Herschel imaging of the dust in the Helix Nebula (NGC 7293)
Herschel imaging of the dust in the Helix Nebula (NGC 7293)
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螺旋星云中尘埃的赫歇尔成像 (NGC 7293)
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
R. Wesson
中科院分区：
文献类型：
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作者：
G. V. D. Steene;P. Hoof;K. Exter;M. Barlow;J. Cernicharo;M. Etxaluze;W. Gear;J. Goicoechea;H. Gomez;M. Groenewegen;P. Hargrave;R. Ivison;S. Leeks;T. Lim;M. Matsuura;G. Olofsson;E. Polehampton;B. Swinyard;T. Ueta;H. Winckel;C. Waelkens;R. Wesson
在我们的一系列论文中，我们展示了赫歇尔对演化行星状星云的成像，我们展示了星云（NGC 7293）中尘埃分布的图像。70，160，250，350和500微米的图像是用赫歇尔卫星上的PACS和SPIRE仪器获得的。宽频带的地图显示，在主星云的尘埃分布是clusified和主要存在于桶壁。我们使用Herschel，IRAS和Planck通量值以一致的方式确定了主星云的光谱能量分布。发射率指数为0.99 +/- 0.09，结合星云富含碳的分子化学，表明尘埃主要由无定形碳组成。在70 μ m处探测到来自中心星星盘的尘埃过量辐射，通量测量与以前的测量一致。我们提出的温度和尘埃柱密度图。在216秒差距的距离上，彗星星云（不含晕）的总尘埃质量被确定为0.0035太阳质量。温度图显示尘埃温度在22至42 K之间，这与分子气体的动力学温度相似，加强了尘埃和气体以高密度团块共存的事实。存档的图像被用来比较尘埃排放的位置在远红外（赫歇尔）与电离（GALEX，Hbeta）和分子氢成分。不同的排放成分与HISTORY一致，HISTORY由一个倾斜于视线的厚壁桶状结构组成。辐射场通过筒壁迅速减小。
In our series of papers presenting the Herschel imaging of evolved planetary nebulae, we present images of the dust distribution in the Helix nebula (NGC 7293). Images at 70, 160, 250, 350, and 500 micron were obtained with the PACS and SPIRE instruments on board the Herschel satellite. The broadband maps show the dust distribution over the main Helix nebula to be clumpy and predominantly present in the barrel wall. We determined the spectral energy distribution of the main nebula in a consistent way using Herschel, IRAS, and Planck flux values. The emissivity index of 0.99 +/- 0.09, in combination with the carbon rich molecular chemistry of the nebula, indicates that the dust consists mainly of amorphous carbon. The dust excess emission from the central star disk is detected at 70 micron and the flux measurement agree with previous measurement. We present the temperature and dust column density maps. The total dust mass across the Helix nebula (without its halo) is determined to be 0.0035 solar mass at a distance of 216 pc. The temperature map shows dust temperatures between 22 and 42 K, which is similar to the kinetic temperature of the molecular gas, strengthening the fact that the dust and gas co-exist in high density clumps. Archived images are used to compare the location of the dust emission in the far infrared (Herschel) with the ionized (GALEX, Hbeta) and molecular hydrogen component. The different emission components are consistent with the Helix consisting of a thick walled barrel-like structure inclined to the line of sight. The radiation field decreases rapidly through the barrel wall.