This work has been supported by the Deutsches Zentrum für Luft- und Raumfahrt (DLR) under grant 50 OR 96173. DK thanks Dr. Jay Holberg and Dr. Jim Liebert for their hospitality during summer 2000 at the University of Arizona and the Deutsche Forschungsgemeinschaft (DFG) for a travel grant. We are grateful to the referee Dr. Stephane Vennes for his helpful comments and particularly for his identification of Zn III.
© European Southern Observatory (ESO) 2000
Online publication: October 2, 2000