Irradiated stars with convective envelopes
arXiv:1611.03290 · doi:10.1051/0004-6361/201630011
Abstract
The observed radii of M dwarfs in eclipsing binaries exceed predicted radii by ~ 5%. To investigate this anomaly, the structure of low-mass stars irradiated by a close companion is considered. Irradiation modifies the surface boundary conditions and thereby also the adiabatic constants of their outer convection zones. This changes the models' radii and luminosities. For short-period M dwarf binaries with components of similar mass, radius inflation due to their mutual irradiation is found to be < 0.4%. This is an order of magnitude too small to explain the observed anomaly. Although stronger irradiation results in a monotonically increasing radius, a saturation effect limits the inflation to <~ 5\%.
9 pages, 5 figures. Revisions incorporate referee's comments. Asymptotic theory added. Accepted by Astronomy & Astrophysics
References in corpus (5)
- A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
- New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
- Evolution of low-mass star and brown dwarf eclipsing binaries
- Hot subluminous stars
- Magnetic Inhibition of Convection and the Fundamental Properties of Low-Mass Stars. II. Fully Convective Main Sequence Stars