DIX Planetary Science Seminar

Our compositional understanding of the Kuiper belt has been limited by the challenges of acquiring high-quality spectroscopy for midsize and small trans-neptunian objects (TNOs), and composition maps of large dwarf planets. NASA's New Horizons mission represents a breakthrough in our understanding of the trans-neptunian population. New Horizons provided a detailed portrait of objects with very different size scales: the 2400-km-diameter dwarf planet Pluto, the midsize ~1200-km-diameter body Charon, the much smaller satellites of Pluto (e.g., Nix and Hydra), and (486958) Arrokoth (provisional designation 2014 MU69), the latter with an 18 km equivalent spherical diameter. This is the result of two successful flybys: that of Pluto and its moons on July 14th, 2015, and that of Arrokoth on January 1st, 2019. I will present an overview of the color and composition of these very diverse bodies in terms of size, evolutionary stage, and dynamical class in the broad context of the physical and chemical properties of other trans-neptunian objects. Comparing and contrasting these objects will shed light on the mechanisms at play on the surface of these bodies.