On the response of a star cluster to a tidal perturbation

ABSTRACT We study the response of star clusters to individual tidal perturbations using controlled N-body simulations. consider by a moving point mass and disc, vary duration perturbation as well cluster density profile. For fast (i.e. ‘shocks’), gains energy in agreement with theoretical predictions impulsive limit. slow disc perturbations, gain is lower, this has previously been attributed adiabatic damping. However, due point-mass similar to, or larger than that shocks, which not expected because damping should be almost independent nature tides. show geometric distortion during comparable importance for damping, combined effect can qualitatively explain results. The half-mass radius bound stars after shock increases up ∼7 per cent low-concentration clusters, decreases ∼3 most concentrated ones. fractional loss non-linear function gain, depends on tides strongly profile, making semi-analytic model lifetimes extremely sensitive adopted