Mass-radius diagrams with simulated planets from nine different realisations of the fiducial model (parameter values listed in Table 1). Simulated planets are plotted by blue dots; TRAPPIST-1 planets by red crosses (data taken from Dorn et al. 2018). The solid, dotted, and dashed lines correspond to mass-radius relations for a rocky composition and a water fraction of 0, 10, and 20%, respectively. The mass-radius relations are the same as the ones used in Dorn et al. (2018). The arrows starting from the simulated planets depict the trajectories on the mass-radius diagram that the simulated planets would cover if they were to lose their entire water content.