Discovery of CH3CHCO in TMC-1 with the QUIJOTE line survey

Abstract

We report the detection of methyl ketene towards TMC-1 with the QUIJOTE line survey. Nineteen rotational transitions with rotational quantum numbers ranging from J = 3 up to J = 5 and Ka =< 2 were identified in the frequency range 32.0-50.4 GHz, 11 of which arise above the 3σ level. We derived a column density for CH3CHCO of N=1.5x10^11 cm-2 and a rotational temperature of 9 K. Hence, the abundance ratio between ketene and methyl ketene, CH2CO/CH3CHCO, is 93. This species is the second C3H4O isomer detected. The other, trans-propenal (CH2CHCHO), corresponds to the most stable isomer and has a column density of N=(2.2+-0.3)x10^11 cm-2, which results in an abundance ratio CH2CHCHO/CH3CHCO of 1.5. The next non-detected isomer with the lowest energy is cis-propenal, which is therefore a good candidate for future discovery. We have carried out an in-depth study of the possible gas-phase chemical reactions involving methyl ketene to explain the abundance detected, achieving good agreement between chemical models and observations.

References in corpus (16)

• Detection of Two Interstellar Polycyclic Aromatic Hydrocarbons via Spectral Matched Filtering
• The 2014 KIDA network for interstellar 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
• Discovery of two isomers of ethynyl cyclopentadiene in TMC-1: Abundances of CCH and CN derivatives of hydrocarbon cycles
• Discovery of fulvenallene in TMC-1 with the QUIJOTE line survey
• Discovery of the propargyl radical (CH2CCH) in TMC-1: one of the most abundant radicals ever found and a key species for cyclization to benzene in cold dark clouds
• Discovery of CH2CHCCH and detection of HCCN, HC4N, CH3CH2CN, and, tentatively, CH3CH2CCH in TMC-1
• What Produces Dust Polarization in the HH 212 Protostellar Disk at 878 μm: Dust Self-Scattering or Dichroic Extinction?
• Discovery of the acetyl cation, CH3CO+, in space and in the laboratory
• Detection of Interstellar HC${}_5$O in TMC-1 with the Green Bank Telescope
• Deep K-band observations of TMC-1 with the Green Bank Telescope: Detection of HC7O, non-detection of HC11N, and a search for new organic molecules
• Discovery of two new interstellar molecules with QUIJOTE: HCCCHCCC and HCCCCS
• Space and laboratory observation of the deuterated cyanomethyl radical HDCCN
• Discovery of HCCCO and C5O in TMC-1 with the QUIJOTE line survey