Unified Microscopic-Macroscopic Monte Carlo Simulations of Complex Organic Molecule Chemistry in Cold Cores

Abstract

The recent discovery of methyl formate and dimethyl ether in the gas phase of cold cores with temperatures as cold as 10 K challenges our previous astrochemical models concerning the formation of complex organic molecules. The strong correlation between the abundances and distributions of methyl formate and dimethyl ether further shows that current astrochemical models may be missing important chemical processes in cold astronomical sources. We investigate a scenario in which complex organic molecules and the methoxy radical can be formed on dust grains via a so-called "chain reaction" mechanism, in a similar manner to CO${}_2$. A unified gas-grain microscopic-macroscopic Monte Carlo approach with both normal and interstitial sites for icy grain mantles is used to perform the chemical simulations. Reactive desorption with varying degrees of efficiency is included to enhance the non-thermal desorption of species formed on cold dust grains. In addition, varying degrees of efficiency for the surface formation of methoxy are also included. The observed abundances of a variety of organic molecules in cold cores can be reproduced in our models. The strong correlation between the abundances of methyl formate and dimethyl ether in cold cores can also be explained. Non-diffusive chemical reactions on dust grain surfaces may play a key role in the formation of some complex organic molecules.

accepted for publication in ApJ

References in corpus (13)

• Complex Chemistry in Star-Forming Regions: An Expanded Gas-Grain Warm-up Chemical Model
• 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
• Formation of complex organic molecules in cold objects: the role of gas phase reactions
• Reactive Desorption and Radiative Association as Possible Drivers of Complex Molecule Formation in the Cold Interstellar Medium
• The cometary composition of a protoplanetary disk as revealed by complex cyanides
• The origin of complex organic molecules in prestellar cores
• Detection of a branched alkyl molecule in the interstellar medium: iso-propyl cyanide
• The largest oxigen bearing organic molecule repository
• Modeling Complex Organic Molecules in dense regions: Eley-Rideal and complex induced reaction
• Gas-grain chemistry in cold interstellar cloud cores with a microscopic Monte Carlo approach to surface chemistry
• The census of complex organic molecules in the solar type protostar IRAS16293-2422
• Interstellar Simulations Using A Unified Microscopic-Macroscopic Monte Carlo Model with a full Gas-Grain Network including Bulk Diffusion in Ice Mantles

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• Formation of Glycerol through Hydrogenation of CO ice under Prestellar Core Conditions
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• O-bearing complex organic molecules at the cyanopolyyne peak of TMC-1: detection of C2H3CHO, C2H3OH, HCOOCH3, and CH3OCH3
• Reactive Desorption of CO Hydrogenation Products under Cold Pre-stellar Core Conditions
• A new model of the chemistry of ionizing radiation in solids: CIRIS
• Efficient formation pathway of methyl formate: the role of OH radicals on ice dust
• The efficiency of photodissociation for molecules in interstellar ices
• The Role of Radiolysis in the Modelling of C${}_2$H${}_4$O${}_2$ Isomers and Dimethyl Ether in Cold Dark Clouds
• Chemical modeling of the complex organic molecules in the extended region around Sagittarius B2
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• Chempl: a playable package for modeling interstellar chemistry
• Ice Age : Chemo-dynamical modeling of Cha-MMS1 to predict new solid-phase species for detection with JWST
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• Determination of the branching ratio of CH${}_3$OH + OH reaction on water ice surface at 10 K
• Sulphur-Bearing and Complex Organic Molecules in an Infrared Cold Core
• A multigrain-multilayer astrochemical model with variable desorption energy for surface species
• Chemical exploration of Galactic cold cores
• Rotational spectroscopy of the HCCO and DCCO radicals in the millimeter and submillimeter range
• Complex Organic Molecules Formation in Cold Cores on Stochastically Heated Grains