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arXiv 1601.01702astro-ph.SRastro-ph.GA
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行星状星云M2-42的快速低电离发射区

Fast, low-ionization emission regions of the planetary nebula M2-42

A. Danehkar, Q. A. Parker, W. Steffen

摘要:

用澳大利亚国立大学2.3米望远镜的宽视场摄谱仪对行星状星云M2-42(PN G008.2-04.8)进行的空间分辨观测揭示了从其主要结构中出现的双极准直喷流的显著特征。从[N II] $λ$ 6584发射谱线得到的速度分辨通道图解开了星云的不同形态成分。这一信息是用来开发一个三维的形态运动学模型,它包括一个赤道致密环面和一对不对称的双极流出。从主壳层上积分的光谱中测得了大约20 km/s $^{-1}$的膨胀速度。然而,被发现是在80-160公里的范围内的$^{-1}$相对于星云中心的喷流的deprojected速度。它被发现,准直流出的平均密度,595 $\pm$ 125厘米$^{-3}$,是5倍低于主壳层,3150厘米$^{-3}$,而它们的单离子化的氮和硫的丰度约3倍高于从致密壳层确定的。结果表明,准直射流的特征是典型的快速,低电离发射区。

英文摘要:

Spatially resolved observations of the planetary nebula M2-42 (PN G008.2-04.8) obtained with the Wide Field Spectrograph on the Australian National University 2.3 m telescope have revealed the remarkable features of bipolar collimated jets emerging from its main structure. Velocity-resolved channel maps derived from the [N II] $λ$6584 emission line disentangle different morphological components of the nebula. This information is used to develop a three-dimensional morpho-kinematic model, which consists of an equatorial dense torus and a pair of asymmetric bipolar outflows. The expansion velocity of about 20 km s$^{-1}$ is measured from the spectrum integrated over the main shell. However, the deprojected velocities of the jets are found to be in the range of 80-160 km s$^{-1}$ with respect to the nebular center. It is found that the mean density of the collimated outflows, 595 $\pm$ 125 cm$^{-3}$, is five times lower than that of the main shell, 3150 cm$^{-3}$, whereas their singly ionized nitrogen and sulfur abundances are about three times higher than those determined from the dense shell. The results indicate that the features of the collimated jets are typical of fast, low-ionization emission regions.

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