Top: real part of the radiative luminosity perturbation for the mode of radial order n = 23 versus logarithm of temperature. The solid line represents the full non-adiabatic computation as described in Sect. A.1, while the dashed line represents the approximate expression given by Eq. (A.6). The rapid variation near log T = 4.17 is the result of the presence of a node of the eigenfunction. Bottom: real part of the convective luminosity perturbation for the mode of radial order n = 23 versus logarithm of temperature. The solid line represents the full non-adiabatic computation as described in Sect. A.1, while the dashed line represents the approximate expression given by Eq. (A.7).