FOLLOWING THE COSMIC EVOLUTION OF PRISTINE GAS. I. IMPLICATIONS FOR MILKY WAY HALO STARS
FOLLOWING THE COSMIC EVOLUTION OF PRISTINE GAS. I. IMPLICATIONS FOR MILKY WAY HALO STARS
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遵循原始气体的宇宙演化。
DOI：
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发表时间：
2016
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通讯作者：
Liubin Pan
中科院分区：
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作者：
Richard Sarmento;E. Scannapieco;Liubin Pan
我们利用新的湍流混合子网格模型来准确跟踪第一批恒星的宇宙演化、超新星 (SN) 喷射物的混合以及对银河晕化学成分的影响。使用宇宙学自适应网格细化代码 ramses，我们实现了原始气体污染模型，如 Pan 等人所述。跟踪金属丰度低于临界值的 Pop III 恒星的金属丰度，使我们能够计算出即使在气体平均金属丰度远高于其的区域中形成的恒星的比例。我们证明，这种部分混合的区域占 z = 5 之前形成的所有 Pop III 恒星的 0.5 到 0.7。此外，我们跟踪了 Pop III 超新星产生的“原始金属”(PM) 的产生和传输。这些中子捕获不足的金属被第二代恒星吸收，并可能导致碳增强、贫金属（CEMP-no）恒星的独特丰度特征。作为一个说明性的例子，我们将原始金属与凯勒等人使用的丰度比联系起来。解释了 SMSS J031300.36-670839.3 恒星中金属的来源，发现与 CEMP-no 银河晕星中观测到的 [Fe/H]、[C/H]、[O/H] 和 [Mg/Ca] 比率非常吻合。类似的未来模拟将有助于利用 CEMP 观测进一步限制 Pop III 恒星的特性，并改进对 Pop III 恒星空间分布的预测，下一代地面和太空望远镜将对此进行探索。
We make use of a new subgrid model of turbulent mixing to accurately follow the cosmological evolution of the first stars, the mixing of their supernova (SN) ejecta, and the impact on the chemical composition of the Galactic Halo. Using the cosmological adaptive mesh refinement code ramses, we implement a model for the pollution of pristine gas as described in Pan et al. Tracking the metallicity of Pop III stars with metallicities below a critical value allows us to account for the fraction of stars formed even in regions in which the gas’s average metallicity is well above We demonstrate that such partially mixed regions account for 0.5 to 0.7 of all Pop III stars formed up to z = 5. Additionally, we track the creation and transport of “primordial metals” (PM) generated by Pop III SNe. These neutron-capture deficient metals are taken up by second-generation stars and likely lead to unique abundance signatures characteristic of carbon-enhanced, metal-poor (CEMP-no) stars. As an illustrative example, we associate primordial metals with abundance ratios used by Keller et al. to explain the source of metals in the star SMSS J031300.36-670839.3, finding good agreement with the observed [Fe/H], [C/H], [O/H], and [Mg/Ca] ratios in CEMP-no Milky Way halo stars. Similar future simulations will aid in further constraining the properties of Pop III stars using CEMP observations, as well as improve predictions of the spatial distribution of Pop III stars, as will be explored by the next generation of ground- and space-based telescopes.