Detection of the Nitric Oxide Dayglow on Mars by MAVEN/IUVS
We report the first remote observation of nitric oxide (NO) densities on Mars. The Imaging Ultraviolet Spectrograph (IUVS) on NASA's Mars Atmosphere and Volatile Evolution (MAVEN) satellite observes NO γ band solar resonance fluorescence between 213.0 and 225.5 nm. We invert an average dayglow limb radiance profile to retrieve a number density profile between 80 and 130 km. The retrieved IUVS NO number density at 117 km is 5 times smaller than those measured by Viking mass spectrometers over 40 years ago but consistent with photochemical model results within the IUVS statistical uncertainty. These observations may therefore help to reconcile a longstanding problem in our understanding of NO photochemistry in the Martian upper atmosphere. We also report the first detection of the CO+ First Negative bands in the Martian dayglow near 219 nm.
Stevens, M. H.,
Siskind, D. E.,
Evans, J. S.,
Fox, J. L.,
Jain, S. K.,
& Schneider, N. M.
(2019). Detection of the Nitric Oxide Dayglow on Mars by MAVEN/IUVS. Journal of Geophysical Research. Planets, 124 (5), 1226-1237.