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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-…
Titan's Atmospheric Temperatures, Winds, and Composition
Strobel, D. F.; Showalter, M. R.; Lellouch, E. +42 more
Temperatures obtained from early Cassini infrared observations of Titan show a stratopause at an altitude of 310 kilometers (and 186 kelvin at 15°S). Stratospheric temperatures are coldest in the winter northern hemisphere, with zonal winds reaching 160 meters per second. The concentrations of several stratospheric organic compounds are enhanced a…
Solar Wind Origin in Coronal Funnels
Wilhelm, Klaus; Marsch, Eckart; Wang, Jing-Xiu +4 more
The origin of the solar wind in solar coronal holes has long been unclear. We establish that the solar wind starts flowing out of the corona at heights above the photosphere between 5 megameters and 20 megameters in magnetic funnels. This result is obtained by a correlation of the Doppler-velocity and radiance maps of spectral lines emitted by var…
Composition and Dynamics of Plasma in Saturn's Magnetosphere
Lewis, G. R.; Coates, A. J.; Linder, D. R. +40 more
During Cassini's initial orbit, we observed a dynamic magnetosphere composed primarily of a complex mixture of water-derived atomic and molecular ions. We have identified four distinct regions characterized by differences in both bulk plasma properties and ion composition. Protons are the dominant species outside about 9 RS (where R