Future evolution of the two clusters (blue line in Fig. 5): snapshots at the present day (cluster age = T_a = 158 Myr), 100 Myr (cluster age = T_a + 100 Myr), 200 Myr (cluster age = T_a + 200 Myr) in the X–Y plane (top) and the X–Z plane (bottom) for the binary clusters with mass segregation degree S = 0. The blue and pink points refer to the members of NGC 2323-a and NGC 2323-b, respectively; the blue and red arrows indicate the relative velocities. Here the relative velocities are the velocities relative to the average velocity of the two clusters. The size of the points represents the stellar mass. The dotted and dashed circles represent the tidal radius of NGC 2323-a and NGC 2323-b. The orange dashed lines represent the line-of-sight direction.