Synthesis of CO and CO2 Molecules by UV Irradiation of Water Ice-covered Hydrogenated Carbon Grains
We present the results of UV irradiation with Lyα photons of carbon grains with a water ice cap at 11 K. Formation of CO and CO2 molecules takes place during irradiation. An estimation of the formation cross section of these molecules by Lyα photons has been obtained from the intensity increase of t...
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ftopenaccessrep:oai:zenodo.org:99129 2023-10-25T01:39:26+02:00 Synthesis of CO and CO2 Molecules by UV Irradiation of Water Ice-covered Hydrogenated Carbon Grains E. A. Bergin Maria Elisabetta Palumbo Vito Mennella G. A. Baratta 2006-06-01 https://www.openaccessrepository.it/record/99129 https://doi.org/10.1086/502965 eng eng url:https://www.openaccessrepository.it/communities/itmirror https://www.openaccessrepository.it/record/99129 doi:10.1086/502965 info:eu-repo/semantics/openAccess Space and Planetary Science Astronomy and Astrophysics info:eu-repo/semantics/article publication-article 2006 ftopenaccessrep https://doi.org/10.1086/502965 2023-09-26T22:19:33Z We present the results of UV irradiation with Lyα photons of carbon grains with a water ice cap at 11 K. Formation of CO and CO2 molecules takes place during irradiation. An estimation of the formation cross section of these molecules by Lyα photons has been obtained from the intensity increase of their infrared stretching bands as a function of the photon fluence. The fraction of carbon in the grains converted to CO and CO2 by UV photons is 0.06 and 0.05, respectively. The spectral profile of the CO stretching feature and that of the CO2 bending mode indicate a polar environment for these molecules. On the basis of the present laboratory results and those obtained in previous work on ion irradiation of similar samples, it has been possible to estimate the contribution of polar CO and CO2 produced on carbon grains by energetic processing to the observed column densities of these molecules for dense clouds whose visual extinction is known. A significant amount of polar CO and CO2 is produced through the mechanism we have studied. Furthermore, we have found that the laboratory profile of the bending band of CO2 produced on carbon grains is compatible with that observed toward the field star Elias 16. Article in Journal/Newspaper Ice cap Istituto Nazionale di Fisica Nucleare (INFN): Open Access Repository The Astrophysical Journal 643 2 923 931 |
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Open Polar |
collection |
Istituto Nazionale di Fisica Nucleare (INFN): Open Access Repository |
op_collection_id |
ftopenaccessrep |
language |
English |
topic |
Space and Planetary Science Astronomy and Astrophysics |
spellingShingle |
Space and Planetary Science Astronomy and Astrophysics E. A. Bergin Maria Elisabetta Palumbo Vito Mennella G. A. Baratta Synthesis of CO and CO2 Molecules by UV Irradiation of Water Ice-covered Hydrogenated Carbon Grains |
topic_facet |
Space and Planetary Science Astronomy and Astrophysics |
description |
We present the results of UV irradiation with Lyα photons of carbon grains with a water ice cap at 11 K. Formation of CO and CO2 molecules takes place during irradiation. An estimation of the formation cross section of these molecules by Lyα photons has been obtained from the intensity increase of their infrared stretching bands as a function of the photon fluence. The fraction of carbon in the grains converted to CO and CO2 by UV photons is 0.06 and 0.05, respectively. The spectral profile of the CO stretching feature and that of the CO2 bending mode indicate a polar environment for these molecules. On the basis of the present laboratory results and those obtained in previous work on ion irradiation of similar samples, it has been possible to estimate the contribution of polar CO and CO2 produced on carbon grains by energetic processing to the observed column densities of these molecules for dense clouds whose visual extinction is known. A significant amount of polar CO and CO2 is produced through the mechanism we have studied. Furthermore, we have found that the laboratory profile of the bending band of CO2 produced on carbon grains is compatible with that observed toward the field star Elias 16. |
format |
Article in Journal/Newspaper |
author |
E. A. Bergin Maria Elisabetta Palumbo Vito Mennella G. A. Baratta |
author_facet |
E. A. Bergin Maria Elisabetta Palumbo Vito Mennella G. A. Baratta |
author_sort |
E. A. Bergin |
title |
Synthesis of CO and CO2 Molecules by UV Irradiation of Water Ice-covered Hydrogenated Carbon Grains |
title_short |
Synthesis of CO and CO2 Molecules by UV Irradiation of Water Ice-covered Hydrogenated Carbon Grains |
title_full |
Synthesis of CO and CO2 Molecules by UV Irradiation of Water Ice-covered Hydrogenated Carbon Grains |
title_fullStr |
Synthesis of CO and CO2 Molecules by UV Irradiation of Water Ice-covered Hydrogenated Carbon Grains |
title_full_unstemmed |
Synthesis of CO and CO2 Molecules by UV Irradiation of Water Ice-covered Hydrogenated Carbon Grains |
title_sort |
synthesis of co and co2 molecules by uv irradiation of water ice-covered hydrogenated carbon grains |
publishDate |
2006 |
url |
https://www.openaccessrepository.it/record/99129 https://doi.org/10.1086/502965 |
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Ice cap |
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Ice cap |
op_relation |
url:https://www.openaccessrepository.it/communities/itmirror https://www.openaccessrepository.it/record/99129 doi:10.1086/502965 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1086/502965 |
container_title |
The Astrophysical Journal |
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643 |
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2 |
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923 |
op_container_end_page |
931 |
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1780734726388056064 |