On Modelling Sputtering of Interstellar Grain Ices
arXiv:2209.02648 · doi:10.1093/mnras/stac2507
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 3-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 (CHOH) and methyl formate (HCOOCH). 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.
15 pages, 11 figures, Submitted to MNRAS
References in corpus (13)
- Complex Chemistry in Star-Forming Regions: An Expanded Gas-Grain Warm-up Chemical Model
- A Unified Representation of Gas-Phase Element Depletions in the Interstellar Medium
- Formation of methyl formate and other organic species in the warm-up phase of hot molecular cores
- Non-thermal desorption from interstellar dust grains via exothermic surface reactions
- Polycylcic Aromatic Hydrocarbons (PAH's) in dense cloud chemistry
- Formation of complex organic molecules in cold objects: the role of gas phase reactions
- The Spatial Distribution of Complex Organic Molecules in the L1544 Pre-stellar Core
- Formation of Complex Organic Molecules in Cold Interstellar Environments through non-diffusive grain-surface and ice-mantle chemistry
- Heavy ion irradiation of crystalline water ice
- Efficiency of non-thermal desorptions in cold-core conditions. Testing the sputtering of grain mantles induced by cosmic rays
- Chemical complexity induced by efficient ice evaporation in the Barnard 5 molecular cloud
- On Simulating the Proton-Irradiation of O and HO Ices Using Astrochemical-type Models, with Implications for Bulk Reactivity
- The Role of Radiolysis in the Modelling of CHO Isomers and Dimethyl Ether in Cold Dark Clouds