Distance-radius diagram from an early population synthesis calculation around 1 M_⊙ stars at 5Gyr. Colors give the fraction of the initial H/He envelope mass that was lost. Gray dots are planets that have lost all H/He in the triangle of evaporation. The red line shows the upper limit at R_bare (a) given by Eq. (2). Just above the line, there is the valley of evaporation. Adapted from Jin et al. (2014).