The time-scale of escape from star clusters |
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| Authors: | T Fukushige D C Heggie |
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| Institution: | Department of General Systems Studies, College of Arts and Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan;Department of Mathematics and Statistics, University of Edinburgh, King's Buildings, Edinburgh EH9 3JZ |
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| 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. |
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| Keywords: | chaos gravitation celestial mechanics stellar dynamics globular clusters: general open clusters and associations: general |
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