Backtracked half-mass radii for a simulation with 1000 stars, Top: using bound (blue) and unbound (red) members only. Red dashed lines show t_emb and r_hm at the time of gas expulsion determined using unbound stars whereas black dashed lines show the actual values of the same. Bottom: using unbound stars within 10 pc (blue), 20 pc (red) and 40 pc (green) from the cluster centre. The actual values of t_emb and r_hm at the time of gas expulsion are shown in cyan.