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Main Authors: Esplugues, G., Agúndez, M., Molpeceres, G., Tercero, B., Cabezas, C., Marcelino, N., Fuentetaja, R., Cernicharo, J.
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2506.12974
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author Esplugues, G.
Agúndez, M.
Molpeceres, G.
Tercero, B.
Cabezas, C.
Marcelino, N.
Fuentetaja, R.
Cernicharo, J.
author_facet Esplugues, G.
Agúndez, M.
Molpeceres, G.
Tercero, B.
Cabezas, C.
Marcelino, N.
Fuentetaja, R.
Cernicharo, J.
contents We report the first detection of HS2 towards the cold dark cloud TMC-1. This is the first observation of a chemical species containing more than one sulphur atom in this type of sources. The astronomical observations are part of QUIJOTE, a line survey of TMC-1 in the Q band (31-50 GHz). The detection is confirmed by the observation of the fine and hyperfine components of two rotational transitions (2(0,2)-1(0,1) and 3(0,3)-2(0,2)). Assuming a rotational temperature of 7 K, we derived an HS2 column density of 5.7x10^11 cm-2, using a local thermodynamic equilibrium model that reproduces the observed spectra. The abundance of HS2 relative to H2 is 5.7x10^-11, which means that it is about seven times more abundant than its oxygenated counterpart HSO. We also explored the main formation and destruction mechanisms of HS2 using a chemical model, which reproduces the observed abundance of HS2 and indicates that dissociative recombination reactions from the ions H2S2+ and H3S2+ play a major role in forming HS2.
format Preprint
id arxiv_https___arxiv_org_abs_2506_12974
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle First detection of HS2 in a cold dark cloud
Esplugues, G.
Agúndez, M.
Molpeceres, G.
Tercero, B.
Cabezas, C.
Marcelino, N.
Fuentetaja, R.
Cernicharo, J.
Astrophysics of Galaxies
Solar and Stellar Astrophysics
We report the first detection of HS2 towards the cold dark cloud TMC-1. This is the first observation of a chemical species containing more than one sulphur atom in this type of sources. The astronomical observations are part of QUIJOTE, a line survey of TMC-1 in the Q band (31-50 GHz). The detection is confirmed by the observation of the fine and hyperfine components of two rotational transitions (2(0,2)-1(0,1) and 3(0,3)-2(0,2)). Assuming a rotational temperature of 7 K, we derived an HS2 column density of 5.7x10^11 cm-2, using a local thermodynamic equilibrium model that reproduces the observed spectra. The abundance of HS2 relative to H2 is 5.7x10^-11, which means that it is about seven times more abundant than its oxygenated counterpart HSO. We also explored the main formation and destruction mechanisms of HS2 using a chemical model, which reproduces the observed abundance of HS2 and indicates that dissociative recombination reactions from the ions H2S2+ and H3S2+ play a major role in forming HS2.
title First detection of HS2 in a cold dark cloud
topic Astrophysics of Galaxies
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2506.12974