极贫金属晕星中Eu元素的起源  

Generation of Europium in Metal-Poor Halo Stars

作　　者：戴俊安[1] 彭秋和[1] 

机构地区：[1]南京大学天文学系,南京210093

出　　处：《天文学报》2008年第3期251-259,共9页Acta Astronomica Sinica

基　　金：国家自然科学基金(10573011;10273006);国家教委优秀学者基金资助

摘　　要：快中子过程(r-过程)发生在富中子的环境中.但是它所在的具体天体物理环境并不是很清楚.随着观测的进展,近年发现了很多的极贫金属的晕星.它们有两个特征:一是快中子元素超丰,并且相对丰度与太阳上的一致.另一个特征是当金属丰度一样时,星体中快中子元素的含量有大的弥散性.这为研究r-过程起源提供了一种独特的途径.模拟计算的方法,用于研究星系演化的过程,以及相伴发生的恒星的快中子核素含量的弥散性,可用来了解快中子元素的起源这样得出的星系演化模型,不仅包含了气体区域自发的恒星形成,而且考虑了超新星爆发激发的恒星形成.结果显示,低质量端的超新星应是快中子核素的产生地.同时,超新星引起的星系演化的不均匀性不足以解释观测到的晕星快中子元素含量的弥散,因此这个问题还有待于更进一步研究.r-process are thought to take place in neutron-rich TypeⅡsuperno- vae,but their sites are not exactly known.Recently some extremely metal-poor halo stars are found.They have two significant characters.One is that their r-process ele- ments are over-abundant and are in excellent agreement with the scaled solar r-process curve.The other is that there have large dispersion of r-process elements with the same metallicity.A simulation on the chemical evolution of the Galaxy and the r-process dis- tribution was made,considering both the star formation of interstellar gas itself and the star formation triggered by the nearby supernovae explosion.Comparing with the ob- servation,the simulation shows that the low-mass TypeⅡsupernovae should be the possible r-process sites,and the supernovae are not response for all the inhomogeneity. In the future,the study on the inhomogeneity of the Galactic chemical evolution and the new observation of halo stars will give more understanding of this problem.

关 键 词：物理数据与过程 核反应 核聚变 丰度 恒星 演化 超新星 普通 

分 类 号：P157[天文地球—天文学]