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arXiv 0806.2662astro-ph
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第一批燃烧暗物质的恒星演化

Evolution of the First Stars with Dark Matter Burning

Sung-Chul Yoon, Fabio Iocco, Shizuka Akiyama

摘要:

最近的理论研究揭示了弱相互作用大质量粒子(WIMPs)的捕获和湮灭过程对第一批恒星可能起的重要作用。使用新的无金属大质量恒星的演化模型,我们调查的影响,这种“暗物质燃烧”的第一批恒星在不同的环境中的暗物质(DM)晕,在周围的WIMP密度(rho_chi)。我们发现,与现有文献一致,恒星寿命可以显着延长一定范围的rho_x(即,10^{10} ~ <p_x GeV/cm 3 ~ < 10^{11},自旋相关弹性散射截面σ = 5*10^{-39} cm 2}的电流上限)。这极大地增强了旋转恒星中旋转诱导的化学混合的作用,有利于从第一批恒星中大量产生原始氮、大质量氦星和长伽马射线暴。我们还发现rho_chi > 2*10^{11} GeV/cm ~ 3的恒星可能不经历核燃烧阶段,证实了以前的工作,并且来自这类DM支持的恒星的电离光子通量非常弱。如果大多数第一批恒星都诞生在具有如此高rho_x的DM晕中,那么早期宇宙中延迟的金属富集和缓慢的再电离将会导致这种结果,除非它在短时间尺度上显著降低到有效DM燃烧的阈值以下。

英文摘要:

Recent theoretical studies have revealed the possibly important role of the capture and annihilation process of weakly interacting massive particles (WIMPs) for the first stars. Using new evolutionary models of metal-free massive stars, we investigate the impact of such ``dark matter burning'' for the first stars in different environments of dark matter (DM) halos, in terms of the ambient WIMP density (rho_chi). We find that, in agreement with existing literature, stellar life times can be significantly prolonged for a certain range of rho_χ(i.e., 10^{10} ~ < ρ_χGeV/cm3 ~ < 10^{11} with the current upper limit for the spin-dependent elastic scattering cross section sigma = 5*10^{-39} cm2}). This greatly enhances the role of rotationally induced chemical mixing in rotating stars, in favor of abundant production of primary nitrogen, massive helium stars and long gamma-ray bursts, from the first stars. We also find that stars with rho_chi > 2*10^{11} GeV/cm3 may not undergo nuclear burning stages, confirming the previous work, and that ionizing photon fluxes from such DM supported stars are very weak. Delayed metal enrichment and slow reionization in the early universe would have resulted if most of the first stars had been born in DM halos with such high rho_χ, unless it had been lowered significantly below the threshold for efficient DM burning on a short time scale.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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