Evolution of the 0.2, 0.5, and 0.8 Lagrangian radius of the tidal tail for the number of stars for model C10G13 (red lines) and model C10W1 (blue lines). The half-number radius is indicated by the thick lines. The dashed line represents the semi-analytical half-number radius calculated by Eq. (22) and scaled to v_e = 4 km s⁻¹, which is chosen according to the median for model C10G13. This demonstrates an excellent agreement of the N-body model C10G13 with the semi-analytic result of Sect. 2.