Atmospheric models with severely depleted hydrogen at orbital distances of 0.01 and 0.04 AU. Top panel: TP profiles for C/O ratios of 1.0 (pink and blue) and 0.2 (faded) and an additional model of a pure silicate atmosphere (cyan). All cases assume dayside heat redistribution (f = 2/3) with volatile-containing atmospheres having 1 bar surface pressure. The total pressure in the pure silicate case is computed using the outgassing code. Top right: abundances of SiO and CO for the 0.01 AU case (blue TP profile), with the faint curves representing a pure silicate atmosphere. Bottom panel: emission spectra colour-coded for their respective TP profiles. The labelled regions denote major opacity contributions for the cases with a C/O ratio of 1.0. Spectral features for other cases are explained in the text. Spectra are shown at a resolution of λ/∆λ = 600.