超新星爆发环境核素^(56,57,59,60)Co的电子俘获

Electron capture of nuclides^(56,57,59,60)Co in supernova explosive surrounding

基于壳模型与Random Phase Approximation理论,利用Shell-Model Monte Carlo方法,研究了超新星爆发环境核素56,57,59,60Co的电子俘获与电子丰度变化率.我们的结果与利用Aufderheide方法计算的结果进行了误差对比.结果表明:电子俘获率受温度和密度的影响大大增加,甚至增加达6个数量级以上(如在ρ7=0.43,Ye=0.48核素57,59,60Co).另一方面,随着温度和密度的增大,电子丰度变化率大大降低,甚至减小达5个数量级以上(如在ρ7=5.86,Ye=0.47核素59Co).通过对误差因子的分析表明,在低温低密度环境二种结果误差较大;而在高温高密度环境,二种结果误差相对较小.

Based on the shell model and random phase approximation theory, and using a shell-model Monte Carlo （SMMC） method, we have investigated the electron capture （EC） for nuclides 56,57,59,60Co, and the rate of change of electron fraction （RCEF） in supernova explosive surroundings. We compared our results, which were obtained by using SMMC method, with those analyzed by using Aufderheide＇s method. The results show that the EC rates increase greatly, even more than 6 orders of magnitude （e. g. for 57,59,60Co at ρ7=0.43, Ye=0.48）. On the other hand, with the increase in temperature and density, the RCEF decreases greatly, even by 5 orders of magnitude （e. g. for 59Co at ρ7=5.86, Ye=0.47）. The discussions of error factor show that in a lower density and temperature surrounding, the error is relatively great. But it may be small in the higher density and temperature surroundings.