We thank the staff at La Silla for their assistance. The construction of the spectrograph HEROS was supported by the Deutsche Forschungsgemeinschaft (Wo 296/20-1) and J.S. acknowledges the grant Wo 296/22-1. We thank Drs. A. Moffat, V. Niemela, and N. St-Louis for fruitful discussions and Drs. H. Nussbaumer and C. Lloyd for editorial comments.
© European Southern Observatory (ESO) 1997
Online publication: March 24, 1998