太阳系中锗元素的来源及大麦哲伦云恒星的元素丰度分析

发布时间：2018-06-12 10:53

本文选题：河外星系 + 大麦哲伦云　；参考：《河北师范大学》2013年硕士论文

【摘要】：对元素来源的理解是现代天体物理学的主要挑战之一，而且贫金属星的元素丰度分布隐藏了很多早期的星系化学演化历史。目前，国际上没有一种合适的方法来很好的拟合贫金属星HD160617和HD108317的元素丰度，而且对Ge元素的来源持不同意见。另外，随着观测数据的完善，，对河外星系元素丰度的分析和研究也不断深入。本文做了两项工作：一个是利用三分量参数化模型拟合贫金属星HD160617和HD108317的元素丰度，定量证明了s-过程对这两颗星是有贡献的，并且得到了太阳系中Ge、As和Se元素的主要r-过程和弱r-过程丰度。另外，我们探究了Ge元素的天体物理来源。在贫金属丰度下，Ge元素是由弱r-过程产生的，具有primary特性；太阳系中大约41%的Ge元素来源于处于热核反应阶段的大质量星，而且，Ge元素剩余丰度具有secondary特性。另一项工作是采用五分量参数化模型拟合河外星系大麦哲伦云（LMC）内盘红巨星的元素丰度。这五个分量分别是主要r-过程分量，弱r-过程分量，主要s-过程分量，弱s-过程分量和SNeIa分量，因为SNeIa与轻元素(8Z20)和铁族元素有关，所以我们将SNeIa的贡献也考虑进去。我们的计算结果与观测值符合得很好，从而证明了本工作中采用的五分量参数化模型的正确性和有效性。我们得到了50颗样本星的五个分量系数与[Fe/H]的关系，从中发现，每个中子俘获过程对重元素丰度的相对贡献与对太阳系重元素丰度的贡献是不相同的。弱r-过程和主要s-过程对样本星的中子俘获元素丰度的贡献大于对太阳系的中子俘获元素丰度的贡献。弱s-过程和SNeIa对样本星中子俘获元素丰度的贡献小于对太阳系中子俘获元素丰度的贡献。我们还分析了Sr、Y、Zr、Ba和La元素的各中子俘获过程丰度分量比。弱r-过程元素和铁族元素的primary部分都是由大质量SNeII产生的。对于较重中子俘获元素（Ba和La）而言，主要s-过程的贡献要大于弱r-过程的贡献。
[Abstract]:Understanding the origin of elements is one of the main challenges in modern astrophysics, and the distribution of element abundance of metal-poor stars hides many early galactic chemical evolution history. At present, there is no suitable method to fit the element abundance of poor metal stars HD160617 and HD108317, and hold different opinions on the origin of GE element. In addition, with the improvement of observational data, the analysis and study of element abundance in extragalactic systems have been deepened. Two tasks have been done in this paper: one is to fit the elemental abundance of poor metal stars HD160617 and HD108317 by using a three-component parameterized model. It is quantitatively proved that the S-process contributes to the two stars and the abundance of the main r-processes and weak r-processes of GeMas and se elements in the solar system are obtained. In addition, we have explored the astrophysical sources of GE. Under the condition of poor metal abundance, Ge is produced by a weak r-process and has primary properties. About 41% of GE in the solar system comes from large mass stars in the thermonuclear reaction stage. Moreover, the residual abundance of GE has secondary characteristics. Another work is to use a five-component parameterized model to fit the element abundance of the red giant in the inner disk of the large Magellanic Cloud of the extragalactic system. These five components are the main r-process component, the weak r-process component, the main s-process component, the weak s-process component and the SNeIa component, respectively, because SNeIa is related to the light element (8Z20) and the iron group element, so we also take the contribution of SNeIa into account. The calculated results are in good agreement with the observed values, which proves the validity and validity of the five-component parameterized model used in this work. We have obtained the relationship between the five component coefficients of 50 sample stars and [Fe / H]. It is found that the relative contribution of each neutron capture process to the abundance of heavy elements is different from that of the contribution to the abundance of heavy elements in the solar system. The contribution of the weak r- process and the main s- process to the neutron capture element abundance of the sample star is greater than that of the solar system neutron capture element abundance. The contribution of weak s- process and SNeIa to the neutron capture element abundance of the sample star is less than that of the solar system neutron capture element abundance. We have also analyzed the abundance component ratios of various neutron capture processes for Sr _ 2O _ Y _ (Zr) Zr _ (Ba) and La elements. The primary part of both the weak r-process element and the iron group element is produced by the large mass SNeII. For the heavy neutron capture elements Ba and La, the contribution of the main s- process is greater than that of the weak r- process.
【学位授予单位】：河北师范大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P154

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