Vertical cut of the main heating and cooling rates within the gap, at 20 AU, for the α= 10⁻³, M_p = 15 M_J model. Heating rates are shown with dashed lines; cooling rates are indicated with solid lines. Molecules and atoms contributingto both heating and cooling share the same color in both panels. The gray solid line shows the total cooling rate, which equals the total heating rate. Different colors indicate different contributors. In the legend, “PE” stands for photoelectric effect.