Mass-radius diagram of exoplanets with mass-radius measurements better than 25% from TEPCat (Southworth 2011) and for our candidates, color-coded by their equilibrium temperature. Two-layer models from Zeng et al. (2016) are displayed with different lines and colors. Here, “Earth-like” refers to a composition of 30% Fe and 70% MgSiO₃. The 2% H₂ line represents a composition consisting of a 98% Earth-like rocky core and a 2% H₂ envelope by mass, while the 49% H₂O + 2% H₂ line corresponds to a composition comprising a 49% Earth-like rocky core, a 49% H₂O layer, and a 2% H₂ envelope by mass. Earth and Venus are identified in this plot as pale blue and orange circles, respectively.