【作者】 朱子忠；

【导师】 张波；

【作者基本信息】 河北师范大学 ， 天体物理， 2010， 硕士

【摘要】 贫金属星被称为是恒星演化历史的"化石"。研究其核合成元素丰度,对检验核合成理论和探索恒星形成具有十分重要的意义。S-过程的理论已经相对完善,但对r-过程的理解还相对模糊。本文以元素核合成基本理论为基础,采用参数化方法将r-过程分为弱r-过程和主要r-过程。用以从理论角度预言元素丰度,探索元素丰度分布的特征和规律,从而进一步讨论r-过程核合成的分量过程及可能的场所。此文分别把HD 122563和CS 22892-001作为弱r-过程和主要r-过程的典型星,采用了用最小二乘法找最小开方的方法,对98颗r-过程超丰贫金属星进行了计算去预言它们的元素丰度。并将误差详细的分为了贫金属星观测误差和典型星观测误差,使我们的模型最大限度的优化。通过计算结果来研究r-过程的两个组成。参数化模型是将具体的物理过程数学化,将这两个过程辅以两个分量系数。从而也可以很直观的看出弱r-过程和主要r-过程所占的比例。通过本文的计算,可以很直观的从图中看出我们模型的准确性。从而证明我们提出的弱r-过程和主要r-过程是相当可信的。r过程与恒星的形成和演化密切相关。通过对核合成的研究,可以了解元素的起源、恒星的形成及星系的化学演化过程。近年来对贫金属星r-过程的研究越来越多。但是,到目前为止还没有一种成熟的理论,对其形成场所也存在许多争议。因此本文的工作对于r-过程,以及核合成的研究都具有非常重要的意义。更多还原

【Abstract】 The metal-poor stars are known as the stellar evolution history of the "fossil." Studying the nucleosynthesis element abundances to test nucleosynthesis theories and exploration of star formation have great significance. S-process theory has been relatively well, but the understanding of r-process are relatively vague.In this paper, based on element nucleosynthesis theory, using parametric method to divide r-process into a weak r-process and a main r-process. Predict from a theoretical point to view for the element abundances, and explore the distribution of element abundances characteristics and laws,so as to further discuss the r-process nucleosynthesis process and the possible site. This article use HD 122563 and CS 22892-001 as a typical star of weak r-process and main r-process.The way is using the least square method to find the smallest prescribing . 98 r-process enhancde metal-poor stars were calculated to predict the abundance of their elements. And the error is detailed into metal-poor stars observation error and the typical satellite observation error, so that our model for maximum optimization. By calculating the metal-poor stars to study two composition of r-process. Parameterized model is the specific physical processes mathematically, and these two processes supported by two-component coefficients.Thus can see intuitively the proportion of the weak and main r-process in the r-process.By this calculation, the accuracy of our model can be intuitively seen from the figure. Thus the weak and main r-process of we mading is quite credible.R- process is closely linked with formation and evolution of the star. Through the study of nuclear synthesis, we can understand the origin of elements, star formation and chemical evolution of galaxies. In recent years, study of the r-process nuclear synthesis on metal-poor stars are more and more。However, there does not have a mature theory so far, and there are also lot of controversy on place of their formation . Therefore, the work for the r-process of this article, as well as for the nucleosynthesis of the studies have very important significance.更多还原