  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.
