Origin of oxygen species in Titan's atmosphere

S. M. Hörst (1) , Véronique Vuitton (1, 2) , R. V. Yelle (1)

1 LPL - Lunar and Planetary Laboratory [Tucson]
2 LPG - Laboratoire de Planétologie de Grenoble

The detection of O+ precipitating into Titan's atmosphere by the Cassini Plasma Spectrometer (CAPS) represents the discovery of a previously unknown source of oxygen in Titan's atmosphere. The photochemical model presented here shows that those oxygen ions are incorporated into CO and CO2. We show that the observed abundances of CO, CO2 and H2O can be simultaneously reproduced using an oxygen flux consistent with the CAPS observations and an OH flux consistent with predicted production from micrometeorite ablation. It is therefore unnecessary to assume that the observed CO abundance is the remnant of a larger primordial CO abundance or to invoke outgassing of CO from Titan's interior as a source of CO.

Mots clés: VOYAGER INFRARED OBSERVATIONS; OPTICAL OSCILLATOR-STRENGTHS; CROSS-SECTION MEASUREMENTS; NEUTRAL MASS-SPECTROMETER; MIXED VERTICAL PROFILE; EVALUATED KINETIC DATA; CARBON-MONOXIDE; TEMPERATURE-DEPENDENCE; FLASH-PHOTOLYSIS; CONTINUUM PHOTOABSORPTION

Domaines: Planète et Univers [physics]

S. M. Hörst, Véronique Vuitton, R. V. Yelle. Origin of oxygen species in Titan's atmosphere. Journal of Geophysical Research. Planets, 2008, 113 (E10), pp.E10006. ⟨10.1029/2008JE003135⟩. ⟨insu-00360354⟩