The red supergiant and supernova rate problems: Implications for core-collapse supernova physics
The red supergiant and supernova rate problems: Implications for core-collapse supernova physics
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DOI：
10.1093/mnrasl/slu146
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发表时间：
2014-08
影响因子：
4.8
通讯作者：
S. Horiuchi;K. Nakamura;T. Takiwaki;K. Kotake;Masaomi Tanaka
中科院分区：
文献类型：
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作者：
S. Horiuchi;K. Nakamura;T. Takiwaki;K. Kotake;Masaomi Tanaka
将超新星映射到它们的祖先是理解大质量恒星坍塌的基础。我们研究了红超巨星问题和超新星速率问题，红超巨星问题是指为什么质量在16美元-30美元之间的红超巨星没有被确定为IIP型超新星的前身，超新星速率问题是指为什么观测到的宇宙超新星速率小于观测到的宇宙恒星形成率。我们在致密性参数中找到了解决这些问题的关键物理，该参数表征了前驱分子的密度结构。如果致密度大于2.5\sim 0.2的大质量恒星不能产生正则超新星，(1)质量在1 6~3 0M的恒星聚集在一座恒星岛上，这些恒星的密度高，不产生正则超新星；(2)这类恒星的比例与超新星相对于恒星形成的缺失比例一致。我们用一系列的二维和三维辐射流体力学堆芯崩塌模拟来支持这一设想。利用覆盖初始质量10.8~75M_(ODOT)和三个初始金属度的300多个母体，我们证明了高致密性有利于失败爆炸。然后我们认为，临界致密度$\sim 0.2$作为成功和失败爆炸之间的分界线与最先进的三维核心坍塌模拟是一致的。我们的研究表明，核心塌缩的数值模拟不需要在致密的大质量恒星初始条件的很大一部分中产生强劲的爆炸。
Mapping supernovae to their progenitors is fundamental to understanding the collapse of massive stars. We investigate the red supergiant problem, which concerns why red supergiants with masses $\sim16$-$30 M_\odot$ have not been identified as progenitors of Type IIP supernovae, and the supernova rate problem, which concerns why the observed cosmic supernova rate is smaller than the observed cosmic star formation rate. We find key physics to solving these in the compactness parameter, which characterizes the density structure of the progenitor. If massive stars with compactness above $\xi_{2.5} \sim 0.2$ fail to produce canonical supernovae, (i) stars in the mass range $16$-$30 M_\odot$ populate an island of stars that have high $\xi_{2.5}$ and do not produce canonical supernovae, and (ii) the fraction of such stars is consistent with the missing fraction of supernovae relative to star formation. We support this scenario with a series of two- and three-dimensional radiation hydrodynamics core-collapse simulations. Using more than 300 progenitors covering initial masses $10.8$-$75 M_\odot$ and three initial metallicities, we show that high compactness is conducive to failed explosions. We then argue that a critical compactness of $\sim 0.2$ as the divide between successful and failed explosions is consistent with state-of-the-art three-dimensional core-collapse simulations. Our study implies that numerical simulations of core collapse need not produce robust explosions in a significant fraction of compact massive star initial conditions.