Evolution of the radius, R, for planets with a given T_eq = 1750,2000,2250 K (from left to right), different masses (M = 0.7,1,2,4 M_j in blue, green, orange, and purple, respectively), and different values of v_avg, marked by increasingly darker shades: υ_avg = {0,1000,2000,3000}/[(M/M_j)(T_eq/1500K)⁶] m/s. In each panel, the grey band indicates the range of observed radii for HJs with T_eq around (±125 K), which is the value assumed in the models, R̄ ± σ_R, as shown by grey background boxes in Fig. 1.