Atmospheres and surfaces of small bodies and dwarf planets in the Kuiper Belt

Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA

^a e-mail: els@lpl.arizona.edu

Abstract

Kuiper Belt Objects (KBOs) are icy relics orbiting the sun beyond Neptune left over from the planetary accretion disk. These bodies act as unique tracers of the chemical, thermal, and dynamical history of our solar system. Over 1000 Kuiper Belt Objects (KBOs) and centaurs (objects with perihelia between the giant planets) have been discovered over the past two decades. While the vast majority of these objects are small (< 500 km in diameter), there are now many objects known that are massive enough to attain hydrostatic equilibrium (and are therefore considered dwarf planets) including Pluto, Eris, MakeMake, and Haumea. The discoveries of these large objects, along with the advent of large (> 6-meter) telescopes, have allowed for the first detailed studies of their surfaces and atmospheres. Visible and near-infrared spectroscopy of KBOs and centaurs has revealed a great diversity of surface compositions. Only the largest and coldest objects are capable of retaining volatile ices and atmospheres. Knowledge of the dynamics, physical properties, and collisional history of objects in the Kuiper belt is important for understanding solar system formation and evolution.