Nucleosynthesis in High-Entropy Hot-Bubbles of SNe and Abundance Patterns of Extremely Metal-Poor Stars

Abstract

There have been suggestions that the abundance of Extremely Metal-Poor (EMP) stars can be reproduced by Hypernovae (HNe), not by normal supernovae (SNe). However, recently it was also suggested that if the innermost neutron-rich or proton-rich matter is ejected, the abundance patterns of ejected matter are changed, and normal SNe may also reproduce the observations of EMP stars. In this letter, we calculate explosive nucleosynthesis with various Ye and entropy, and investigate whether normal SNe with this innermost matter, which we call "hot-bubble" component, can reproduce the abundance of EMP stars. We find that neutron-rich (Ye = 0.45-0.49) and proton-rich (Ye = 0.51-0.55) matter can increase Zn/Fe and Co/Fe ratios as observed, but tend to overproduce other Fe-peak elements. In addition to it, we find that if slightly proton-rich matter with 0.50 <= Ye < 0.501 with s/kb ~ 15-40 is ejected as much as ~ 0.06 Msolar, even normal SNe can reproduce the abundance of EMP stars, though it requires fine-tuning of Ye. On the other hand, HNe can more easily reproduce the observations of EMP stars without fine-tuning. Our results imply that HNe are the most possible origin of the abundance pattern of EMP stars.

arXiv comment10 pages, 3 figures, Accepted to ApJL; modified references

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Cited by in corpus (8)

• Abundance Profiling of Extremely Metal-Poor Stars and Supernova Properties in the Early Universe
• Principal Component Analysis on Chemical Abundances Spaces
• Evolution of Fluorine Abundances with the ν-Process
• Chemical Enrichment in the Carbon-enhanced Damped Lyman $\alpha$ System
• Spectroscopic Studies of Extremely Metal-Poor Stars with the Subaru High Dispersion Spectrograph. IV. The alpha-Element-Enhanced Metal-Poor Star BS16934-002
• Abundance anomalies in metal-poor stars from Population III supernova ejecta hydrodynamics
• Spectroscopic Studies of Extremely Metal-Poor Stars with the Subaru High Dispersion Spectrograph. V. The Zn-Enhanced Metal-Poor Star BS 16920-017
• The explosion energy of early stellar populations: The Fe-peak element ratios in low metallicity damped Lyman-alpha systems