An Astronomical Pump Probe Experiment with Deep Impact and the Keck Telescope.

High resolution spectra from 3050–5800 Å from the emissions from the coma of comet 9P/Tempel 1 were recorded using the high resolution echelle spectrograph, HIRES, attached to the Keck 1 telescope. The spectra were taken before the Deep Impact encounter in May as well as during and after it on July 4, 5, and 6. All of the typical cometary radicals such as OH, NH, NH2, CN, C2, and C3 have been identified. The O(1S) emission from the comet has clearly been separated from the auroral line and identified. The spectral distributions of the emissions observed in May before impact was similar to those after the impact in July. This indicates that in this comet the material that was evacuated 20 meters under the surface of the comet was similar to the material at the surface of the comet. It suggests that solar processing of surface material does not significantly affect the UV and visible emissions from comets so that variations in the spectra are probably useful for inferring the region where the comets are formed in the early solar system. No new emissions or prompt emissions stand out in the data. The chemical mechanism for the production of these radicals is described, along with gaps in our knowledge that needs to be addressed. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]