Comparison between the Type-2 and Type-3 planets. Left column: depth of the surface oceans. Middle column: ocean mass fraction in the Type-3 planets. Of course, in the Type-3 planets corresponds to the values of the Type-2 planets. Right column: relative effect δR₂ ≡ (R₃ − R₂)∕R₂ of ocean differentiation on total planetary radius at given mass, composition and surface temperature (see also Fig. 1). For high values of ΔT_TBL and low masses, separation into an isolated surface ocean can lead to a net increase in the planetary density in comparison to the Type-2 planets. This is a result from the combined effects of ocean differentiation on the EoS parameters.