We like to thank Jan Bernkopf for valuable discussions on the evolutionary status of Procyon. Several suggestions of the referee are gratefully acknowledged. This research was supported by the BMBF under grant 0 5 2MU114 7 and partly by the Deutsche Forschungsgemeinschaft, DFG under grant Ge 490/9-2. K.F. finally is grateful to his wife Meike for financial support.
© European Southern Observatory (ESO) 1997
Online publication: May 26, 1998