NOAO >   Observing Info >   Approved Programs >   2006A-0527

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Proposal Information for 2006A-0527


PI: Walter Harris, University of Washington, harris@ess.washington.edu
Address: Earth and Space Sciences, Box 351310, Seattle, WA 98195, U.S.A

CoI: Beatrice Mueller, PSI
CoI: Nalin Samarasinha, NOAO
CoI: Michael A'Hearn, UMD
CoI: Fred Roesler, University of Wisconsin
CoI: Tony Farnham, UMD
CoI: Yanga Fernandez, University of Central Florida
CoI: Jeff Morgenthaler, University of Washington
CoI: Matthew Knight, UMD
CoI: Casey Lisse, APL

Title: Fragmented comet 73P/Schwassmann-Wachmann 3: A rare close approach

Abstract: We propose to observe 3 fragments of the split Jupiter-family comet 73P/Schwassmann-Wach\-mann 3 (SW3) during their close approach to Earth in May 2006. The comet broke up in 1995, which suggests that much of the outgassing we see now is from relatively pristine nuclear material. This apparition is unique: We have never before been able to study fresh material from a Jupiter-family comet at such close geocentric distances (<0.1 AU). We propose narrowband visible and J,H,K near-IR imaging and visible spectroscopic observations that will take full advantage of the close approach to Earth and large change in viewing geometry. Our science goals are: (a) to compare the composition, color, and physical characteristics of the fragments to look for heterogeneity. Formation timescales and radial mixing in the protoplanetary disk could have affected cometary structure and composition. (b) to follow coma morphology of the dust and gas. This lets us derive the rotational states and active areas of the newly liberated fragments and study the photochemical behavior of short-lived coma species. (c) to understand the coupling between the solar wind and the comet's ion tail.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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