Cosmic Ray Compaction of Porous Interstellar Ices

2008 ◽  
Vol 687 (2) ◽  
pp. 1070-1074 ◽  
Author(s):  
U. Raut ◽  
M. Famá ◽  
M. J. Loeffler ◽  
R. A. Baragiola
Keyword(s):  
Cosmic Ray ◽  
Interstellar Ices

scholarly journals A study of interstellar aldehydes and enols as tracers of a cosmic ray-driven nonequilibrium synthesis of complex organic molecules

2016 ◽  
Vol 113 (28) ◽  
pp. 7727-7732 ◽  
Author(s):  
Matthew J. Abplanalp ◽  
Samer Gozem ◽  
Anna I. Krylov ◽  
Christopher N. Shingledecker ◽  
Eric Herbst ◽  
...  
Keyword(s):  
Organic Molecules ◽  
Cosmic Ray ◽  
Formation Mechanisms ◽  
Molecular Precursors ◽  
Star Forming ◽  
Star Forming Regions ◽  
Interstellar Ices ◽  
A Chain ◽  
Nonequilibrium Chemistry ◽  
Complex Organic

Complex organic molecules such as sugars and amides are ubiquitous in star- and planet-forming regions, but their formation mechanisms have remained largely elusive until now. Here we show in a combined experimental, computational, and astrochemical modeling study that interstellar aldehydes and enols like acetaldehyde (CH3CHO) and vinyl alcohol (C2H3OH) act as key tracers of a cosmic-ray-driven nonequilibrium chemistry leading to complex organics even deep within low-temperature interstellar ices at 10 K. Our findings challenge conventional wisdom and define a hitherto poorly characterized reaction class forming complex organic molecules inside interstellar ices before their sublimation in star-forming regions such as SgrB2(N). These processes are of vital importance in initiating a chain of chemical reactions leading eventually to the molecular precursors of biorelevant molecules as planets form in their interstellar nurseries.

scholarly journals Efficient Production of S8 in Interstellar Ices: The Effects of Cosmic-Ray-driven Radiation Chemistry and Nondiffusive Bulk Reactions

2020 ◽  
Vol 888 (1) ◽  
pp. 52 ◽  
Author(s):  
Christopher N. Shingledecker ◽  
Thanja Lamberts ◽  
Jacob C. Laas ◽  
Anton Vasyunin ◽  
Eric Herbst ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
Radiation Chemistry ◽  
Efficient Production ◽  
Interstellar Ices

scholarly journals Cosmic-Ray Induced Diffusion in Interstellar Ices

2014 ◽  
Vol 23 (2) ◽  
Author(s):  
Juris Kalvāns
Keyword(s):  
Outer Surface ◽  
Interstellar Dust ◽  
Cosmic Ray ◽  
Whole Grain ◽  
Dark Cloud ◽  
Interstellar Dust Grains ◽  
Stable Species ◽  
Three Phase ◽  
Interstellar Ices ◽  
Cloud Cores

AbstractCosmic rays are able to heat interstellar dust grains. This may enhance molecule mobility in icy mantles that have accumulated on the grains in dark cloud cores. A three-phase astrochemical model was used to investigate the molecule mobility in interstellar ices. Specifically, diffusion through pores in ice between the subsurface mantle and outer surface, assisted by whole-grain heating, was considered. It was found that the pores can serve as an efficient transport route for light species. The diffusion of chemical radicals from the mantle to the outer surface are most effective. These species accumulate in the mantle because of photodissociation by the cosmic-ray induced photons. The faster diffusion of hydrogen within the warm ice enhances the hydrogenation of radicals on pore surfaces. The overall result of the whole grain heating-induced radial diffusion in ice are higher abundances of ice species, whose synthesis involve light radicals. Examples of stable species synthesized this way include complex organic molecules, OCS, H

scholarly journals Infrared Observations of Interstellar Ices

2000 ◽  
Vol 197 ◽  
pp. 135-146 ◽  
Author(s):  
P. Ehrenfreund ◽  
W. A. Schutte
Keyword(s):  
Molecular Clouds ◽  
Cosmic Ray ◽  
Dust Particles ◽  
Early Solar System ◽  
Infrared Space Observatory ◽  
Infrared Observations ◽  
Interstellar Ice ◽  
Low Mass ◽  
Interstellar Ices ◽  
Ice Chemistry

In the recent years revolutionary results concerning the nature of icy dust particles have been obtained with the help of the Infrared Space Observatory (ISO) and ground based observations. To date interstellar ice features of H2O, CO, CO2, CH3OH, CH4, H2CO, OCS and HCOOH as well as other minor species are observed. Interstellar grains act as important catalysts in the interstellar medium. Processes such as UV irradiation, cosmic ray processing and temperature variations determine the grain mantle growth and chemical evolution. ISO has revealed that ice segregation is an important and ubiquitous process in the vicinity of massive protostars and reflects the extensive thermal processing of grains in such environments.In this paper a recent view on the inventory of interstellar ices is presented. Constraints on the reservoirs of oxygen in dense clouds are discussed, taking into account recent measurements of oxygen-bearing species. Large abundances of CO2 and CH3OH in dense molecular clouds provide challenging perspectives to investigate the differences of ice chemistry in the vicinity of high and low-mass protostars. Accurate abundances of ice species and knowledge on the ice distribution in the protostellar regions are an important tool to define the environmental conditions in molecular clouds. A global understanding of interstellar ice chemistry also allows monitoring the incorporation and evolution of volatiles in planetesimals and comets and to reveal processes predominant in the early Solar System.

DEVELOPMENT OF THE COSMIC RAY TECHNIQUES

1982 ◽  
Vol 43 (C8) ◽  
pp. C8-69-C8-88 ◽  
Author(s):  
B. Rossi
Keyword(s):  
Cosmic Ray
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