Shock heating rate by planet’s spirals estimated by method in Sect. 2 and damped using Eq. (8) for different shock strengths (σ = Σ₂∕Σ₁, γ =⁷∕₅) compared to viscous and irradiative heating rates (dashed and solid black lines; see Sect. 3.1). Lilac band indicates the corotating region, in which the estimates are not valid due to potential gap opening. The model used for this plot assumes M_p = 100 M_⊕, Ṁ = 10⁻⁸ M_⊙ yr⁻¹, α = 10⁻³, r_p = 4 au (see Sects. 3.1 and 3.2).