A&A Supplement series, Vol 122, February 1997, 368-378
Received April 22; accepted June 6, 1996
observations collected in
Sep.-Oct. 1990
G. Cutispoto 
- G. Leto 
Send offprint request: G. Cutispoto
Osservatorio Astrofisico di Catania,
V.le A.Doria 6, I-95125 Catania, Italy
e-mail: gcutispoto@astrct.ct.astro.it
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