Observed spectrum of HN Peg B (heavy black line), compared to synthetic spectra with various ﹩T_{\mathrm{eff}\,}﹩, gravity, sedimentation efficiency ﹩f_{\mathrm{sed}\,}﹩, and vertical mixing diffusion coefficient ﹩K_{zz}﹩ parameters, as indicated in the legends. The model fluxes have been scaled to flux at the Earth using the known distance to HN Peg and the HN Peg B radii calculated by evolutionary models. The top panel shows our best‐fitting model (red line) together with a similar model with thicker cloud decks (brown line). The bottom panel shows the best‐fitting cooler model (blue line), together with a warmer model spectrum demonstrating the effect of less vertical transport (green line; compare to brown line in top panel).