Global Aurora on Mars during the September 2017 Space Weather Event

Nicholas M. Schneider (1) , Sonal K. Jain (1) , Justin Deighan (1) , Nasr Camella-Rosa (1) , David A. Brain (1) , Davin Larson (2) , Robert J. Lillis (2) , Ali Rahmati (2) , Jasper S Halekas (3) , Christina O. Lee (2) , Michael S. Chaffin (1) , Arnaud Stiepen (4) , Matteo Crismani (1) , J. Scott Evans (5) , Michael H. Stevens (6) , Daniel Y. Lo (7) , William E. Mcclintock (1) , A. Ian F. Stewart (1) , Roger V. Yelle (7) , John T. Clarke (8) , Gregory M. Holsclaw (1) , Franck Lefèvre (9) , Franck Montmessin (9) , Bruce M. Jakosky (1)

1 LASP - Laboratory for Atmospheric and Space Physics [Boulder]
2 SSL - Space Sciences Laboratory [Berkeley]
3 Department of Physics and Astronomy [Iowa City]
4 LPAP - Laboratoire de Physique Atmosphérique et Planétaire
5 Computational Physics, Inc.
6 NRL - Naval Research Laboratory
7 LPL - Lunar and Planetary Laboratory [Tucson]
8 CSP - Center for Space Physics [Boston]
9 PLANETO - LATMOS

We report the detection of bright aurora spanning Mars’ nightside during the space weather event occurring in September 2017. The phenomenon was similar to diffuse aurora detected previously at Mars, but 25 times brighter and detectable over the entire visible nightside. The observations were made with the Imaging UltraViolet Spectrograph (IUVS), a remote sensing instrument on the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft orbiting Mars. Images show that the emission was brightest around the limb of the planet, with a fairly uniform faint glow against the disk itself. Spectra identified four molecular emissions associated with aurora, and limb scans show the emission originated from an altitude of ~60 km in the atmosphere. Both are consistent with very high energy particle precipitation. The auroral brightening peaked around 13 September, when the flux of solar energetic electrons and protons both peaked. During the declining phase of the event, faint but statistically significant auroral emissions briefly appeared against the disk of the planet in the form of narrow wisps and small patches. These features are approximately aligned with predicted open field lines in the region of strong crustal magnetic fields in Mars’ southern hemisphere.

Domains: Astrophysics [astro-ph]

Nicholas M. Schneider, Sonal K. Jain, Justin Deighan, Nasr Camella-Rosa, David A. Brain, et al.. Global Aurora on Mars during the September 2017 Space Weather Event. Geophysical Research Letters, 2018, 45 (15), pp.7391-7398. ⟨10.1029/2018GL077772⟩. ⟨insu-01803835⟩