A comparison of 3‐D model predictions of Mars' oxygen corona with early MAVEN IUVS observations

We have compared our 3‐D hot O corona model predictions with the OI 130.4 nm emission detected by Imaging Ultraviolet Spectrograph/Mars Atmosphere and Volatile EvolutioN (IUVS/MAVEN) based completely on our best pre‐MAVEN understanding of the 3‐D structure of the thermosphere and ionosphere. The model was simulated appropriately for the observational conditions. In addition to dissociative recombination (DR) of O2+, DR of CO2+is also considered as an important hot O source. The model predictions showed excellent agreement with the transition altitude, the observed altitude variation of density, and the spatial variation of the corona with respect to the Mars‐Sun geometry. While previous models predicted escape rates covering a range of nearly 100, the brightness of the modeled hot O densities is a factor of ~1.5 lower than the observations. We discuss possible changes to the model that could come from further analysis of MAVEN measurements and that might close the gap between the modeled and observed brightness. We compared our 3‐D model predictions of the hot O corona with the coronal scans taken by IUVS/MAVENThe transition altitude and altitude vitiation of hot O show good agreement with the observationsThe 3‐D geographic variability of the model prediction is also seen in the IUVS coronal scans