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J. Pittichova, K. J. Meech (IfA, UH)
Deep Impact is the first planetary mission to carry out direct experimentation on a cometary body. Comets represent the most pristine accessible remnants of Solar system formation. However, over time, the exterior mantle of these objects has been highly altered by orbit induced solar insulation fluctuations. Ground, space, and in-situ observations have not been able to easily determine the physical and chemical characteristics of the primordial material. The Deep Impact mission will deliver a 360-kg impactor to comet 9P/Tempel 1 at 10.2 km/s on UT July 4, 2005. The impact will remove the evolved material and excavate into the pristine interior. This event will release dust and volatiles that may be observable for many weeks after impact. Some of the ejecta may be slow-moving large fragments, and a mass determination may be possible.
We will present wide-field R- and I-band images of comet 9P/Tempel 1, taken with the MegaCam CCD (FOV 1 degree square) on the 3.6-m Canada-France-Hawaii Telescope on Mauna Kea. Our observations on UT July 3-6, 2005 will cover the night prior to impact to ensure that we have data for the pre-impact dust environment. The two nights following impact will allow us to monitor the inner coma for changes in the grain size and color induced by creating a new active area on the nucleus. The scientific questions that this presentation will address are: How does the post-impact dust differ from the pre-impact dust? Is there any compositional difference between surface and subsurface grains? Does surface mantling change this?
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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.