C. Cabezas, M. Agúndez, R. Fuentetaja, Y. Endo, N. Marcelino, B. Tercero, J. R. Pardo, P. de Vicente, and J. Cernicharo
reported on the
Discovery of the Cyclic C₅H Radical in TMC-1
Astron Astrophys. 663, Art. No. L2 (2022).
Transitions with J“ = 4 to 6 and K_a = 1 between 33.0 and 46.4 GHz 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. Fine structure splitting was resolved throughout, hyperfine splitting in many cases. The rotational temperature was determined as 6.0 ± 0.5 K. The c-C₅H to l-C₅H ratio is about 0.07, very different from the c-C₃H to l-C₃H ratio of ~5.5.

Contributor(s): H. S. P. Müller 07, 2022