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船底座星云气泡的一维动力学模型

One Dimensional Dynamical Models of the Carina Nebula Bubble

E. Harper-Clark, N. Murray

备注：
Accepted to APJ. 47 pages, 13 figures
发表信息：
Astrophys.J.693:1696-1712,2009
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摘要：

我们已经测试了两个主要的理论模型的气泡周围的大质量星团，Castor等。和Chevalier和Clegg，对观测的良好研究船底座星云。Castor等人的理论高估了船底座泡的X射线光度，预测值是原来的60倍，膨胀过快，是原来的4倍;如果使用正确的半径和年龄，预测的X射线光度甚至更大。相比之下，Chevalier & Clegg模型将X射线亮度的预测低估了10倍。我们修改了Castor等人的理论，考虑到较低的恒星风质量损失率，辐射压力，重力，以及热冲击气体的逃逸或能量损失。我们认为，能量是平流，而不是辐射的泡沫。我们进行参数研究减少恒星质量损失率和各种泄漏率，并能够找到可行的模型。船底座的X射线表面亮度在靠近气泡壁处最高，这与冷云的传导蒸发相一致。由此可见，热气体的压力远低于用时间积分的风光度除以气泡体积所得到的压力;相反，热气体中的压力是由与光电离气体在T=10^4 K时的压力平衡决定的。由此可见，受冲击的恒星风在形成气泡方面并不具有动力学重要性。

英文摘要：

We have tested the two main theoretical models of bubbles around massive star clusters, Castor et al. and Chevalier & Clegg, against observations of the well studied Carina Nebula. The Castor et al. theory over-predicts the X-ray luminosity in the Carina bubble by a factor of 60 and expands too rapidly, by a factor of 4; if the correct radius and age are used, the predicted X-ray luminosity is even larger. In contrast, the Chevalier & Clegg model under-predicts the X-ray luminosity by a factor of 10. We modify the Castor et al. theory to take into account lower stellar wind mass loss rates, radiation pressure, gravity, and escape of or energy loss from the hot shocked gas. We argue that energy is advected rather than radiated from the bubble. We undertake a parameter study for reduced stellar mass loss rates and for various leakage rates and are able to find viable models. The X-ray surface brightness in Carina is highest close to the bubble wall, which is consistent with conductive evaporation from cold clouds. The picture that emerges is one in which the hot gas pressure is far below that found by dividing the time-integrated wind luminosity by the bubble volume; rather, the pressure in the hot gas is set by pressure equilibrium with the photoionized gas at T=10^4 K. It follows that the shocked stellar winds are not dynamically important in forming the bubbles.

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