MDS benefitted greatly from the hospitality of the Max-Planck-Institut für Astronomie. We thank R. Klessen and E. Zweibel for advice and discussions. Computations were performed at the MPG Rechenzentrum Garching. M-MML holds a CAREER fellowship from the US National Science Foundation, grant number AST 99-85392.
© European Southern Observatory (ESO) 2000
Online publication: October 30, 19100