Top panel: chemical equilibrium abundances calculated with rate at 1 bar (solid lines), 100 mbar (dashed lines), and 10 mbar (dotted lines) (Cubillos et al. 2019). For reference, model-dependent effective temperatures of β Pic b (derived in Sect. 4.3) and of the rest of the sample (Maire et al. 2016; Delorme et al. 2017; Cheetham et al. 2019) are indicated by horizontally dashed lines. Bottom panel: molecular opacities calculated with petitRADTRANS at 1 bar and 1500 K (Mollière et al. 2019). Filter bandpasses are indicated with horizontal bars.