考虑时间延迟后较重r-过程元素的化学演化

Chemical Evolution of Heavy r-Process Elements Considered the Time Delay

考虑有效产生r-过程（快中子俘获过程）元素的Ⅱ型超新星延迟爆发的因素,大体上经过10次大质量Ⅱ型超新星（M〉35 M⊙）先爆发后,产生r-过程元素的Ⅱ型超新星（M=（28~35）M⊙）才开始爆发.从星系化学演化角度看,r-过程元素的主要来源为较大质量Ⅱ型超新星（M=（28~35）M⊙）.Ⅱ型超新星占Ⅱ型超新星总数的4%.核合成区域内种子核和中子源主要来自恒星自身的核反应.经计算得到星系晕中较重的r-过程元素Eu,Ba,Ce,La,Nd,Pr,Sm等元素丰度的离散情况及其化学演化.

Considering the time delay between two supernovae events,the typeⅡsupernovae（M=（28—35） M⊙）which produced r-process broke out after the typeⅡsupernovae（M35 M⊙） done ten times.Our conclusion is that the r-process elements are mainly produced in a small fraction of the type Ⅱ supernovae（M=（28—35）M⊙）.The typeⅡsupernovae which produce heavy r-process elements originate from a small fraction 4% of all typeⅡsupernovae stars.The nucleus of theseed and neutron source in the nucleosynthesis sites were produced in nuclear reaction of the stellar themselves.The abundance scatter of Eu,Ba,Ce,La,Nd,Pr,Sm versus was calculated.The galactic chemical evolution of heavy elements from Ba to Eu was obtained.