Deep Impact ejection from Comet 9P/Tempel 1 as a triggered outburst

Abstract

Ejection of material after the Deep Impact collision with Comet Tempel 1 was studied based on analysis of the images made by the Deep Impact cameras during the first 13 minutes after impact. Analysis of the images shows that there was a local maximum of the rate of ejection at time of ejection ~10 s with typical velocities ~100 m/s. At the same time, a considerable excessive ejection in a few directions began, the direction to the brightest pixel changed by ~50 deg, and there was a local increase of brightness of the brightest pixel. The ejection can be considered as a superposition of the normal ejection and the longer triggered outburst.