Densities of planets in the TOI-178, Trappist-1, K2-138, Kepler-60, Kepler-80, and Kepler-223 systems as a function of their equilibrium temperatures. The error bars give the 16 and 84% quantiles, and the marker is located at the median of the computed distribution. The colour code gives the planetary masses in Earth masses. The parameters of the planets are taken from the references mentioned in Fig. 15.