1302.5830 (L. Tal-Or et al.)

CoRoT 101186644: A transiting low-mass dense M-dwarf on an eccentric 20.7-day period orbit around a late F-star    [PDF]

L. Tal-Or, T. Mazeh, R. Alonso, F. Bouchy, J. Cabrera, H. J. Deeg, M. Deleuil, S. Faigler, M. Fridlund, G. Hebrard, C. Moutou, A. Santerne, B. Tingley

We present the study of the CoRoT transiting planet candidate 101186644, also named LRc01_E1_4780. Analysis of the CoRoT lightcurve and the HARPS spectroscopic follow-up observations of this faint (m_V = 16) candidate revealed an eclipsing binary composed of a late F-type primary (T_eff = 6090 +/- 200 K) and a low-mass, dense late M-dwarf secondary on an eccentric (e = 0.4) orbit with a period of ~20.7 days. The M-dwarf has a mass of 0.096 +/- 0.011 M_Sun, and a radius of 0.104 +0.026/-0.006 R_Sun, which probably makes it the smallest and densest late M-dwarf reported so far. Unlike the claim that theoretical models predict radii that are 5%-15% smaller than measured for low-mass stars, this one seems to have a radius that is consistent and might even be below the radius predicted by theoretical models.

View original: http://arxiv.org/abs/1302.5830