AAS 205th Meeting, 9-13 January 2005
Session 56 Planets and Solar System Objects
Poster, Tuesday, January 11, 2005, 9:20am-6:30pm, Exhibit Hall

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[56.13] Spitzer Infrared Observations of Comets

R. D. Gehrz (University of Minnesota), W. T. Reach (Spitzer Science Center), C. E. Woodward, M. S. Kelley (University of Minnesota)

We present selected Spitzer Space Telescope IRAC/MIPS images and IRS spectra of comet comae, tails, and debris trails made during the first year of operations. MIPS images of 20/P Comet Schwassmann-Wachmann 1 show structure consistent with jet activity on a rotating nucleus that is generally ablating according to the "standard model". IRS spectra of the coma and nucleus show that the nucleus is large (r = 27 5 km) and that grains released from the nucleus are similar in composition to grains in some stellar debris disks. Images of the debris trails of several comets are shown. The debris trail of Comet P/Encke is notable because its uniform intensity confirms that the entire orbit is well populated by the sand to gravel sized particles associated with meteor showers. IRAC 3.6-8 micron images of LINEAR (2002 T7) reveal the extended dust tail. Spitzer IRS spectra of several short period periodic comets confirm that the grains populating their comae are substantially larger than the grains in the comae of more pristine comets. Support for this work was provided by NASA through Contract Number 1256406 issued to RDG by JPL/Caltech.


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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.