a) Relative final disc size (asterisks) and disc mass (open squares) after an equal-mass encounter event (m₁₂ = 1) as a function of the relative periastron distance r_p = r_peri/r_previous, with r_peri periastron distance [AU] and r_previous disc size before the encounter [AU]. b) Parameter pairs (encounter mass ratio m₁₂ and relative periastron distance r_p) leading to 5% reduction in disc-size (asterisks) and disc mass (open squares). The light and dark grey areas depict the parameter space in which the disc size and mass are reduced.