Investigating the Efficiency of Explosion Chemistry as a Source of Complex Organic Molecules in TMC-1

TL;DR

This study evaluates whether explosion chemistry from dust grain ice mantle explosions can explain the presence of complex organic molecules in TMC-1, concluding it does not significantly improve model predictions.

Contribution

The paper modifies the UCLCHEM code to include explosion chemistry and assesses its impact on modeling COMs in TMC-1, finding it unnecessary based on current understanding.

Findings

Explosions do not improve the match to observed simple species abundances.

Including explosions does not produce COMs at observed levels.

Surface diffusion chemistry alone is insufficient to explain COM abundances.

Abstract

Many species of complex organic molecules (COMs) have been observed in several astrophysical environments but it is not clear how they are produced, particularly in cold, quiescent regions. One process that has been proposed as a means to enhance the chemical complexity of the gas phase in such regions is the explosion of the ice mantles of dust grains. In this process, a build up of chemical energy in the ice is released, sublimating the ices and producing a short lived phase of high density, high temperature gas. The gas-grain chemical code UCLCHEM has been modified to treat these explosions in order to model the observed abundances of COMs towards the TMC-1 region. It is found that, based on our current understanding of the explosion mechanism and chemical pathways, the inclusion of explosions in chemical models is not warranted at this time. Explosions are not shown to improve the model's match to the observed abundances of simple species in TMC-1. Further, neither the inclusion of surface diffusion chemistry, nor explosions, results in the production of COMs with observationally inferred abundances.

Full text

An example of a Research Note of the American Astronomical Society (RNAAS)

Ethan Vishniac

Editor-in-Chief

Johns Hopkins University

Chris Lintott

RNAAS Editor

Oxford University

Greg J. Schwarz

American Astronomical Society

2000 Florida Ave., NW, Suite 300

Washington, DC 20009-1231, USA

August Muench

American Astronomical Society

2000 Florida Ave., NW, Suite 300

Washington, DC 20009-1231, USA

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