Temperature contours from our model with T_eff = 6500 K and log   g = 4.5 with [Fe / H] = 0.0 (left) and − 3.0 (right). The top panels display horizontal slices with the reversed granulation pattern imprinted in the temperature map (from 3 to 7 × 10³ K) taken at ~ 230 km above the surface, which is also indicated in the second panel (dashed lines). The panels below show vertical slices (T-contours from 2 to 17 × 10³ K) ranging from − 5.0 ≤ log τ_Ross ≤ 5.0 on layers of constant geometrical height (second), column mass density (third) and Rosseland optical depth (last panel). These panels include isocontours of the temperature (5, 10 and 12 × 10³ K; yellow lines) and density (0.1, 1.0 and 2.5 × 10^-7g / cm³; blue lines) and both increase with decreasing vertical depth. We show also lines of constant optical depth (second) and geometrical depth (third and last) indicated with white lines.