Ionizing feedback from massive stars in massive clusters - III. Disruption of partially unbound clouds
Ionizing feedback from massive stars in massive clusters - III. Disruption of partially unbound clouds
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DOI：
10.1093/mnras/sts592
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发表时间：
2012-12
影响因子：
4.8
通讯作者：
J. Dale;B. Ercolano;I. Bonnell
中科院分区：
文献类型：
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作者：
J. Dale;B. Ercolano;I. Bonnell
我们扩展了之前的 SPH 参数研究，即 O 星光电离对恒星形成云的影响，以包括最初未束缚的云。我们生成一组质量范围为 $10^{4}-10^{6}$M$_{\odot}$ 的模型云，初始维里比为 $E_{\rm kin}/E_{\rm pot}$=2.3，允许它们形成恒星，并研究大质量恒星产生的光电离辐射的影响。我们发现，在超新星预计开始爆炸之前的 3Myr 时间尺度上，电离反馈排出的质量分数是云逃逸速度的一个非常强的函数。高质量云在很大程度上不受动态影响，而低质量云的大部分气体储备在这个时间尺度上被排出。然而，未束缚的恒星质量的比例很小，并且大部分未束缚的恒星之所以如此，只是因为云本身最初是部分未束缚的。我们发现，由于其内在的膨胀，电离更能够在未束缚的云中产生清晰的气泡，但这种气泡的存在并不一定表明给定的云已受到反馈的强烈影响。我们还发现，与我们早期工作中的束缚云一样，这里模拟的许多系统对于光子和超新星喷射物来说都是高度多孔的，并且它们中的大多数很可能会在第一次超新星爆炸中幸存下来。
We extend our previous SPH parameter study of the effects of photoionization from O-stars on star-forming clouds to include initially unbound clouds. We generate a set of model clouds in the mass range $10^{4}-10^{6}$M$_{\odot}$ with initial virial ratios $E_{\rm kin}/E_{\rm pot}$=2.3, allow them to form stars, and study the impact of the photoionizing radiation produced by the massive stars. We find that, on the 3Myr timescale before supernovae are expected to begin detonating, the fractions of mass expelled by ionizing feedback is a very strong function of the cloud escape velocities. High-mass clouds are largely unaffected dynamically, while lower-mass clouds have large fractions of their gas reserves expelled on this timescale. However, the fractions of stellar mass unbound are modest and significant portions of the unbound stars are so only because the clouds themselves are initially partially unbound. We find that ionization is much more able to create well-cleared bubbles in the unbound clouds, owing to their intrinsic expansion, but that the presence of such bubbles does not necessarily indicate that a given cloud has been strongly influenced by feedback. We also find, in common with the bound clouds from our earlier work, that many of the systems simulated here are highly porous to photons and supernova ejecta, and that most of them will likely survive their first supernova explosions.