Activity in Comet Tempel 1: Linking the Coma and the Nucleus’ Surface

Abstract

We present an overview of the dust coma observations of comet Tempel 1 that were obtained in support of and during the Deep Impact mission and discuss how the data are being used to determine the source locations of the activity on the nucleus. Ground-based images covering the six-month period before impact show a long-lived southern asymmetry in the coma, though little detailed structure is seen. The wealth of Deep Impact images provides temporal coverage spanning a two-month period, with spatial resolution that continuously improves as the spacecraft closes on the nucleus. Three distinct jets are seen turning on and off and rotating with the nucleus’ 1.7-day period. The brightest of these jets is likely to be a main contributor to the southern asymmetry. In the high resolution images obtained near close approach, intricate, primarily radial structures are seen in the coma. In the highest resolution images, small detailed jets can be seen emanating from the surface of the nucleus, and appear to be related, in some manner, to the patches of exposed water ice.