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arXiv 1901.11136astro-ph.HEastro-ph.SR
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脉动对不稳定性超新星。I.坍缩前演化与脉动物质抛射

Pulsational Pair-instability Supernovae. I. Pre-collapse Evolution and Pulsational Mass Ejection

Shing-Chi Leung, Ken'ichi Nomoto, Sergei Blinnikov

摘要:

我们计算了大质量恒星的演化,当富氧核心形成时,它们会经历脉动对不稳定性(PPI)。计算了初始质量为$80 - 140$ $M_{\odot}$、金属丰度为$Z = 10^{-3} - 1.0$ $Z_\odot$的恒星从主序星到PPI起始的演化。由于质量损失,$Z \leq 0.5$ $Z_\odot$是恒星形成足够大质量的He核所必需的(即,质量$>40 ~M_\odot$)进行PPI。计算了质量为$40 - 62 ~M_\odot$和$Z = 0$的He核从PPI到Fe核开始坍塌的流体动力学演化阶段。在PPI期间,电子-正电子对的产生导致富氧核心的快速收缩,从而引发爆炸性的O燃烧和核心的脉动。我们研究了脉动动力学、热力学和核合成的质量依赖性。对于质量更大的He核,脉动更强,并导致如此大量的质量喷射,例如对于$40 - 62 ~M_\odot$ He核的$3 - 13$ $M_\odot$。这些He核最终经历Fe核坍缩。$64 ~M_\odot$ He核心完全破裂,成为一颗对不稳定超新星。这些氦核周围的无氢拱星物质的质量足以解释所观察到的I型(无氢)超亮超新星与拱星相互作用的光变曲线。我们还注意到,质量喷射将黑洞(BH)的最大质量设置为$\sim 50$ $M_{\odot}$,这与VIRGO和aLIGO最近检测到的BH质量一致。

英文摘要:

We calculate the evolution of massive stars, which undergo pulsational pair-instability (PPI) when the O-rich core is formed. The evolution from the main-sequence through the onset of PPI is calculated for stars with the initial masses of $80 - 140$ $M_{\odot}$ and metallicities of $Z = 10^{-3} - 1.0$ $Z_\odot$. Because of mass loss, $Z \leq 0.5$ $Z_\odot$ is necessary for stars to form He cores massive enough (i.e., mass $>40 ~M_\odot$) to undergo PPI. The hydrodynamical phase of evolution from PPI through the beginning of Fe core collapse is calculated for the He cores with masses of $40 - 62 ~M_\odot$ and $Z = 0$. During PPI, electron-positron pair production causes a rapid contraction of the O-rich core which triggers explosive O-burning and a pulsation of the core. We study the mass dependence of the pulsation dynamics, thermodynamics, and nucleosynthesis. The pulsations are stronger for more massive He cores and result in such a large amount of mass ejection such as $3 - 13$ $M_\odot$ for $40 - 62 ~M_\odot$ He cores. These He cores eventually undergo Fe-core collapse. The $64 ~M_\odot$ He core undergoes complete disruption and becomes a pair-instability supernova. The H-free circumstellar matter ejected around these He cores is massive enough for to explain the observed light curve of Type I (H-free) superluminous supernovae with circumstellar interaction. We also note that the mass ejection sets the maximum mass of black holes (BHs) to be $\sim 50$ $M_{\odot}$, which is consistent with the masses of BHs recently detected by VIRGO and aLIGO.

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