Exoplanets versus brown dwarfs: the CoRoT view and the future

TL;DR

This paper reviews CoRoT's discoveries of objects ranging from Earth-sized planets to brown dwarfs, highlighting the lack of a clear mass-radius relation and discussing the implications for distinguishing planets from brown dwarfs.

Contribution

It provides observational data from CoRoT that challenges the simple mass-radius relation and informs the ongoing debate on differentiating planets from brown dwarfs.

Findings

No clear mass-radius relation for CoRoT objects

Objects range from Earth-sized planets to brown dwarfs

Implications for planet-brown dwarf classification

Abstract

CoRoT has detected by transit several tens of objects whose radii run from 1.67 Earth radius. Their mass run from less than 5.7 Earth mass (CoRoT-24 b, Alonso et al. 2014) to 63 Jupiter mass (CoRoT-15 b, Bouchy et al. 2011). One could be tempted to think that more massive the object is, the larger it is in size and that there is some limit in mass and/or radius beyond which objects are not planets but very low mass stars below the 80 Jupiter mass limit to trigger nuclear fusion (namely "brown dwarfs" ). CoRoT findings contribute to the planet versus brown dwarf debate since there is no clear mass-radius relation.