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arXiv 2107.12397astro-ph.SRastro-ph.GA
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中等质量恒星周围的吹泡:来自主序星风的反馈是不够的

Blowing Bubbles around Intermediate-Mass Stars: Feedback from Main-Sequence Winds is not Enough

Anna L. Rosen, Stella S. R. Offner, Michael M. Foley, Laura A. Lopez

摘要:

在年轻的恒星形成环境中观察到许多球形"壳”,这些环境中有低质量和中等质量的恒星。这些观测结果表明,这些壳层可能是由年轻主序星的各向同性恒星风反馈产生的。然而,这些壳的驱动机制仍然不确定,因为风注入的动量太低,无法解释它们的大小和动力学,因为它们的质量损失率很低。然而,这些研究忽略了风的动能是如何转移到ISM的,而是假设它是通过辐射瞬间失去的,这表明这些壳是动量驱动的。中等质量的恒星有快速的($v_w \gtrsim 1000$ km/s)恒星风,因此风注入的能量应该产生能量驱动的绝热风泡,比动量驱动的风泡大。在这里,我们探讨,如果能量驱动的风反馈可以通过执行一系列的3D磁流体动力学模拟的风反馈从中等质量和高质量的恒星,放置在磁化,湍流分子云。我们发现,对于高质量的恒星模型,能量驱动的风反馈产生$\sim$ pc尺度的风气泡的分子云,同意所观察到的壳的大小,但风从中等质量的恒星不能产生类似的壳,因为他们的质量损失率和速度较低。因此,这些壳层必须由低质量和中等质量恒星形成所固有的其他反馈过程驱动。

英文摘要:

Numerous spherical ``shells" have been observed in young star-forming environments that host low- and intermediate-mass stars. These observations suggest that these shells may be produced by isotropic stellar wind feedback from young main-sequence stars. However, the driving mechanism for these shells remains uncertain because the momentum injected by winds is too low to explain their sizes and dynamics due to their low mass-loss rates. However, these studies neglect how the wind kinetic energy is transferred to the ISM and instead assume it is instantly lost via radiation, suggesting that these shells are momentum-driven. Intermediate-mass stars have fast ($v_w \gtrsim 1000$ km/s) stellar winds and therefore the energy injected by winds should produce energy-driven adiabatic wind bubbles that are larger than momentum-driven wind bubbles. Here, we explore if energy-driven wind feedback can produce the observed shells by performing a series of 3D magneto-hydrodynamic simulations of wind feedback from intermediate-mass and high-mass stars that are placed in a magnetized, turbulent molecular cloud. We find that, for the high-mass stars modeled, energy-driven wind feedback produces $\sim$pc scale wind bubbles in molecular clouds that agree with the observed shell sizes but winds from intermediate-mass stars can not produce similar shells because of their lower mass-loss rates and velocities. Therefore, such shells must be driven by other feedback processes inherent to low- and intermediate-mass star formation.

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