Left panel: internal luminosity as a function of (total) mass (3 to 10 M_♃) at 10 (half-filled), 20 (filled), and 50 Myr (empty circles) in the cold-nominal population. But the color code now gives the core mass in units of Earth masses. The planets with a more massive core are more luminous for a given total mass and age. Right panel: internal luminosity as a function of [Fe/H] of the host star (and parent protoplanetary disk) at 20 Myr. The colors give again the core mass. Planets with M ≥ 3 M_♃ are shown.