Comparison of our numerical and analytical radiative-convective solutions for different adiabatic gradients in the non-irradiated, non-grey case. The thin line is the radiative zone and the thick one represents the convective zone. We used T_int = 500 K, g = 25 m/s², κ₂/κ₁ = 10², and β = 0.83. The cases ∇_ad × 2 (green) and ∇_ad × 4 (red) are superimposed.