Authors: Fuentetaja, R.; Cabezas, C.; Agundez, M.; Tercero, B.; Marcelino, N.; Pardo, J. R.; de Vicente, P.; Cernicharo, J.


Publication date: 2022/07/08

DOI: 10.1051/0004-6361/202243857

Abstract: Using the QUIJOTE line survey in the 32.0-50.4 GHz range, we report the discovery of the molecule CH2CCHC4H towards the prestellar cold core TMC-1 in the Taurus region. We also present a rigorous detection of CH2CCHC3N, 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 CH2CCHC4H is N = (2.2 +/- 0.2) x 10(12) cm(-2), while for CH2CCHC3N, we derived N = (1.2 +/- 0.15) x 10(11) cm(-2). The rotational temperature is 9.0 +/- 0.5 K for both species. The abundance ratiobetween CH2CCHC4H and CH2CCHC3N is 18 +/- 4. We also compared the column densities of these species with those of their isomers CH3C6H and CH3C5N, 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.