A DRAO and VLA Investigation of the Environment of WR 130
A DRAO and VLA Investigation of the Environment of WR 130
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DRAO 和 VLA 对 WR 130 环境的调查
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
C. Cappa
中科院分区：
文献类型：
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作者：
S. Cichowolski;S. Pineault;E. M. Arnal;J. C. Testori;W. Goss;C. Cappa
利用自治领射电天体物理天文台（DRAO）综合望远镜在408和1420 MHz获得的21 cm H I线和射电连续谱数据，研究了Wolf-Rayet（WR）星星WR 130的环境。此外，在DnC和D组态下，用甚大列阵观测到了H 110 α复合线和21 cm H I线。夏普勒斯H II区，Sh 98（大小为15“）和两颗OB星在沃尔夫-拉叶星星位置附近被观测到。在射电连续谱和红外数据中观测到一个扩展的环形结构（G68.1+1.1），其大小为1.20 ′。在环上叠加的四个致密射电源中，一个是H II区，大小为103 ′（G68.14+0.92），而其他的可能是河外射电源。G68.1+1.1的光谱指数（Sνα）为α = 0.0 ± 0.1。利用红外天文卫星（IRAS）观测到的21 cm亮温和60 μm亮温的相关分析，证实了G68.1+1.1的热性质。DRAO H I数据显示在-12到1 km s-1的速度范围内存在H I泡。H I腔最显著的特点是与射电连续环的良好相关性。WR星星并不在环的中心，而是在东边密集的边缘。这种偏心位置可以用星星的高空间速度和投影效应的组合来解释。还考虑了该地区存在的OB星的可能贡献。根据我们对H110α的观测，以及在该区域观测到的其他复合谱线，我们推断致密H II区G68.14+0.92的距离为12 kpc，G68.1+1.1的距离为5 kpc。我们认为G68.1+1.1是光学H Ⅱ区Sh 98的射电对应物，而G68.14+0.92是一个更远源的偶然叠加。环的电离质量估计为3000 M，均方根电子密度为303 cm-3，假设分布均匀。对于空腔，获得了500 M Ω的缺失H I质量，而对于壳体，获得了1500 M Ω的过量H I质量。
The environment of the Wolf-Rayet (WR) star WR 130 has been studied using the 21 cm H I line and radio continuum data at 408 and 1420 MHz obtained with the Dominion Radio Astrophysical Observatory (DRAO) Synthesis Telescope. In addition, the H110α recombination line and 21 cm H I line were observed using the Very Large Array in the DnC and D configurations. The Sharpless H II region, Sh 98 (size ∼15′), and two OB stars are observed near the Wolf-Rayet star position. An extended ring-shaped structure (G68.1+1.1) of size ∼20′ is observed in the radio continuum and infrared data. Of four compact radio sources seen superposed on the ring, one is an H II region of size ∼3′ (G68.14+0.92), while the others are probably extragalactic. The spectral index (Sν ∝ να) of G68.1+1.1 is α = 0.0 ± 0.1. The thermal nature of G68.1+1.1 is confirmed by an analysis of the correlation between the brightness temperature at 21 cm and the brightness at 60 μm, as observed with IRAS. The DRAO H I data show an H I bubble in the velocity range -12 to 1 km s-1. The most striking characteristic of the H I cavity is the excellent correlation with the radio continuum ring. The WR star is not at the center of the ring, but in the dense border to the east. This eccentric position can be explained by a combination of a high spatial velocity for the star and projection effects. The possible contribution of the OB stars present in the area is also considered. From our H110α observations, together with other recombination lines observed in the area, we deduce a distance of 12 kpc for the compact H II region G68.14+0.92 and 5 kpc for G68.1+1.1. We conclude that G68.1+1.1 is the radio counterpart of the optical H II region Sh 98, while G68.14+0.92 is a chance superposition of a much more distant source. The ionized mass of the ring is estimated at ∼3000 M⊙ and the rms electron density at ∼3 cm-3, assuming a homogeneous distribution. A missing H I mass of 500 M⊙ is obtained for the cavity and an excess H I mass of 1500 M⊙ for the shell.