Статья

Radar Detection of Near-Earth Asteroids 2062 Aten, 2101 Adonis, 3103 Eger, 4544 Xanthus, and 1992 QN

L. A. M. BennerJet Propulsion Laboratory, California Institute of Technology, Pasadena, California, 91109-8099, [email protected]S. J. OstroJet Propulsion Laboratory, California Institute of Technology, Pasadena, California, 91109-8099, [email protected]Jon D. GiorginiJet Propulsion Laboratory, California Institute of Technology, Pasadena, California, 91109-8099, [email protected]R. F. JurgensJet Propulsion Laboratory, California Institute of Technology, Pasadena, California, 91109-8099, [email protected]D. L. MitchellJet Propulsion Laboratory, California Institute of Technology, Pasadena, California, 91109-8099, [email protected]Randy RoseJet Propulsion Laboratory, California Institute of Technology, Pasadena, California, 91109-8099, [email protected]K. D. RosemaJet Propulsion Laboratory, California Institute of Technology, Pasadena, California, 91109-8099, [email protected]M. A. SladeJet Propulsion Laboratory, California Institute of Technology, Pasadena, California, 91109-8099, [email protected]R. WinklerJet Propulsion Laboratory, California Institute of Technology, Pasadena, California, 91109-8099, [email protected]D. K. YeomansJet Propulsion Laboratory, California Institute of Technology, Pasadena, California, 91109-8099, [email protected]D. B. CampbellNational Astronomy and Ionosphere Center, Cornell University, Ithaca, New York, 14853J. F. ChandlerHarvard-Smithsonian Center for Astrophysics, 60 Garden St. Cambridge, Massachusetts, 02138I. I. ShapiroHarvard-Smithsonian Center for Astrophysics, 60 Garden St. Cambridge, Massachusetts, 02138

1997en

ABI

Аннотация

We describe Doppler-only radar observations of near-Earth asteroids 2062 Aten, 2101 Adonis, 3103 Eger, 4544 Xanthus, and 1992 QN that were obtained at Arecibo and Goldstone between 1984 and 1996. Estimates of the echo spectral bandwidths, radar cross sections, and circular polarization ratios of these objects constrain their pole-on breadths, radar albedos, surface roughnesses, taxonomic classes, rotation periods, and pole directions. Aten's bandwidth is consistent with its radiometrically determined diameter of 0.9 km. Adonis has a rotation periodP≤ 11 h and an effective diameter (the diameter of a sphere with the same projected area as the asteroid) between 0.3 and 0.8 km. The radar properties of Adonis suggest it is not a member of taxonomic classes C or M. The effective diameter of Xanthus is between 0.4 and 2.2 km with a rotation periodP≤ 20 h. Echoes from 1992 QN constrain the asteroid's pole-on breadth to be ≥0.6 km and probably exclude it from the C and M taxonomic classes. The strongest Eger echoes are asymmetric with bandwidths that set lower bounds of 1.5 and 2.3 km on the minimum and maximum breadths of the asteroid's pole-on silhouette. If Eger is modeled as a 1.5 × 2.3 km biaxial ellipsoid, then its effective diameter for an equatorial view is 1.5 km end-on and 1.9 km broadside or pole-on, implying a geometric albedo smaller than published values but still consistent with a classification as an E-type object. The near-unity circular polarization ratios of Adonis, Eger, and 1992 QN are among the highest values measured for any asteroid or comet and suggest extreme near-surface roughness at centimeter to meter scales.

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Идентификаторы

DOI: 10.1006/icar.1997.5834

Цитирования и источники

Цитирований: 2Использованных источников: 0

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