Comparison between simulation results and the simple estimates derived in Sect. 5.2 after 3 Myr of dust evolution. The upper panel is for a turbulence value of α_t = 10^-3, the lower panel for α_t = 10^-2. The estimates have been calculated using the dust accretion rate of the simulations at 50 AU which are 1.6 × 10^-6 and /yr, respectively. The division between the different fit formulas is described in Sect. 5.2.