Observing and modelling Mars' airglow

Cyril Simon (1) , Olivier Witasse (1) , François Leblanc (2) , Guillaume Gronoff (3) , Jean Lilensten (3) , Jean-Loup Bertaux (2)

1 RSSD - Research and Scientific Support Department, ESTEC
2 SA - Service d'aéronomie
3 LPG - Laboratoire de Planétologie de Grenoble

SPICAM is the UV spectrometer onboard ESA's Mars Express, which has been recording for more than four years upper atmospheric emissions ([1], [2]). 70000 dayglow limb spectra were analysed using an updated and variable point spread function, yielding altitude profiles of the Cameron bands (a3Π − X1Σ) of CO, the CO2 + ultraviolet doublet (B2Σu + − X2Πg) at 289 nm and the oxygen emission at 297.2 nm. The seasonal evolution of these emissions (Fig. 1) exhibits an unexpected increase around LS = 140 degrees, which is correlated with a sudden increase of neutral densities due to a dust storm event. A comparison with a newlydeveloped kinetic electron and airglow model ([3], [4]) yields promising results on emission altitude profiles. Improvements on the neutral atmosphere and cross sections are discussed. The new data analysis performed enables the search for faint emissions underlying the main Cameron emission bands. This comparison and analysis work is being extended to nightside auroral emissions using multi-instrument data on Mars Express.

Domains: Sciences of the Universe [physics]

Cyril Simon, Olivier Witasse, François Leblanc, Guillaume Gronoff, Jean Lilensten, et al.. Observing and modelling Mars' airglow. European Planetary Science Congress 2008, Sep 2008, Münster, Germany. pp.EPSC2008-A-00111. ⟨insu-00366192⟩