Total Hα luminosity (line color) from the shocks on the planet and CPD surfaces as a function of the local (gap-reduced) gas surface density Σ (see the text for discussion of meaning) and the size of centrifugal radius relative to the Hill radius f_cent. A thin dashed line highlights our fiducial value f_cent = 0.03. The radius is fixed to R_p = 2.1R_J, but the mass is M_p = 2, 5, 10 M_J (thin to thick lines). The black dashed lines are for L_Hα = (6.5 ± 0.9) × 10⁻⁷ L_⊙ for PDS 70 b at one epoch (Y. Zhou et al. 2021) for each mass.