The authors are grateful to the Referee Dr. F. Kerschbaum for helpful comments and suggestions.
The authors are grateful to R. Ventura for providing the periodogram analysis code.
The acquisition of photometric data with the Catania APT has been possible thanks to the dedicated and highly competent technical assistance of a number of people, notably P. Bruno, S. Sardone and E. Martinetti.
Active star research at the Department of Physics and Astronomy of Catania University and Catania Astrophysical Observatory is funded by MURST (Ministero dell'Università e della Ricerca Scientifica e Tecnologica ), and the Regione Siciliana , whose financial support is gratefully acknowledged. This research has made use of the SIMBAD database, operated at CDS, France, which is gratefully acknowledged.
© European Southern Observatory (ESO) 2000
Online publication: January 29, 2001