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Ocean tides heat Enceladus
Tyler, R. H.
With a young, highly reflective surface and vigorous geological activity, Saturn's tiny moon Enceladus has been one of the most mysterious planetary bodies in the solar system. Recent observations from the Cassini spacecraft show vast plumes of vapor erupting from geysers near the south pole, and inferred heat fluxes of about 100 mW/m2 for the sam…
Fluvial network analysis on Titan: Evidence for subsurface structures and west-to-east wind flow, southwestern Xanadu
Burr, Devon M.; Mitchell, Karl L.; Jacobsen, Robert E. +3 more
Data of Titan's surface from the Cassini-Huygens mission show inferred fluvial networks interpreted as products of liquid alkane flow. Using synthetic aperture radar (SAR) data, we delineated drainage networks, measured network parameters, and used these measurements in a simplified algorithm for classifying terrestrial drainage patterns. The resu…
Disappearing induced magnetosphere at Venus: Implications for close-in exoplanets
Russell, C. T.; Lammer, H.; Zhang, T. L. +4 more
The solar wind interaction with a planetary atmosphere produces a magnetosphere-like structure near the planet whether or not the planet has an intrinsic global magnetic field. In the case of planets like Venus or Mars, which have no global intrinsic magnetic field but possess a significant atmosphere, a magnetosphere is induced in the highly cond…
Photometric changes on Saturn's Titan: Evidence for active cryovolcanism
Drossart, Pierre; Sotin, Christophe; Sicardy, Bruno +30 more
We report infrared spectrophotometric variability on the surface of Saturn's moon Titan detected in images returned by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini Saturn Orbiter. The changes were observed at 7°S, 138°W and occurred between October 27, 2005 and January 15, 2006. After that date the surface was unchanged …
Electron density dropout near Enceladus in the context of water-vapor and water-ice
Gurnett, D. A.; Johnson, R. E.; Kurth, W. S. +4 more
On 12 March 2008, the Cassini spacecraft made a close encounter with the Saturnian moon Enceladus, passing within 52 km of the moon. The spacecraft trajectory was intentionally-oriented in a southerly direction to create a close alignment with the intense water-dominated plumes emitted from the south polar region. During the passage, the Cassini R…
One-hundred-km-scale basins on Enceladus: Evidence for an active ice shell
Schenk, Paul M.; McKinnon, William B.
Stereo-derived topographic mapping of ∼50% of Enceladus reveals at least 6 large-scale, ovoid depressions (basins) 90-175 km across and 800-to-1500 m deep and uncorrelated with geologic boundaries. In contrast, the south polar depression is larger and apparently shallower and correlates with active resurfacing. The shape and scale of the basins is…
Northward field excursions in Saturn's magnetotail and their relationship to magnetospheric periodicities
Wilson, R. J.; Jackman, C. M.; McAndrews, H. J. +2 more
We present results from an investigation of Cassini encounters with Saturn's magnetotail current sheet, using magnetic field and plasma data. In the first of two intervals shown, small periodic changes in the north-south component of the magnetic field are matched by periodic density enhancements associated with the plasma sheet center. In the sec…
MESSENGER and Venus Express observations of the solar wind interaction with Venus
Barabash, Stas; Zhang, Tielong; Boardsen, Scott A. +15 more
At 23:08 UTC on 5 June 2007 the MESSENGER spacecraft reached its closest approach altitude of 338 km during its final flyby of Venus en route to its 2011 orbit insertion at Mercury. The availability of the simultaneous Venus Express solar wind and interplanetary magnetic field measurements provides a rare opportunity to examine the influence of up…
Saturn's equinoctial auroras
Dougherty, M. K.; Kurth, W. S.; Mitchell, D. G. +13 more
We present the first images of Saturn's conjugate equinoctial auroras, obtained in early 2009 using the Hubble Space Telescope. We show that the radius of the northern auroral oval is ∼1.5° smaller than the southern, indicating that Saturn's polar ionospheric magnetic field, measured for the first time in the ionosphere, is ∼17% larger in the nort…
Observations of Jovian polar auroral filaments
Nichols, J. D.; Clarke, J. T.; Grodent, D. +1 more
In this paper we report a phenomenon hitherto unobserved in Jupiter's ultraviolet polar auroras, specifically thin (∼0.6° wide), long-lived quasi-sun-aligned polar auroral filaments (PAFs) of brightness ∼100 kR spanning the highly variable region poleward of the main oval. This observation, made using Hubble Space Telescope images, is significant …