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Communication Dans Un Congrès Année : 2020

Constraining the 3D Distribution of the Martian Hot Oxygen Corona using MAVEN Observations

Résumé

Escape to space of non-thermal "hot" oxygen produced by dissociative recombination of O2+ is an important atmospheric loss mechanism for Mars at the current epoch. The MAVEN mission uses the IUVS instrument to observe the hot oxygen corona via fluorescence of the O I 130.4 nm triplet. The solar ionizing radiation that drives the process is simultaneously measured by the EUVM instrument. We present here results based on the MAVEN mission to date, extending from LS = 270 in Mars Year 32 near the maximum of Solar Cycle 24 through LS = 240 in Mars Year 35 near the beginning of Solar Cycle 25. By integrating the 1D coronal scan data acquired at various geometries across the mission and accounting for variations in solar inputs it is possible to extract information about the average 3D density distribution of the hot oxygen corona. A strong day/night hemispherical asymmetry is found, as expected for a process driven by dayside photochemistry. We also find that sampling biases impair the ability to constrain any asymmetries in local time, however the data allows constraints to be put on the hemispherical asymmetry in latitude. These results provide insight into how the Martian upper atmosphere modulates the hot oxygen corona and its escape to space.
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Dates et versions

insu-04418352 , version 1 (25-01-2024)

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Citer

J. Deighan, S. Jain, M. Chaffin, Jean-Yves Chaufray, N. M. Schneider, et al.. Constraining the 3D Distribution of the Martian Hot Oxygen Corona using MAVEN Observations. American Geophysical Union, Fall Meeting 2020, Dec 2020, Online, Unknown Region. pp.abstract #P033-0003. ⟨insu-04418352⟩
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