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Radar detection of Asteroid 2002 AA29 |
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| Authors: | Steven J Ostro Jon D Giorgini Alice A Hine Jean-Luc Margot Christian Veillet |
| Institution: | a Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099, USA b National Astronomy and Ionosphere Center, Arecibo Observatory, HC3 Box 53995, Arecibo, PR 00612, USA c California Institute of Technology, Pasadena, CA 91125, USA d Canada-France-Hawaii Telescope Corporation, 65-1238 Mamaloha Hwy, Kamuela, HI 96743, USA |
| Abstract: | Radar echoes from Earth co-orbital Asteroid 2002 AA29 yield a total-power radar cross section of 2.9×10−5 km2 ±25%, a circular polarization ratio of SC/OC=0.26±0.07, and an echo bandwidth of at least 1.5 Hz. Combining these results with the estimate of its visual absolute magnitude, HV=25.23±0.24, from reported Spacewatch photometry indicates an effective diameter of 25±5 m, a rotation period no longer than 33 min, and an average surface bulk density no larger than 2.0 g cm−3; the asteroid is radar dark and optically bright, and its statistically most likely spectral class is S. The HV estimate from LINEAR photometry (23.58±0.38) is not compatible with either Spacewatch's HV or our radar results. If a bias this large were generally present in LINEAR's estimates of HV for asteroids it has discovered or observed, then estimates of the current completeness of the Spaceguard Survey would have to be revised downward. |
| Keywords: | Asteroids Radar Photometry |
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