Nucleosynthesis of Zinc and Iron Peak Elements in Population III Type II Supernovae: Comparison with Abundances of Very Metal Poor Halo Stars
Abstract
We calculate nucleosynthesis in core collapse explosions of massive Population III stars and compare the results with abundances of metal-poor halo stars to constrain the parameters of Population III supernovae. We focus on iron peak elements, and, in particular, we try to reproduce the large [Zn/Fe] observed in extremely metal-poor stars. The interesting trends of the observed ratios [Zn, Co, Mn, Cr, V/Fe] can be related to the variation of the relative mass of the complete and incomplete Si-burning regions in supernova ejecta. We find that [Zn/Fe] is larger for deeper mass cuts, smaller neutron excess, and larger explosion energies. The large [Zn/Fe] and [O/Fe] observed in the very metal-poor halo stars suggest deep mixing of complete Si-burning material and a significant amount of fallback in Type II supernovae. Furthermore, large explosion energies (E51>~2 for M~13 Msolar and E51>~20 for M>~20 Msolar) are required to reproduce [Zn/Fe]~0.5. The observed trends of the abundance ratios among the iron peak elements are better explained with this high-energy (``hypernova'') model than with the simple ``deep'' mass cut effect because the overabundance of Ni can be avoided in the hypernova models. We also present the yields of pair instability supernova explosions of M~=130-300 Msolar stars and discuss that the abundance features of very metal-poor stars cannot be explained by pair instability supernovae.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 2002
- DOI:
- 10.1086/323946
- arXiv:
- arXiv:astro-ph/0103241
- Bibcode:
- 2002ApJ...565..385U
- Keywords:
-
- Galaxy: Halo;
- Nuclear Reactions;
- Nucleosynthesis;
- Abundances;
- Stars: Abundances;
- Stars: Population II;
- Stars: Supernovae: General;
- Astrophysics
- E-Print:
- 32 pages, 19 figures, 18 tables. To appear in the Astrophysical Journal 2002, 565. Table 18 of yields of Pop III Pair-Instability Supernovae is replaced with a new one