Contraction of CoRoT-2b relative to its measured radius and inferred age (see Fig. 12). The evolution models are labeled as follows: standard (black): irradiated, solar-composition planet with no extra heat source; 1% K.E. (blue): 1% of the incoming stellar flux is assumed to be dissipated at the planet’s center; opacities  ×  30 (light blue): opacities have been artificially multiplied by 30 compared to the standard model; 10²⁹(red): model in which 10²⁹   erg   s^-1 is deposited at the planet’s center.