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Long-term monitoring of active stars. X. Photometry collected in 1994
As part of an extensive program focused on the global properties andevolution of active stars, high-precision UBV(RI)_c and UBV photometryof 18 selected stars is presented. UBV(RI)_c observations were collectedat the European Southern Observatory over the intervals 21-28 September1994 and 25 November-05 December 1994. Additional UBV photometryobtained late in 1994 by Catania Astrophysical Observatory AutomaticPhotoelectric Telescope is also presented. Significant evolution of thelight curves, period variations and evidence for long-term variabilityof the global degree of spottedness are found. Some spectralclassifications are revised and photometric parallaxes are compared,whenever possible, with the values measured by the Hipparcos satellite.These observations are finalized to the construction of an extendedphotometric database, which can give important clues on topics such asthe stability of spotted areas, differential stellar rotation,solar-like activity cycles and the correlation between inhomogeneitiesat different atmospheric levels.Based on data collected at the European Southern Observatory, La Silla,Chile.Tables 1, 2 and 4 and the complete data set are only available inelectronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/400/659 (Table 3 is alsoavailable at the CDS).
| Long-term monitoring of active stars. IX. Photometry collected in 1993
As a part of an extensive program focused on the global properties andevolution of active stars, high-precision UBV(RI)_c and UBV photometryof 31 selected stars is presented. The UBV(RI)_c observations werecollected at the European Southern Observatory over the 31 December1992-18 January 1993 and the 20 November-3 December 1993 intervals.Additional UBV photometry obtained by the ``Phoenix" and by the CataniaAstrophysical Observatory Automatic Photoelectric Telescopes from 1990to 1993 is also presented for some of the program stars. Significantevolution of the light curves, period variations and evidence forlong-term variability of the global degree of spottedness are found.Some spectral classifications are revised and the inferred photometricparallaxes are compared, whenever possible, with the values measured bythe Hipparcos satellite. These observations are finalized to theconstruction of an extended photometric database, which can giveimportant clues on topics such as the stability of spotted areas,differential rotation, solar-like cycles and the correlation betweeninhomogeneities at different atmospheric levels. Based on data collectedat the European Southern Observatory, La Silla, Chile. Tables and thecomplete data set are also available in electronic form at the CDS viaanonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/367/910
| Long-term monitoring of active stars. IV. UBV(RI)_c_ observations obtained at La Silla in December 1989.
High-precision UBV(RI)_c_ photometry of 23 selected acitve stars,collected at the European Southern Observatory (La Silla, Chile) overthe period 9-28 December 1989, is presented. This paper is part of alarger program focusing on the global properties and evolution of activestars and is aimed at establishing a time-extended database which cangive important clues on topics such as the stability of the spottedareas, differential rotation and solar-like cycles. Significantevolution of the wave-like light curves, period variations and, in mostcases, evidence for long-term variability of the global degree ofspottedness are found for the observed stars. Some spectralclassifications are rediscussed and evidence for a newly discoveredvariable star is given.
| UBVRI observations of southern hemisphere active stars. II - 1987 data
Results are presented on high-precision UBV (RI)c photometricobservations of 13 southern-hemisphere RS CVn, BY Dra, and FK Com-typevariable stars, carried out in December 1987 at the European SouthernObservatory at La Silla (Chile). Compared with previous observations,significant changes of the light curves were detected, both in amplitudeand shape.
| Period Ambiguity Resolved for HD 8358
Not Available
| HD 8358 and HD 106225: Two New Variable Stars
Not Available
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