Olivier S. Barnouin-Jha

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During the interval from September through early December 2005, the Hayabusa spacecraft was in close proximity to near-Earth asteroid 25143 Itokawa, and a variety of data were taken on its shape, mass, and surface topography as well as its mineralogic and elemental abundances. The asteroid's orthogonal axes are 535, 294, and 209 meters, the mass is 3.51 x(More)
A 3200-kilometers-long profile of Mercury by the Mercury Laser Altimeter on the MESSENGER spacecraft spans approximately 20% of the near-equatorial region of the planet. Topography along the profile is characterized by a 5.2-kilometer dynamic range and 930-meter root-mean-square roughness. At long wavelengths, topography slopes eastward by 0.02 degrees ,(More)
[1] The Noachian terrain west of the Isidis basin hosts a diverse collection of alteration minerals in rocks comprising varied geomorphic units within a 100,000 km region in and near the Nili Fossae. Prior investigations in this region by the Observatoire pour l’Minéralogie, l’Eau, les Glaces, et l’Activité (OMEGA) instrument on Mars Express revealed large(More)
As an ejecta curtain advances through an atmosphere, it creates a vortex ring. By analogy with smoke rings, the curtain-driven vortex ring develops instabilities that result in waves. The number of these waves depends upon the aspect ratio of the vortex ring (i.e., the ratio of the core vortex radius to the vortex radius) and the Reynolds number (or(More)
Scott L. Murchie, Frank P. Seelos, Christopher D. Hash, David C. Humm, Erick Malaret, J. Andrew McGovern, Teck H. Choo, Kimberly D. Seelos, Debra L. Buczkowski, M. Frank Morgan, Olivier S. Barnouin-Jha, Hari Nair, Howard W. Taylor, Gerald W. Patterson, Christopher A. Harvel, John F. Mustard, Raymond E. Arvidson, Patrick McGuire, Michael D. Smith, Michael J.(More)
The ranging instrument aboard the Hayabusa spacecraft measured the surface topography of asteroid 25143 Itokawa and its mass. A typical rough area is similar in roughness to debris located on the interior wall of a large crater on asteroid 433 Eros, which suggests a surface structure on Itokawa similar to crater ejecta on Eros. The mass of Itokawa was(More)
High-resolution images of the surface of asteroid Itokawa from the Hayabusa mission reveal it to be covered with unconsolidated millimeter-sized and larger gravels. Locations and morphologic characteristics of this gravel indicate that Itokawa has experienced considerable vibrations, which have triggered global-scale granular processes in its dry, vacuum,(More)
During the Near Earth Asteroid Rendezvous (NEAR)-Shoemaker's low-altitude flyover of asteroid 433 Eros, observations by the NEAR Laser Rangefinder (NLR) have helped to characterize small-scale surface features. On scales from meters to hundreds of meters, the surface has a fractal structure with roughness dominated by blocks, structural features, and walls(More)
A new experimental technique to measure crater growth is presented whereby a high speed video captures profiles of a crater forming after impact obtained using a vertical laser sheet centered on the impact point. Unlike previous so called “quarter-space experiments”, where projectiles were launched along a transparent Plexiglas sheet so that growth of half(More)
Laboratory experiments indicate that an advancing ejecta curtain displaces the atmosphere and creates strong winds that entrain large amounts of fine-grained ejecta. A theoretical model describing the interaction between an atmosphere and the outward moving ejecta curtain allows one to estimate the magnitude and velocity of the winds in the induced ring(More)