银河系移动星群Group1、2、3元素的天体物理来源研究
发布时间：2018-10-13 17:45
【摘要】：观测表明,银河系移动星群Group1、2、3恒星的α元素(O、Mg、Si、Ca、Ti)、铁族元素(Sc、V、Cr、Fe、Co、Ni)和中子俘获元素(Y、Zr、Ba、La、Ce、Pr、Nd,Sm、Eu)丰度比随[Fe/H]变化趋势不同。为了寻找Group 1、2、3恒星的α元素、铁族元素和中子俘获元素丰度趋势的天体物理原因,在本文中我们通过五分量元素丰度模型拟合了这些恒星α元素,铁族元素和中子俘获元素的丰度,并分析了这些元素的天体物理来源。计算结果表明,对于[Fe/H]-0.4的情况,主要r-过程和primary过程分量的贡献随金属丰度的增大呈平坦趋势,而对于[Fe/H]-0.4的情况,主要r-过程和primary过程相对贡献随金属丰度的增大呈下降趋势;主要s-过程、Ia型超新星和secondary过程的贡献随金属丰度的增大呈上升趋势。由于O元素是一个“纯”primary过程元素,因此对于[Fe/H]-0.4的情况,[O/Fe]随着金属丰度的增长而单调下降。其他α元素Mg、Si、Ca、Ti的主要天体物理来源也是大质量星primary过程。以Mg元素为例,对于[Fe/H]-0.4的情况,[Mg/Fe]随[Fe/H]呈平坦趋势;但对于[Fe/H]-0.4的情况,大质量星secondary过程分量贡献随金属丰度的增加而增大,导致[Mg/Fe]下降趋势较为平缓。相对α元素而言,铁族元素的天体物理来源要复杂一些。以Cr元素为例,对于[Fe/H]-0.4的情况,[Cr/Fe]随[Fe/H]的增加呈平坦趋势,其原因是这些元素的主要天体物理来源是大质量星primary过程;而对于[Fe/H]-0.4的情况,Ia型超新星的贡献随金属丰度的增加而逐渐增大,补偿了大质量星primary过程丰度比的下降,从而使所以元素[Cr/Fe]呈平坦趋势。对于中子俘获元素而言,以Y、Ba和Eu元素为例,在[Fe/H]-0.4的情况下,Y的丰度比随金属丰度的增加呈平坦趋势,因为Y的天体物理来源是弱r-过程,而弱r-过程的产量具有primary特性;对于[Fe/H]-0.4的情况,弱r-过程相对贡献随[Fe/H]的增加呈下降趋势,主要s-过程分量贡献随金属丰度的增加而增大补偿了弱r-过程的下降使[Y/Fe]仍呈平坦趋势。对于[Fe/H]-0.4的情况,[Ba/Fe]随[Fe/H]的增大呈平坦趋势,其原因是Ba的主要天体物理来源是主要r-过程,而主要r-过程的产量具有primary特性。对于[Fe/H]-0.4的情况,[Ba/Fe]随[Fe/H]的增大呈上升趋势,其原因是主要s-过程贡献随[Fe/H]的增加而增大。对于[Fe/H]-0.4的情况,[Eu/Fe]随[Fe/H]的增加呈现平坦趋势,其原因是Eu元素的主要天体物理来源始终是主要r-过程;而对于高金属丰度的情况,[Eu/Fe]呈下降趋势,其原因是主要r-过程丰度比随[Fe/H]的增大呈下降趋势。本文把O元素看作一个标准元素代替Fe元素,这时,大质量星primary过程和主要r-过程分量比呈平坦趋势,具有primary特性,而主要s-过程、大质量星secondary过程分量和Ia超新星的分量比呈上升趋势。由于α元素Mg为例,在较低金属丰度情况下,[Mg/O]随金属丰度的增加呈平坦趋势;而在高金属丰度的情况下,大质量星secondary过程分量比随[Fe/H]的增大而增大,从而导致在较高金属丰度情况下[Mg/O]呈上升趋势。对于α元素而言,铁族元素的天体物理来源要复杂一些,以Cr元素为例,对于[Fe/H]-0.4的情况下,[Cr/O]随[Fe/H]的增大呈平坦趋势,其原因是Cr的主要天体物理来源是大质量星primary分量;而对于[Fe/H]-0.4的情况,[Cr/O]呈平坦趋势,是因为Ia型超新星的补偿效应。对于较轻中子俘获元素而言,以Y,Ba和Eu元素为例,在[Fe/H]-0.4的情况下,[Y/O]随[Fe/H]的增大呈平坦趋势,其原因是Y元素的主要天体物理来源是弱r-过程分量,而弱r-过程具有primary特性;对于[Fe/H]-0.4的情况,[Y/O]随[Fe/H]呈上升趋势,其天体物理原因是主要s-过程对Y元素的贡献随[Fe/H]的增大而逐渐增大并超过弱r-分量过程贡献。对于[Fe/H]-0.4的情况,[Ba/O]随[Fe/H]的增大呈平坦趋势,其原因是Ba的主要天体物理来源是主要r-过程和主要s-过程贡献,二者几乎不随金属丰度变化。对于[Fe/H]-0.4的情况,[Ba/O]呈上升趋势,其原因是主要s-过程对Ba元素的贡献随[Fe/H]的增大而增大并超过主要r-过程的贡献。[Eu/O]随[Fe/H]的增大呈平坦趋势,其原因是Eu元素的主要天体物理来源是主要r-过程。
[Abstract]:The observation shows that the abundance ratio of elements (O, Mg, Si, Ca, Ti), Fe family elements (Sc, V, Cr, Fe, Co, Ni) and neutron capture elements (Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu) in the moving star group Group1, 2 and 3 of the Milky Way is different from that of[Fe/ H]. In order to find the astrophysical cause of the geochemical element, iron family element and neutron capture element abundance trend of Group 1, 2, 3 stars, we fit the abundance of these star elements, iron family elements and neutron capture elements by five-element abundance model in this paper. The physical sources of these elements are analyzed and analyzed. The results show that for[Fe/ H]-0.4, the contribution of the main r-process and primary process components varies with the increase of metal abundance, whereas for[Fe/ H]-0.4, the relative contribution of the main r-process and primary process decreases with the increase of metal abundance; the main s-process, The contribution of type Ia supernova and secondary process increases with the increase of metal abundance. since the o element is one, "Pure" The primary process element, therefore, for[Fe/ H]-0.4,[O/ Fe] decreases monotonically with increasing metal abundance. The main physical source of other