Dynamical masses across the Hertzsprung–Russell diagram

Abstract

ABSTRACT We infer the dynamical masses of stars across the Hertzsprung–Russell (H–R) diagram using wide binaries from the Gaia survey. Gaia’s high-precision astrometry measures the wide binaries’ orbital motion, which contains the mass information. Using wide binaries as the training sample, we measure the mass of stars across the 2D H–R diagram using the combination of statistical inference and neural networks. Our results provide the dynamical mass measurements for main-sequence stars from 0.1 to 2 M⊙, unresolved binaries, and unresolved triples on the main sequence, and the mean masses of giants and white dwarfs. Two regions in the H–R diagram show interesting behaviours in mass, where one of them is pre-main-sequence stars, and the other one may be related to close compact object companions like M dwarf-white dwarf binaries. These mass measurements depend solely on Newtonian dynamics with minimal assumptions on eccentricities, providing independent constraints on stellar evolutionary models, and the occurrence rate of compact objects.