Electron temperature as a function of the optical depth at 100 GHz. The thick black line is the result of our inversion of the CLV curves of Fig. 4, together with the data of Bastian et al. (1993). Thin black lines are inversions of individual wavelength bands. The symbols denote the Eddington-Barbier solution of the transfer equation. The full lines in color were computed from the models of Fontenla et al. (1993; FAL93) and Avrett & Loeser (2008).