Photometry of PDS 70b in comparison with evolutionary models, evaluated at an age of 5.4 Myr. The green crosses mark the measurements corresponding to the different H2 and L′ epochs. Upper panel: “hottest”, “hot”, and “warm” models from Mordasini et al. (2017), as well as the DUSTY model in a H2 vs. H2-K1 diagram. The lower panel compares the L′ vs. H2-L′ colour of the DUSTY model with the measured photometry. The corresponding masses in units of M_Jup are indicated bythe coloured labels.