The time-scale of escape from star clusters

• Published in: Monthly notices of the Royal Astronomical Society Vol. 318; no. 3; pp. 753 - 761
• Main Authors: Fukushige, T., Heggie, D. C.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.11.2000
• Subjects: celestial mechanics; celestial mechanics; stellar dynamics; chaos; globular clusters: general; gravitation; open clusters and associations: general; stellar dynamics; celestial mechanics; stellar dynamics; chaos; gravitation; open clusters and associations: general; globular clusters: general
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1046/j.1365-8711.2000.03811.x

Abstract In this paper a cluster is modelled as a smooth potential (due to the cluster stars) plus the steady tidal field of the Galaxy. In this model there is a minimum energy below which stars cannot escape. Above this energy, however, the time-scale on which a star escapes varies with the orbital parameters of the star (mainly its energy) in a way which we attempt to quantify, with both theoretical arguments and computer simulations. Within the limitations of the model we show that the time-scale is long enough to complicate the interpretation of full N-body simulations of clusters, and that stars above the escape energy may remain bound to the cluster for about a Hubble time.