Adiabatic exponent as a function of total pressure in UPM (dashed magenta line) and PM (solid green and blue lines). For PM, ones for the GGM (Γ₁, green) and for the RGM (, blue) are shown as functions of the total pressure. The vertical solid line indicates the matching point between 1D and 3D models. The vertical dashed lines indicate the bottom and top of the convection zone determined by the Schwarzschild criterion, labelled as BCZ and TCZ, respectively.