Top: emission spectra generated to fit the Spitzer occultation depth, as described in Sect. 7.4. The spectrum from the HELIOS grid is shown in magenta and the best fitting blackbody is shown in orange. The unbinned spectra are shown with thin, lighter lines. Binned spectra are also shown in darker, thicker lines for display purposes. The measured CHEOPS and Spitzer occultation depths are shown with black squares with error bars, and the implied depths according to the spectra are shown with coloured circles (obscured by the measured depth in the case of Spitzer). The CHEOPS and Spitzer response functions are shown in grey. Inset top: the temperature–pressure profile of the best fitting HELIOS spectrum. Bottom: the same spectra, but shown in terms of flux instead of occultation depth. The PHOENIX spectrum used for the star is shown in red, shrunk by a factor of 50 for display purposes. Right inset: a closer look at the flux at wavelengths covered by the Spitzer/IRAC 4.5 μm bandpass. Other dotted lines in both panels are regions that are displayed in Fig. 12.