Predicted gap depth, Σ_min/Σ₀, from Kanagawa et al. (2018) versus value obtained from the simulations. Different colours represent different levels of viscosity as shown in the legend. The lower the viscosity, the bigger the difference in gap depth. However, down to the viscosities considered by Kanagawa et al. (2018), we see good agreement, as expected (the data for α_t = 3.16 × 10⁻³ are shown with smaller symbols as they are only used for the analysis of the gap depth). Different shapes are used to represent different aspect ratios and planetary masses; squares, downward-pointing triangles, and upward-pointing triangles represent aspect ratios of 0.04, 0.05, and 0.06, respectively; empty, filled and crossed symbols represent m_pl/M_* = 10⁻⁵, 3 × 10⁻⁵, and 6 × 10⁻⁵, respectively.