Depletion of 13C in CO in the Atmosphere of Mars Suggested by ExoMars-TGO/NOMAD Observations
The atmosphere of Mars is mainly composed by carbon dioxide (CO _2 ). It has been predicted that photodissociation of CO _2 depletes ^13 C in carbon monoxide (CO). We present the carbon ^13 C/ ^12 C isotopic ratio in CO at 30–50 km altitude from the analysis of the solar occultation measurements tak...
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| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Planetary Science Journal |
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| Online Access: | https://doi.org/10.3847/PSJ/acd32f |
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| author | S. Aoki K. Shiobara N. Yoshida L. Trompet T. Yoshida N. Terada H. Nakagawa G. Liuzzi A. C. Vandaele I. R. Thomas G. L. Villanueva M. A. Lopez-Valverde A. Brines M. R. Patel S. Faggi F. Daerden J. T. Erwin B. Ristic G. Bellucci J. J. Lopez-Moreno H. Kurokawa Y. Ueno |
| author_facet | S. Aoki K. Shiobara N. Yoshida L. Trompet T. Yoshida N. Terada H. Nakagawa G. Liuzzi A. C. Vandaele I. R. Thomas G. L. Villanueva M. A. Lopez-Valverde A. Brines M. R. Patel S. Faggi F. Daerden J. T. Erwin B. Ristic G. Bellucci J. J. Lopez-Moreno H. Kurokawa Y. Ueno |
| author_sort | S. Aoki |
| collection | DOAJ |
| description | The atmosphere of Mars is mainly composed by carbon dioxide (CO _2 ). It has been predicted that photodissociation of CO _2 depletes ^13 C in carbon monoxide (CO). We present the carbon ^13 C/ ^12 C isotopic ratio in CO at 30–50 km altitude from the analysis of the solar occultation measurements taken by the instrument Nadir and Occultation for Mars Discovery on board the ExoMars Trace Gas Orbiter (ExoMars-TGO). We retrieve ^12 C ^16 O, ^13 C ^16 O, and ^12 C ^18 O volume mixing ratios from the spectra taken at 4112–4213 cm ^−1 , where multiple CO isotope lines with similar intensities are available. The intensities of the ^12 C ^16 O lines in this spectral range are particularly sensitive to temperature, thus we derive the atmospheric temperature by retrieving CO _2 density with simultaneously measured spectra at 2966–2990 cm ^−1 . The mean δ ^13 C value obtained from the ^13 C ^16 O/ ^12 C ^16 O ratios is −263‰, and the standard deviation and standard error of the mean are 132‰ and 4‰, respectively. The relatively large standard deviation is due to the strong temperature dependences in the ^12 C ^16 O lines. We also examine the ^13 C ^16 O/ ^12 C ^18 O ratio, whose lines are less sensitive to temperature. The mean δ value obtained with ^12 C ^18 O instead of ^12 C ^16 O is −82‰ with smaller standard deviation, 60‰. These results suggest that CO is depleted in ^13 C when compared to CO _2 in the Martian atmosphere as measured by the Curiosity rover. This depletion of ^13 C in CO is consistent with the CO _2 photolysis-induced fractionation, which might support a CO-based photochemical origin of organics in Martian sediments. |
| first_indexed | 2024-03-08T06:52:33Z |
| format | Article |
| id | doaj.art-f2df7105ed77418c850dbfa72828aa77 |
| institution | Directory Open Access Journal |
| issn | 2632-3338 |
| language | English |
| last_indexed | 2024-03-08T06:52:33Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
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| series | The Planetary Science Journal |
| spelling | doaj.art-f2df7105ed77418c850dbfa72828aa772024-02-03T06:50:01ZengIOP PublishingThe Planetary Science Journal2632-33382023-01-01459710.3847/PSJ/acd32fDepletion of 13C in CO in the Atmosphere of Mars Suggested by ExoMars-TGO/NOMAD ObservationsS. Aoki0https://orcid.org/0000-0001-6727-125XK. Shiobara1N. Yoshida2https://orcid.org/0000-0001-5214-5680L. Trompet3https://orcid.org/0000-0001-6259-2054T. Yoshida4https://orcid.org/0000-0001-5214-5680N. Terada5https://orcid.org/0000-0001-5685-9736H. Nakagawa6https://orcid.org/0000-0001-8166-0171G. Liuzzi7https://orcid.org/0000-0003-3638-5750A. C. Vandaele8https://orcid.org/0000-0001-8940-9301I. R. Thomas9https://orcid.org/0000-0003-3887-6668G. L. Villanueva10https://orcid.org/0000-0002-2662-5776M. A. Lopez-Valverde11https://orcid.org/0000-0002-7989-4267A. Brines12https://orcid.org/0000-0002-7044-3638M. R. Patel13https://orcid.org/0000-0002-8223-3566S. Faggi14https://orcid.org/0000-0003-0194-5615F. Daerden15https://orcid.org/0000-0001-7433-1839J. T. Erwin16https://orcid.org/0000-0003-0200-3195B. Ristic17https://orcid.org/0000-0002-9635-1125G. Bellucci18https://orcid.org/0000-0003-0867-8679J. J. Lopez-Moreno19https://orcid.org/0000-0002-7946-2624H. Kurokawa20https://orcid.org/0000-0003-1965-1586Y. Ueno21https://orcid.org/0000-0002-9095-4742Department of Complexity Science and Engineering, Graduate School of Frontier Sciences, The University of Tokyo , 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan ; shohei.aoki@edu.k.u-tokyo.ac.jp; Royal Belgian Institute