Left: transit radius of CoRoT-25b as a function of age, as computed with SET. The 68.3%, 95.5%, and 99.7% confidence regions are denoted by three shades of gray. The curves represent the thermal evolution of a 0.27 M_J planet with an equilibrium temperature of 1330 K. Text labels indicate the amount of heavy elements in the planet (its core mass, in Earth masses). Solid lines represent planetary evolution models for which 0.25% of the incoming stellar flux is dissipated into the core of the planet, whereas dashed lines do not account for this dissipation (standard models). Right: the same for CoRoT-26b, for an 0.52 M_J planet with an equilibrium temperature of 1600 K.