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Micrometer observations of double stars and new pairs. XII
Measurements of 2132 pairs and 103 double stars, obtained in both theNorthern and Southern Hemispheres in the period June 1982 to September1984, are listed in a table. The observations were carried out using theSwarthmore College 61-cm refractor, and the 100 and 91 cm telescopes ofthe Cerro Tololo Inter-American Observatory. Corrections to the IDScatalog (1961 version) are given for some of the fainter stars in thesurvey.
| Nickel overabundances in extremely metal-deficient red giants
Local thermodynamic equilibrium model-atmosphere abundance analyses of37 metal-poor (the Fe/H abundance ratio being between -3.0 and -6.0)field red-giant stars are carried out on the basis of high-dispersionechelle spectrograms. Nickel has been found to be overabundant in allstars with an abundance ratio less than -1.8; for the mostmetal-deficient star in the sample, the Ni/Fe abundance ratio is equalto +0.8. The elements in extreme Population II stars were probablysynthesized in very massive Type II supernovae. Therefore, the resultsimply that such supernovae eject material with a much higher Ni/Fe ratiothan do the less massive and more typical supernovae that made theelements in the solar system and young stars.
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Osservazione e dati astrometrici
| Costellazione: | Vergine |
| Ascensione retta: | 14h10m58.49s |
| Declinazione: | -02°40'28.0" |
| Magnitudine apparente: | 7.676 |
| Distanza: | 1219.512 parsec |
| Moto proprio RA: | -18.6 |
| Moto proprio Dec: | 10.3 |
| B-T magnitude: | 9.031 |
| V-T magnitude: | 7.788 |
Cataloghi e designazioni:
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