Modeling the complete set of Cassini’s UVIS occultation observations of Enceladus’ plume

The Cassini Ultraviolet Imaging Spectrograph (UVIS) observed a plume of water vapor spewing out from the south polar regions Enceladus via occultations 7 times during mission. Five them yielded spatially resolved data that allowed fits to set individually modeled jets. We created direct simulation Monte Carlo (DSMC) model simulate individual jets with aim fitting abundances along UVIS line sight occultation observations. Accurate location and attitude spacecraft together positions Saturn at each observation determine relationship between three-dimensional number density in two-dimensional profiles recorded by UVIS. By jets, every presented unique perspective physical properties distribution minimum velocity is determined narrowest jet profile: it ranges 800 m/s 1.8 km/s for 41 were required fit highest resolution dataset taken Solar however, an alternative larger linearly-dependent cannot be excluded without invoking additional unrelated other instruments. A smaller stellar because their spatial geometry. identify 37 repeatedly present best several These probably active through whole • summarize analysis observations have DSMC-modeled 5 Each presents Minimum range km/s. was occultations. constantly