Search Publications
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…
Mechanisms and timescales of fluvial activity at Mojave and other young Martian craters
Warner, Nicholas H.; Gupta, Sanjeev; Kim, Jung-Rack +1 more
Mojave Crater, and five other relatively young Late Hesperian to Amazonian-age Martian craters exhibit channelized alluvial fans that are sourced from bedrock-eroded catchments. These catchments emerge from the crests of sloping surfaces, suggesting a formation mechanism that involved precipitation. The evidence for fluvial activity at all six cra…
Insights into Titan's geology and hydrology based on enhanced image processing of Cassini RADAR data
Lucas, Antoine; Aharonson, Oded; Hayes, Alexander G. +3 more
The Cassini Synthetic Aperture Radar has been acquiring images of Titan's surface since October 2004. To date, 59% of Titan's surface has been imaged by radar, with significant regions imaged more than once. Radar data suffer from speckle noise hindering interpretation of small-scale features and comparison of reimaged regions for change detection…
Modeling VIRTIS/VEX O2(a1∆g) nightglow profiles affected by the propagation of gravity waves in the Venus upper mesosphere
Bellucci, G.; Altieri, F.; Piccioni, G. +3 more
In this work we describe a model of the perturbation of the O2(a1Δg) nightglow limb profiles by the action of gravity waves (GWs) propagating in the Venus' upper atmosphere. Data have been acquired by the Visible and InfraRed Thermal Imaging Spectrometer (VIRTIS) on board the European Space Agency mission Venus Exp…
The atypical generation mechanism of Titan's Schumann resonance
Béghin, Christian
The observation of a presumed Schumann resonance (SR) during the landing of the Huygens Probe in Titan's atmosphere on January 2005 was subsequently reported and interpreted by Béghin et al. (2007, 2009, 2010, 2012) as being generated through the interaction of Saturn's magnetosphere with Titan's ionosphere rather than from the lightning activity …
Eastern Olympus Mons Basal Scarp: Structural and mechanical evidence for large-scale slope instability
Weller, M. B.; McGovern, P. J.; Fournier, T. +1 more
The expression of the Eastern Olympus Mons Basal Scarp (EOMBS) is seemingly unique along the edifice. It exhibits two slope-parallel structures: a nearly 100 km long upslope extensional normal fault system and a downslope contractional wrinkle ridge network, a combination that is found nowhere else on Olympus Mons. Through structural mapping and n…
The location of Airy-0, the Mars prime meridian reference, from stereo photogrammetric processing of THEMIS IR imaging and digital elevation data
Neukum, G.; Kirk, R. L.; Neumann, G. A. +7 more
The small crater Airy-0 was selected from Mariner 9 images to be the reference for the Mars prime meridian. Initial analyses in the year 2000 tied Viking Orbiter and Mars Orbiter Camera images of Airy-0 to the evolving Mars Orbiter Laser Altimeter global digital terrain model to update the location of Airy-0. Based upon this tie and radiometric tr…