We thank Dr. S.J. Aarseth for providing his computer code, for reading the manuscript and for helpful comments. The authors are also grateful to Dr. S.J. Aarseth and Dr. R.A. Mardling for the use of their stability criterion before publication. The authors thank the Department of Astrophysics of Universidad Complutense de Madrid for allotting excellent computing facilities. In preparation of this paper, we made use of the SIMBAD database at CDS, Strasbourg, France, the ASTRO-PH e-print server, and the NASA Astrophysics Data System. Our deepest thanks are due to the referee, Tsevi Mazeh, for many comments and suggestions, which substantially improved this manuscript.
© European Southern Observatory (ESO) 1997
Online publication: April 8, 1998