Tracks of the massive bodies in the simulation with α = 5 × 10⁻⁴. Each colour shows one of the five simulations corresponding to those in the final panel of Fig. 2, where the key timestamps are also denoted along the time axis on the right. The solid lines show the semimajor axis of the bodies reached 10 M_⊕ by the end of the simulations. The shaded areas indicate the extents of the lower and upper quartiles of the semimajor axes of all bodies when the total number is above 50.