Exploring the composition of icy bodies at the fringes of the Solar System with next generation space telescopes

Abstract: Determining the distribution and spectral signature of volatile ices and organics exposed on icy body surfaces can provide crucial clues for deciphering how the outer solar system formed and evolved. Over the past few decades, ground- and space-based telescope observations have probed the compositions of a wide range of icy objects with primordial and processed surfaces, revealing the presence of numerous volatile ices and organic residues. Although these telescope observations have advanced our understanding of icy bodies beyond Saturn, the sensitivity and spatial resolution of collected datasets are limited by the large heliocentric distances of these far-flung objects. Furthermore, most observations have focused on the visible (VIS, 0.4 - 0.7 microns) and near-infrared (NIR, 0.7 - 2.5 microns), with fewer observations at longer NIR wavelengths (2.5 - 5.0 microns) and in the far to near ultraviolet (UV, 0.1 - 0.4 microns), which represents a critical wavelength region for investigating modification of ices and organics by UV photolysis and charged particle radiolysis. Thus, our understanding of icy bodies beyond Saturn is limited by the capabilities of available facilities, and key questions regarding their surface compositions remain to be explored. Next generation space telescopes (NGSTs) with greater sensitivity and angular resolution in the UV, VIS, and longer NIR are therefore needed to help unveil the surface compositions of icy bodies residing at the fringes of our solar system.