A Model for Abundances in Metal-poor Stars
A Model for Abundances in Metal-poor Stars
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DOI：
10.1086/322367
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发表时间：
2001-06
期刊：
影响因子：
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通讯作者：
Y. Qian;G. Wasserburg
中科院分区：
文献类型：
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作者：
Y. Qian;G. Wasserburg
提出了一个模型，旨在定量解释 r 过程元素和与 r 过程站点相关的其他元素的恒星丰度。有人认为，所有这些元素的丰度在具有 -3 ≲ [Fe/H] 130) r 元素但没有 Fe 的恒星中（可能会留下黑洞）。 L 事件频率较低，产生 Fe 和主要为轻 (A ≲ 130) r 元素（基本上不高于 Ba）。通过使用观测到的两颗超金属贫恒星的丰度和太阳的 r 丰度，可以确定第一代超大质量恒星产生的元素的初始或即时库存以及 H 和 L 事件的产量。然后，可以仅使用观测到的 Eu 和 Fe 丰度，从模型中计算出恒星中大量元素的丰度。为了将模型结果与 -3 < [Fe/H] < -1 的恒星的观测数据相匹配，要求 Sr、Y、Zr 和 Ba 的太阳 r 丰度必须从标准值显着增加。所有其他元素似乎都不需要进行此类更改。如果不允许 Sr、Y、Zr 和 Ba 的太阳 r 丰度发生变化，则该模型在 -3 < [Fe/H] < -1 时失败，但对于这四种元素在 [Fe/H] ≈ -3 时仍然有效。通过使用这些元素的校正太阳 r 丰度，模型结果和 -3 < [Fe/H] < -1 范围内的数据之间获得了良好的一致性。在该区域没有发现 s 过程贡献的证据，但该区域的所有观测数据现在都显示 Ba/Eu 定期增加到标准太阳 r 过程值以上。尚不清楚此处用于获得恒星数据拟合的 Sr、Y、Zr 和 Ba 的太阳 r 分量是否可以与通过减去模型计算的 s 分量而从太阳丰度获得的那些相一致。
A model is presented that seeks to explain quantitatively the stellar abundances of r-process elements and other elements associated with the r-process sites. It is argued that the abundances of all these elements in stars with -3 ≲ [Fe/H] 130) r-elements but no Fe (presumably leaving behind black holes). The L events are of low frequency and produce Fe and dominantly light (A ≲ 130) r-elements (essentially none above Ba). By using the observed abundances in two ultra-metal-poor stars and the solar r-abundances, the initial or prompt inventory of elements produced by the first generations of very massive stars and the yields of H and L events can be determined. The abundances of a large number of elements in a star can then be calculated from the model by using only the observed Eu and Fe abundances. To match the model results and the observational data for stars with -3 < [Fe/H] < -1 requires that the solar r-abundances for Sr, Y, Zr, and Ba must be significantly increased from the standard values. No such changes appear to be required for all other elements. If the changes in the solar r-abundances for Sr, Y, Zr, and Ba are not permitted, the model fails at -3 < [Fe/H] < -1 but still works at [Fe/H] ≈ -3 for these four elements. By using the corrected solar r-abundances for these elements, good agreement is obtained between the model results and data over the range -3 < [Fe/H] < -1. No evidence of s-process contributions is found in this region, but all the observational data in this region now show regular increases of Ba/Eu above the standard solar r-process value. Whether the solar r-components of Sr, Y, Zr, and Ba used here to obtain a fit to the stellar data can be reconciled with those obtained from solar abundances by subtracting the s-components calculated from models is not clear.