The low-mass companions in eclipsing binaries with F/G primaries: a large sample analysis

Abstract

We present the absolute and orbital parameters of eleven very-low mass stars in eclipsing binaries, featuring F/G/K primaries and M dwarf secondaries, all positioned within the fully convective regime (M* < 0.35 ⊙) and down to the hydrogen burning mass limit (MHB∼0.07 ⊙). They show orbital periods exceeding several days, enabling us to explore the differences between observed and theoretical temperatures and radii. Our analyses, based on high-precision space photometry and enhanced by optical and infrared spectroscopy, yield measurements that closely match stellar evolution models. We suspect a slight systematic inflation in the radii of low-mass stars are likely due to observational errors, when compared to model predictions in the fully convective low-mass regime. The vital role of these results lies in their proof that low-mass eclipsing binaries provide an important chance to determine empirical masses and radii for these stars. In the end, our findings contribute eleven remarkable observations to the mass-radius diagram of fully convective M-dwarfs.