C. Cabezas, B. Tercero, M. Agúndez, N. Marcelino, J. R. Pardo, P. de Vicente, and J. Cernicharo
reported on
Cumulene carbenes in TMC-1: Astronomical discovery of //l//-H₂C₅
Astron. Astrophys. 650, Art. No. L9 (2021).
The molecule was identified through 11 a-type unblended to somewhat blended transitions with 6 ≤ J ≤ 10 and K_a = 0 and 1 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 between 32.8 and 49.2 GHz. A value of about 10 K was derived for T_rot. The column density ratios of the l-H₂C_n molecules with n = 3 to 6 is about 344 : 561 : 1 : 4.4; reflecting the decrease with n on one hand and the lower column densities for n being odd on the other hand.