We report the results of an initial survey in a variety of Galactic sources for cyclopropenylidene (C3H2), the first interstellar hydrocarbon ring molecule. C3H2 is found to be very widespread throughout the Galaxy. This, together with its large dipole moment and many observable transitions, makes cyclopropenylidene a promising probe for physical conditions in the interstellar medium. The ortho 1(10)-1(01) transition at 18 GHz is detected in a variety of environments, including giant molecular clouds, diffuse clouds, cold dark clouds, the spiral arm clouds in the direction of distant continuum sources, and the envelope of the carbon star IRC + 10216. The 2(20)-2(11) para line at 21.6 GHz was surveyed in many sources having strong 1(10)-1(01) emission, and, when detected, it was always seen in absorption. A more limited survey of the ortho 2(12)-1(01) transition at 85.3 GHz has been conducted. In addition, the 2(11)-2(02) line of the para species at 46.8 GHz was detected in the dark clouds TMC-1 and L134N. Maps have been made of the clouds TMC-1, L134N, W51, and Orion, confirming that the C3H2 emission is extended in these objects. The data obtained thus far suggest that C3H2 is one of the more abundant organic constituents of the dense interstellar medium.

中文翻译：

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银河源中环丙烯（C3H2）的调查

我们报告了对环亚丙烯基 (C3H2)（第一个星际烃环分子）的各种银河来源的初步调查结果。发现 C3H2 在整个银河系中非常普遍。这一点，加上它的大偶极矩和许多可观察到的跃迁，使环丙烯基成为星际介质中物理条件的有希望的探测器。18 GHz 的正交 1(10)-1(01) 跃迁在各种环境中被检测到，包括巨大的分子云、漫射云、冷暗云、远处连续源方向的旋臂云和包络碳星 IRC + 10216。21.6 GHz 的 2(20)-2(11) 平行线在许多具有强 1(10)-1(01) 发射的源中进行了测量，并且在检测到时，总是可以看到在吸收。已经对 85.3 GHz 的正交 2(12)-1(01) 过渡进行了更有限的调查。此外，在暗云TMC-1和L134N中检测到46.8 GHz的副物种的2(11)-2(02)谱线。已经绘制了云 TMC-1、L134N、W51 和猎户座的地图，证实 C3H2 发射在这些物体中扩展。迄今为止获得的数据表明，C3H2 是致密星际介质中最丰富的有机成分之一。