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C.M. Lisse (JHU-APL), M.F. A'Hearn (UMD), M.J.S. Belton (Belton Space Initiatives, Inc.), D. Bodewits (KVI), D.J. Christian (Queens University, Belfast), J. VanCleve (Ball Aerospace), M. Combi (U. Michigan), K. Dennerl (MPE), T.L. Farnham (UMD), Y.R. Fernandez (UCF), O. Groussin (UMD), R. Hoekstra (KVI), T. Makinen (FMI), L.A. McFadden (UMD), K.J. Meech (UH), P. Schultz (Brown University), H. Weaver (JHU-APL), S. Wolk (CXC)
On July 4, 2005 NASA’s discovery mission Deep Impact (hereafter DI) sent a 375 kg impactor into the nucleus of comet 9P/Tempel 1 at 10.2 km/s relative velocity (A'Hearn et al. 2005). In the IR, Spitzer observed the comet in the unique 5-38 µm spectral range provided by the IRS instrument, allowing direct determination of silicaceous dust, PAHs, carbonates, and aluminum and iron oxides/sulfides in the subsurface material. The Spitzer observations contrasted well with the 1-5 µm spectra obtained by the DI High Resolution Instrument’s IR spectrometer and ground based measurements at 1-5 um from the Keck and IRTF observatories (Meech et al. 2005), enabling us to obtain full coverage of the comet’s IR spectrum from 1.0 to 38 µm.
In the x-ray, the DI experiment allowed for a controlled test of the charge exchange (CXE) emission mechanism that drives cometary x-ray emission (Lisse et al. 2001, Kharchenko and Dalgarno 2001, Krasnopolsky et al. 2002) using observations with the Chandra ACIS-S CCD. The Chandra spectra show a fresh amount of neutral material was injected into a finite volume of the extended atmosphere, or coma, of the comet. In the matter of minutes, this new material directly increased the emission measure for the comet by ~ 30 production from other measurements. Additional contemporaneous measurements by the XMM and SWIFT low energy x-ray imagers provided complimentary lightcurve data points, providing a good long term estimate of the comet's gas emission before, during, and after the Deep Impact encounter. Over the longer term, the combined lightcurves showed evidence of multiple natural outbursts of neutral gas emission from the comet.
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.