Log P – Log T plots for sub-photospheric layers at three points on the surface of the irradiated segment as well as for the dark segment. The incident direction cosines μ are indicated. The filled circles locate the onset of convection at the indicated optical depths τ. These plots correspond to the point L_⋆/L₀ = 57.5,R/R₀ = 1.04 in Fig. 4 where the mean albedo ⟨ A_μ ⟩ = 0.834.