Temporal evolution (for cold start objects) of the luminosity as seen by an observer, i.e. including the accretion luminosity (first row, left), the surface temperature (first row, right), the radius (second row, left), the gravitational acceleration at the surface (second row, right), the specific entropy above the core (third row, left) and the degeneracy related factor Θ_e (third row, right) for objects with masses varying from 10 M_J to 23 M_J using our fiducial model as defined in Table 1. The black dashed line in all plots corresponds to the 13 M_J object. The horizontal green line in the plot of the radius indicates the position of 1 R_J. The masses corresponding to the lines are indicated in the plot.