Col-OSSOS: Probing Ice Line/Color Transitions within the Kuiper Belt’s Progenitor Populations

Abstract Dynamically excited objects within the Kuiper Belt show a bimodal distribution in their surface colors, and these differing colors may be tracer of where formed. In this work, we explore radial color distributions primordial planetesimal disk implications for positions ice line/color transitions Belt’s progenitor populations. We combine full dynamical model evolution due to Neptune’s migration with precise measured by Colours Outer Solar System Origins Survey order examine true ratios lines disk. investigate position dominant, color–changing line, two possible layouts initial disk: (1) inner neutral surfaces outer red (2) neutral. performed simulations that truncates at 30 au. By radially stepping transition out through 0.5 au intervals, both configurations are consistent observed fraction. For an neutral, disk, find can 28 − 3 + 2 95% confidence level. red, ${27}_{-3}^{+3}$?> 27