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Long-term monitoring of active stars. VIII. UBV(RI)_(c) photometry collected in February 1992
As a part of an extensive program focusing on the global properties andevolution of active stars, high-precision UBV(RI)_c photometry of 31selected stars, collected at the European Southern Observatory over the14-29 February 1992 interval, is 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 the inferred photometric parallaxes arecompared, whenever possible, with the values measured by the Hipparcossatellite. Flare events were detected for the star HD16157 = CC Eri, EXO 055609-3804.4 TY Coland HD 119285 = V851 Cen. Optical variability wasdiscovered for the Pop II binary HD 89499. Theseobservations contribute to the establishment of a time-extendedphotometric database which can give important clues on topics such asthe stability of spotted areas, differential rotation, solar-like cyclesand the correlation between inhomogeneities at different atmosphericlevels. based on data collected at the European Southern Observatory, LaSilla, Chile.
| Long-term monitoring of active stars. VII. UBV(RI)_c photometry collected in March 1991
In the framework of an extensive program focusing on the globalproperties and evolution of active stars, high-precision UBV(RI)_cphotometry of 19 selected stars, collected at the European SouthernObservatory over the 15-31 March 1991 interval is presented. Significantevolution of the light curves, period variations and evidence forlong-term variability of the global degree of spottedness are found.Most of the spectral classifications are discussed. A flare event wasdetected for the star HD 127535 = V 841 Cen. These observationscontribute to the establishment of a time-extended photometric databasewhich can give important clues on topics such as the stability ofspotted areas, differential rotation, solar-like cycles and thecorrelation between inhomogeneities at different atmospheric levelsFigure 1 to 24 are only available on the on-line version of A&A athttp://www.ed-phys.fr}. based on data collected at the European SouthernObservatory, La Silla, Chile. Tables and the complete data set are alsoavailable in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr or via http://cdsweb.u-strasbg.fr/Abstract.html
| Long-term monitoring of active stars. V. UBV(RI)_ c_ photometry collected in Feb.-Mar. 1990.
High-precision UBV(RI)_c_ photometry of 12 selected active stars,collected at the European Southern Observatory (La Silla, Chile) overthe period February - March 1990, is presented. Significant evolution ofthe light curves, period variations and, in most cases, evidence forlong-term variability of the global degree of spottedness are found.Some of the spectral classifications are discussed. This paper is partof a more extensive program focusing on the global properties andevolution of active stars and is aimed at establishing a time-extendedphotometric database which can give important clues on topics such asthe stability of the spotted areas, differential rotation and solar-likecycles.
| Longterm Monitoring of Active Stars - Part Three - UBV Ri/c Photometry of 14 Southern Hemisphere Variables
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1993A&AS..102..655C&db_key=AST
| UBVRI observations of southern hemisphere active stars
A program of high-precision UBVRI photometry of selected southernhemisphere active stars has been carried out at the European SouthernObservatory (La Silla, Chile) from November 1985 to February 1987. Oneresult of such monitoring has been the acquisition of the complete orpartially complete light curves for 11 stars. Significant changes oftheir wavelike light curves, both in amplitude and shape, are found.These observations are important to produce a homogeneous and extendeddatabase, which is necessary to track the formation and evolution ofphotospheric active regions.
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Osservazione e dati astrometrici
| Costellazione: | Regolo |
| Ascensione retta: | 15h38m52.66s |
| Declinazione: | -58°12'40.4" |
| Magnitudine apparente: | 8.741 |
| Distanza: | 374.532 parsec |
| Moto proprio RA: | -3 |
| Moto proprio Dec: | -3 |
| B-T magnitude: | 10.064 |
| V-T magnitude: | 8.851 |
Cataloghi e designazioni:
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