HD 39636

Monitoring of spotted RS CVn and BY Dra type stars. I. Simultaneous optical and infrared photometry UBV(RI)cJHK photometry of 6 active stars, collected at theSouth African Astronomical Observatory in 1996 and 1997, is presented.The light and colour curves, which are compared with those observed atprevious epochs, show significant variation in their wave-likemodulation and in their maximum brightness.
A large, complete, volume-limited sample of G-type dwarfs. I. Completion of Stroemgren UVBY photometry Four-colour photometry of potential dwarf stars of types G0 to K2,selected from the Michigan Spectral Catalogues (Vol. 1-3), has beencarried out. The results are presented in a catalogue containing 4247uvby observations of 3900 stars, all south of δ = -26deg. Theoverall internal rms errors of one observation (transformed to thestandard system) of a program star in the interval 8.5 < V < 10.5are 0.0044, 0.0021, 0.0039, and 0.0059, respectively, in V, b-y, m_1_ ,and c_1_. The purpose of the catalogue, combined with earliercatalogues, is to allow selection of a large, complete, volume-limitedsample of G- and K-type dwarfs, investigate their metallicitydistribution, and compare it to predictions of various models ofgalactic chemical evolution. Future papers in this series will discussthese subjects.
On the Rotation Period of HD 39576 Not Available

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