Top left panel: difference of β from the MBBV fits to the data and MBBF with β = 2 vs. temperature from MBBF fits. Top right panel: the same but vs. the difference in MBBV T_dust – MBBF T_dust. Bottom panels: the same as for the top panels but for the MBBV and MBBF fits to the DL07 best-fit models. Points are coded by their oxygen abundance, with filled symbols corresponding to R/R_opt≤ 0.8 and open ones to larger radii. Only those MBBV and MBBF fits with ≤ 2 are shown.