* Astronomy

Title: CoRoT 101186644: A transiting low-mass dense M-dwarf on an eccentric 20.7-day period orbit around a late F-star
Authors: 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 Solar masses, and a radius of 0.104 +0.026/-0.006 Solar radii, 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.

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