First Analysis of Martian Nightglow Seasonal Variations Observed by MAVEN's Imaging Ultraviolet Spectrograph

We report results from a study of nitric oxide nightglow over the northern
hemisphere of Mars during winter and southern hemisphere during equinox. We
present observations of the nitric oxide δ and γ band emissions between 190 and
270 nm by the Imaging UltraViolet Spectrograph on the MAVEN spacecraft. The
emission reveals recombination of N and O atoms dissociated on the dayside of
Mars, and is known to trace upper atmosphere hemispheric circulation patterns.
We extend previous studies to higher latitudes, finding brighter emissions closer to
the poles as predicted from global circulation models. Statistically significant
variability suggests variation of the fluxes of N and O carried from the dayside
thermosphere, as well as possible variations of the wind pattern in the nightside
thermosphere and mesosphere.