Panel a: relative heating capacity e_ν in values of e_ν,max as a functionof altitude for 4 different core masses M_C =  0.1 M_⊕ (black), 1 M_⊕ (blue), 3 M_⊕ (green), and 5 M_⊕ (red). Here, e_ν is the heating/cooling rate of the atmosphere evaluated with 701 mass bins, folded with the size distribution function ν and weighted with the planet’s mass accretion rate M_C [M_⊕ yr ⁻¹]. Whereas forsmaller planets planetesimals cause a general heating of the atmosphere, for larger cores local cooling can occur (compare M_C = 3 and M_C = 5 M_⊕). Panel b: e_ν in values of e_ν,tot as a functionof optical depth τ. Again we compare 4 different core masses with M_C = 0.1 M_⊕ (black), 1 M_⊕ (blue), 3 M_⊕ (green), and 5 M_⊕ (red). The dashed lines represent the individual protoplanetary surfaces. Planetesimal infall results in a maximum energy input/output within the optical thick layers of the atmosphere.