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arXiv 1002.4612astro-ph.GA
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Sh2-132中的电离气体、分子和尘埃

Ionized gas, molecules, and dust in Sh2-132

J. Vasquez, C. E. Cappa, S. Pineault, N. U. Duronea

摘要:

我们分析了HII区域Sh 2 -132的各种星际成分。主要的恒星来源是双双星系统,其中包括沃尔夫-拉叶星WR 153 ab。我们使用无线电连续图像在408和1420 MHz,和HI 21厘米线数据从加拿大银河平面调查,分子观测的12 CO(1-0)线在115 GHz的五个学院射电天文台,和可用的中,远红外观测获得的MSX和IRAS卫星,分别。Sh 2 -132由两个外壳组成,在两个频率上都显示出无线电连续谱。发射本质上是热的。估计该星云的均方根电子密度和电离质量分别为n_e = 20 cm^{-3}和M_HII = 1500 Mo。CO辐射的分布表明分子气体与电离星云相邻并与之相互作用,分子气体的速度在-38 ~-53 km/s之间,与电离气体的速度相似。发射在8.3 mic。显示出围绕明亮光学区域的约15'的环状特征。这种发射是由于多环芳烃和标记的位置的光解区域。Sh 2 -132周围的气体分布可以用这样一种情况来解释:该区域的大质量恒星通过强烈的恒星风和强烈的紫外光子通量,光解离、电离并从母云中扫过致密的分子物质。

英文摘要:

We analyze the various interstellar components of the HII region Sh2-132. The main stellar source is the double binary system that includes the Wolf-Rayet star WR153ab. We use radio continuum images at 408 and 1420 MHz, and HI 21cm line data taken from the Canadian Galactic Plane Survey, molecular observations of the 12CO(1-0) line at 115 GHz from the Five College Radio Astronomy Observatory, and available mid and far IR observations obtained with the MSX and IRAS satellites, respectively. Sh2-132 is composed of two shells showing radio continuum counterparts at both frequencies. The emission is thermal in nature. The estimated rms electron density and ionized mass of the nebula are n_e = 20 cm^{-3} and M_HII = 1500 Mo. The distribution of the CO emission shows molecular gas bordering the ionized nebula and interacting with it. The velocities of the molecular gas is in the range --38 to --53 km/s, similar to the velocity of the ionized gas. The emission at 8.3 mic. reveals a ring like feature of about 15' that encircles the bright optical regions. This emission is due to the PAHs and marks the location of photodissociation regions. The gas distribution in the environs of Sh2-132 can be explained in a scenario where the massive stars in the region photodissociated, ionized, and swept-up the dense molecular material from the parental cloud through their strong stellar winds and intense UV photon flux.

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