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Discovery of diffuse aurora on Mars.
N M Schneider1, J I Deighan2, S K Jain2
1Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Boulder, CO 80303, USA. nick.schneider@lasp.colorado.edu.
Science (New York, N.Y.)
|November 7, 2015
Summary
Mars exhibits deep, widespread auroras caused by solar energetic particles penetrating its atmosphere. These diffuse auroras, detected by the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft, extend lower than previously observed on any planet.
Area of Science:
- Planetary Science
- Atmospheric Physics
- Space Physics
Background:
- Planetary auroras are key indicators of atmospheric-plasma interactions.
- Mars possesses a thin atmosphere and weak global magnetic field, making its auroral processes distinct from Earth's.
Purpose of the Study:
- To report the discovery of low-altitude, diffuse auroras on Mars.
- To investigate the connection between solar energetic particle events and Martian auroras.
Main Methods:
- Utilizing the Imaging Ultraviolet Spectrograph (IUS) instrument on the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft.
- Analyzing remote sensing data of auroral emissions across Mars' northern hemisphere.
Main Results:
- Diffuse auroral emissions were detected across nearly all nightside longitudes for approximately five days.
- Auroral emissions reached altitudes as low as 60 km (1 microbar), deeper than previously confirmed on any planet.
- The auroras coincided with a solar energetic particle (SEP) outburst, with particles up to 200 keV observed.
Conclusions:
- Solar energetic particles are responsible for exciting the observed low-altitude Martian auroras.
- Mars' minimal magnetic field likely facilitates more global auroral displays compared to Earth.
- These findings enhance our understanding of atmospheric dynamics and space weather on Mars.
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