Pulkovo compilation of radial velocities for 35495 stars in a common system.
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Long-term monitoring of active stars. VI. UBV(RI)_c observations collected in Sep.-Oct. 1990
In the framework of an extensive program focusing on the globalproperties and evolution of active stars, high-precision UBV(RI)_cphotometry of 9 selected stars, collected at the European SouthernObservatory over the intervals 7-17 September and 30 September - 10October 1990, is presented. Significant evolution of the light curves,period variations and evidence for long-term variability of the globaldegree of spottedness are found. Some of the spectral classificationsare discussed. These observations contribute to the establishment of atime-extended photometric database which can give important clues ontopics such as the stability of the spotted areas, differentialrotation, solar-like cycles and the correlation between inhomogeneitiesat different atmospheric levels. Based on data collected at the EuropeanSouthern Observatory, La Silla, Chile. Tables and the complete data setare also available in electronic form at the CDS via anonymous ftp tocdsarc.u-strasbg.fr or via http://cdsweb.u-strasbg.fr/Abstract.html
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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.
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Positional reference stars in the Magellanic Clouds
The equatorial coordinates are determined of 926 stars (mainly ofgalactic origin) in the direction of the Magellanic Clouds at the meanepoch T = 1978.4 with an overall accuracy characterized by the meanvalues of the O-C coordinates, Sa = 0.35 arcsec and Sd = 0.38 arcsec,calculated from the coordinates of the Perth reference stars. Thesevalues are larger than the accuracy expected for primary standard stars.They allow the new positions to be considered as those of reliablesecondary standard stars. The published positions correspond to anunquestionable improvement of the quality of the coordinates provided inthe current catalogs. This study represents an 'astrometric step' in thestarting of a 'Durchmusterung' of the Magellanic Clouds organized by deBoer (1988, 1989).
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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.
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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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Observations and analysis of CF TUC
Recent UBV photometry of the RS CVn binary CF Tuc is discussed andanalyzed. Combining the results with previously published spectroscopy,radii of 1.63 solar radii for the hotter (6000 K) and 3.11 solar radiifor the cooler (4500 K) component are found; both stars having a mass ofabout 1.3 solar masses. The distance to the system is put at 86 + or -15 pc. Though the photometric data is incomplete in the coverage of someregions out of the minima, there is no significant evidence of the'wave-type distortions' - a known hallmark of RS CVn stars - and thedata can be modeled by a standard eclipsing binary system in which thestatistical test of goodness-of-fit produces quite acceptable values forreasonable estimates of observational accuracy.
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UBV(RI)c photometry for CaII emission stars. II - Observations at Mt. John University Observatory and at Mt. Stromlo
UBV(RI)c data are given for 17 stars with strong Ca II H and K emission.Techniques of observation and reduction are described briefly.
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Comparsion Stars which Turn Out to be Variable
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Evidence for the Variability of HD 5210: a Comparsion Star for HD 5303
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uvby Observations of HD 5303 in October 1981
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Radial velocities of supergiants in the Small Magellanic Cloud
This paper presents the kinematic results of a study, comparing SmallMagellanic Cloud supergiants to galactic supergiants. The stars werechosen from the lists of Florsch (1972a) and Sanduleak (1968). A roughcorrelation is found between the radial velocities of the supergiantsand the radial velocities of neutral hydrogen. In some cases a betterrelation exists with the radial velocities of the H II regions.
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Etude DU Petit Nuage de Magellan par la technique DU prisme-objectif de Fehrenbach.
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INHABITED SKY
