Distribution of solid mass with Discs A and B (left and right panels, respectively). The pebble mass fluxes of the upper and lower panels are Ṁ_peb = 10⁻⁴ and 10⁻⁵ M_E yr⁻¹, respectively.The purple curves represent the cumulative mass of the pebbles flowing into the calculation area from the outside of 50 au. The green curves represent the cumulative mass of the pebbles flowing out from the calculation area through the orbit of the planet. The light blue and orange curves indicate the total mass of the pebbles and planetesimals within the calculation area at each time, respectively. The dotted curves indicate those with the half migration speed.