Molecular cloud evolution – V. Cloud destruction by stellar feedback
Molecular cloud evolution – V. Cloud destruction by stellar feedback
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分子云演化 – V. 恒星反馈对云的破坏
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
G. Gómez
中科院分区：
文献类型：
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作者：
P. Colín;E. Vázquez;G. Gómez
我们对分子云的演化进行了数值研究，从它们在温暖的 ISM 中会聚流的形成，到它们形成的大质量恒星的电离反馈的破坏。我们通过引入不同的恒星粒子形成算法对之前的模拟进行了改进，该算法允许它们具有与单星而不是小星团相对应的质量，并且质量分布遵循近硝基恒星 IMF。我们还采用了一种简化的辐射传输算法，该算法允许恒星粒子以取决于其质量和局部密度的速率反馈到介质上。我们的结果如下： a) 与我们之前的研究结果相反，所有恒星粒子以相当于一颗恒星的 10 M⊙ 的速率注入能量，现在稠密气体在 10-20 Myr 内从恒星周围的 10-pc 区域完全疏散，这表明这一壮举基本上是由最大质量的恒星完成的。 b）在整个数值模拟的规模上，尽管恒星形成（SF）从未完全停止，致密气体质量减少了一个数量级，这表明反馈在局部终止了SF，但新的SF事件继续在云中的其他地方发生。 c) SF效率（SFE）在全球范围内维持在±10%的水平，尽管在局部，吸积流集中度最大的云达到了SFE±30%。 d) 在恒星反馈开始主导动力学之前，云的维里参数接近一致，一旦反馈占主导地位，就会变得更大，这表明云由于恒星反馈而变得无束缚，而不是无束缚是低 SFE 的原因。 e) 为恒星形成团块提供营养的细丝的侵蚀产生了一系列孤立的致密斑点，让人想起在暗球体 B68 附近观察到的那些斑点。
We present a numerical study of the evolution of molecular clouds, from their formation by converging flows in the warm ISM, to their destruction by the ionizing feedback of the massive stars they form. We improve with respect to our previous simulations by including a different stellar-particle formation algorithm, which allows them to have masses corresponding to single stars rather than to small clusters, and with a mass distribution following a near-Salpeter stellar IMF. We also employ a simplified radiative-transfer algorithm that allows the stellar particles to feed back on the medium at a rate that depends on their mass and the local density. Our results are as follows: a) Contrary to the results from our previous study, where all stellar particles injected energy at a rate corresponding to a star of � 10 M⊙, the dense gas is now completely evacuated from 10-pc regions around the stars within 10–20 Myr, suggesting that this feat is accomplished essentially by the most massive stars. b) At the scale of the whole numerical simulations, the dense gas mass is reduced by up to an order of magnitude, although star formation (SF) never shuts off completely, indicating that the feedback terminates SF locally, but new SF events continue to occur elesewhere in the clouds. c) The SF efficiency (SFE) is maintained globally at the � 10% level, although locally, the cloud with largest degree of focusing of its accretion flow reaches SFE � 30%. d) The virial parameter of the clouds approaches unity before the stellar feedback begins to dominate the dynamics, becoming much larger once feedback dominates, suggesting that clouds become unbound as a consequence of the stellar feedback, rather than unboundness being the cause of a low SFE. e) The erosion of the filaments that feed the star-forming clumps produces chains of isolated dense blobs reminiscent of those observed in the vicinity of the dark globule B68.
影响因子：
4.8
作者：
J. Dale;B. Ercolano;I. Bonnell
通讯作者：
J. Dale;B. Ercolano;I. Bonnell