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We study the formation of water and methanol in the dense cloud conditions to find the dependence of its production rate on the binding energies, reaction mechanisms, temperatures, and grain site number. We wish to find the effective grain…

Astrophysics · Physics 2009-11-13 Ankan Das , Kinsuk Acharyya , Sonali Chakrabarti , Sandip Kumar Chakrabarti

A model is proposed for the formation of water ice mantles on grains in interstellar clouds. This occurs by direct accretion of monomers from the gas, be they formed by gas or surface reactions. The model predicts the existence of a…

Astrophysics · Physics 2009-11-13 Renaud Papoular

We present an extended version of the 2-phase gas-grain code NAUTILUS to the 3-phase modelling of gas and grain chemistry of cold cores. In this model, both the mantle and the surface are considered as chemically active. We also take into…

Astrophysics of Galaxies · Physics 2016-04-19 Maxime Ruaud , Valentine Wakelam , Franck Hersant

Gas-phase processes were long thought to be the key formation mechanisms for complex organic molecules in star-forming regions. However, recent experimental and theoretical evidence has cast doubt on the efficiency of such processes.…

Astrophysics · Physics 2009-11-13 Robin T. Garrod , Susanna L. Widicus Weaver , Eric Herbst

The study of the chemical evolution of glycine in the interstellar medium is one of challenging topics in astrochemistry. Here, we present the chemical modeling of glycine in hot cores using the state-of-the-art three-phase chemical model…

Astrophysics of Galaxies · Physics 2018-08-15 Taiki Suzuki , Liton Majumdar , Masatoshi Ohishi , Masao Saito , Tomoya Hirota , Valentine Wakelam

We investigate the formation and evolution of interstellar dust-grain ices under dark-cloud conditions, with a particular emphasis on CO2. We use a three-phase model (gas/surface/mantle) to simulate the coupled gas--grain chemistry,…

Astrophysics of Galaxies · Physics 2015-05-28 Robin T. Garrod , Tyler Pauly

Formaldehyde is a key precursor in the formation routes of many complex organic molecules (COMs) in space. It is also an intermediate step in CO hydrogenation sequence that leads to methanol formation on the surface of interstellar grains…

Astrophysics of Galaxies · Physics 2025-02-04 A. F. Punanova , K. Borshcheva , G. S. Fedoseev , P. Caselli , D. S. Wiebe , A. I. Vasyunin

Icy grain mantles are commonly observed through infrared spectroscopy toward dense clouds, cloud cores, protostellar envelopes and protoplanetary disks. Up to 80% of the available oxygen, carbon and nitrogen are found in such ices; the most…

Context. Interstellar ice is the main form of metal species in dark molecular clouds. Experiments and observations have shown that the ice is significantly processed after the freeze-out of molecules onto grains. The processing is caused by…

Astrophysics of Galaxies · Physics 2013-06-14 Juris Kalvāns , Ivar Shmeld

The degree of porosity in interstellar dust-grain material is poorly defined, although recent work has suggested that the grains could be highly porous. Aside from influencing the optical properties of the dust, porosity has the potential…

Astrophysics of Galaxies · Physics 2021-04-28 Drew A. Christianson , Robin T. Garrod

We have designed an improved algorithm that enables us to simulate the chemistry of cold dense interstellar clouds with a full gas-grain reaction network. The chemistry is treated by a unified microscopic-macroscopic Monte Carlo approach…

Earth and Planetary Astrophysics · Physics 2015-06-19 Qiang Chang , Eric herbst

We present the results of astrochemical modeling of complex organic molecules (COMs) in the ice and gas of the prestellar core L1544 with the recently updated MONACO rate equations-based model. The model includes, in particular,…

Context. The abundances of many observed compounds in interstellar molecular clouds still lack an explanation, despite extensive research that includes both gas and solid (dust-grain surface) phase reactions. Aims. We aim to qualitatively…

Astrophysics of Galaxies · Physics 2012-07-12 Juris Kalvans , Ivar Shmeld

The mobility of lighter species on the surface of interstellar dust grains plays a crucial role in forming simple through complex molecules. Carbon monoxide is one of the most abundant molecules, its surface diffusion on the grain surface…

Astrophysics of Galaxies · Physics 2022-03-30 Kinsuk Acharyya

The quantity of NH3 produced on grain surfaces in the prestellar core is thought to be one of the determining factors regarding the chemical complexity achievable at later stages of stellar birth. In order to investigate how this quantity…

Astrophysics of Galaxies · Physics 2020-12-09 Azrael A. von Procházka , T. J. Millar

Aims. We aim to investigate whether a multilayer ice model can be as successful as a bulk ice model in reproducing the observed abundances of various deuterated gas-phase species toward starless cores. Methods. We calculate abundances for…

Astrophysics of Galaxies · Physics 2016-06-08 O. Sipilä , P. Caselli , V. Taquet

Interstellar dust grain growth in dense clouds and protoplanetary disks, even moderate, affects the observed interstellar ice profiles as soon as a significant fraction of dust grains is in the size range close to the wave vector at the…

Astrophysics of Galaxies · Physics 2022-10-26 Emmanuel Dartois , Jennifer A. Noble , Nathalie Ysard , Karine Demyk , Marin Chabot

While astrochemical models are successful in reproducing many of the observed interstellar species, they have been struggling to explain the observed abundances of complex organic molecules. Current models tend to privilege grain surface…

Solar and Stellar Astrophysics · Physics 2015-06-23 Nadia Balucani , Cecilia Ceccarelli , Vianney Taquet

Grain surface chemistry and its treatment in gas-grain chemical models is an area of large uncertainty. Whilst laboratory experiments are making progress, there is still much that is unknown about grain surface chemistry. Further, the…

Astrophysics of Galaxies · Physics 2018-12-04 Jonathan Holdship , Niall Jeffrey , Antonios Makrymallis , Serena Viti , Jeremy Yates

1-propanol (CH3CH2CH2OH) is a three carbon-bearing representative of primary linear alcohols that may have its origin in the cold dark cores in interstellar space. To test this, we investigated in the laboratory whether 1-propanol ice can…

Solar and Stellar Astrophysics · Physics 2019-06-26 D. Qasim , G. Fedoseev , K. -J. Chuang , V. Taquet , T. Lamberts , J. He , S. Ioppolo , E. F. van Dishoeck , H. Linnartz