Fingerprint of the first stars: multi-enriched extremely metal-poor stars in the TOPoS survey
Fingerprint of the first stars: multi-enriched extremely metal-poor stars in the TOPoS survey
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DOI：
10.1093/mnras/sty2783
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发表时间：
2018-10
影响因子：
4.8
通讯作者：
T. Hartwig;M. Ishigaki;R. Klessen;N. Yoshida
中科院分区：
文献类型：
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作者：
T. Hartwig;M. Ishigaki;R. Klessen;N. Yoshida
银河系中的极贫金属（EMP）恒星继承了它们形成的气体的化学成分。因此，它们的谱线中带有第一批恒星的化学指纹。人们普遍认为电磁脉冲恒星是由仅由一颗前体超新星（“单富集”）富集的气体形成的。然而，最近的数值模拟表明，第一批恒星是在小星团中形成的。因此，我们预计几颗超新星会对 EMP 恒星的丰度做出贡献（“多重富集”）。我们通过应用化学位移的散度分析了 TOPoS 巡天中最近观测到的七颗 EMP 恒星，发现 J1035+0641 是单富集的 ($p_{mono}=53\%$)，而 J1507+0051 是多富集的 ($p_{mono}=4\%$)。对于剩下的五颗星，由于理论和观测的不确定性，我们无法做出明确的预测（$p_{mono} \lesssim 50\%$）。在近紫外区的进一步观察将有助于改进我们的诊断，从而有助于限制第一批恒星的性质。
Extremely metal poor (EMP) stars in the Milky Way inherited the chemical composition of the gas out of which they formed. They therefore carry the chemical fingerprint of the first stars in their spectral lines. It is commonly assumed that EMP stars form from gas that was enriched by only one progenitor supernova ('mono-enriched'). However, recent numerical simulations show that the first stars form in small clusters. Consequently, we expect several supernovae to contribute to the abundances of an EMP star ('multi-enriched'). We analyse seven recently observed EMP stars from the TOPoS survey by applying the divergence of the chemical displacement and find that J1035+0641 is mono-enriched ($p_{mono}=53\%$) and J1507+0051 is multi-enriched ($p_{mono}=4\%$). For the remaining five stars we can not make a distinct prediction ($p_{mono} \lesssim 50\%$) due to theoretical and observational uncertainties. Further observations in the near-UV will help to improve our diagnostic and therefore contribute to constrain the nature of the first stars.