A&A Supplement series, Vol 122, February 1997, 368-378
Received April 22; accepted June 6, 1996
G. Cutispoto - G. Leto
Send offprint request: G. Cutispoto
Osservatorio Astrofisico di Catania, V.le A.Doria 6, I-95125 Catania, Italy
Istituto di Rastronomia, C.P. 141, I-96017, Noto (SR), Italy
In the framework of an extensive program focusing on the global properties and evolution of active stars, high-precision photometry of 9 selected stars, collected at the European Southern Observatory over the intervals 7-17 September and 30 September - 10 October 1990, is presented. Significant evolution of the light curves, period variations and evidence for long-term variability of the global degree of spottedness are found. Some of the spectral classifications are discussed. These observations contribute to the establishment of a time-extended photometric database which can give important clues on topics such as the stability of the spotted areas, differential rotation, solar-like cycles and the correlation between inhomogeneities at different atmospheric levels.
keywords: stars: activity -- stars: late-type -- stars: variables