Cumulene carbenes in TMC-1: Astronomical discovery of $l$-H$_2$C$_5$

C. Cabezas; B. Tercero; M. Agúndez; N. Marcelino; J. R. Pardo; P. de Vicente; J. Cernicharo

doi:10.1051/0004-6361/202141274

paper

Cumulene carbenes in TMC-1: Astronomical discovery of $l$ -H $_{2}$ C $_{5}$

arXiv:2106.00635 · doi:10.1051/0004-6361/202141274

Abstract

We report the first detection in space of the cumulene carbon chain $l$ -H $_{2}$ C $_{5}$ . A total of eleven rotational transitions, with $J_{u p}$ = 7-10 and $K_{a}$ = 0 and 1, were detected in TMC-1 in the 31.0-50.4 GHz range using the Yebes 40m radio telescope. We derive a column density of (1.8 $\pm$ 0.5) $\times$ 10 $^{10}$ cm $^{- 2}$ . In addition, we report observations of other cumulene carbenes detected previously in TMC-1, to compare their abundances with the newly detected cumulene carbene chain. We find that $l$ -H $_{2}$ C $_{5}$ is $\sim$ 4.0 times less abundant than the larger cumulene carbene $l$ -H $_{2}$ C $_{6}$ , while it is $\sim$ 300 and $\sim$ 500 times less abundant than the shorter chains $l$ -H $_{2}$ C $_{3}$ and $l$ -H $_{2}$ C $_{4}$ . We discuss the most likely gas-phase chemical routes to these cumulenes in TMC-1 and stress that chemical kinetics studies able to distinguish between different isomers are needed to shed light on the chemistry of C $_{n}$ H $_{2}$ isomers with $n$ \, $>$ \,3.

Accepted for publication in A&A Letters

Cumulene carbenes in TMC-1: Astronomical discovery of $l$ -H $_{2}$ C $_{5}$

Abstract

References in corpus (7)

Cited by in corpus (12)

Cumulene carbenes in TMC-1: Astronomical discovery of l-H2​C5​

Abstract

References in corpus (7)

Cited by in corpus (12)

Cumulene carbenes in TMC-1: Astronomical discovery of $l$ -H $_{2}$ C $_{5}$