Ballistic Transport and Deposition of Ejected material on Comet Hartley 2

Ballistic transport processes on comet nuclei may dramatically alter their surface activity and geomorphology. Comet 103P/Hartley 2 has a small, bilobate nucleus with a hyperactive region at the tip of its small lobe, and terrains of varying degrees of smoothness, indicative of depositional processes. These deposited materials are considered to result from the ejection process and the fluidized flow from such a hyperactive region. Understanding the formation and evolution of this smooth terrain is essential to understanding the history and bulk properties of comet Hartley 2 and, by extension, comets in general. However, the underlying depositional process, and resulting surface evolution is poorly understood. Additionally, all currently estimated bulk properties of this comet are based on untested assumptions of post-depositional fluidized flow emplacements. Therefore, a better understanding of the depositional processes will give tighter constraints on the bulk properties of the nucleus. We propose to study how materials are ejected and ballistically transported from active areas to depositional terrains on Hartley 2 and how depositional locations and thicknesses correlate with surface geomorphology and nucleus rotation state history.