Mean internal energy against mean density for dwarf models (log g = 4.5) with [Fe/H] = 0.0 and − 2.0 (left and right respectively). The specific isocontours for the entropy s_bot (green solid) and s_min (green dotted), Rosseland opacity per volume, ρκ_Ross, (blue) and temperature T (orange) are underlayed. Moreover, the positions of entropy minimum s_min (plus), optical surface (large square), vertical peak velocity (diamonds) and maximum in ∇_sad (triangle) are marked respectively. The amplitude of is indicated with horizontal bars with markings in 1 km s^-1. We also included the 1D models with α_MLT = 1.5 (blue dashed lines). The range in optical depth is shown from log τ_Ross =  −5.0 to + 5.0 for each dex (small squares). However, we note that our simulations boxes are much deeper (⟨log τ_Ross⟩ ≈  + 7.5).