Discovery of thiofulminic acid with the QUIJOTE line survey: A study of the isomers of HNCS and HNCO in TMC-1
J. Cernicharo, M. Agúndez, C. Cabezas, B. Tercero, R. Fuentetaja, N. Marcelino, P. de Vicente
Abstract
We present the first detection of HCNS (thiofulminic acid) in space with the QUIJOTE line survey in the direction of TMC-1. We performed a complete study of the isomers of CHNS and CHNO, including NCO and NCS. The derived column densities for HCNS, HNCS, and HSCN are (9.0 ± 0.5) × 10 9 , (3.2 ± 0.1) × 10 11 , and (8.3 ± 0.4) × 10 11 cm −2 , respectively. The HNCS/HSCN abundance ratio is 0.38. The abundance ratios HNCO/HNCS, HCNO/HCNS, HOCN/HSCN, and NCO/NCS are 34 ± 4, 8.3 ± 0.7, 0.18 ± 0.03, and 0.78 ± 0.07, respectively. These ratios cannot be correctly reproduced by our gas-phase chemical models, which suggests that formation paths for these species are missing, and/or that the adopted dissociative recombination rates for their protonated precursors have to be revised. The isotopologues H 15 NCO, DNCO, HN 13 CO, DCNO, H 34 SCN, and DSCN have also been detected with the ultrasensitive QUIJOTE line survey.