Spectroscopic Studies of Extremely Metal-poor Stars with the Subaru High-Dispersion Spectrograph. IV. The α-Element-Enhanced Metal-poor Star BS 16934-002
Abstract
A detailed elemental abundance analysis has been carried out for the very metal-poor ([Fe/H]=-2.7) star BS 16934-002, which was identified in our previous work as a star exhibiting large overabundances of Mg and Sc. A comparison of the abundance pattern of this star with that of the well-studied metal-poor star HD 122563 indicates excesses of O, Na, Mg, Al, and Sc in BS 16934-002. Of particular interest, no excess of C or N is found in this object, in contrast to CS 22949-037 and CS 29498-043, two previously known carbon-rich, extremely metal-poor stars with excesses of the α-elements. No established nucleosynthesis model exists that explains the observed abundance pattern of BS 16934-002. A supernova model, including mixing and fallback and assuming severe mass loss before explosion, is discussed as a candidate progenitor of BS 16934-002.
Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 2007
- DOI:
- 10.1086/512601
- arXiv:
- arXiv:astro-ph/0701159
- Bibcode:
- 2007ApJ...660..747A
- Keywords:
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- Nuclear Reactions;
- Nucleosynthesis;
- Abundances;
- Stars: Abundances;
- stars: individual (BS 16934-002);
- Stars: Population II;
- Stars: Supernovae: General;
- Astrophysics
- E-Print:
- 34 pages, 4 tables, 7 figures, Astrophysical Jounal, in press