SCYON Abstract

Received on June 25 2009

On the dissolution of star clusters in the Galactic centre. I. Circular orbits

AuthorsAndreas Ernst (1,2), Andreas Just (1), and Rainer Spurzem (1)
Affiliation(1) Astronomisches Rechen-Institut am Zentrum für Astronomie der Universität Heidelberg
(2) Max-Planck-Institut für Astronomie
Accepted byMonthly Notices of the Royal Astronomical Society
Contactaernst@ari.uni-heidelberg.de
URLhttp://arxiv.org/abs/0906.4459
Links

Abstract

We present N-body simulations of dissolving star clusters close to galactic centres. For this purpose, we developed a new N-body program called nbody6gc based on Aarseth's series of N-body codes. We describe the algorithm in detail. We report about the density wave phenomenon in the tidal arms which has been recently explained by Kuepper et al. (2008). Standing waves develop in the tidal arms. The wave knots or clumps develop at the position, where the emerging tidal arm hits the potential wall of the effective potential and is reflected. The escaping stars move through the wave knots further into the tidal arms. We show the consistency of the positions of the wave knots with the theory in Just et al. (2009). We also demonstrate a simple method to study the properties of tidal arms. By solving many eigenvalue problems along the tidal arms, we construct numerically a 1D coordinate system whose direction is always along a principal axis of the local tensor of inertia. Along this coordinate system, physical quantities can be evaluated. The half-mass or dissolution times of our models are almost independent of the particle number which indicates that two-body relaxation is not the dominant mechanism leading to the dissolution. This may be a typical situation for many young star clusters. We propose a classification scheme which sheds light on the dissolution mechanism.