Value of ﹩{R}_{\mathrm{XUV}}^{3}﹩ at times τ = 0, 25, 50, 75, and 100 Myr (shown by the blue, green, red, cyan, and magenta curves, respectively) for planets between 1.75 M_⊕ and 10 M_⊕ around a Sun-like star at 0.1 au. The model parameters were set to T = 880 K, F_XUV = 55 W m⁻², α = 0.03, η = 0.1, p_XUV = 5 Pa, and R_g = 4157 J kg⁻¹ K⁻¹. The low-mass planets have large ﹩{R}_{\mathrm{XUV}}^{3}﹩ values that cause rapid loss. By ∼6 M_⊕, ﹩{R}_{\mathrm{XUV}}^{3}﹩ has become roughly constant with mass. The approximately flat line at low masses (below ∼2.5 M_⊕ for the magenta curve) indicates that, for a given τ, the atmosphere has been entirely lost and ﹩{R}_{\mathrm{XUV}}^{3}﹩ is at the surface of the planet.