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K.J. Meech, J.M. Bauer (IfA, UH), M.F. A'Hearn (UMd)
The Deep Impact mission, one of the two recently approved Discovery missions, will deliver a 500 kg copper projectile to the comet 9P/Tempel 1 on July 4, 2005, to excavate a crater. The goal will be to watch the cratering event, measure the change in activity level caused by the impact, and will be the first experiment to sample deeply below the surface of a comet. In preparation for a successful mission, we will begin a vigorous ground-based observing campaign to characterize the nucleus of 9P/Tempel 1. The ground-based observations will characterize the pre-impact activity levels for comparison after the impact, characterize the nucleus in terms of a rotational light curve and pole position, get an estimate of the nucleus size and albedo, model the dust production rates, and search for the appearance of gaseous species as the comet approaches perihelion. The observing campaign as already begun with some intensive observations of the comet during the following observing runs:
\begin{footnotesize} \begin{center} \begin{tabular}{lccccc} \hline UT Date & Nts & Telescope & r[AU] & No. & Exp \\ \hline 12/97 & 1 &Keck II & 4.48 & 2 & 240 \\ 1/98 & 1 &UH 2.2m & 4.44 & 7 & 4200 \\ 2/98 & 1 &CTIO1.5m & 4.36 & 3 & 1800 \\ 4/98 & 2 &UH 2.2m & 4.26 & 8 & 4800 \\ 1/99 & 6 &UH 2.2m & 3.14 &133 &17220 \\ 3/99 & 4 &UH 2.2m & 2.88 &181 &54000 \\ 5/99 & 2 &UH 2.2m & 2.47 & 9 & 810 \\ 7/99 & 2 &UH 2.2m & 2.19 & 9 & 1620\\ \hline \end{tabular} \end{center} \end{footnotesize} \vspace{0.1cm}
The 1999 January and March observations were made to search for the rotation period of the comet, as well as to obtain deep images to model the coma. The results of the rotational light curve observations will be presented, as well as a compilation of the heliocentric light curve from the data from earlier epochs. In addition, a detailed, comprehensive multi-wavelength ground-based observing plan will be presented to characterize the nucleus before the 2005 July 4 Deep Impact encounter with the comet.
This project has been funded through the NASA Planetary Astronomy Program to date, NAG 4494.