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Subdwarf studies. II - Abundances and kinematics from medium resolution spectra. III - The halo metallicity distribution
Stars previously identified as having UV excesses are observed at 1-Aresolution in the Ca II K-line region. Comparisons of these data withother samples and with Monte Carlo simulations involving a singlecomponent halo have yielded estimates of halo velocity dispersions androtation velocity, corrected for the kinematic biases in the sample. Itis suggested that the data are not consistent with a model in which thehalo formed from star formation in a dissipating, collapsing cloud; theyare, however, reconcilable with the formation of the halo stars bynumerous, independently evolving gas clouds. The metallicitydistribution of a sample of 372 kinematically selected halo stars isthen constructed, with a view to selection effects in the data. Goodagreement is noted between the globular cluster metallicity distributionand a stochastic model with a mean of 10 enrichments/fragment.
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Gözlemler ve gökölçümü verileri
| Takýmyýldýz: | Kartal |
| Sað Açýklýk: | 19h51m29.57s |
| Yükselim: | +06°13'17.8" |
| Görünürdeki Parlaklýk: | 9.614 |
| özdevim Sað Açýklýk: | 9.2 |
| özdevim Yükselim: | -14.3 |
| B-T magnitude: | 9.899 |
| V-T magnitude: | 9.638 |
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