Issue |
A&A
Volume 688, August 2024
|
|
---|---|---|
Article Number | L15 | |
Number of page(s) | 5 | |
Section | Letters to the Editor | |
DOI | https://doi.org/10.1051/0004-6361/202348777 | |
Published online | 08 August 2024 |
Letter to the Editor
Discovery of HCCCH2CCH in TMC-1 with the QUIJOTE line survey⋆
1
Dept. de Astrofísica Molecular, Instituto de Física Fundamental (IFF-CSIC), C/ Serrano 121, 28006 Madrid, Spain
e-mail: r.fuentetaja@csic.es; jose.cernicharo@csic.es
2
Centro de Desarrollos Tecnológicos, Observatorio de Yebes (IGN), 19141 Yebes, Guadalajara, Spain
3
Observatorio Astronómico Nacional (OAN, IGN), C/ Alfonso XII, 3, 28014 Madrid, Spain
Received:
28
November
2023
Accepted:
19
June
2024
We present the first detection in space of 1,4-pentadiyne. It has been found towards TMC-1 with the QUIJOTE line survey in the 31–50 GHz range. We observed a total of 17 transitions with J = 2 up to 13 and Ka = 0, 1 and 2. The observed transitions allowed us to derive a rotational temperature of 9.5 ± 0.5 K and a column density of (5.0 ± 0.5) × 1012 cm−2. This molecule was the last non-cyclic isomer of the C5H4 family that could be detected via radio astronomy. A computational chemistry study was performed to determine the energies of the five most stable isomers. The isomer (c-C3H3CCH) has a considerably higher energy than the others, and it has not yet been detected. To better understand the chemical reactions involving these species, we compared the ethynyl and cyano derivatives. The observed abundances of these species are in good agreement with the branching ratios of the formation reactions studied with our chemical model of TMC-1.
Key words: astrochemistry / line: identification / molecular data / ISM: molecules / ISM: individual objects: TMC-1
© The Authors 2024
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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