We acknowledge the excellent support by the CFHT staff, especially J.Glaspey, and the night help at the telescope. One author (C.B.) thanks in Lyon, France, the computing Department for its support. This research used the bibliographical stellar database, Simbad, operated at the "Centre de Données Stellaires" in Strasbourg, France. We thank the referee, S.J.Adelman, for his careful reading of the manuscript and his suggestions.
© European Southern Observatory (ESO) 1998
Online publication: September 17, 1998