Issue |
A&A
Volume 667, November 2022
|
|
---|---|---|
Article Number | A169 | |
Number of page(s) | 22 | |
Section | Planets and planetary systems | |
DOI | https://doi.org/10.1051/0004-6361/202244447 | |
Published online | 30 November 2022 |
A photochemical model of Triton’s atmosphere paired with an uncertainty propagation study★
1
Laboratoire d’Astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N,
Allée Geoffroy Saint-Hilaire,
33615
Pessac, France
e-mail: benjamin.benne@u-bordeaux.fr
2
LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Univ. Paris Diderot,
Sorbonne Paris Cité, 5 place Jules Janssen,
92195
Meudon, France
3
Institut des Sciences Moléculaires, CNRS, Univ. Bordeaux,
351 Cours de la Libération,
33400
Talence, France
Received:
7
July
2022
Accepted:
29
August
2022
Context. The largest satellite of Neptune, Triton, is a likely Kuiper Belt object captured by the planet. It has a tenuous nitrogen atmosphere, similar to that of Pluto, and it may be an ocean world. The Neptunian system has only been visited once: by Voyager 2 in 1989. Over the past few years, the demand for a new mission to the ice giants and their systems has risen. Thus, a theoretical basis upon which to prepare for such a mission is needed.
Aims. We aim to develop a photochemical model of Triton’s atmosphere with an up-to-date chemical scheme, as previous photochemical models date back to the post-flyby years. This purpose is to achieve a better understanding of the mechanisms governing Triton’s atmospheric chemistry and to highlight the critical parameters that have a significant impact on the atmospheric composition. We also study the model uncertainties to find what chemical studies are necessary to improve the modeling of Triton’s atmosphere.
Methods. We used a model of Titan’s atmosphere and tailored it to Triton’s conditions. We first used Titan’s chemical scheme before updating it to better model Triton’s atmospheric conditions. Once the nominal results were obtained, we studied the model uncertainties with a Monte Carlo procedure, considering the reaction rates as random variables. Finally, we performed global sensitivity analyses to identify the reactions responsible for model uncertainties.
Results. With the nominal results, we determined the composition of Triton’s atmosphere and studied the production and loss processes for the main atmospheric species. We highlighted key chemical reactions that are most important for the overall chemistry. We also identified some key parameters that have a significant impact on the results. The uncertainties are high for most of the main atmospheric species since the atmospheric temperature is very low. We identified key uncertainty reactions that have the greatest impact on the result uncertainties. These reactions must be studied as a priority in order to improve the significance of our results by finding ways of lowering these uncertainties.
Key words: planets and satellites: atmospheres / astrochemistry
Supplementary material related to this article is available at: https://doi.org/10.13140/RG.2.2.12820.99203
© B. Benne et al. 2022
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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