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arXiv 0802.2243astro-ph
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Sh2-205：I.周围的星际介质

Sh2-205: I. The surrounding interstellar medium

G. A. Romero, C. E. Cappa

备注：
Accepted for publication in MNRAS. 10 figures and 6 tables
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摘要：

我们提出了一个研究的HII区域Sh 2 -205及其周围地区，从CGPS，12 CO观测和MSX数据获得的数据的基础上。我们发现，Sh 2 -205可以分为三个独立的光学结构：SH 149.25-0.0，SH 148.83-0.67，和LBN 148.11-0.45。导出的光谱指数显示SH 148.83-0.67和LBN 148.11-0.45的热性质。SH 148.83-0.67的光学和无线电数据以及能量需求表明，该特征是由HD 24431（O 9 III）的紫外光子驱动的星际气泡。LBN 148.11-0.45具有典型的Al HII区的形态，它们的电离源仍然不确定。发现尘埃和分子气体与LBN 148.11- 0.45有关。特别地，在电离区和分子区之间的界面处检测到一个光解区。如果HD 24094是一颗O 8-O 9类型的恒星，就像它的近红外颜色所暗示的那样，它的紫外光子通量就足以解释星云的电离。光学，无线电连续谱和21厘米线数据使我们能够得出结论，SH 148.83-0.67是一个由HD 24431的能量驱动的星际气泡。相关的中性原子和电离质量分别为180 Mo和300 Mo。SH 149.25-0.0的发射太微弱，无法导出尘埃和气体参数。还鉴定了以（l，b）=（149.0，1.5）为中心的HI壳层。它在形态上与分子气体排放相关。中性的原子质量和分子质量分别为1600 Mo和2.6 x 10^4 Mo。疏散星团NGC 1444最有可能是形成HI结构的原因。

英文摘要：

We present a study of the HII region Sh2-205 and its environs, based on data obtained from the CGPS, 12CO observations, and MSX data. We find that Sh2-205 can be separated in three independent optical structures: SH 149.25-0.0, SH 148.83-0.67, and LBN 148.11-0.45. The derived spectral indices show the thermal nature of SH 148.83-0.67 and LBN 148.11-0.45. The morphology of SH 148.83-0.67, both in the optical and radio data, along with the energetic requ irements indicate that this feature is an interstellar bubble powered by the UV photons of HD 24431 (O9 III). LBN 148.11-0.45 has the morphology of a classic al HII region and their ionizing sources remain uncertain. Dust and molecular gas are found related to LBN 148.11-0.45.Particularly, a photodissociation region is detected at the interface between the ionized and molecular regions. If the proposed exciting star HD 24094 were an O8--O9 type star, as suggested by its near-infrared colors, its UV photon flux would be enough to explain the ionization of the nebula. The optical, radio continuum, and 21-cm line data allow us to conclude that SH 148.83-0.67 is an interstellar bubble powered by the energetic action of HD 24431. The associated neutral atomic and ionized masses are 180 Mo and 300 Mo, respectively. The emission of SH 149.25-0.0 is too faint to derive the dust and gas parameters. An HI shell centered at (l,b) = (149.0, 1.5) was also identified. It correlates morphologically with molecular gas emission. The neutral atomic and molecular masses are 1600 Mo and 2.6 x 10^4 Mo, respectively. The open cluster NGC 1444 is the most probable responsible for shaping this HI structure.

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