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Radar observations and the shape of near-Earth asteroid 2008 EV5 |
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| Authors: | Michael W Busch Steven J Ostro Lance AM Benner Jon D Giorgini Daniel J Scheeres Michael C Nolan Patrick A Taylor Walter Brisken |
| Institution: | a Department of Earth and Space Sciences, University of California Los Angeles, 595 Charles Young Dr. E., Los Angeles, CA 90095, United States b Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099, United States c Department of Aerospace Engineering Sciences, University of Colorado at Boulder, 429 UCB, Boulder, CO 80309, United States d University of Maine at Farmington, 173 High Street, Preble Hall, Farmington, ME 04938, United States e Arecibo Observatory, HC3 Box 53995, Arecibo, PR 00612, United States f Department of Physics and Astronomy, University of California Los Angeles, 595 Charles Young Dr. E., Los Angeles, CA 90095, United States g National Radio Astronomy Observatory, 1003 Lopezville Road, Socorro, NM 87801, United States |
| Abstract: | We observed the near-Earth ASTEROID 2008 EV5 with the Arecibo and Goldstone planetary radars and the Very Long Baseline Array during December 2008. EV5 rotates retrograde and its overall shape is a 400 ± 50 m oblate spheroid. The most prominent surface feature is a ridge parallel to the asteroid’s equator that is broken by a concavity about 150 m in diameter. Otherwise the asteroid’s surface is notably smooth on decameter scales. EV5’s radar and optical albedos are consistent with either rocky or stony-iron composition. The equatorial ridge is similar to structure seen on the rubble-pile near-Earth asteroid (66391) 1999 KW4 and is consistent with YORP spin-up reconfiguring the asteroid in the past. We interpret the concavity as an impact crater. Shaking during the impact and later regolith redistribution may have erased smaller features, explaining the general lack of decameter-scale surface structure. |
| Keywords: | Asteroids Asteroids Surfaces Asteroids Dynamics Radar observations |
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