University of Maryland
Atlantic Building, Room 2400 4:30 PM Monday, April 24, 2006
Coffee, Tea & Snacks 4:15-4:30 PM

Lucy McFadden
University of Maryland

Update of Deep Impact Results

Deep Impact is a NASA mission that sent an impactor spacecraft on a collision course to Comet Tempel 1 on July 4, 2005, excavating debris cloud from the comet that brought material from beneath the surface. A flyby spacecraft traveling at 10 km/s observed the nucleus with two imagers and an infrared spectrometer. Current analysis carried out by the team at U. Maryland has focused on the state of the pre-impact comet nucleus and coma. We captured about half a dozen cometary outbursts on approach to the comet, that are associated with active regions coming into sunlight. Interestingly, the outbursts are not periodic. We have located areas of cometary activity on the nucleus and have observed variation in chemical abundances within the inner coma. The region off the Southern Hemisphere of the comet shows a greater abundance of CO2 relative to H2O relative to the Northern Hemisphere. This is due to a second active region. The color variations on the comet nucleus lead us to regions where solid water ice is present. Surface morphology is diverse and initial comparison with the surface of Wild 2 shows some large scale differences that are really not understood. Initial results from Spitzer and Chandra telescopes will be presented to suggest topics of talks that might follow in the fall. The results presented are from the combined efforts of the Deep Impact team.