Evolution of radii (top row, with dots indicating the dynamo radius and the solid the planetary radius), estimated magnetic field produced in the dynamo region (second row, with dots for B_dyn and solid lines for the planetary surface, B_atm, assuming f_dip = 0.1), Ohmic efficiency (third row), and σ_atm (bottom row). Each column represent a mass, from left to right: M = 0.7,1,4 M_j. In all panels, colours indicate T_eq = 1500,1750,2000,2250 K (blue, green, orange, respectively), and four values υ_avg = {0,1,2,3}/[(M/M_j)(T_eq/1500K)⁶] km/s are indicated by increasingly darker shades. The curves of magnetic fields have been smoothed out by a Savitzky–Golay filter (window length 21, polynomial degree 3) to visually smooth out the frequent oscillations seen in the most heated and irradiated cases in light planets (see text).