Constraining Neptune's Migration: The Surface Composition of Trans-Neptunian 
Objects / Dr  Rosemary Pike (ASIAA)
	
The outer Solar System beyond Neptune is populated with the icy remnants of 
planetary formation, the Trans-Neptunian Objects (TNOs).  TNOs have a wide 
range of surface colors, from nearly solar to very red, and the majority of the 
targets can only be studied using broad-band photometry.  As part of a large 
TNO surface color survey, Col-OSSOS (Colours of the Outer Solar System Origins 
Survey), I acquired u, g, r, z, and J band photometry for 20-100 targets (all 
targets have g,r,J).  The g-r and r-z photometry proved uniquely diagnostic of 
surface type, and provides a surface criteria for separating objects with 
different orbit types.  Critically, the surfaces of 'cold classical TNOs', 
which have low-excitation orbits and are thought to be primordial, are uniquely 
red in these colors.  Based on these results, I am searching for TNOs with cold 
classical surfaces in other regions of the Kuiper belt.  These objects could 
have formed in the cold classical region and been captured into other orbits 
during Neptune's migration.  The distribution and density of cold classical 
surfaces will provide strict constraints on the speed and distance of Neptune's 
migration.