论文标题
人口II星的随机富集
The stochastic enrichment of Population II stars
论文作者
论文摘要
我们研究了金属贫困样品的化学丰度（[Fe/H] <-2.5）银河系的固有散射。我们从四次历史性调查中获取样本，并将注意力集中在恒星MG，CA，NI和FE丰度上。使用这些元素，我们使用随机化学富集模型研究了这些金属贫困恒星的化学富集。假设这些恒星已被第一代无金属恒星富集，我们考虑了其超新星的恒星混合和爆炸能量的丰富种群的质量分布。对于我们选择出色的产量，我们的模型表明，平均而言，最大的金属贫困恒星富含N*= 5^{+13} _ { - 3}（1 Sigma）人口III星。这与最贫穷的DLA的富集恒星数量相媲美。因此，我们的分析表明，Z〜3处的一些最低质量结构包含<13（2 sigma）种群III富集的Minihaloes的化学产物。推断的IMF与Salpeter分布的IMF一致，并且偏爱从微型混合高诺伏那氏菌中弹出。但是，估计的富集模型对恒星样品的小变化敏感。 [mg/ca]丰度中的〜0.1 dex的偏移被证明对推断的富集恒星敏感。我们建议该方法有可能限制第一代恒星的多样性，但这需要：（1）一个恒星样本，其系统误差已被充分理解； （2）记录了与核合成产量相关的不确定性。
We investigate the intrinsic scatter in the chemical abundances of a sample of metal-poor ([Fe/H]<-2.5) Milky Way halo stars. We draw our sample from four historic surveys and focus our attention on the stellar Mg, Ca, Ni, and Fe abundances. Using these elements, we investigate the chemical enrichment of these metal-poor stars using a model of stochastic chemical enrichment. Assuming that these stars have been enriched by the first generation of massive metal-free stars, we consider the mass distribution of the enriching population alongside the stellar mixing and explosion energy of their supernovae. For our choice of stellar yields, our model suggests that the most metal-poor stars were enriched, on average, by N*=5^{+13}_{-3} (1 sigma) Population III stars. This is comparable to the number of enriching stars inferred for the most metal-poor DLAs. Our analysis therefore suggests that some of the lowest mass structures at z~3 contain the chemical products from <13 (2 sigma) Population III enriched minihaloes. The inferred IMF is consistent with that of a Salpeter distribution and there is a preference towards ejecta from minimally mixed hypernovae. However, the estimated enrichment model is sensitive to small changes in the stellar sample. An offset of ~0.1 dex in the [Mg/Ca] abundance is shown to be sensitive to the inferred number of enriching stars. We suggest that this method has the potential to constrain the multiplicity of the first generation of stars, but this will require: (1) a stellar sample whose systematic errors are well understood; and, (2) documented uncertainties associated with nucleosynthetic yields.
