Temperature dependence of the mass–radius relationship for isothermal models of wet super-Earth planets containing 50% water denoted as Wet. The surface temperatures are indicated in the figure. The dots represent detected planets in this range of planetary mass. Isothermal models: pure water (water), silicates (MgSiO₃), iron (Fe), Earth-like composition containing 66% silicates and 33% iron (Earth-like; Bouchet et al. 2013; Mazevet et al. 2015). The benchmark calculations for wet super-Earth planets are from Thomas & Madhusudhan (2016).