Gone with the wind: Where is the missing stellar wind energy from massive star clusters?
Gone with the wind: Where is the missing stellar wind energy from massive star clusters?
复制标题
随风而逝：巨大星团中缺失的恒星风能量在哪里？
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
E. Ramirez
中科院分区：
文献类型：
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作者：
A. Rosen;L. Lopez;M. Krumholz;E. Ramirez
大于$sim 10^{3}$$M_ODOT$的星团包含多颗发射快速恒星风的热星。这些风携带的综合动能与超新星爆炸提供的动能相当，这表明在早期，风可能是对形成星团的周围冷物质的一种重要反馈形式。然而，这些风与周围块状、湍急、寒冷的气体的相互作用是复杂的，人们对此知之甚少。在这里，我们通过一个会计练习来研究这个问题：我们使用四个经过充分研究的大质量星团的经验确定的属性来确定恒星风注入的能量最终会流向哪里。我们考虑了一系列的动能损失通道，包括辐射冷却、冷星际介质上的机械功、热传导、热气体碰撞对尘埃的加热以及热气体对热能的整体平流。我们发现，至少对于一些团簇来说，这些通道都不能超过注入能量的一小部分。我们认为，热冷界面处的湍流混合或来自HII区的热气体的物理泄漏可以有效地消除年轻星团中大质量恒星注入的动能。即使对于我们能够解释所有注入动能的星系团，我们的计算也表明，我们的计算对恒星风作为反馈寒冷星际介质的机制的重要性设置了强烈的限制。
Star clusters larger than $sim 10^{3}$ $M_odot$ contain multiple hot stars that launch fast stellar winds. The integrated kinetic energy carried by these winds is comparable to that delivered by supernova explosions, suggesting that at early times winds could be an important form of feedback on the surrounding cold material from which the star cluster formed. However, the interaction of these winds with the surrounding clumpy, turbulent, cold gas is complex and poorly understood. Here we investigate this problem via an accounting exercise: we use empirically determined properties of four well-studied massive star clusters to determine where the energy injected by stellar winds ultimately ends up. We consider a range of kinetic energy loss channels, including radiative cooling, mechanical work on the cold interstellar medium, thermal conduction, heating of dust via collisions by the hot gas, and bulk advection of thermal energy by the hot gas. We show that, for at least some of the clusters, none of these channels can account for more than a small fraction of the injected energy. We suggest that turbulent mixing at the hot-cold interface or physical leakage of the hot gas from the HII region can efficiently remove the kinetic energy injected by the massive stars in young star clusters. Even for the clusters where we are able to account for all the injected kinetic energy, we show that our accounting sets strong constraints on the importance of stellar winds as a mechanism for feedback on the cold interstellar medium.