A radical route to interstellar propylene formation

Abstract

Complex organic molecules, such as propylene (CH3CHCH2), are detected in molecular clouds (such as TMC1) with high fractional abundances (~2.10^{-9}, relative to hydrogen) that cannot be explained by gas-phase chemical reactions under normal dark cloud conditions. To obtain such high abundances requires an efficient grain-driven chemistry to be operating, coupled with effective desorption of the complex organics back into the gas-phase. We propose that the mechanism that we have previously described; rapid high density gas-phase chemistry in the gas released following sudden, total, ice mantle sublimation - can explain the high abundances, without recourse to ill-defined surface chemical pathways. Our model provides a natural explanation for why it is that some sources harbour high abundances of propylene, whilst others do not; based on the age and level of dynamical activity within the source (which affects the ice composition) and the chemical composition of the ambient gas.

5 pages, letter

References in corpus (4)

• The UMIST database for astrochemistry 2012
• Complex Chemistry in Star-Forming Regions: An Expanded Gas-Grain Warm-up Chemical Model
• Discovery of Interstellar Propylene (CH_2CHCH_3): Missing Links in Interstellar Gas-Phase Chemistry
• Episodic Explosions in Interstellar Ices

Cited by in corpus (6)

• The complex organic molecular content in the L1517B starless core
• Discovery of five cyano derivatives of propene with the QUIJOTE line survey
• Gas phase Elemental abundances in Molecular cloudS (GEMS) V. Methanol in Taurus
• A study of methanol and silicon monoxide production through episodic explosions of grain mantles in the Central Molecular Zone
• Millimetre and submillimetre spectroscopy of isobutene and its detection in the molecular cloud G+0.693
• Investigating the Efficiency of Explosion Chemistry as a Source of Complex Organic Molecules in TMC-1