Spectroscopic Studies of Extremely Metal-poor Stars with the Subaru High Dispersion Spectrograph. V. The Zn-enhanced Metal-poor Star BS 16920-017
Abstract
We report Zn abundances for 18 very metal-poor stars studied in our previous work, covering the metallicity range -3.2< [Fe/H] <-2.5. The [Zn/Fe] values of most stars show an increasing trend with decreasing [Fe/H] in this metallicity range, confirming the results found by previous studies. However, the extremely metal-poor star BS 16920-017([Fe/H] =-3.2) exhibits a significantly high [Zn/Fe] ratio ([Zn/Fe] = +1.0). Comparison of the chemical abundances of this object with HD 4306, which has similar atmospheric parameters to BS 16920-017, clearly demonstrates a deficiency of α elements and neutron-capture elements in this star, along with enhancements of Mn and Ni, as well as Zn. The association with a hypernova explosion that has been proposed to explain the high Zn abundance ratios found in extremely metal-poor stars is a possible explanation, although further studies are required to fully interpret the abundance pattern of this object.
Based on data collected at the Subaru Telescope, which is operated by the National Astronomical Observatory of Japan.- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2011
- DOI:
- 10.1088/0004-637X/730/2/77
- arXiv:
- arXiv:1101.4432
- Bibcode:
- 2011ApJ...730...77H
- Keywords:
-
- nuclear reactions;
- nucleosynthesis;
- abundances;
- stars: abundances;
- stars: individual: BS 16920-017;
- stars: Population II;
- supernovae: general;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 22 pages, 6 figures, accepted for publication in ApJ