Similar to Fig. 2, but using Eq. (31) as an approximation for the gap depth, showing better agreement with the data. As in Fig. 2, different colours represent different levels of viscosity as shown in the legend, and different symbols represent different aspect ratios and planetary masses: squares, downward-pointing triangles, and upward-pointing triangles for h = 0.04, 0.05, and 0.06 respectively; empty, filled, and crossed symbols for m_pl/M_* = 10⁻⁵, 3 × 10⁻⁵, and 6 × 10⁻⁵, respectively.