arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2007.09518astro-ph.GAastro-ph.SR
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超新星对分子云Turbulence和扩散的影响

The Effect of Supernovae on the Turbulence and Dispersal of Molecular Clouds

Zu-Jia Lu, Veli-Matti Pelkonen, Paolo Padoan, Liubin Pan, Troels Haugbølle, Åke Nordlund

摘要:

虽然超新星反馈在星系中的重要性已经得到了很好的证实,但它在分子云尺度上的作用仍然存在争议。在这项工作中,我们专注于超新星对单个云的影响,使用高分辨率的磁流体动力学模拟250 pc的区域,我们解决了单个大质量恒星的形成。超新星反馈是用真正的超新星来实现的,这些超新星是被解析的大质量恒星的自然演化,因此它们的位置和时间是自洽的。我们选择了一个大样本的分子云的模拟研究超新星能量注入和由此产生的分子云的属性。我们发现,分子云有几个动力学时间的寿命,不到一半的人的合同成为引力约束点,和绑定云的分散时间,一阶动力学时间,是一个因素的两个短于未绑定云。我们强调内部超新星的重要性,即大质量恒星在其母云中爆炸,在设置云分散时间,以及与超新星随机分布的模型相比其巨大的密度过高。我们还量化了超新星的能量注入效率作为超新星到云的距离的函数。我们的结论是,间歇性的驱动超新星可以维持分子云的湍流,并可能是云分散的主要过程。超新星在分子云演化中的作用,如果没有自洽的反馈,就不能完全解释。

英文摘要:

While the importance of supernova feedback in galaxies is well established, its role on the scale of molecular clouds is still debated. In this work, we focus on the impact of supernovae on individual clouds, using a high-resolution magneto-hydrodynamic simulation of a region of 250 pc where we resolve the formation of individual massive stars. The supernova feedback is implemented with real supernovae that are the natural evolution of the resolved massive stars, so their position and timing are self-consistent. We select a large sample of molecular clouds from the simulation to investigate the supernova energy injection and the resulting properties of molecular clouds. We find that molecular clouds have a lifetime of a few dynamical times, less then half of them contract to the point of becoming gravitationally bound, and the dispersal time of bound clouds, of order one dynamical time, is a factor of two shorter than that of unbound clouds. We stress the importance of internal supernovae, that is massive stars that explode inside their parent cloud, in setting the cloud dispersal time, and their huge overdensity compared to models where the supernovae are randomly distributed. We also quantify the energy injection efficiency of supernovae as a function of supernova distance to the clouds. We conclude that intermittent driving by supernovae can maintain molecular-cloud turbulence and may be the main process of cloud dispersal. The role of supernovae in the evolution of molecular clouds cannot be fully accounted for without a self-consistent implementation of their feedback.

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