CoRoT 101186644: A transiting low-mass dense M-dwarf on an eccentric 20.7-day period orbit around a late F-star Discovered in the CoRoT lightcurves

L. Tal-Or , T. Mazeh , R. Alonso , F. Bouchy , J. Cabrera , H. J. Deeg , M. Deleuil (1) , S. Faigler , M. Fridlund , G. Hebrard , C. Moutou (1) , A. Santerne (1) , B. Tingley

1 LAM - Laboratoire d'Astrophysique de Marseille

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 similar to 20.7 days. The M-dwarf has a mass of 0.096 +/- 0.011 M-circle dot, and a radius of 0.104(-0.006)(+0.026) R-circle dot, which possibly 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.

Domaines: Astrophysique [astro-ph]

L. Tal-Or, T. Mazeh, R. Alonso, F. Bouchy, J. Cabrera, et al.. CoRoT 101186644: A transiting low-mass dense M-dwarf on an eccentric 20.7-day period orbit around a late F-star Discovered in the CoRoT lightcurves. Astronomy and Astrophysics - A&A, 2013, 553, ⟨10.1051/0004-6361/201220862⟩. ⟨hal-01439439⟩