Explosive Nucleosynthesis in Axisymmetrically Deformed Type II Supernovae
Explosive Nucleosynthesis in Axisymmetrically Deformed Type II Supernovae
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轴对称变形 II 型超新星中的爆炸性核合成
DOI：
10.1086/304565
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
S. Yamada
中科院分区：
文献类型：
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作者：
S. Nagataki;M. Hashimoto;Katsuhiko Sato;S. Yamada
本文用二维流体动力学计算方法研究了II型超新星轴对称爆炸下的爆炸核合成。并与SN 1987 A的观测结果进行了比较。我们的主要发现如下：（1）合成的~（44）Ti足以解释SN 1987 A的辐射热光变曲线的尾部。我们认为这是因为在轴对称爆炸下，富α粒子的冻结发生得更活跃。（2）57 Ni和58 Ni相对于观测值有过剩的趋势。然而，这种倾向强烈依赖于祖先的模型。我们还比较了质量数A = 16-73范围内各元素的丰度与太阳值。我们发现了三个突出的特点。(1)对于A = 16-40范围内的核，它们的丰度对激波的初始形式不敏感。这种不敏感性是有利的，因为迄今为止的球形计算可以解释太阳系在这个质量范围内的丰度。(2)在轴对称爆炸中，在A = 45附近有一个增强，与球形爆炸相当好。特别是，44 Ca，这是在目前的球形计算不足，显着增强。(3)此外，在A = 65附近存在增强。这一特征依赖于初始冲击波的形式，而不是质量切割的形式。这种增强可能会导致这个质量范围内的生产过剩问题，尽管这种影响相对较小，因为I型超新星主要负责这个质量范围。
Explosive nucleosynthesis under the axisymmetric explosion in Type II supernovae has been examined by means of two-dimensional hydrodynamic calculations. We have compared the results with the observations of SN 1987A. Our chief findings are as follows: (1)44Ti is synthesized in a sufficient amount to explain the tail of the bolometric light curve of SN 1987A. We think this is because the alpha-rich freezeout takes place more actively under the axisymmetric explosion. (2)57Ni and 58Ni tend to be overproduced compared with the observations. However, this tendency relies strongly on the model of the progenitor. We have also compared the abundance of each element in the mass number range A = 16-73 with the solar values. We have found three outstanding features. (1) For the nuclei in the range A = 16-40, their abundances are insensitive to the initial form of the shock wave. This insensitivity is favored since the spherical calculations thus far can explain the solar system abundances in this mass range. (2) There is an enhancement around A = 45 in the axisymmetric explosion that compares fairly well with that of the spherical explosion. In particular,44Ca, which is underproduced in the present spherical calculations, is enhanced significantly. (3) In addition, there is an enhancement around A = 65. This feature relies on the form not of the mass cut but of the initial shock wave. This enhancement may cause the problem of overproduction in this mass range, although this effect would be relatively small since Type I supernovae are chiefly responsible for this mass number range.