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Liquid water on Enceladus from observations of ammonia and 40Ar in the plume
Young, D. T.; Ip, W. -H.; Lunine, J. I. +13 more
Jets of water ice from surface fractures near the south pole of Saturn's icy moon Enceladus produce a plume of gas and particles. The source of the jets may be a liquid water region under the ice shell-as suggested most recently by the discovery of salts in E-ring particles derived from the plume-or warm ice that is heated, causing dissociation of…
Sodium salts in E-ring ice grains from an ocean below the surface of Enceladus
Kempf, S.; Postberg, F.; Srama, R. +5 more
Saturn's moon Enceladus emits plumes of water vapour and ice particles from fractures near its south pole, suggesting the possibility of a subsurface ocean. These plume particles are the dominant source of Saturn's E ring. A previous in situ analysis of these particles concluded that the minor organic or siliceous components, identified in many ic…
Analysis of Titan's neutral upper atmosphere from Cassini Ion Neutral Mass Spectrometer measurements
Waite, J. H.; Yelle, R. V.; Kasprzak, W. T. +10 more
In this paper we present an in-depth study of the distributions of various neutral species in Titan's upper atmosphere, between 950 and 1500 km for abundant species (N 2, CH 4, H 2) and between 950 and 1200 km for other minor species. Our analysis is based on a large sample of Cassini/INMS (Ion Neutral Mass Spectro…
Negative ion chemistry in Titan's upper atmosphere
Lewis, G. R.; Coates, A. J.; Wahlund, J. -E. +5 more
The Electron Spectrometer (ELS), one of the sensors making up the Cassini Plasma Spectrometer (CAPS) revealed the existence of numerous negative ions in Titan's upper atmosphere. The observations at closest approach (∼1000 km) show evidence for negatively charged ions up to ∼10,000 amu/q, as well as two distinct peaks at 22±4 and 44±8 amu/q, and m…
Response of Jupiter's and Saturn's auroral activity to the solar wind
Crary, F.; Cecconi, B.; Lamy, L. +18 more
While the terrestrial aurorae are known to be driven primarily by the interaction of the Earth's magnetosphere with the solar wind, there is considerable evidence that auroral emissions on Jupiter and Saturn are driven primarily by internal processes, with the main energy source being the planets' rapid rotation. Prior observations have suggested …
Cassini imaging of Titan's high-latitude lakes, clouds, and south-polar surface changes
West, R. A.; Porco, C. C.; McEwen, A. S. +5 more
Cassini's Imaging Science Subsystem (ISS) has been observing Titan since April 2004, compiling a nearly global surface map and monitoring the surface and atmosphere for activity. Early images of the south-polar region revealed numerous dark surface features and contemporaneous convective cloud systems, suggesting the presence of hydrocarbon lakes …
Phosphine on Jupiter and Saturn from Cassini/CIRS
Fletcher, L. N.; Irwin, P. G. J.; Teanby, N. A. +1 more
The global distribution of phosphine (PH 3) on Jupiter and Saturn is derived using 2.5 cm -1 spectral resolution Cassini/CIRS observations. We extend the preliminary PH 3 analyses on the gas giants [Irwin, P.G.J., and 6 colleagues, 2004. Icarus 172, 37-49; Fletcher, L.N., and 9 colleagues, 2007a. Icarus 188, 72-88]…
An asymmetric distribution of lakes on Titan as a possible consequence of orbital forcing
Lorenz, R. D.; Lunine, J. I.; Hayes, A. G. +3 more
A set of lakes filled or partially filled with liquid hydrocarbon and empty lake basins have been discovered in the high latitudes of Saturn's moon Titan. These features were mapped by the radar instrument on the Cassini orbiter. Here we quantify the distribution of the lakes and basins, and show a pronounced hemispheric asymmetry in their occurre…
Discovery of a north-south asymmetry in Saturn's radio rotation period
Gurnett, D. A.; Persoon, A. M.; Kurth, W. S. +5 more
For many years it has been known that Saturn emits intense radio emissions at kilometer wavelengths and that this radiation is modulated by the rotation of the planet at a rate that varies by up to one percent on a time scale of years. Recent radio observations from the Cassini spacecraft have revealed the appearance of a second component, with a …
INMS-derived composition of Titan's upper atmosphere: Analysis methods and model comparison
Mandt, Kathleen E.; Waite, J. Hunter; Magee, Brian A. +3 more
The Cassini Ion and Neutral Mass Spectrometer (INMS) has recorded full altitude profile data from 20 low-altitude Titan encounters during the nominal mission (July 2004-2008). These encounters were TA, T5, T16, T18, T19, T21, T23, T25, T26, T28, T29, T30, T32, T36, T37, T39, T40, T41, T42, and T43. In this work we present an analysis of the data o…