Search Publications
Enceladus: Cosmic Gymnast, Volatile Miniworld
Kargel, Jeffrey S.
The exploration of Saturn by the Cassini/Huygens mission has yielded a rich collection of data about the planet and its rings and moons, in particular its small satellite Enceladus and giant satellite Titan. Once believed too small to be active, Enceladus has been found to be one of the most geologically dynamic objects in the solar system. Among …
New Dust Belts of Uranus: One Ring, Two Ring, Red Ring, Blue Ring
de Pater, Imke; Showalter, Mark R.; Hammel, Heidi B. +1 more
We compared near-infrared observations of the recently discovered outer rings of Uranus with Hubble Space Telescope results. We find that the inner ring, R/2003 U 2, is red, whereas the outer ring, R/2003 U 1, is very blue. Blue is an unusual color for rings; Saturn's enigmatic E ring is the only other known example. By analogy to the E ring, R/20…
Does Enceladus Govern Magnetospheric Dynamics at Saturn?
Kivelson, Margaret Galland
Instruments on the Cassini spacecraft reveal that a heat source within Saturn's moon Enceladus powers a great plume of water ice particles and dust grains, a geyser that jets outward from the south polar regions and most likely serves as the dominant source of Saturn's E ring. The interaction of flowing magnetospheric plasma with the plume modifie…
Sulfates in Martian Layered Terrains: The OMEGA/Mars Express View
Le Mouélic, Stéphane; Gendrin, Aline; Mangold, Nicolas +8 more
The OMEGA/Mars Express hyperspectral imager identified hydrated sulfates on light-toned layered terrains on Mars. Outcrops in Valles Marineris, Margaritifer Sinus, and Terra Meridiani show evidence for kieserite, gypsum, and polyhydrated sulfates. This identification has its basis in vibrational absorptions between 1.3 and 2.5 micrometers. These m…
Mars Surface Diversity as Revealed by the OMEGA/Mars Express Observations
Sotin, Christophe; Fouchet, Thierry; Drossart, P. +39 more
The Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA) investigation, on board the European Space Agency Mars Express mission, is mapping the surface composition of Mars at a 0.3- to 5-kilometer resolution by means of visible-near-infrared hyperspectral reflectance imagery. The data acquired during the first 9 months of the…
Sulfates in the North Polar Region of Mars Detected by OMEGA/Mars Express
Bibring, Jean-Pierre; Langevin, Yves; Gondet, Brigitte +1 more
The Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA) imaging spectrometer observed the northern circumpolar regions of Mars at a resolution of a few kilometers. An extended region at 240°E, 85°N, with an area of 60 kilometers by 200 kilometers, exhibits absorptions at wavelengths of 1.45, 1.75, 1.94, 2.22, 2.26, and 2.48 …
Olivine and Pyroxene Diversity in the Crust of Mars
Mangold, N.; Bibring, J. -P.; Gendrin, A. +6 more
Data from the Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activité (OMEGA) on the Mars Express spacecraft identify the distinct mafic, rock-forming minerals olivine, low-calcium pyroxene (LCP), and high-calcium pyroxene (HCP) on the surface of Mars. Olivine- and HCP-rich regions are found in deposits that span the age range of geolog…
Ion Neutral Mass Spectrometer Results from the First Flyby of Titan
Ip, Wing-Huen; McNutt, Ralph L.; Waite, J. Hunter +19 more
The Cassini Ion Neutral Mass Spectrometer (INMS) has obtained the first in situ composition measurements of the neutral densities of molecular nitrogen, methane, molecular hydrogen, argon, and a host of stable carbon-nitrile compounds in Titan's upper atmosphere. INMS in situ mass spectrometry has also provided evidence for atmospheric waves in th…
Deflection of the Interstellar Neutral Hydrogen Flow Across the Heliospheric Interface
Bertaux, J. L.; Lallement, R.; Quémerais, E. +3 more
Using an absorption cell, we measured the Doppler shifts of the interstellar hydrogen resonance glow to show the direction of the neutral hydrogen flow as it enters the inner heliosphere. The neutral hydrogen flow is found to be deflected relative to the helium flow by about 4°. The most likely explanation of this deflection is a distortion of the…
Radar Soundings of the Subsurface of Mars
Gurnett, Donald A.; Johnson, William T. K.; Stofan, Ellen R. +31 more
The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-…