恒星演化晚期核素K壳层连续态电子俘获过程中微子能量损失

The Neutrino Energy Loss of Nuclides by K-shell Continuum State Electron Capture at the Late Stage of Stellar Evolution

基于WeinBerg-Salam理论,考虑Coulomb效应对连续态电子气体的影响,对恒星演化晚期核素^(12)C、^(16)O、^(20)Ne、^(24)Mg、^(28)Si和^(56)Fe在完全电离环境下的K壳层连续态自由电子俘获过程的中微子能量损失进行了讨论.根据,Beaudet、Petrosian和Salpeter(BPS)的方法所得结果与我们的结果进行了比较.结果表明:相对较高温度环境(如T_9=0.1和T_9=1.T_9是以10~9K为单位的温度),两种结果符合很好;而低温环境(如T_9=0.01和T_9=0.001)核素^(16)O、^(20)Ne、^(24)Mg和^(28)Si的中微子能量损失,BPS的结果比我们的结果高10～70倍,对核素^(12)C甚至高出2个数量级.我们的研究可能对恒星演化晚期尤其是白矮星核坍塌到相对低温和中等密度阶段冷却机制的研究具有重要意义.

Based on the Weinberg-Salam theory and taken into consideration of the Coulomb effect on electron gas, the neutrino energy loss rates by K-shell continuum state electron capture are discussed for 12C, 160, 20Ne, 24Mg, 28Si and 56Fe under the condition of complete ionization and at the late stage of stellar evolution. Our results are compared with those of Beaudet, Petrosian and Salpeter （BPS）. It is shown that at relatively high temperatures （e.g., T9 = 0.1 and T9 - 1, T9 represents the temperature in units of 109 K）, our results agree well with BPS＇s. However, at relatively low temperatures （e.g., T9 = 0.01 and T9 = 0.001）, the neutrino energy loss rates of BPS for 160, 20Ne, 24Mg and 28Si are higher than our results by 10 - 70 times, and even by 2 orders of magnitude for nuclide 12C. Our results may be of great importance in the research of late stellar evolution, especially for the cooling mechanism of white dwarf, during which the nucleus collapsed to the stage with a relatively low temperature and intermediate density.