The Deep Impact Earth-Based Campaign

Abstract

Prior to the selection of the comet 9P/Tempel 1 as the Deep Impact mission target, the comet was not well-observed. From 1999 through the present there has been an intensive worldwide observing campaign designed to obtain mission critical information about the target nucleus, including the nucleus size, albedo, rotation rate, rotation state, phase function, and the development of the dust and gas coma. The specific observing schemes used to obtain this information and the resources needed are presented here. The Deep Impact mission is unique in that part of the mission observations will rely on an Earth-based (ground and orbital) suite of complementary observations of the comet just prior to impact and in the weeks following. While the impact should result in new cometary activity, the actual physical outcome is uncertain, and the Earth-based observations must allow for a wide range of post-impact phenomena. A worldwide coordinated effort for these observations is described.

Mid-infrared spectra of comet nuclei

“…This fraction is much larger than the estimates for Tempel 2 and Arend-Rigaux approximately 1% and <1%, respectively (Millis et al 1988, A'Hearn et al 1989. Based on the compilation of photometry by Meech et al (2005), the first signs of activity of comet Tempel 1 occur between 600 and 400 days before perihelion (4-3 au). Spitzer images of the comet at 478 and 464 days pre-perihelion (3.7 au) show no evidence for near aphelion activity (Lisse et al 2005, Reach et al 2007, and neither do R-band images at 4.2 au postperihelion (Hergenrother et al 2007).…”

Submillimetre observations of comets with Odin: 2001–2005

“…Observing this comet in support to the Deep Impact mission (Meech et al 2005) was a major objective of Odin in 2005. This comet returned to perihelion on 5 July 2005 at 1.50 AU, the day after it was hit by the Deep Impact impactor (A'Hearn et al 2005).…”

Ground-based visible and near-IR observations of Comet 9P/Tempel 1 during the Deep Impact encounter

“…The scientific results were augmented by observations made by observers around the world in wavelengths and timescales unavailable to the spacecraft. As part of the extensive groundbased observing campaign in support of the mission (Meech et al, 2005a(Meech et al, , 2005b, we observed the comet in the days prior to, during, and after impact from Kitt Peak National Observatory (J, H, K) and Observatorio Astronómico Nacional at the Sierra de San Pedro Mártir, B.C. 3 (B, V, R, I).…”