M. Agúndez, C. Cabezas, N. Marcelino, R. Fuentetaja, B. Tercero, P. de Vicente, and J. Cernicharo
reported on
A new protonated molecule discovered in TMC-1: HCCNCH⁺
Astron Astrophys. 659, Art. No. L9 (2022).
Two transitions, J“ = 3 and 4 near 37.3 and 46.6 GHz, of a new, unknown molecule were detected 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. Subsequently, two additional transitions, J” = 8 and 9 near 84.0 and 93.3 GHz, were identified in data from an older IRAM 30 m line survey of TMC-1. Quantum-chemical calculations supported the assignment to HCCNCH⁺.

The abundance ratio of HCCCNC to HCCCNCH⁺ is ~10. This extremely low ratio is reproduced well with the reaction of C⁺ and CH₃CN being the main source of HCCNCH⁺.

Contributor(s): H. S. P. Müller 03, 2022