===== On Pentatetraenylidene in the ISM =====

C. Cabezas, B. Tercero, M. Agúndez, N. Marcelino, J. R. Pardo, P. de Vicente, and J. Cernicharo\\
reported on\\
**[[https://doi.org/10.1051/0004-6361/202141274|Cumulene carbenes in TMC-1: Astronomical discovery of //l//-H<sub>2</sub>C<sub>5</sub>]]**\\
//Astron. Astrophys.// **650**, Art. No. L9 (2021).\\
The molecule was identified through 11 unblended to somewhat blended //a//-type transitions with 6 ≤ //J// ≤ 10 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 32.8 and 49.2 GHz. A value of about 10 K was derived for //T//<sub>rot</sub>. The column density ratios of the //l//-H<sub>2</sub>C<sub>//n//</sub> molecules with //n// = 3 to 6 is about 344 : 561 : 1 : 4.4, reflecting the decrease with //n// on one hand and the lower column densities for //n// being odd on the other hand.\\



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

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