===== On the Detection of Heptatriynylidyne, C7H, in Space =====

The heptatriynylidyne radical in its <sup>2</sup>Π<sub>r</sub> state has been detected with the IRAM 30 M telescope in five lines of three rotational transitions toward the nearby C-rich AGB star CW Leonis by\\
M. Guélin, J. Cernicharo, M. J. Travers, M. C. McCarthy, C. A. Gottlieb, P. Thaddeus, M. Ohishi, S. Saito, and S. Yamamoto,\\
**[[https://ui.adsabs.harvard.edu/abs/1997A%26A...317L...1G|Detection of a new Linear Carbon Chain Radical: C<sub>7</sub>H]]**,\\
//Astron. Astrophys.// **317** L1–L4 (1997).\\
The //J// = 47.5 – 46.5, 48.5 – 47.5, and half of the 49.5 – 48.5 were detected betwen 83.0 and 86.6 GHz.

M. Araki, S. Takano, N. Sakai, S. Yamamoto, T. Oyama, N. Kuze, and K. Tsukiyama\\
reported on\\
**[[https://doi.org/10.3847/1538-4357/aa8637|Long Carbon Chains in the Warm Carbon-chain-chemistry Source L1527: First Detection of C<sub>7</sub>H in Molecular Clouds]]**,\\
//Astrophys. J.// **847** Art. No. 51 (2017).\\
Using the 100 m GBT, four Λ-components of the two transitions with //J// = 24.5 – 23.5 and 25.5 – 24.5 near 42.85 and 44.60 GHz were detected barely to reasonably well; a composite spectrum is beyond doubt.


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Contributor(s): H. S. P. Müller; 05, 2007; 10, 2017

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