binary systems with SB9 and 13 systems with APOGEE. We furthermore derived the masses of 6 low-mass binaries that are resolved with Gaia. We then derived an empirical mass-luminosity relation in the Gaia G band down to 0.12 ℳ⊙.