Mass radius relations of isothermal spheres in hydrostatic equilibrium made of 100 wt.% H₂O (solid lines) or 50 wt.% H₂O and 50 wt.% Earth-like composition as in Zeng et al. (2019) (dashed lines), for different EoS and different surface temperatures T_surf. The surfacepressure was chosen to be 1 mbar as in Zeng et al. (2019). For the cases with Earth-like composition, we used Hakim et al. (2018) as EoS for the Fe and Sotin et al. (2007) to calculate the density in the MgSiO₃ layer. Top left panel: Earth-like composition case is also plotted (dotted lines) in order to quantify the contribution from the underlying rocky part to the cases of mixed composition.