Astronomy and Astrophysics, volume 627A, 153-153 (2019/7-2)
Absolute dimensions of the low-mass eclipsing binary system NSVS 10653195.
IGLESIAS-MARZOA R., AREVALO M.J., LOPEZ-MORALES M., TORRES G., LAZARO C. and COUGHLIN J.L.
Abstract (from CDS):
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 Teff 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 Mbol-log Teff diagram. Conclusions. NSVS 10653195 is composed of two oversized and active K stars. While their radii is above model predictions their Teff are in better agreement with models.