This work was started while both authors were at the MPI für Astronomie in Heidelberg: we would like to thank Prof. H. Elsässer for his support. We are very grateful to the Calar Alto staff and to the FLASH-Spectrograph team at the Landessternwarte Heidelberg for their help during the observations. We especially thank R. Hewett and L. Hartmann for the use of their cross-correlation software, and G. Basri for very helpful comments on the first version of the manuscript. E.G. acknowledges financial support from PPARC and the assistance of STARLINK hardware and software in analysing our data. This research has made use of the Simbad database, operated at CDS, Strasbourg, France.
© European Southern Observatory (ESO) 1997
Online publication: June 30, 1998