AGB星辐射s-过程核合成模型中子辐照量分布的计算方法和特点

发布时间：2018-04-05 21:37

本文选题：恒星　切入点：AGB　出处：《天文学报》2013年01期

【摘要】：考虑到模型参量随脉冲数的变化,推导出~(13)C辐射燃烧的低质量AGB星s-过程核合成模型中子辐照量分布的计算方法,该方法具有普适性和简洁性.利用该方法,计算了3M_⊙、太阳金属丰度恒星模型的中子辐照量分布.结果表明,若合理假设~(13)C薄层内中子数密度均匀分布,则辐射核合成模型最终的中子辐照量分布趋近于指数分布.对于初始质量一定、金属丰度一定的恒星模型,平均中子辐照量τ_0与每个脉冲的中子辐照量△7存在确定的关系:τ_0=0.434λ(q_1,q_2…q_(m_(max))+1,r_1,r_2…r_(m_(max))+1)△7,式中m_(max)是带挖掘的脉冲总数,比例系数λ(q_1,q_2…q_(m_(max))+1,r_1,r_2…r_(m_(max))+1)可通过对最终中子辐照量分布的指数拟合得到.该式从中子辐照量分布角度定量地将经典模型和辐射s-过程核合成模型统一起来,使经典模型能为恒星模型核合成数值计算提供指导和约束.
[Abstract]:Considering the variation of model parameters with the number of pulses, a method for calculating the neutron irradiation distribution of the low mass AGB star sprocess model for radiation combustion is derived. The method is of universality and conciseness.By using this method, the neutron irradiance distribution of the 3M _ 298, solar metal abundance star model has been calculated.The results show that if it is reasonably assumed that the neutron number density is uniformly distributed in the thin layer, the final neutron radiation distribution of the radionuclide synthesis model approaches the exponential distribution.For a star model with a constant initial mass and a constant metal abundance, the relationship between the average neutron irradiance 蟿 _ 0 and the neutron irradiance of each pulse is determined: 蟿 _ 0 _ 0 _ (0.434) 位 / Q _ S _ (1) / _ _ _...) 1 / 1 / 1 / / /M _ S _ max) is the total number of pulses with excavations.) 1 / 1 / 1 / / /1) can be obtained by the exponential fitting of the final neutron radiation distribution.The formula quantitatively unifies the classical model and the radiation-sprocess nuclear synthesis model from the angle of the distribution of the neutrons irradiance. The classical model can provide guidance and constraints for the numerical calculation of the nuclear synthesis of the star model.
【作者单位】：沧州师范学院物理与电子信息系;河北师范大学物理科学与信息工程学院;
【基金】：国家自然科学基金项目(11003002,10973006) 河北省杰出青年基金项目(A2011205102,A2009000251) 河北省教育厅创新人才支持计划(CPRC034) 河北省教育厅高等学校自然科学研究指导计划(z2010108)资助
【分类号】：P142

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