elements Mg, Si, Ca and Ti is also the primary process of large mass star. In the case of[Fe/ H]-0.4, Mg/ Fe has a flat tendency with[Fe/ H]. However, in the case of[Fe/ H]-0.4, the contribution of the large mass star secondary process component increases with the increase of the metal abundance, leading to a more gradual decrease in[Mg/ Fe]. For relatively small elements, the astrophysical source of the iron-family elements is complex. In the case of[Fe/ H]-0.4, Cr/ Fe has a flat tendency with the increase of[Fe/ H]-0.4. The reason is that the main physical source of these elements is the primary process of large mass star; and for[Fe/ H]-0.4, the contribution of type Ia supernovae gradually increases with the increase of metal abundance, The decrease of the abundance ratio of the large mass star primary process is compensated, so that the element[Cr/ Fe] has a flat tendency. For neutron capture elements, in the case of[Fe/ H]-0.4, Y, Ba and Eu elements are in a flat tendency in the[Fe/ H]-0.4, because the physical source of the celestial body of Y is the weak r-process, while the yield of the weak r-process has primary characteristics; for the case of[Fe/ H]-0.4, The relative contribution of weak r-process decreases with the increase of[Fe/ H]. The contribution of main s-process components increases with the increase of metal abundance, and the decrease of weak r-process makes[Y/ Fe] still flat. In the case of[Fe/ H]-0.4,[Ba/ Fe] has a flat tendency with the increase of[Fe/ H]. The reason is that the main physical source of Ba is the main r-process, while the yield of the main r-process is primary. For[Fe/ H]-0.4,[Ba/ Fe] increases with the increase of[Fe/ H]. The reason is that the main s-process contribution increases with the increase of[Fe/ H]. In the case of[Fe/ H]-0.4,[Eu/ Fe] exhibits a flat tendency with the increase of[Fe/ H]. The reason is that the main physical source of Eu element is always the main r-process; while for the case of high metal abundance,[Eu/ Fe] exhibits a decreasing tendency. The reason is that the main r-process abundance ratio decreases with the increase of[Fe/ H]. In this paper, the O element is regarded as a standard element instead of the Fe element. At this time, the primary process and the main r-process component ratio of the large mass star have a flat tendency, and have the primary characteristic, while the main s-process, the large mass star secondary process component and the component ratio of the Ia supernova are on the rise. in that case of low metal abundance,[Mg/ O] increases with the increase of metal abundance in the case of low metal abundance, and in the case of high metal abundance, the large mass star secondary process component ratio increases with the increase of[Fe/ H], resulting in an upward trend in[mg/ o] in the case of higher metal abundance. In the case of Fe/ H[Fe/ H]-0.4,[Cr/ O] has a flat tendency with[Fe/ H]. The reason is that the main physical source of Cr is the primary component of large mass star; and for the case of[Fe/ H]-0.4,[Cr/ O] has a flat tendency because of the compensation effect of type Ia supernovae. For lighter neutron capture elements, Y, Ba and Eu elements are in an example, in the case of[Fe/ H]-0.4,[Y/ O] becomes a flat tendency with[Fe/ H]. The reason is that the main physical