Midplane dust-to-gas ratio as a function of time (ordinate) and space (abscissa). The color map was chosen like in Fig. 18, with the solid green line indicating the position of the snow line. The top row shows simulations based on the R1 core collapse simulation and the bottom row shows simulations based on R7. Panels on the left-hand side present simulations with $\overline{a}$ = 1 μm, ε_mid,crit = 1, ε₀ = 0.01, χ = 100 and ξ = 3. This corresponds to the case discussed in Sect. 4.3 for R2. The panels on the right-hand side show simulations with $\overline{a}$ = a₁, ε_mid,crit = 0.5, ε₀ = 0.05, χ = 100 and ξ = 5, which corresponds to the case discussed in Sect. 4.5 for R2.