Chapter 18 - Surface properties of large TNOs: Expanding the study to longer wavelengths with the James Webb Space Telescope

Abstract

The largest Trans-Neptunian objects (TNOs) represent an extremely diverse collection of primitive bodies in the outer solar system. The community typically refers to these objects as “dwarf planets, (DPs)” though the IAU acknowledges only four TNOs officially such as Pluto, Eris, Makemake, and Haumea. We present a list of 36 potential candidates for reclassification as DPs, namely candidate dwarf planets (CDPs), which cover a wide range of sizes, geometric albedos, surface colors, and probably, composition. Understanding the properties across this population, and how those properties change with size, will yield useful constraints on the environment in which these TNOs formed, as well as their dynamical evolution, and bulk interior composition. TNO surface characteristics are ideal for study with the James Webb Space Telescope (JWST), which provides imaging and spectroscopic capabilities from ∼0.6–28μm. The four available science instruments, MIRI, NIRCam, NIRISS, and NIRSpec, and their capabilities for the study of TNOs are presented. JWST will expand on the wavelength range observable from the ground in the near-infrared (NIR) (0.6–5μm) for compositional studies and will open a new window on TNOs in the mid-infrared (5–28μm) for thermal characterization.