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arXiv 2601.06355astro-ph.GA
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分子云碰撞 IV:反馈和磁场在正面碰撞中的作用

Collision between molecular clouds IV: The role of feedback and magnetic field in head on collisions

Iowa State University(爱荷华州立大学);Australian National University(澳大利亚国立大学);Flatiron Institute(平顿研究所)

Tabassum S. Tanvir, Michael Y. Grudić

AI总结:

研究通过分子云碰撞模拟,探讨碰撞速度、磁场方向和反馈机制对恒星形成的影响,发现低速碰撞促进持续恒星形成,高速碰撞导致短暂爆发,磁场方向显著影响恒星质量分布。

摘要:

我们系统地研究了分子云碰撞如何影响恒星形成,强调碰撞速度、磁场方向和辐射反馈的作用。利用首次模拟分子云碰撞的模拟,该模拟建模了单个恒星形成和吸积,并包含所有恒星反馈机制,我们探讨了形态演变、恒星形成效率(SFE)、碎片化、恒星质量分布和反馈驱动的气体散散。我们的结果表明,分子云碰撞相比孤立场景显著提高了恒星形成率和时间,尽管最终SFE在所有设置中大致相似。较低的碰撞速度促进了较长的引力相互作用和气体积累,促进持续的恒星形成,表现为细长的丝状结构。相反,高速碰撞导致快速气体压缩和湍流运动,导致剧烈但短暂的恒星形成事件,这些事件被反馈驱动的气体散散所遏制。磁场方向对碰撞结果有显著影响。平行磁场允许气体沿着磁场线高效坍缩,形成较少但质量更大的恒星。相反,垂直磁场产生显著的磁压,稳定压缩气体的激波,延迟引力坍缩,导致更分散且质量较小的恒星碎片。来自大质量恒星的辐射反馈持续调节恒星形成,阻止进一步的气体吸积在中等效率(10-15%)时,并启动反馈驱动的气体散散。尽管云动态变化显著,但恒星质量函数在所有场景中保持稳健,其形状受磁场方向轻微影响,但受碰撞速度影响较弱。

英文摘要:

We systematically investigate how cloud-cloud collisions influence star formation, emphasizing the roles of collision velocity, magnetic field orientation, and radiative feedback. Using the first cloud-cloud collision simulations that model individual star formation and accretion with all stellar feedback mechanisms, we explore the morphological evolution, star formation efficiency (SFE), fragmentation, stellar mass distribution, and feedback-driven gas dispersal. Our results show that cloud collisions substantially enhance the rate and timing of star formation compared to isolated scenarios, though the final SFE remains broadly similar across all setups. Lower collision velocities facilitate prolonged gravitational interaction and accumulation of gas, promoting sustained star formation characterized by elongated filamentary structures. Conversely, high-velocity collisions induce rapid gas compression and turbulent motions, leading to intense but transient episodes of star formation, which are curtailed by feedback-driven dispersal. The orientation of the magnetic field markedly affects collision outcomes. Parallel fields allow gas to collapse efficiently along magnetic lines, forming fewer but more massive stars. In contrast, perpendicular fields generate significant magnetic pressure, which stabilizes the shock-compressed gas and delays gravitational collapse, resulting in more distributed and less massive stellar fragments. Radiative feedback from massive stars consistently regulates star formation, halting further gas accretion at moderate efficiencies (10-15%) and initiating feedback-driven dispersal. Although the cloud dynamics vary significantly, the stellar mass function remains robust across scenarios-shaped modestly by magnetic orientation but only weakly influenced by collision velocity.

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