Element synthesis in the late and explosive stages of stellar evolution

1.我们已经开发了一个计算机程序，可以处理大质量星星演化的详细核网络。用该程序计算了8 M<of sun>-25 M<of sun>恒星的演化。8 M<of sun>和3.3 M<of sun>氦星星的铁核质量分别为1.6 M<of sun>和1.2 M<of sun>。这个小铁芯（1.2M<of sun>）具有特殊的重要性，因为在崩溃阶段产生的冲击波将能够在几毫秒内炸毁外部区域。对于10- 11 M<of sun>恒星，氖燃烧锋向中心传播，并将出现爆炸性氖闪光.本文将I型超新星碳燃烧白色矮星模型的元素合成结果与光谱、光变曲线和X射线辐射等实验数据进行了比较。他们的协议很好。本文研究了作为I型超新星前身的C+O白色矮星模型。在假设球模型的情况下，计算了质量吸积和碳燃烧。当吸积率大于2x &lt;10^（-6）&gt; M <of sun>&lt;y^（-1）&gt;时，碳闪光向中心传播，并将形成中子星。我们还研究了非球形的配置。然而，由于引力辐射，两颗白色矮星之间的分离变得很小，因此不太可能形成重盘。因此，质量开始从系统中流出，两颗白色矮星开始合并。但达到的最大密度还不足以引发超新星爆炸。

1. We have developed a computer code which can handle the massive star evolution with detail nuclear network. By this code we computed evolution of 8M <of sun> -25M <of sun> stars. For 8M <of sun> and 3.3M <of sun> helium star the mass of the iron core is 1.6M <of sun> and 1.2M <of sun> , respectively. This small iron core (1.2M <of sun> ) has special importance because the shock wave generated during the collapse stage will be able to blow up the outer region in a few millisecond. For 10-11M <of sun> stars neon burning front propagates towards the center and an explosive neon flash will be expected.2. The results from elementsynthesis of carbon burning white dwarf model for Type I supernova have been compared to the obseravtional data such as specrtum, light curve and X-ray emission. Their agreement is quite well. C+O white dwarf models as progenitor of Type I supernova have been studied. By assuming a spherical model we computed mass accretion and carbon burning When the accretion rate is greater than 2x <10^(-6)> M <of sun> <y^(-1)> , the carbon flash propagates towards the center and a neutron satr will be expected to form. We also studied non-spherical configurations. However the heavy disk formation is unlikely to occur and due to the garvitational radiation separation between two white dwarfs becomes small. Thus mass begins to flow out from the system and two white dwarfs begins to merge. But the maximum density reached is not high enough to trigger the supernova explosion.