THE INTERPLAY OF MAGNETIC FIELDS, FRAGMENTATION, AND IONIZATION FEEDBACK IN HIGH-MASS STAR FORMATION
THE INTERPLAY OF MAGNETIC FIELDS, FRAGMENTATION, AND IONIZATION FEEDBACK IN HIGH-MASS STAR FORMATION
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DOI：
10.1088/0004-637x/729/1/72
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发表时间：
2010-10
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影响因子：
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通讯作者：
T. Peters;R. Banerjee;R. Klessen;M. M. Low-M.
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文献类型：
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作者：
T. Peters;R. Banerjee;R. Klessen;M. M. Low-M.
大质量恒星不成比例地影响着周围的环境。它们是如何形成的，直到最近才通过辐射气体动力学模拟开始变得清晰。然而，到目前为止，还没有模拟同时包括磁场和电离辐射。在这里，我们提出的结果从第一辐射磁流体动力学（RMHD）模拟包括电离反馈，比较RMHD模型的1000 M的旋转云早期辐射气体动力学模型具有相同的初始密度和速度分布。我们发现，尽管开始与一个强超临界的质量流量比，磁场有三个效果。首先，该领域提供了本地支持，对引力坍缩的吸积流，大大减少了二次破碎的气体动力学的情况下相比。第二，磁场从坍缩的气体中排出角动量，进一步增加了中央大质量原恒星可供吸积的物质数量，从而使其最终质量比纯气体动力学的情况增加了约50%。第三，场被流动的旋转卷起，驱动塔流。然而，这种流动从来没有达到在低质量星星形成模拟中看到的强度，原因有两个：引力破碎破坏了原恒星形成的中心区域的环形流动，以及不断扩大的H ii区域倾向于进一步破坏场的几何形状。因此，电离辐射很可能主导大质量星星形成区域的外流动力学。
Massive stars disproportionately influence their surroundings. How they form has only started to become clear recently through radiation gas dynamical simulations. However, until now, no simulation has simultaneously included both magnetic fields and ionizing radiation. Here we present the results from the first radiation-magnetohydrodynamical (RMHD) simulation including ionization feedback, comparing an RMHD model of a 1000 M☉ rotating cloud to earlier radiation gas dynamical models with the same initial density and velocity distributions. We find that, despite starting with a strongly supercritical mass-to-flux ratio, the magnetic field has three effects. First, the field offers locally support against gravitational collapse in the accretion flow, substantially reducing the amount of secondary fragmentation in comparison to the gas dynamical case. Second, the field drains angular momentum from the collapsing gas, further increasing the amount of material available for accretion by the central, massive, protostar, and thus increasing its final mass by about 50% from the purely gas dynamical case. Third, the field is wound up by the rotation of the flow, driving a tower flow. However, this flow never achieves the strength seen in low-mass star formation simulations for two reasons: gravitational fragmentation disrupts the circular flow in the central regions where the protostars form, and the expanding H ii regions tend to further disrupt the field geometry. Therefore, ionizing radiation is likely to dominate outflow dynamics in regions of massive star formation.