SIMBAD references

Context. Low-mass stars in eclipsing binary systems show radii larger and effective temperatures lower than theoretical stellar models predict for isolated stars with the same masses. Eclipsing binaries with low-mass components are hard to find due to their low luminosity. As a consequence, the analysis of the known low-mass eclipsing systems is key to understand this behavior. Aims. We aim to investigate the mass-radius relation for low-mass stars and the cause of the deviation of the observed radii in low-mass detached eclipsing binary stars (LMDEB) from theoretical stellar models. Methods. We developed a physical model of the LMDEB system NSVS 10653195 to accurately measure the masses and radii of the components. We obtained several high-resolution spectra in order to fit a spectroscopic orbit. Standardized absolute photometry was obtained to measure reliable color indices and to measure the mean T_eff of the system in out-of-eclipse phases. We observed and analyzed optical VRI and infrared JK band differential light-curves which were fitted using PHOEBE. A Markov chain Monte-Carlo (MCMC) simulation near the solution found provides robust uncertainties for the fitted parameters. Results. NSVS 10653195 is a detached eclipsing binary composed of two similar stars with masses of M₁=0.6402±0.0052M_☉ and M₂=0.6511±0.0052M_☉ and radii of R₁=0.687^+0.017_–0.024R_☉ and R₂=0.672^+0.018_–0.022R_☉. Spectral types were estimated to be K6V and K7V. These stars rotate in a circular orbit with an orbital inclination of i=86.22±0.61 degrees and a period of P=0.5607222(2)d. The distance to the system is estimated to be d=135.2^+7.6_–7.9pc, in excellent agreement with the value from Gaia. If solar metallicity were assumed, the age of the system would be older than log(age)∼8 based on the M_bol-log T_eff diagram. Conclusions. NSVS 10653195 is composed of two oversized and active K stars. While their radii is above model predictions their T_eff are in better agreement with models.