arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1306.2745astro-ph.CO
收藏

在turbulence存在下大质量Pop III星的形成

The formation of massive Pop III stars in the presence of turbulence

M. A. Latif, D. R. G. Schleicher, W. Schmidt, J. Niemeyer

摘要:

在z=30时形成的第三星族恒星预示着宇宙黑暗时代的结束。它们被认为是组装在所谓的迷你晕中,维里温度为几千K,塌缩是由分子氢冷却引发的。一个核心问题是它们的最终质量,以及在它们的形成过程中是否发生了碎裂。虽然采用拉格朗日代码的研究表明,通过自引力盘的碎片,最近的高分辨率模拟表明,磁盘的形成受到抑制。在这里,我们报告的第一个高分辨率的大涡模拟与欧拉网格为基础的代码恩佐以下的演变超出形成的第一个高峰,调查吸积的中央大规模的团块和潜在的碎片。对于总共3个晕,我们看到第一个团周围形成了一个圆盘。中心的团块在40年后达到$\sim10$太阳质量,而随后的吸积预计将以每年$10^{-2}$太阳质量的速度进行。在其中一个晕中,由于在更大尺度上进行的碎裂,形成了额外的团块。我们注意到,亚网格尺度的湍流产生相关的贡献的原恒星盘的稳定性。我们的结论是,第一个原恒星可能达到质量高达$\rm 40-100 M_{\odot}$,这是唯一的辐射反馈的影响有限。

英文摘要:

Population III stars forming in the infant universe at z=30 heralded the end of the cosmic dark ages. They are presumed to be assembled in so-called minihaloes with virial temperatures of a few thousand K where collapse is triggered by molecular hydrogen cooling. A central question concerns their final masses, and whether fragmentation occurs during their formation. While studies employing Lagrangian codes suggest fragmentation via a self-gravitating disk, recent high resolution simulations indicated that disk formation is suppressed. Here we report the first high-resolution large-eddy simulations performed with the Eulerian grid-based code Enzo following the evolution beyond the formation of the first peak, to investigate the accretion of the central massive clump and potential fragmentation. For a total of 3 halos, we see that a disk forms around the first clump. The central clump reaches $\sim10$ solar masses after 40 years, while subsequent accretion is expected at a rate of $10^{-2}$ solar masses per year. In one of these halos, additional clumps form as a result of fragmentation which proceeds at larger scales. We note that subgrid-scale turbulence yields relevant contributions to the stability of the protostellar disks. We conclude that the first protostar may reach masses up to $\rm 40-100 M_{\odot}$, which are only limited by the effect of radiative feedback.

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。

↑