Issue |
A&A
Volume 693, January 2025
|
|
---|---|---|
Article Number | L14 | |
Number of page(s) | 5 | |
Section | Letters to the Editor | |
DOI | https://doi.org/10.1051/0004-6361/202453419 | |
Published online | 13 January 2025 |
Letter to the Editor
Identification of the interstellar 1-cyano propargyl radical (HCCCHCN) in TMC-1
1
Departamento de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
2
Observatorio de Yebes, IGN, Cerro de la Palera s/n, 19141 Yebes Guadalajara, Spain
3
Observatorio Astronómico Nacional (OAN, IGN), C/ Alfonso XII, 3, 28014, Madrid, Spain
4
Department of Basic Science, Graduate School of Arts & Sciences, The University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo 153-8902, Japan
5
Department of Applied Chemistry, Science Building II, National Yang Ming Chiao Tung University, Hsinchu 300098, Taiwan
⋆ Corresponding authors; carlos.cabezas@csic.es; jose.cernicharo@csic.es
Received:
12
December
2024
Accepted:
29
December
2024
We report the first detection in interstellar medium of the 1-cyano propargyl radical, HC3HCN. This species is an isomer of the 3-cyano propargyl radical (CH2C3N), which was recently discovered in TMC-1. The 1-cyano propargyl radical was observed in the cold dark cloud TMC-1 using data from the ongoing QUIJOTE line survey, which is being carried out with the Yebes 40m telescope. A total of seven rotational transitions with multiple hyperfine components were detected in the 31.0–50.4 GHz range. We derived a column density of (2.2 ± 0.2) × 1011 cm−2 and a rotational temperature of 7±1 K. The abundance ratio between HC3HCN and CH2C3N is 1.4. The almost equal abundance of these isomers indicates that the two species may be produced in the same reaction with a similar efficiency, probably in the reaction C + CH2CHCN and perhaps also in the reaction C2 + CH3CN and the dissociative recombination with electrons of CH2C3NH+.
Key words: astrochemistry / line: identification / ISM: molecules / ISM: individual objects: TMC-1
© The Authors 2025
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