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Title: On modelling cosmic ray sputtering of interstellar grain ices
ABSTRACT In the interstellar medium (ISM), the formation of complex organic molecules (COMs) is largely facilitated by surface reactions. However, in cold dark clouds, thermal desorption of COMs is inefficient because of the lack of thermal energy to overcome binding energies to the grain surface. Non-thermal desorption methods are therefore important explanations for the gas-phase detection of many COMs that are primarily formed on grains. Here, we present a new non-thermal desorption process: cosmic ray sputtering of grain ice surfaces based on water, carbon dioxide, and a simple mixed ice. Our model applies estimated rates of sputtering to the three-phase rate equation model nautilus-1.1, where this inclusion results in enhanced gas-phase abundances for molecules produced by grain reactions such as methanol (CH3OH) and methyl formate (HCOOCH3). Notably, species with efficient gas-phase destruction pathways exhibit less of an increase in models with sputtering compared to other molecules. These model results suggest that sputtering is an efficient, non-specific method of non-thermal desorption that should be considered as an important factor in future chemical models.  more » « less
Award ID(s):
1906489
PAR ID:
10371871
Author(s) / Creator(s):
; ;
Publisher / Repository:
Oxford University Press
Date Published:
Journal Name:
Monthly Notices of the Royal Astronomical Society
Volume:
516
Issue:
3
ISSN:
0035-8711
Page Range / eLocation ID:
p. 4097-4110
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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