Search Publications
Geology and composition of the Orientale Basin impact melt sheet
Spudis, Paul D.; Martin, Dayl J. P.; Kramer, Georgiana
Orientale Basin is one of the largest (930 km diameter) and youngest (~3.8 Ga) impact craters on the Moon. As the basin is only partly flooded by mare lava, its floor materials expose a major portion of the basin impact melt sheet, which some previous work has suggested might have undergone igneous differentiation. To test this idea, we remapped t…
Three-dimensional Martian ionosphere model: II. Effect of transport processes due to pressure gradients
Forget, F.; Chaufray, J. -Y.; Leblanc, F. +7 more
To study the transport of the ionospheric plasma on Mars, we have included a 3-D multifluid dynamical core in a Martian general circulation model. Vertical transport modifies the ion density above ~160 km on the dayside, especially the ions produced at high altitudes like O+, N+, and C+. Near the exobase, the daysi…
SHARAD soundings and surface roughness at past, present, and proposed landing sites on Mars: Reflections at Phoenix may be attributable to deep ground ice
Mellon, Michael T.; Putzig, Nathaniel E.; Phillips, Roger J. +3 more
We use the Shallow Radar (SHARAD) on the Mars Reconnaissance Orbiter to search for subsurface interfaces and characterize surface roughness at the landing sites of Viking Landers 1 and 2, Mars Pathfinder, the Mars Exploration Rovers Spirit and Opportunity, the Phoenix Mars lander, the Mars Science Laboratory Curiosity rover, and three other sites …
Water in the Martian regolith from OMEGA/Mars Express
Bibring, Jean-Pierre; Langevin, Yves; Gondet, Brigitte +5 more
Here we discuss one of the current reservoirs of water on Mars, the regolith and rocks exposed at the surface. This reservoir is characterized by the presence of H2O- and OH-bearing phases that produce a broad absorption at a wavelength of ~3 µm in near-infrared (NIR) reflectance spectra. This absorption is present in every ice-free spe…
The Venus nighttime atmosphere as observed by the VIRTIS-M instrument. Average fields from the complete infrared data set
Drossart, P.; Piccioni, G.; Lebonnois, S. +7 more
We present and discuss here the average fields of the Venus atmosphere derived from the nighttime observations in the 1960-2350 cm-1 spectral range by the VIRTIS-M instrument on board the Venus Express satellite. These fields include: (a) the air temperatures in the 1-100 mbar pressure range (~85-65 km above the surface), (b) the altitu…
Surface albedo spectral properties of geologically interesting areas on Titan
Le Mouélic, S.; Rodriguez, S.; Sotin, C. +13 more
We investigate the nature and possible formation processes of three areas on Titan's surface which have been suggested as geologically interesting: Hotei Regio, Tui Regio, and Sotra Patera. We also reanalyze the spectral characteristics of the Huygens Landing Site. We apply a statistical Principal Component Analysis (PCA) and a radiative transfer …
Chandrayaan-1 observations of backscattered solar wind protons from the lunar regolith: Dependence on the solar wind speed
Barabash, Stas; Futaana, Yoshifumi; Wieser, Martin +3 more
We study the backscattering of solar wind protons from the lunar regolith using the Solar Wind Monitor of the Sub-keV Atom Reflecting Analyzer on Chandrayaan-1. Our study focuses on the component of the backscattered particles that leaves the regolith with a positive charge. We find that the fraction of the incident solar wind protons that backsca…
Fresh shallow valleys in the Martian midlatitudes as features formed by meltwater flow beneath ice
Moore, Jeffrey M.; Howard, Alan D.; Hobley, Daniel E. J.
Significant numbers of valleys have been identified in the Martian midlatitudes (30-60°N/S), spatially associated with extant or recent ice accumulations. Many of these valleys date to the Amazonian, but their formation during these cold, dry epochs is problematic. In this study, we look in detail at the form, distribution, and quantitative geomor…
Energization of planetary pickup ions in the solar system
Kallio, E.; Jarvinen, R.
We study the solar wind-induced ion escape from planetary atmospheres at different radial heliospheric distances in the solar system. We derive histograms of the gyroaveraged E×B velocities, energies, and Larmor radii of planetary ions in the solar wind at Mercury, Venus, Earth, and Mars. The statistical analysis is based on the interplanetary Pio…
Stratigraphy and mineralogy of Candor Mensa, West Candor Chasma, Mars: Insights into the geologic history of Valles Marineris
Hauber, E.; Rossi, A. P.; Flahaut, J. +2 more
Candor Mensa, an interior layered deposit (ILD) in Valles Marineris, Mars, consists of two stratigraphically distinct units, the lower of which comprises the bulk of the mensa. This lower unit is approximately 5 km thick and composed of parallel layers, 4 to 14 m in thickness and associated with monohydrated sulfates. The lower unit is disconforma…