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Chemical evolution of the galaxy - A comparison of the abundances of light metals in disk and halo dwarfs
High resolution and high signal-to-noise spectra of 36 field dwarf starshave been obtained in the red and used to calculate Na, Al, Mg, and Siabundances relative to iron, with Fe/H abundance ratios varying between-2.60 and +0.30. The results indicate that the relative abundances oflight metals such as Mg and Si in halo stars are independent of Fe/Hratios, and that the relative abundances of the Al/Mg and Na/Mg ratiosare probably also constant, demonstrating that the odd-even effect isenhanced in the halo. The relative abundances of metals is found tochange progressively form halo-type ratios to disk ratios in the dwarfsof the disk. Interpretations of the observed phenomena include the lightelement abundances being produced in constant ratios in the halo, forexample, by a unique type of supernova; and the disk abundances being amixing of halo and disk abundances leading asymptotically to solarratios.
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| Сазвежђа: | Секстант |
| Ректацензија: | 10h32m06.39s |
| Deклинација: | +05°14'48.7" |
| Apparent магнитуда: | 9.051 |
| Proper motion RA: | -50 |
| Proper motion Dec: | 5.9 |
| B-T magnitude: | 9.622 |
| V-T magnitude: | 9.099 |
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