Surface density profile, Σ_t/Σ₀, after orbits and t_max = 3000 orbits of a m_pl/M_* = 3×10⁻⁵ planet in a disc with α_t = 3.16 × 10⁻⁴ and h = 0.05. We note that after the last 50 orbits, the surface density has reached a steady state, with a change of less than 0.1%. The black horizontal dashed line represents the prediction of the gap depth from Kanagawa et al. (2018). The two dot-dashed horizontal lines are used here to measure the observed depth of the gap carved by the planet by taking the average of their values.