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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.
| 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).
| Etude DU Petit Nuage de Magellan par la technique DU prisme-objectif de Fehrenbach. Not Available
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Gözlemler ve gökölçümü verileri
Takýmyýldýz: | Tukan |
Sað Açýklýk: | 01h14m13.70s |
Yükselim: | -74°37'46.0" |
Görünürdeki Parlaklýk: | 9.19 |
özdevim Sað Açýklýk: | 9.1 |
özdevim Yükselim: | 2.2 |
B-T magnitude: | 11.01 |
V-T magnitude: | 9.341 |
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