χ² map comparing a simulated observation of a rotating CoRoT-7b with a 0.3 Bond albedo to a family of models with various albedos, rotation periods, and an inertia-layer thickness of 25 cm. The cross is at the location of the best fitted model in the albedo–period space, and the star marks the position of the initial model (albedo =0.3 and rotation period =10.25 h =1/2 orbital period of CoRoT-7b).