Deep wide-field near-infrared survey of the Carina Nebula

Deep wide-field near-infrared survey of the Carina Nebula
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船底座星云深广视场近红外巡天

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发表时间：
2011
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通讯作者：
H. Zinnecker
H. Zinnecker
中科院分区：
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文献类型：
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作者：
T. Preibisch;T. Ratzka;B. Kuderna;H. Ohlendorf;R. R. King;S. Hodgkin;M. Irwin;J. Lewis;M. McCaughrean;H. Zinnecker

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(简写)我们在ESO VLT使用了Hawk-I对船底座星云进行了一次近红外探测，深度足以探测到整个低质量恒星群。最近的一次深度X射线调查的结果被用来区分船底座的年轻恒星和背景污染物。我们发现，低质量恒星的年龄(来自船底座星云中独立星团的颜色-星等图)与之前对大质量恒星的年龄估计一致。在X射线选择的恒星中，约有3200颗恒星的质量为<gt；=1 mSun；这一数字与场IMF根据大质量恒星的数量所作的外推符合得很好，并表明不存在低质量恒星的亏损。船底座恒星群的近红外过剩比例比其他类似年龄的质量较小的星团的典型比例要低，这表明星盘扩散的时间尺度比更安静的区域更快，这很可能是由于非常高水平的大质量恒星反馈。窄带图像显示了六个分子氢喷流。然而，没有一个光学HH天体显示出分子氢发射，这表明推动喷流的原恒星位于它们所在的球体边缘非常近的地方。这有力地支持了它们的形成是由前进的电离锋面触发的这一假设。
(abbreviated) We used HAWK-I at the ESO VLT to produce a near-infrared survey of the Carina Nebula that is deep enough to detect the full low-mass stellar population. The results of a recent deep X-ray survey are used to distinguish between young stars in Carina and background contaminants. We find that the ages of the low-mass stars (derived from color-magnitude diagrams of the invidual cluster in the Carina Nebula) agree with previous age estimates for the massive stars. About 3200 of the X-ray selected stars have masses >= 1 Msun; this number is in good agreement with extrapolations of the field IMF based on the number of high-mass stars and shows that there is no deficit of low-mass stars. The near-infrared excess fractions for the stellar populations in Carina are lower than typical for other, less massive clusters of similar age, suggesting a faster timescale of circumstellar disk dispersal than in the more quiescent regions, most likely due to the very high level of massive star feedback. Narrow-band images reveal six molecular hydrogen jets. However, none of the optical HH objects shows molecular hydrogen emission, suggesting that the jet-driving protostars are located very close to the edges of the globules in which they are embedded. This adds strong support to the scenario that their formation was triggered by the advancing ionization fronts.