A Survey of Large Molecules toward the Proto-Planetary Nebula CRL 618
A Survey of Large Molecules toward the Proto-Planetary Nebula CRL 618
复制标题
对原行星状星云 CRL 618 大分子的调查
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
L. Snyder
中科院分区：
文献类型：
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作者：
A. Remijan;F. Wyrowski;D. Friedel;D. Meier;L. Snyder
我们介绍了我们对原行星星云CRL 618的几个大的，高度饱和的，具有生物重要性的含氧有机分子的调查结果，包括乙醛（CH3CHO），乙酸（CH3COOH），二甲醚（CH3OCH3），乙醇（CH3CH2OH），甲酸（HCOOH）和甲酸甲酯（HCOOCH3）；大碳链分子包括甲基氰化物（CH3CN）、甲基氰乙炔（CH3C3N）、氰乙炔（HC3N）、氰二乙炔（HC5N）和C6H；最后是更小的分子，包括34SO、SO2、OC34S和MgNC。没有检测到生物学上重要的有机分子。然而，我们报告了首次对该源的CH3CN和振动激发的HC3N和HC5N的干涉检测。CH3CN向CRL 618方向的温度和分布表明，CH3CN形成于围绕超致密H II区的外包膜内。此外，Cygni P线轮廓和相应的振动激发HC5N通道图支持其分布在从中心恒星径向扩展的扩展包膜中。振动激发的HC3N的检测证实了Wyrowski及其同事发现的内层膜中HC3N的温度结构和柱密度。最后，我们的观察清楚地表明，CRL 618是一个很好的大碳链物种来源，但对于检测或产生具有生物学重要性的有机物种来说，它是一个非常差的来源。
We present the results of our survey toward the proto-planetary nebula CRL 618 for several large, highly saturated, oxygen-bearing organic molecules of biological importance including acetaldehyde (CH3CHO), acetic acid (CH3COOH), dimethyl ether (CH3OCH3), ethanol (CH3CH2OH), formic acid (HCOOH) and methyl formate (HCOOCH3); large carbon chain molecules including methyl cyanide (CH3CN), methylcyanoacetylene (CH3C3N), cyanoacetylene (HC3N), cyanodiacetylene (HC5N), and C6H; and, finally, smaller molecules including 34SO, SO2, OC34S, and MgNC. No biologically important organic molecules were detected. However, we report the first interferometric detections of CH3CN and vibrationally excited HC3N and HC5N toward this source. The temperature and distribution of CH3CN toward CRL 618 indicates that it is formed in the outer envelope surrounding the ultracompact H II region. Furthermore, the P Cygni line profile and corresponding channel maps of vibrationally excited HC5N support its distribution in the extended envelope expanding radially from the central star. The detection of vibrationally excited HC3N confirmed the temperature structure and column density of HC3N in the inner envelope found by Wyrowski and colleagues. Finally, our observations clearly indicate that CRL 618 is a good source of large carbon chain species but a very poor source for detecting or producing organic species of biological importance.