for Space Aeronomy , 3 Avenue Circulaire, B-1180 Brussels, BelgiumTohoku University, 6-3, Aramaki Aza-Aoba, Sendai 980-8578, JapanTohoku University, 6-3, Aramaki Aza-Aoba, Sendai 980-8578, JapanRoyal Belgian Institute for Space Aeronomy , 3 Avenue Circulaire, B-1180 Brussels, BelgiumTohoku University, 6-3, Aramaki Aza-Aoba, Sendai 980-8578, JapanTohoku University, 6-3, Aramaki Aza-Aoba, Sendai 980-8578, JapanTohoku University, 6-3, Aramaki Aza-Aoba, Sendai 980-8578, JapanScuola di Ingegneria, Universitá degli Studi della Basilicata , Via dell’Ateneo Lucano, 10, I-85100 Potenza, ItalyRoyal Belgian Institute for Space Aeronomy , 3 Avenue Circulaire, B-1180 Brussels, BelgiumRoyal Belgian Institute for Space Aeronomy , 3 Avenue Circulaire, B-1180 Brussels, BelgiumNASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, 20771 MD, USAInstituto de Astrofísica de Andalucía , Glorieta de la Astronomia, E-18008 Granada, SpainInstituto de Astrofísica de Andalucía , Glorieta de la Astronomia, E-18008 Granada, SpainSchool of Physical Sciences, The Open University , Milton Keynes, MK7 6AA, UKNASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, 20771 MD, USA; American University , 4400 Massachusetts Avenue Northwest, Washington, DC 20016, USARoyal Belgian Institute for Space Aeronomy , 3 Avenue Circulaire, B-1180 Brussels, BelgiumRoyal Belgian Institute for Space Aeronomy , 3 Avenue Circulaire, B-1180 Brussels, BelgiumRoyal Belgian Institute for Space Aeronomy , 3 Avenue Circulaire, B-1180 Brussels, BelgiumIstituto Nazionale di Astrofisica , Via del Fosso del Cavaliere 100, I-00133 Rome, ItalyInstituto de Astrofísica de Andalucía , Glorieta de la Astronomia, E-18008 Granada, SpainDepartment of Earth Science and Astronomy, Graduate School of Arts and Sciences, The University of Tokyo , Japan; Tokyo Institute of Technology , 2-12-1 Ookayama, Tokyo 152-8550, JapanTokyo Institute of Technology , 2-12-1 Ookayama, Tokyo 152-8550, JapanThe atmosphere of Mars is mainly composed by carbon dioxide (CO _2 ). It has been predicted that photodissociation of CO _2 depletes ^13 C in carbon monoxide (CO). We present the carbon ^13 C/ ^12 C isotopic ratio in CO at 30–50 km altitude from the analysis of the solar occultation measurements taken by the instrument Nadir and Occultation for Mars Discovery on board the ExoMars Trace Gas Orbiter (ExoMars-TGO). We retrieve ^12 C ^16 O, ^13 C ^16 O, and ^12 C ^18 O volume mixing ratios from the spectra taken at 4112–4213 cm ^−1 , where multiple CO isotope lines with similar intensities are available. The intensities of the ^12 C ^16 O lines in this spectral range are particularly sensitive to temperature, thus we derive the atmospheric temperature by retrieving CO _2 density with simultaneously measured spectra at 2966–2990 cm ^−1 . The mean δ ^13 C value obtained from the ^13 C ^16 O/ ^12 C ^16 O ratios is −263‰, and the standard deviation and standard error of the mean are 132‰ and 4‰, respectively. The relatively large standard deviation is due to the strong temperature dependences in the ^12 C ^16 O lines. We also examine the ^13 C ^16 O/ ^12 C ^18 O ratio, whose lines are less sensitive to temperature. The mean δ value obtained with ^12 C ^18 O instead of ^12 C ^16 O is −82‰ with smaller standard deviation, 60‰. These results suggest that CO is depleted in ^13 C when compared to CO _2 in the Martian atmosphere as measured by the Curiosity rover. This depletion of ^13 C in CO is consistent with the CO _2 photolysis-induced fractionation, which might support a CO-based photochemical origin of organics in Martian sediments.https://doi.org/10.3847/PSJ/acd32fPlanetary atmospheres |
| spellingShingle | S. Aoki K. Shiobara N. Yoshida L. Trompet T. Yoshida N. Terada H. Nakagawa G. Liuzzi A. C. Vandaele I. R. Thomas G. L. Villanueva M. A. Lopez-Valverde A. Brines M. R. Patel S. Faggi F. Daerden J. T. Erwin B. Ristic G. Bellucci J. J. Lopez-Moreno H. Kurokawa Y. Ueno Depletion of 13C in CO in the Atmosphere of Mars Suggested by ExoMars-TGO/NOMAD Observations The Planetary Science Journal Planetary atmospheres |
| title | Depletion of 13C in CO in the Atmosphere of Mars Suggested by ExoMars-TGO/NOMAD Observations |
| title_full | Depletion of 13C in CO in the Atmosphere of Mars Suggested by ExoMars-TGO/NOMAD Observations |
| title_fullStr | Depletion of 13C in CO in the Atmosphere of Mars Suggested by ExoMars-TGO/NOMAD Observations |
| title_full_unstemmed | Depletion of 13C in CO in the Atmosphere of Mars Suggested by ExoMars-TGO/NOMAD Observations |
| title_short | Depletion of 13C in CO in the Atmosphere of Mars Suggested by ExoMars-TGO/NOMAD Observations |
| title_sort | depletion of 13c in co in the atmosphere of mars suggested by exomars tgo nomad observations |
| topic | Planetary atmospheres |
| url | https://doi.org/10.3847/PSJ/acd32f |
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