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Interstellar reddening in the Southern Hemisphere. I - The UVBY beta observations The uvby-beta photometric data obtained from a Southern Hemisphereobservational project is presented. A uvby-beta photometric network ofnearly 3900 A and early F stars has been established with the intentthat the stars serve as 'space probes' for measurements of interstellarreddening.
| The chemical evolution of the solar neighborhood. I - A bias-free reduction technique and data sample The possible ways of measuring the age-metallicity relation for thegalactic disk in the neighborhood of the sun are discussed. It is shownthat the use of a field star sample chosen on the basis of effectivetemperature introduces a bias which results in a monotonic increase inthe metal abundance of the disk with time. However, if theage-metallicity relation for the disk can be shown to satisfy certaincriteria, the bias introduced in such a sample can be neglected: thegalactic disk apparently satisfies the criteria. It is concluded that asample analyzed through the use of uvby and H(beta) photometry inconjunction with a self-consistent set of theoretical isochronesprovides the least biased, most accurate estimate of the age-metallicityrelation for the disk.
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Gözlemler ve gökölçümü verileri
Takýmyýldýz: | Hintli |
Sað Açýklýk: | 21h56m29.11s |
Yükselim: | -53°02'54.0" |
Görünürdeki Parlaklýk: | 7.965 |
Uzaklýk: | 150.15 parsek |
özdevim Sað Açýklýk: | -11.9 |
özdevim Yükselim: | 3.7 |
B-T magnitude: | 8.265 |
V-T magnitude: | 7.99 |
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