NASA reports that its Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft detected some unexpected auroral activity above the red planet for several days leading up to Christmas last year. The spacecraft, using its Imaging Ultraviolet Spectrograph (IUVS), observed a bright ultraviolet glow spanning Mar’s northern hemisphere. Observations from the spacecraft’s Solar Energetic Particle instrument points to the Sun as the source for an energetic burst of electrons detected at the beginning of the aurora.
MAVEN’s Langmuir Probe and Waves (LPW) instrument also detected a cloud of dust at orbital altitudes above Mars. This cloud has not been detected by any of the spacecraft’s other instruments but perhaps is still somehow related to the plasma detected by the Solar Energetic Particle instrument.
Full press release:
http://www.nasa.gov/press/2015/march/nasa-spacecraft-detects-aurora-and-mysterious-dust-cloud-around-mars/