Normalised model spectra (upper panel) and |V|² (lower panel) for our base model with simple radiative equilibrium (red) and the chromospheric temperature inversion profile by Harper et al. (2001; blue). Both models with a M_⊙ yr⁻¹. We can see that the main differences are in the regions λ = 2.35–3.0 µm and λ > 4.0 µm due to CO, where for the Harper+01 case the molecular lines appear more strongly in emission, and the visibilities are decreased due to a larger apparent diameter of the star.