Nightglow in the Upper Atmosphere of Mars and Implications for Atmospheric Transport

Jean-Loup Bertaux (1) , François Leblanc (1) , Séverine Perrier (1) , Eric Quémerais (1) , Oleg Korablev (2) , Emmanuel Dimarellis (1) , Aurélie Reberac (1) , François Forget (3) , P. C. Simon (4) , S.A. Stern (5) , Bill R. Sandel (6)

1 SA - Service d'aéronomie
2 IKI - Space Research Institute of the Russian Academy of Sciences
3 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
4 BIRA-IASB - Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique
5 SwRI - Southwest Research Institute [Boulder]
6 LPL - Lunar and Planetary Laboratory [Tucson]

We detected light emissions in the nightside martian atmosphere with the SPICAM (spectroscopy for the investigation of the characteristics of the atmosphere of Mars) ultraviolet (UV) spectrometer on board the Mars Express. The UV spectrum of this nightglow is composed of hydrogen Lyman emission (121.6 nanometers) and the and bands of nitric oxide (NO) (190 to 270 nanometers) produced when N and O atoms combine to produce the NO molecule. N and O atoms are produced by extreme UV photodissociation of O2, CO2, and N2 in the dayside upper atmosphere and transported to the night side. The NO emission is brightest in the winter south polar night because of continuous downward transport of air in this region at night during winter and because of freezing at ground level.

Mots clés: Atmosphère planétaire; Planète mars

Domaines: Océan, Atmosphère; Astrophysique [astro-ph]

Jean-Loup Bertaux, François Leblanc, Séverine Perrier, Eric Quémerais, Oleg Korablev, et al.. Nightglow in the Upper Atmosphere of Mars and Implications for Atmospheric Transport. Science, 2005, 307, pp.566-569. ⟨10.1126/science.1106957⟩. ⟨hal-00069766⟩