Notes. L_b is the luminosity of the blackbody, which in our model corresponds to the so-called internal luminosity; L_em is the amount of blackbody radiation that escapes the envelope, i.e., ; L_g is the luminosity of the greybody component; L_bol is the sum of L_em and L_g, the total observable luminosity predicted by the model; L_SED is the observed luminosity found by integrating the measured fluxes.