===== On the Detection of Cyanopropyne in the ISM =====

Cyanopropyne, CH<sub>3</sub>C<sub>3</sub>N, also known as methylcyanoacetylene or methylpropionitrile, has been detected with the 45 m NRAO telescope in the //J// = 6 – 5 to 8 – 7 transitions with //K// = 0 and 1 between 27.7 and 33.1 GHz in emission toward TMC-1, by\\
N. W. Broten, J. M. MacLeod, L. W. Avery, W. M. Irvine, B. Höglund, P. Friberg, and Å. Hjalmarson,\\
**[[https://ui.adsabs.harvard.edu/abs/1984ApJ...276L..25B|Detection of Interstellar Methylcyanoacetylene]]**\\
//Astrophys. J.// **276**, L25–L29 (1984).\\
In addition, the //J// = 5 – 4, //K// = 0 transition was barely detected.\\

C. Cabezas, E. Roueff, B. Tercero, M. Agúndez, N. Marcelino, P. de Vicente, and J. Cernicharo\\
reported on the\\
**[[https://doi.org/10.1051/0004-6361/202141371|Detection of deuterated methylcyanoacetylene, CH<sub>2</sub>DC<sub>3</sub>N, in TMC-1]]**\\
//Astron. Astrophys.// **650**, Art. No. L15 (2021).\\
The molecule was identified through 15 //a//-type transitions with 7 ≤ //J// ≤ 12 and //K<sub>a</sub>// = 0 and 1 in the course of a molecular line survey of the prototypical cold dark molecular cloud TMC-1 carried out with the Yebes 40 m radio telescope between 31.0 and 50.4 GHz. A value of //T//<sub>rot</sub> = 8.0 ± 0.5 K was derived. The column density of monodeuterated methylcyanoacetylene is about a factor of 22 lower than that of the fully hydrogenated isotopolog; thus the H/D ratio per H atom is about 66.\\



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Contributor(s): H. S. P. Müller; 08, 2012; 06, 2021

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