All that is known about Mars discrete aurorae so far

The discrete aurorae on Mars were discovered with the SPICAM spectrograph on board Mars Express. Now, they have been analyzed in detail using the much more sensitive MAVEN/IUVS imaging spectrograph.

This presentation gives a summary of the very latest results obtained by Schneider et al. and Soret et al. on this topic.

The main conclusions are the following:

• the number of auroral event detections has considerably increased since the Mars Express observations;
• many detections have been made outside of the Southern crustal magnetic field structures;
• the MUV spectrum shows the same emissions as those observed in the dayglow, with similar intensity ratios;
• the Vegard-Kaplan bands of N₂ have been observed for the first time in the Martian aurora;
• the CO Cameron and the CO₂⁺ UVD emissions occur at the same altitude;
• the OI emission at 297.2 nm has been analyzed;
• the CO Cameron/CO₂⁺ UVD ratio is quasi-constant;
• intensities are higher in B-field regions;
• auroral emissions are more frequent in the pre-midnight sector;
• the altitude of the emission layer is independent of local time and presence or absence of a crustal magnetic field;
• the altitude of the emission layer varies moderately with season (atmospheric effect);
• the events are spatially correlated with an increase in the flux of energetic electrons simultaneously measured by the MAVEN/SWEA (Solar Wind Electron Analyzer) detectors;
• the peak altitude of the emission is in good agreement with that expected from the average electron energy.