===== On C7H4 Isomers in the Interstellar Medium =====

R. Fuentetaja, C. Cabezas, M. Agúndez, B. Tercero, N. Marcelino, J. R. Pardo, P. de Vicente, and J. Cernicharo\\
reported on the\\
**[[https://doi.org/10.1051/0004-6361/202243857|Discovery of CH<sub>2</sub>CCHC<sub>4</sub>H and a Rigorous Detection of H<sub>2</sub>CCCHC<sub>3</sub>N in TMC-1 with the QUIJOTE Line Survey]]**\\
//Astron. Astrophys.// **663**, Art. No. L3 (2022).\\
1,2-Heptadiene-4,6-diyne, also known as propadienylbutadiyne or allenyldiacetylene, was detected with the Yebes 40 m radio telescope between 31.2 and 43.0 GHz. 21 lines with 16 ≤ //J// ≤ 22 and //K<sub>a</sub>// ≤ 2 were identified as being between unblended and not completely blended. //T//<sub>rot</sub> was determined as 9.0 ± 0.5 K. The isoelectronic H<sub>2</sub>CCCHC<sub>3</sub>N was identified in TMC-1 for the first time through individual lines. The CH<sub>2</sub>CCHC<sub>4</sub>H to H<sub>2</sub>CCCHC<sub>3</sub>N ratio was determined as 18 ± 4, somewhat higher than the C<sub>4</sub>H to C<sub>3</sub>N ratio of ~8. Similarly, the CH<sub>3</sub>C<sub>6</sub>H to CH<sub>2</sub>CCHC<sub>4</sub>H ratio is ~0.32, whereas the CH<sub>3</sub>C<sub>4</sub>H to CH<sub>2</sub>CCHC<sub>2</sub>H ratio is ~1.1.\\
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Contributor(s): H. S. P. Müller; 07, 2022

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