Publication Date:
2006-10-14
Description:
High-resolution radar images reveal near-Earth asteroid (66391) 1999 KW4 to be a binary system. The approximately 1.5-kilometer-diameter primary (Alpha) is an unconsolidated gravitational aggregate with a spin period approximately 2.8 hours, bulk density approximately 2 grams per cubic centimeter, porosity approximately 50%, and an oblate shape dominated by an equatorial ridge at the object's potential-energy minimum. The approximately 0.5-kilometer secondary (Beta) is elongated and probably is denser than Alpha. Its average orbit about Alpha is circular with a radius approximately 2.5 kilometers and period approximately 17.4 hours, and its average rotation is synchronous with the long axis pointed toward Alpha, but librational departures from that orientation are evident. Exotic physical and dynamical properties may be common among near-Earth binaries.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ostro, Steven J -- Margot, Jean-Luc -- Benner, Lance A M -- Giorgini, Jon D -- Scheeres, Daniel J -- Fahnestock, Eugene G -- Broschart, Stephen B -- Bellerose, Julie -- Nolan, Michael C -- Magri, Christopher -- Pravec, Petr -- Scheirich, Petr -- Rose, Randy -- Jurgens, Raymond F -- De Jong, Eric M -- Suzuki, Shigeru -- New York, N.Y. -- Science. 2006 Nov 24;314(5803):1276-80. Epub 2006 Oct 12.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109-8099, USA. ostro@reason.jpl.nasa.gov〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/17038586" target="_blank"〉PubMed〈/a〉
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
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Chemistry and Pharmacology
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Computer Science
,
Medicine
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Natural Sciences in General
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Physics
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