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Stroemgren photometry of F- and G-type stars brighter than V = 9.6. I. UVBY photometry
Within the framework of a large photometric observing program, designedto investigate the Galaxy's structure and evolution, Hβ photometryis being made for about 9000 stars. As a by-product, supplementary uvbyphotometry has been made. The results are presented in a cataloguecontaining 6924 uvby observations of 6190 stars, all south ofδ=+38deg. The overall internal rms errors of one observation(transformed to the standard system) of a program star in the interval6.5
| A map-based determination of the nature of Beta Delphini
The Beta Delphini binary system presents a stringent test of the theoryof stellar evolution. Improved parallax and component masses are foundfor its giant (F5 III and F5 IV) stars. A study of the evolutionarystatus of the system indicates it to be 1.9 Gyr (1.9 billion years) oldand to have a metallicity of approximately 1.5 times that of the Sun.The perturbation due to the 26.6 yr orbital motion is clearly shown inthis 2.2 yr study and allows the most precise determination of therelative masses of the component stars to date. The next few monthspresent an unusual opportunity for orbital study as the system passesthrough periastron. Two of the reference stars are found to havedistances of less than 100 parsecs.
| Spectral types and luminosity classifications of MAP region stars using UBVRI and DDO photometry
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1989AJ.....98.1768C&db_key=AST
| Estimation of spectral classifications for bright northern stars with interesting Stromgren indices
The purpose of this investigation is to provide spectroscopic observerswith finding lists of potentially interesting objects. From anunpublished UVBY catalogue of 7026 northern stars (mostly brighter than8.3m) 1094 objects with interesting combinations of UVBY indices havebeen selected. Most stars with post-HD classifications have beenexcluded, as well as late F dwarfs belonging to the intermediatepopulation II. For the 792 remaining stars estimated spectralclassifications are given. The techniques and experience from a previouspaper dealing with southern stars have been utilized here. Among thepredicted spectral classifications are 40 OB stars; 262 Ap, Am, or Fmstars; 16 supergiants of types A to G; 110 bright giants of types A to K(class II); 156 double stars or objects with composite spectra; 26 lateF dwarfs; 91 weak-lined dwarf and giant stars of types F to K, includingearly F-type population II field blue stragglers; and a few possiblefield horizontal branch stars, lambda Bootis-type stars, and late-typehalo giants.
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Pozíciós és asztrometriai adatok
| Csillagkép: | Delfin |
| Rektaszcenzió: | 20h37m03.79s |
| Deklináció: | +14°51'12.2" |
| Vizuális fényesség: | 8.252 |
| RA sajátmozgás: | 16.4 |
| Dec sajátmozgás: | 8.4 |
| B-T magnitude: | 8.738 |
| V-T magnitude: | 8.293 |
Katalógusok és elnevezések:
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