Results of planet evolution simulations in the orbital period-transit radius plane at 5 Gyr (left panel: energy- and recombination-limited model; right panel: hydrodynamic model). Each dot represents a planet which is coloured based on the fraction of its initial H and He envelope mass that was evaporated. Grey symbols indicate a complete loss of the envelope, corresponding to sub-Neptunes that have evolved into super-Earths. The magenta lines show the fit to determine the slope α of the valley as represented by the largest super-Earth at a given period (i.e. the bottom of the valley). We note the shallower slope in the hydrodynamic model. The squares show two individual cases (one far planet in lilac, one close in black). Both start with identical initial conditions in the two models and are discussed in Sect. 4.2. They end up on different sides of the valley in the two models in a way to make the slope shallower in the hydrodynamic model.