Compositional Measurements of Saturn's Upper Atmosphere and Rings from Cassini INMS

Abstract

The Cassini spacecraft's last orbits directly sampled Saturn's thermosphere and revealed a much more chemically complex environment than previously believed. Observations from the Ion and Neutral Mass Spectrometer (INMS) aboard Cassini provided compositional measurements of this region and found an influx of material raining into Saturn's upper atmosphere from the rings. We present here an in-depth analysis of the CH4, H2O, and NH(3)signal from INMS and provide further evidence of external material entering Saturn's atmosphere from the rings. We use a new mass spectral deconvolution algorithm to determine the amount of each species observed in the spectrum and use these values to determine the influx and mass deposition rate for these species.