source of the Y element is the weak r-process component, and the weak r-process has the primary characteristic. In the case of[Fe/ H]-0.4,[Y/ O] increases with[Fe/ H], whose physical reason is that the contribution of the main s-process to the Y element gradually increases with[Fe/ H] and exceeds the weak r-component process contribution. In the case of[Fe/ H]-0.4,[Ba/ O] has a flat tendency with the increase of[Fe/ H]. The reason is that the main physical source of Ba is the main r-process and the main s-process contribution, and the two do not change with the metal abundance. In the case of[Fe/ H]-0.4,[Ba/ O] is on the rise, and the reason is that the contribution of the main s-process to the Ba element increases with[Fe/ H] and exceeds the contribution of the main r-process.[Eu/ O] has a flat tendency with the increase of[Fe/ H]. The reason is that the main physical source of Eu element is the main 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】：2016
【分类号】：P156
本文编号：2269424
[Abstract]:The observation shows that the abundance ratio of elements (O, Mg, Si, Ca, Ti), Fe family elements (Sc, V, Cr, Fe, Co, Ni) and neutron capture elements (Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu) in the moving star group Group1, 2 and 3 of the Milky Way is different from that of[Fe/ H]. In order to find the astrophysical cause of the geochemical element, iron family element and neutron capture element abundance trend of Group 1, 2, 3 stars, we fit the abundance of these star elements, iron family elements and neutron capture elements by five-element abundance model in this paper. The physical sources of these elements are analyzed and analyzed. The results show that for[Fe/ H]-0.4, the contribution of the main r-process and primary process components varies with the increase of metal abundance, whereas for[Fe/ H]-0.4, the relative contribution of the main r-process and primary process decreases with the increase of metal abundance; the main s-process, The contribution of type Ia supernova and secondary process increases with the increase of metal abundance. since the o element is one, "Pure" The primary process element, therefore, for[Fe/ H]-0.4,[O/ Fe] decreases monotonically with increasing metal abundance. The main physical source of other elements Mg, Si, Ca and Ti is also the primary process of large mass star. In the case of[Fe/ H]-0.4, Mg/ Fe has a flat tendency with[Fe/ H]. However, in the case of[Fe/ H]-0.4, the contribution of the large mass star secondary process component increases with the increase of the metal abundance, leading to a more gradual decrease in[Mg/ Fe]. For relatively small elements, the astrophysical source of the iron-family elements is complex. In the case of[Fe/ H]-0.4, Cr/ Fe has a flat tendency with the increase of[Fe/ H]-0.4. The reason is that the main physical source of these elements is the primary process of large mass star; and for[Fe/ H]-0.4, the contribution of type Ia supernovae gradually increases with the increase of metal abundance, The decrease of the abundance ratio of the large mass star primary process is compensated, so that the element[Cr/ Fe] has a flat tendency. For neutron capture elements, in the case of[Fe/ H]-0.4, Y, Ba and Eu elements are in a flat tendency in the[Fe/ H]-0.4, because the physical source