Results of determining the dust-to-gas ratio using the three different methods described in Sect. 3.5.3 are shown for Model 2 in Table 4. The horizontal bar indicates the part of the envelope traced by the method. The vertical bar indicates the uncertainty on the indicated value. ψ_mom is a lower limit, whereas ψ_H2O is an upper limit. For reference, the dashed red line indicates ψ_H2O − fo assuming 20% freeze-out of H₂O vapor into H₂O ice. The relative differences between the three values of the dust-to-gas ratio for the other models in Table 4 are similar, but scale upward or downward uniformly depending on the gas-mass-loss rate. See Sect. 4.3 for a more detailed description.