Trajectory of the nanodust particle with Q∕m = 10⁻⁴ e/m_p ejected fromthe comet (with orbital parameters of the comet Ikeya–Seki) at perihelium. The trajectory is shown in the (r, v_r) plane. Also shown is the approximate trajectory obtained in the phase space model, and the separatrix trajectory which defines the boundary of the trapped region (the closed curve). The crosses show the positions of the fixed points of the phase space model. The outer fixed point is of the saddle point type, while the inner is a node, encircled by the trapped trajectories.