Ostro, S. J. and Magri, C. and Benner, L. A. M. and Giorgini, J. D. and Nolan, M. C. and Hine, A. A. and Busch, M. W. and Margot, J. L. (2010) Radar imaging of Asteroid 7 Iris. Icarus, 207 (1). pp. 285-294. ISSN 0019-1035 http://resolver.caltech.edu/CaltechAUTHORS:20100520-144613483
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Arecibo radar images of Iris obtained in November 2006 reveal a topographically complex object whose gross shape is approximately ellipsoidal with equatorial dimensions within 15% of 253 × 228 km. The radar view of Iris was restricted to high southern latitudes, precluding reliable estimation of Iris’ entire 3D shape, but permitting accurate reconstruction of southern hemisphere topography. The most prominent features, three roughly 50-km-diameter concavities almost equally spaced in longitude around the south pole, are probably impact craters. In terms of shape regularity and fractional relief, Iris represents a plausible transition between ~50-km-diameter asteroids with extremely irregular overall shapes and very large concavities, and very much larger asteroids (Ceres and Vesta) with very regular, nearly convex shapes and generally lacking monumental concavities.
|Additional Information:||© 2009 Elsevier Inc. Received 26 June 2009; revised 10 October 2009; accepted 7 November 2009. Available online 24 November 2009. Steve Ostro, deceased, led the radar observations of 7 Iris, played the principal role in the analysis of those data, and created several drafts of this paper, nearly bringing the process to completion before his untimely death on December 15, 2008. His determination in the face of illness was remarkable. The second author then supervised the completion of the manuscript (primarily by composing Fig. 1 and the Appendix) and handled the editorial process. We thank the Arecibo 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). We thank M. Kaasalainen for kindly providing information regarding the Iris lightcurve data set, E. Asphaug for helpful discussions, and an anonymous reviewer and I. de Pater for constructive reviews that improved the presentation of this work. C. Magri was partially supported by NSF Grant AST-0205975. Some of this work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA). This material is based in part upon work supported by NASA under the Science Mission Directorate Research and Analysis Programs.|
|Subject Keywords:||Asteroids; Radar observations|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||21 May 2010 16:12|
|Last Modified:||26 Dec 2012 12:03|
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