arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1104.3477astro-ph.GAastro-ph.SR
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船底座星云深宽视场近红外巡天

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

Thomas Preibisch, Thorsten Ratzka, Benjamin Kuderna, Henrike Ohlendorf, Robert R. King, Simon Hodgkin, Mike Irwin, James R. Lewis, Mark J. McCaughrean, Hans Zinnecker

摘要:

我们在ESO VLT上使用HAWK-I对船底座星云进行了近红外测量,该星云足够深,可以探测到全部低质量恒星星族。最近的深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(来自船底座星云中的单个星团的色星等图)同意与以前的大质量恒星的年龄估计。大约有3200颗X射线选择的恒星质量>= 1 Msun;这个数字与基于高质量恒星数量的IMF场外推非常一致,并表明没有低质量恒星的缺陷。船底座中恒星星族的近红外过剩分数低于其他年龄相近、质量较小的星团,这表明星周盘扩散的时间尺度比静止区域更快,这很可能是由于大质量恒星反馈的水平非常高。窄带图像揭示了六个氢分子喷流。然而,没有一个光学HH天体显示出分子氢发射,这表明喷气驱动的原恒星非常靠近它们所嵌入的球状体的边缘。这为它们的形成是由前进的电离锋触发的这一假设提供了强有力的支持。

英文摘要:

(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.

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