Temporal evolution of the mean temperature stratification in the two metal-poor red giant simulations at  [Fe/H]  =  −2 from Fig. 7. The curves show the differences of the mean temperature with respect to the standard case (self-consistent solution of the radiative transfer equation for a source function with a coherent scattering term) as a function of time. The total temporal coverage is 28 h, with snapshots taken every 10 min. Left panel: temporal evolution for the simulation assuming a Planckian source function and no contribution of scattering to the total extinction in optically thin layers. Right panel: corresponding evolution under the assumption of Planckian source function with scattering treated as true absorption. See Fig. 3 for more details.