Left panel : comparison between the radius of the third sink, R₃, and the spatial separation of the second and third sink particles, dr_2,3 in the J₂₁ = 5000 simulation where sink particle mergers are not allowed. The radius of the second sink is similar to R₃, so it was left out for simplicity. The solid gray line shows the resolution limit of the simulation. Right panel : evolution of the protostellar mass in runs with (solid) and without (dashed) sink particle mergers. The epoch of the merger corresponds to the time when the solid and dashed lines diverge. The mass of the third star (orange) is added to that of the second star (green), creating a sudden jump in the stellar mass.