Radar Observations of Near-Earth and Main-Belt Asteroids
Abstract
Radar is a very powerful technique for characterizing near-Earth and main-belt asteroids and for improving their orbits. This results from radar's ability to spatially resolve objects that often cannot be resolved at comparable resolutions by other groundbased techniques. Radar has revealed binary and contact binary objects, at least two triple systems, non-principal-axis rotators, objects whose radar reflectivity and circular polarization ratio have longitudinal variation, irregularly shaped near-Earth asteroids, objects with metallic compositions, objects with rubble-pile structures, and detailed radar images of main-belt asteroids that reveal complicated surfaces and substantial topographic relief. This chapter concentrates on the most significant advances in the field since publication of the radar chapter by Ostro et al. (2002) in Asteroids III. Detailed descriptions of asteroid radar observing techniques and terminology have appeared in Ostro (1993) and Ostro et al. (2002) (Asteroids III), so we refer readers to those papers for background information. This chapter emphasizes the first ground-truth tests of asteroid shape models by spacecraft encounters, population trends among near-Earth and main-belt asteroids, results for selected objects, new observing techniques, improved capabilities at radar telescopes, and improvements in three-dimensional shape modeling. We conclude with a discussion of future prospects.
- Publication:
-
Asteroids IV
- Pub Date:
- 2015
- DOI:
- 10.2458/azu_uapress_9780816532131-ch009
- Bibcode:
- 2015aste.book..165B