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arXiv 1007.3998astro-ph.HEnucl-th
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SNe高熵热泡的核合成与极端贫金属星的Abdication斑图

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

Natsuko Izutani, Hideyuki Umeda

摘要:

有人认为,极贫金属(EMP)星的丰度可以由超新星(HNe)复制,而不是由正常超新星(SNe)复制。然而,最近也有人提出,如果最里面的富中子或富质子物质被喷射出来,则喷射物质的丰度模式会发生变化,正常的SNe也可能重现EMP星的观测结果。在这封信中,我们计算爆炸性核合成与各种叶和熵,并调查是否正常SNe与这个最内层的物质,我们称之为“热泡”的组成部分,可以重现丰富的EMP星。我们发现富中子(Ye = 0.45 - 0.49)和富质子(Ye = 0.51 - 0.55)的物质可以增加Zn/Fe和Co/Fe比值,但倾向于过量产生其他Fe峰元素。除此之外,我们还发现,如果稍微富含质子的物质(0.50 <= Ye <0.501,s/kb~15 - 40)被喷射到~0.06 Msolar,即使是正常的SNe也可以再现EMP星的丰度,尽管它需要微调Ye。另一方面,HNe可以更容易地再现EMP星的观测,而无需微调。我们的结果表明,HNe是EMP星丰度分布最有可能的起源。

英文摘要:

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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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