Spherical averages of luminosity (integrated radiative flux; top panel), corundum density (middle panel), and silicate density (bottom panel) in model st28gm06n038, as a function of radial distance and time. In the top panel, two isotherms with temperatures representative of corundum and silicate condensation are shown (at 1500 and 1150 K, respectively, same as in Figs. 2 and 6), to demonstrate the interplay between variable radiative heating and the inner edges of dust layers. The dark area in the lower part of the top panel represents the deep stellar interior, where most of the energy flux is transported by convection. The colored vertical lines in the bottom panel mark the instants selected for Figs. 2 and 3.