贫金属星r过程核合成相关问题的研究进展  

Progress of the Study About R-process Nucleosynthesis in Metal-poor Stars

作　　者：张江[1,2,3] 崔文元[2] 张波[2] 

机构地区：[1]中国科学院国家天文台/云南天文台,昆明650011 [2]河北师范大学物理系,石家庄050016 [3]石家庄经济学院数理学院,石家庄050016

出　　处：《天文学进展》2011年第4期387-407,共21页Progress In Astronomy

基　　金：国家自然科学基金(10973006;11003002;10821061;11033008);河北省杰出青年基金(A2011205102);河北省高校创新基金CPRC034

摘　　要：快中子俘获过程(r过程)可以解释大约一半比铁重的稳定(和一些长寿命放射性的)富中子核素的产生,这已经被太阳系及各种金属丰度下恒星的观测结果所证实。为建立r过程模型,需要大量的核物理信息:涉及到β稳定谷与中子滴线之间的各种核素的稳定特性及β衰变分支等物理参数,实验和理论都面临巨大的挑战。综述了近年来贫金属星r过程核合成理论的研究情况,包括人们比较关注的主要r过程与弱r过程核合成、元素丰度分布规律及其产生场所等。The rapid neutron-capture process （r-process） is traditionally believed to be responsible for the nucleosynthesis of approximately half of the heavy nuclei beyond the iron peak with long-decay half-lives in the solar material. In globular clusters and Galactic halo stars, the observed abundances show a nearly universal presence of r-process. With the rapid development of the abundance determinations, more elements （e.g., Lu, Z = 71） are firstly detected in metal-poor r-process-enriched halo stars, which can be used as the r-process indicators for the early Galaxy. Moreover, these r-rich stars provide a strong constraint on the models of the r-process nucleosynthesis, especially the early galaxy chemical evolution of neutron-capture elements. Based on new atomic lab data, recent neutron-capture abundance comparisons between six r-rich Galactic halo stars and the Solar System r-only abundance distribution indicate that the heavier stable neutron-capture elements beyond Ba （Z ≥ 56） agree completely with a scaled solar system r-process abundance value. Nevertheless, the lighter neutron-capture elemental abundances in these stars are not in agreement with Solar-system r-only values. Although there is controversy over the origin of weak r-process, the neutron-capture elements are proposed to be formed possibly from multiple synthesis mechanisms, even if there exists little uncertainty. Whether the r-process at different astrophysical environments is diverse is also controversial. As needed for the r-process modelling, much effort has been put recently in the measurement of nuclear data of relevance to the r-process, including decay branch characteristics and nuclear stability properties of thousands of nuclides located between the valley of stability up to the neutron-drip line. The challenge is enormous in the theory and experiments of nucleosynthesis. In this paper, a review of r-process nucleosynthesis in metal-poor stars is presented outlining the development of theoretical models and their comparis

关 键 词：贫金属星 中子俘获 s过程 r过程 核合成 

分 类 号：P152[天文地球—天文学]