A search for the three isomers of cyano-1,3-butadiene in TMC-1: Implications for bottom-up routes involving 1,3-butadiene

Abstract

The molecule 1,3-butadiene (CH2CHCHCH2) could play a key role in the synthesis of the cyclic molecules cyclopentadiene and benzene in cold dense clouds. Since 1,3-butadiene is non-polar, we searched for its cyano derivative, which exists in the form of three different polar isomers, in the cold dense cloud TMC-1. We used the most recent data obtained with the Yebes 40m telescope in the Q band (31.0-50.3 GHz) in the frame of the QUIJOTE project. We do not detect any of the two isomers of 1-cyano-1,3-butadiene, and derive 3sigma upper limits to their column densities of 1.2e10 cm-2 and 2.0e10 cm-2 for E- and Z-1-cyano-1,3-butadiene, respectively. Our results are not consistent with those from Cooke et al. (2023), who determine a column density of 3.8e10 cm-2 for E-1-cyano-1,3-butadiene in TMC-1 using GBT data and a line stack technique. At the current level of sensitivity of our data, there is tentative evidence for the presence of the third cyano derivative isomer, 2-cyano-1,3-butadiene, although a firm detection must await more sensitive data. We derive an upper limit to its column density of 3.1e10 cm-2. This isomer cannot be formed in the reaction between CN and 1,3-butadiene, according to experimental and theoretical studies, and thus we speculate whether it could arise from neutral-neutral reactions like C2H3 + CH2CHCN and CH2CCN + C2H4. From the upper limit on the abundance of 1-cyano-1,3-butadiene derived here, we estimate that the abundance of 1,3-butadiene in TMC-1 is below 1e-11 - 1e-10 relative to H2. The low abundance inferred for 1,3-butadiene makes it unlikely that it plays an important role in bottom-up routes to cyclopentadiene and benzene.

Accepted for publication in A&A

References in corpus (28)

• A Unified Representation of Gas-Phase Element Depletions in the Interstellar Medium
• Detection of Two Interstellar Polycyclic Aromatic Hydrocarbons via Spectral Matched Filtering
• Pure hydrocarbon cycles in TMC-1: Discovery of ethynyl cyclopropenylidene, cyclopentadiene and indene
• Discovery of the Pure Polycyclic Aromatic Hydrocarbon Indene ($c$-C${}_9$H${}_8$) with GOTHAM Observations of TMC-1
• Discovery of Interstellar Propylene (CH_2CHCH_3): Missing Links in Interstellar Gas-Phase Chemistry
• Discovery of benzyne, o-C6H4, in TMC-1 with the QUIJOTE line survey
• Discovery of Interstellar 2-Cyanoindene (2-C${}_9$H${}_7$CN) in GOTHAM Observations of TMC-1
• Yebes 40 m radio telescope and the broad band NANOCOSMOS receivers at 7 mm and 3 mm for line surveys
• A New Reference Chemical Composition for TMC-1
• Discovery of two isomers of ethynyl cyclopentadiene in TMC-1: Abundances of CCH and CN derivatives of hydrocarbon cycles
• Benzonitrile as a proxy for benzene in the cold ISM: low temperature rate coefficients for CN + C${}_6$H${}_6$
• Discovery of fulvenallene in TMC-1 with the QUIJOTE line survey
• The Horizon Run 5 Cosmological Hydrodynamic Simulation: Probing Galaxy Formation from Kilo- to Giga-parsec Scales
• Discovery of two cyano derivatives of acenaphthylene (C${}_{12}$H${}_8$) in TMC-1 with the QUIJOTE line survey
• Discovery of CH2CHCCH and detection of HCCN, HC4N, CH3CH2CN, and, tentatively, CH3CH2CCH in TMC-1
• Interstellar Detection of 2-Cyanocyclopentadiene, C${}_5$H${}_5$CN, a Second Five-Membered Ring Toward TMC-1
• Tentative detection of HC5NH+ in TMC-1
• A study of C4H3N isomers in TMC-1: line by line detection of HCCCH2CN
• Discovery of H${}_2$CCCH${}^{+}$ in TMC-1
• Discovery of C5H+ and detection of C3H+ in TMC-1 with the QUIJOTE line survey
• Aromatic cycles are widespread in cold clouds
• The abundance and excitation of molecular anions in interstellar clouds
• The spatial distribution of an aromatic molecule, C6H5CN, in the cold dark cloud TMC-1
• Detection of Interstellar $E$-1-cyano-1,3-butadiene in GOTHAM Observations of TMC-1
• CH3-Terminated Carbon Chains in the GOTHAM Survey of TMC-1: Evidence of Interstellar CH3C7N
• Discovery of five cyano derivatives of propene with the QUIJOTE line survey
• Discovery of interstellar NC4NH+: dicyanopolyynes are indeed abundant in space
• Laboratory and astronomical discovery of the cyanovinyl radical H2CCCN

Cited by in corpus (1)

• Ion-molecule routes towards cycles in TMC-1. An automated study of the C2H4 + CH2CCH+ reaction