Mean Rosseland opacities as a function of orbital distance and height for the different α values, the lowest gas surface densities, and the highest dust-to-gas ratio. Due to the larger grain sizes for the MRN distribution (Fig. A.1), the opacities for the MRN distribution are also generally lower compared to the BOD distribution. The light blue line corresponds to optical depth τ = 1 integrated vertically starting from infinity towards midplane, so it divides the optically thin (above) and thick region (below).