Abstract

Ellipsoidal red giant binaries are a particular class of binary stars where the primary gets tidally deformed by the interaction with the companion. They are the prelude stage before binary interactions, and the study of their population properties is therefore of great relevance to understanding the effects of tidal circularization and the binary evolution of these systems. Combining various Gaia data sets, including astrometry, photometry and spectroscopy, as well as variability information, we derived the physical parameters of more than 300 ellipsoidal red giant binary candidates. An estimate for the mass of the secondary star was also recovered. This unprecedentedly large sample allows us to compare its physical properties (mass, luminosity, radius), orbital parameters (mass-ration, filling factor, eccentricity) and chemical information (metallicity, [alpha/Fe] abundances), to better understand this stage in binary evolution.