Searching for new massive eclipsing binaries

M. JAQUE ARANCIBIA; R. H. BARBÁ; J. F. GONZÁLEZ; M. E. VERAMENDI; C. LÓPEZ; D. PONCE; N. MORRELL

La Serena

Congreso; Segunda Reunión Binacional AAA-SOCHIAS; 2018

Asociación Argentina de Astronomía - Sociedad Chilena de Astronomía

Massive eclipsing binary stars are rare objects. Considering all spectral types, there are about 120,000 eclipsing binaries, but only about 173 Galactic ones are known to have spectral types between O2 and B0, including 22 Wolf-Rayet stars, from a total sample of about 900 and 650 stars, respectively. Less than one-third of them are systems with mass and radius determination at 5% accuracy level. This scarcity of well-studied eclipsing systems have impact on confrontation with stellar models and on several open issues like the long-standing disagreement between the stellar masses predicted by evolutionary models and stellar atmospheres, and the empirical masses determined for massive binary stars, which introduces uncertainties to the mass-luminosity relationship for massive stars and the initial mass function at the upper-end. In this work, we are presenting the spectral classification of a first sample of more than one hundred eclipsing systems extracted from the VSX database, without previous reliable spectroscopic information. The sample selection is based on specific criteria applied to the spectral energy distribution, so that it corresponds toearly-type stars. Spectroscopic data were obtained at Complejo Astronómico El Leoncito O (Argentina). The systems confirmed spectroscopically as OB stars are being spectroscopically monitored to derive radial-velocity curves (see poster "Spectroscopic monitoring of massive eclipsing binaries").