Study Of The Elemental Abundances About The Disk Stars

The observations show that different neutron-capture elements reveal different abundance trends for the disk stars. It is very significant for us to investigate the formation mechanism and the evolutionary process of the stars of the Milky Way. That can set an example for us to understand the formation process of the stars,which is in or out of our Galaxy. Numbers of dissertations have been reported to study the evolution of our Galaxy, while, there are still some problems puzzling us.There are many reasons responsible for forming one element in stars. As a consequence, the observed elemental abundances are the comprehensive results. Studying the chemical elemental abundance in detail of the stars is an effective method to research their formation history. The purpose of this work is to deepen the understanding of the chemical evolution of the MW’s disk. Therefore, we use the five components elemental abundance model to analyze the observed data of the sample stars. The calculated elements include α elements, the iron group elements and the neutron-capture elements. By analyzing the calculation results, we know about the astrophysical sources of the elements.Two parts are included in the paper:In the part one, we present the five components elemental abundance model and calculative method firstly, and then, we analyze the observed the elemental abundance of the 233 stars belonging to the disk of the Galaxy. And we present the best two fitting results secondly. Through the analysis of the overall fitting effect, we can draw a conclusion that it is valid for us to use the five components elemental abundance model in our work. Finally we analyze and discuss the fitting results.In the part two, we give the conclusion in this paper. With the metallicaty increasing, the contributions from the main r-process and the weak r-process are constantly decreasing. While, the the contributions from the main s-process, the weak s-process and the SNe Ia are increasing. Through the analysis of the fitting results, we obtain the astrophysical sources of the trends of each element(O, Mg, Si, Ca, Y, Zr, Ba, La, Ce, Nd, Sm, Eu) [X/O] with increasing [Fe/H]. For α elements, the dominant contributor is primary component, so that [α/Fe] decrease with increasing [Fe/H]. However, because of the increased contributions of the secondary component, once the contributions of the secondary component are close to those of the primary component, the trends of the [α/Fe] become flat. For the Fe, the observed [Fe/Fe]=0 can be explained by the contribution from the SNe Ia. And for the Ni, during the metal-rich part, the increasing trend of the [Ni/Fe] should be due to the contributions from the secondary component and the SNe Ia. While, for the neutron-capture elements, the observed trends of the [X/Fe] should be explained by the more and more contributions of the main s-process. For the Sm and Eu, the contribution of the main r-process is dominant all the time.