Time evolution of orbital eccentricity for different ejection outcomes in forward and backward integrations. (a) Ejection (forward): asteroids ejected in the forward integration but remaining bound in the backward integration. (b) Ejection (forward and backward): asteroids ejected in both integration directions. (c) No ejection: asteroids that remain bound in both forward and backward integrations. (d) Ejection (backward): asteroids ejected in the backward integration but remaining bound in the forward integration. The time zero corresponds to the present epoch; negative and positive times denote backward and forward propagation, respectively.