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Titan's young surface: Initial impact crater survey by Cassini RADAR and model comparison
Lorenz, R. D.; Anderson, Y. Z.; Lunine, J. I. +9 more
Cassini's Radar instrument has mapped over 10% of Titan's surface through the T18 flyby in August 2006 and has detected remarkably few impact craters. Three impact craters have been conclusively identified and named, and a handful of unconfirmed candidate impact structures are documented. These results indicate that the overall crater density is a…
Ring current at Saturn: Energetic particle pressure in Saturn's equatorial magnetosphere measured with Cassini/MIMI
Krupp, N.; Krimigis, S. M.; Mitchell, D. G. +5 more
The Magnetospheric Imaging Instrument (MIMI) on the Cassini spacecraft provides measurements of the energetic ion population within the magnetosphere of Saturn. Energetic ion directional intensities, energy spectra and ion composition, are measured by the Charge Energy Mass Spectrometer (CHEMS) over the range ~3 to 236 keV per charge and by the Lo…
Ionospheric electrons in Titan's tail: Plasma structure during the Cassini T9 encounter
Coates, A. J.; Hartle, R. E.; Sittler, E. C. +6 more
We present results from the CAPS electron spectrometer obtained during the downstream flyby of Titan on 26 December 2005, which occurred during a period of enhanced plasma pressure inside the magnetosphere. The electron data show an unusual split signature with two principal intervals of interest outside the nominal corotation wake. Interval 1 sho…
Convection in Enceladus' ice shell: Conditions for initiation
McKinnon, William B.; Barr, Amy C.
Observations of Enceladus by the Cassini spacecraft indicate that this tiny Saturnian moon is geologically active, with plumes of water vapor and ice particles erupting from its southern polar region. This activity suggests that tidal dissipation has become spatially localized, perhaps due to a compositional, rheological, and/or thermal anomaly in…
TRAMS: A new dynamic cloud model for Titan's methane clouds
Barth, Erika L.; Rafkin, Scot C. R.
Convective clouds on Titan may play an important role in climate dynamics, atmospheric chemistry, and the overall volatile cycle. To study the formation and evolution of these clouds, we have developed the Titan Regional Atmospheric Modeling System (TRAMS). TRAMS is a three-dimensional, time-dependent, coupled fully compressible dynamic and microp…
Mobility and topographic effects for large Valles Marineris landslides on Mars
Mangeney, A.; Lucas, A.
Recent experiments on dry granular flows over horizontal plane bare some similarities with large Martian landslides observed in Valles Marineris (VM). However, Martian normalized runout are twice as large as those that observed in dry granular flow experiments. Numerical simulations on theoretical 2D and real 3D topographies reconstructed from rem…
Strong bulk plasma acceleration in Earth's magnetosheath: A magnetic slingshot effect?
Thomsen, M. F.; Lavraud, B.; Fazakerley, A. N. +5 more
In the near-Earth environment, strong bulk plasma accelerations are frequently taken to be the diagnostic of the occurrence of magnetic reconnection. In this letter, we report new and unambiguous spacecraft observations and corresponding magnetohydrodynamic (MHD) simulation of strong bulk plasma acceleration in the terrestrial magnetosheath during…
Role of photoionization in the formation of complex organic molecules in Titan's upper atmosphere
Imanaka, Hiroshi; Smith, Mark A.
Recent observations by the Cassini Orbiter suggest that complex organic chemistry occurs in the upper atmosphere of Titan. To understand the role of EUV-VUV light in the complex organic chemistry of Titan's upper atmosphere, we investigate the formation of gaseous species from a N2/CH4 gas mixture as a function of irradiation…
Global view of dayside magnetic reconnection with the dusk-dawn IMF orientation: A statistical study for Double Star and Cluster data
Lucek, E.; Dunlop, M. W.; Rème, H. +14 more
Double Star/TC-1 and Cluster data show that both component reconnection and anti-parallel reconnection occur at the magnetopause when the interplanetary magnetic field (IMF) is predominantly dawnward. The occurrence of these different features under these very similar IMF conditions are further confirmed by a statistical study of 290 fast flows me…
Mass of Saturn's magnetodisc: Cassini observations
André, N.; Coates, A. J.; Russell, C. T. +5 more
Saturn's ring current was observed by Pioneer 11 and the two Voyager spacecraft to extend 8-16 R S in the equatorial plane and appeared to be driven by stress balance with the centrifugal force. We present Cassini observations that show thin current sheets on the dawn flank of Saturn's magnetosphere, symptomatic of the formation of a …