DPS 2001 meeting, November 2001
Session 46. Cometary Atmospheres and Solar Wind Interaction
Oral, Chairs: M. Hanner, A. Levasseur-Regourd, Friday, November 30, 2001, 3:00-4:10pm, Regency E

## [46.07] Recalibration of IRAS Data on 9P/Tempel 1 and Implications for Deep Impact

M. F. A'Hearn, C. M. Lisse (U. Md.), R. Walker (Vanguard Research), Deep Impact Team

In July and August 1983, IRAS made many observations of 9P/Tempel 1, the target of the Deep Impact mission. These data have been carefully recalibrated and reanalyzed. The effective black-body temperature (250 K) is higher and the total flux is lower than one would deduce from the originally published data.

These data, combined with optical measurements sensitive to the smaller particles, have been fit with models of the dust emission to predict the dust impacts, as a function of particle mass, on the two Deep Impact spacecraft, the flyby and the impactor. The size distribution must be less steep than found in situ at 1P/Halley. The total estimated burden of mass on the flyby is predicted to be 0.01 g m-2 and that on the impactor to be 2 g m-2. We also compare the widely used optical parameter Af\rho with an equivalent, model-independent measure for thermal emission, which we denote Ef\rho. This enables construction of an extensive heliocentric light curve.

Funded by NASA.