Top panel: time dependence of the tail half-mass radius r_h, tail for the semi-analytic model (Eq. (22)). Middle panel: time evolution of the mean velocity v_y(r_h, tail) near the radius r_h, tail. The velocity oscillates substantially, and becomes negative when the tail moves towards the cluster. Lower panel: time evolution of the dynamical age of the tail, i.e. t_dyn = r_h, tail/v_y(r_h, tail). The black dotted line represents the real age t_dyn = t. The dynamical age is often substantially different from the real age, making t_dyn an unreliable estimate for the real age. All plots are calculated for clusters orbiting at three Galactocentric radii (6.5 kpc, green line; 8.5 kpc, red line; 10.5 kpc, blue line), and for stars escaping at velocity v_e = 1 km s⁻¹.