Discovery of CH<sub>2</sub>CCHC<sub>4</sub>H and a rigorous detection of CH<sub>2</sub>CCHC<sub>3</sub>N in TMC-1 with the QUIJOTE line survey
R. Fuentetaja, C. Cabezas, M. Agúndez, B. Tercero, N. Marcelino, J. R. Pardo, P. de Vicente, J. Cernicharo
Abstract
Using the QUIJOTE line survey in the 32.0–50.4 GHz range, we report the discovery of the molecule CH 2 CCHC 4 H towards the prestellar cold core TMC-1 in the Taurus region. We also present a rigorous detection of CH 2 CCHC 3 N, along with its detailed analysis. We identified a total of twenty rotational transitions for each one of these molecules. The rotational quantum numbers range from J u = 17 up to 24 and K a ≤ 3. The column density for CH 2 CCHC 4 H is N = (2.2 ± 0.2) × 10 12 cm −2 , while for CH 2 CCHC 3 N, we derived N = (1.2 ± 0.15) × 10 11 cm −2 . The rotational temperature is 9.0 ± 0.5 K for both species. The abundance ratiobetween CH 2 CCHC 4 H and CH 2 CCHC 3 N is 18 ± 4. We also compared the column densities of these species with those of their isomers CH 3 C 6 H and CH 3 C 5 N, derived from their J = 20 − 10 up to J = 31 − 30 rotational transitions observed with the QUIJOTE line survey. The observed abundances for all these species are reasonably well explained by state-of-the-art chemical models of TMC-1. The observed astronomical frequencies were merged with laboratory frequencies from the literature to derive improved spectroscopic parameters.