of the celestial body of Y is the weak r-process, while the yield of the weak r-process has primary characteristics; for the case of[Fe/ H]-0.4, The relative contribution of weak r-process decreases with the increase of[Fe/ H]. The contribution of main s-process components increases with the increase of metal abundance, and the decrease of weak r-process makes[Y/ Fe] still flat. In the case of[Fe/ H]-0.4,[Ba/ Fe] has a flat tendency with the increase of[Fe/ H]. The reason is that the main physical source of Ba is the main r-process, while the yield of the main r-process is primary. For[Fe/ H]-0.4,[Ba/ Fe] increases with the increase of[Fe/ H]. The reason is that the main s-process contribution increases with the increase of[Fe/ H]. In the case of[Fe/ H]-0.4,[Eu/ Fe] exhibits a flat tendency with the increase of[Fe/ H]. The reason is that the main physical source of Eu element is always the main r-process; while for the case of high metal abundance,[Eu/ Fe] exhibits a decreasing tendency. The reason is that the main r-process abundance ratio decreases with the increase of[Fe/ H]. In this paper, the O element is regarded as a standard element instead of the Fe element. At this time, the primary process and the main r-process component ratio of the large mass star have a flat tendency, and have the primary characteristic, while the main s-process, the large mass star secondary process component and the component ratio of the Ia supernova are on the rise. in that case of low metal abundance,[Mg/ O] increases with the increase of metal abundance in the case of low metal abundance, and in the case of high metal abundance, the large mass star secondary process component ratio increases with the increase of[Fe/ H], resulting in an upward trend in[mg/ o] in the case of higher metal abundance. In the case of Fe/ H[Fe/ H]-0.4,[Cr/ O] has a flat tendency with[Fe/ H]. The reason is that the main physical source of Cr is the primary component of large mass star; and for the case of[Fe/ H]-0.4,[Cr/ O] has a flat tendency because of the compensation effect of type Ia supernovae. For lighter neutron capture elements, Y, Ba and Eu elements are in an example, in the case of[Fe/ H]-0.4,[Y/ O] becomes a flat tendency with[Fe/ H]. The reason is that the main physical source of the Y element is the weak r-process component, and the weak r-process has the primary characteristic. In the case of[Fe/ H]-0.4,[Y/ O] increases with[Fe/ H], whose physical reason is that the contribution of the main s-process to the Y element gradually increases with[Fe/ H] and exceeds the weak r-component process contribution. In the case of[Fe/ H]-0.4,[Ba/ O] has a flat tendency with the increase of[Fe/ H]. The reason is that the main physical source of Ba is the main r-process and the main s-process contribution, and the two do not change with the metal abundance. In the case of[Fe/ H]-0.4,[Ba/ O] is on the rise, and the reason is that the contribution of the main s-process to the Ba element increases with[Fe/ H] and exceeds the contribution of the main r-process.[Eu/ O] has a flat tendency with the increase of[Fe/ H]. The reason is that the main physical source of Eu element is the main 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】：2016
【分类号】：P156
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