Physical properties of near-Earth Asteroid (33342) 1998 WT24
Abstract
During its close Earth approach in 2001, the E-class near-Earth Asteroid (33342) 1998 WT24 was the focus of extensive radar, optical, and thermal infrared observations.We present a physical model of this object, estimated from Arecibo and Goldstone radar images that cover multiple rotations and span over 100◦ of sky motion. The asteroid has an equivalent diameter of 415±40 m and a diffuse radar scattering law that is identical in both senses of circular polarization, implying a surface that is extremely rough on centimeter-to-decimeter scales. The shape is dominated by three large basins, which may be impact craters or a relic of past dynamical disruption of the object. Analysis of YORP perturbations on WT24's spin state predicts that the asteroid's spin rate is decreasing at a rate of 2 × 10−7 degs−1 yr−1. Simply extrapolating this rate suggests that the asteroid will despin over the next 150 kyr and was spinning at its surface disruption rate 75 kyr ago, but the rotational evolution of WT24 depends on the surface's thermal properties and probably is more complex than a simple spin-down.
Additional Information
© 2008 Elsevier Inc. All rights reserved. Received 5 November 2007; revised 29 January 2008. Available online 29 February 2008. The online version of this article contains additional supplementary material. Please visit DOI: 10.1016/j.icarus.2008.01.020. We thank the Arecibo and Goldstone technical and support staffs for help with the radar observations. The Arecibo Observatory is part of the National Astronomy and Ionosphere Center, which is operated by Cornell University under a cooperative agreement with the National Science Foundation (NSF) and, during this experiment, also had support from the National Aeronautics and Space Administration (NASA). Some of this work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. This material is based in part upon work supported by NASA under the Science Mission Directorate Research and Analysis Programs. Michael Busch was partially supported by the John and Fannie Hertz Foundation. DOI of original article: 10.1016/j.icarus.2008.01.020.Additional details
- Eprint ID
- 13899
- Resolver ID
- CaltechAUTHORS:20090409-082630298
- NASA Science Mission Directorate Research and Analysis Programs
- John and Fannie Hertz Foundation
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2009-07-17Created from EPrint's datestamp field
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2023-04-21Created from EPrint's last_modified field