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Compositional Measurements of Saturn's Upper Atmosphere and Rings From Cassini INMS: An Extended Analysis of Measurements From Cassini's Grand Finale Orbits
Yelle, R. V.; Hörst, S. M.; Koskinen, T. T. +5 more
The Cassini spacecraft's final orbits sampled Saturn's atmosphere and returned surprisingly complex mass spectra from the Ion and Neutral Mass Spectrometer. Signal returned from the instrument included native Saturn species, as expected, as well as a significant amount of signal attributed to vaporized ices and higher mass organics believed to be …
Energy Exchanges in Saturn's Polar Regions From Cassini Observations: Eddy-Zonal Flow Interactions
Read, Peter L.; Sanchez-Lavega, Agustin; Antuñano, Arrate +3 more
Saturn's polar regions (polewards of ∼63° planetocentric latitude) are strongly dynamically active with zonal jets, polar cyclones and the intriguing north polar hexagon (NPH) wave. Here we analyze measurements of horizontal winds, previously obtained from Cassini images by Antuñano et al. (2015), htt…
The Bathymetry of Moray Sinus at Titan's Kraken Mare
Lunine, J. I.; Hayes, A. G.; Le Gall, A. +4 more
Moray Sinus is an estuary located at the northern end of Titan's Kraken Mare. The Cassini RADAR altimeter acquired three segments over this mare during the T104 flyby of Titan, on August 21, 2014. Herein, we present a detailed analysis of the received echoes. Some of these waveforms exhibit a reflection from the seafloor, from up to 85-18+28 m of …
Small Impact Crater Populations on Saturn's Moon Tethys and Implications for Source Impactors in the System
Ferguson, S. N.; Rhoden, A. R.; Kirchoff, M. R.
Current estimates place the ages of the inner Saturnian satellites (Mimas, Enceladus, Tethys, Dione, and Rhea) between 4.5 Gyr and 100 Myr. These estimates are based on impact crater measurements and dynamical simulations, both of which have uncertainties. Models of satellite evolution are inherently simplified and rely on uncertain or unknown par…
Updated Equipotential Shapes of Jupiter and Saturn Using Juno and Cassini Grand Finale Gravity Science Measurements
Helled, Ravit; Folkner, William M.; Parisi, Marzia +2 more
A commonly used shape model for the giant plants of Jupiter and Saturn is an oblate ellipsoid, a simplified model of the equipotential shape. The ellipsoidal shape models were originally derived from radio occultation data and gravity data after the Voyager flybys in 1979. Through precise Doppler tracking of NASA's Juno and Cassini spacecraft tele…
Compositional Measurements of Saturn's Upper Atmosphere and Rings from Cassini INMS
Yelle, R. V.; Hörst, S. M.; Koskinen, T. T. +4 more
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 at…
Relative Crater Scaling Between the Major Moons of Saturn: Implications for Planetocentric Cratering and the Surface Age of Titan
Bell, Samuel W.
The chronology of the moons of Saturn, especially Titan, has been limited by a lack of strong constraints on the cratering rate, low number statistics for small-N counts of large-diameter craters, and uncertainty about whether impactors are mostly heliocentric impactors orbiting the Sun or planetocentric impactors orbiting Saturn itself. Here, I p…
Nondetection of Radio Emissions From Titan Lightning by Cassini RPWS
Gurnett, D. A.; Kurth, W. S.; Fischer, G. +1 more
The Saturn-orbiting Cassini spacecraft completed 126 close Titan flybys from 2004 until 2017. During almost all of them the Cassini Radio and Plasma Wave Science (RPWS) instrument was turned on to search for radio emissions attributed to Titan lightning. Here we report about their nondetection after close inspection of all Titan flybys throughout …
A Thermal Inertia Map of Titan
MacKenzie, Shannon M.; Lorenz, Ralph D.; Lora, Juan M.
Like Earth, the atmosphere of Titan, Saturn's largest moon, is affected by the ability of the surface to store and release heat. Modeling efforts have shown that global temperature distributions and wind profiles differ between simulations describing Titan's surface with a uniform thermal inertia. Cassini-Huygens demonstrated, however, that a vari…
Cassini UVIS Detection of Saturn's North Polar Hexagon in the Grand Finale Orbits
Lamy, L.; West, R. A.; Esposito, L. W. +6 more
Cassini's final orbits in 2016 and 2017 provided unprecedented spatial resolution of Saturn's polar regions from near-polar spacecraft viewing geometries. Long-wavelength channels of Cassini's Ultraviolet Imaging Spectrograph instrument detected Saturn's UV-dark north polar hexagon near 180 nm at planetocentric latitudes near 75°N. The dark polar …