Molecular hydrogen in the upper atmospheres of Saturn and Titan

Molecular hydrogen is the third most abundant species in Titan's atmosphere with a tropospheric/lower stratospheric mole fraction of 0.001 derived from Voyager and Cassini measurements and the major species in Saturn's atmosphere. The motivation for this paper is to explore the hypothesis that the corrected H-2 density measurements reported by Cassini Ion Neutral Mass Spectrometer (INMS) team were too high by a factor of 2.2, the factor that the INMS team reported in Teolis et al. (2015) as applicable to all species with no exceptions. For Titan, this would lead to the resolution of a possible missing H-2 source and eliminate the need for a large downward gas phase H-2 flux. For Saturn this would bring the INMS in-situ and UVIS stellar occultation H-2 density measurements into agreement in the low latitude thermosphere and attribute the additional mass density derived from Cassini Attitude and Articulation Control Subsystem (AACS) exceeding the reduced INMS H-2 mass density to infalling ring particles.

Automated summary

The paper aims to investigate whether the H-2 density measurements reported by Cassini were overestimated by a factor of 2.2, and the potential impact of this overestimation on the atmospheres of Titan and Saturn.