Orbital evolution of a planetesimal initially located at 13.8 AU dictated via the gravitational interaction with a migrating Jupiter-mass protoplanet. The dots and crosses show the locations of the planetesimal and the protoplanet, respectively, and are colour-coded according to time. In this simulation the surface density of disk gas is set to that of the minimum-mass solar nebula and aerodynamic gas drag is included. Here, the protoplanet migrates from 15.0 AU with a migration rate of 10⁵ AU yr⁻¹. For the details of the numerical simulation, see Sect. 3.