From the Centaurs to the Inner Oort Cloud: Exploring the Kuiper belt Connection

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The small bodies of the Outer Solar System are the material leftover from the construction of the planets and serve as a fossil record of the Solar System's history. These planetesimals can be broadly divided in the Centaurs, the Kuiper belt, and the Inner Oort cloud. The Kuiper belt consists of orbits beyond Neptune residing between approximately 30-250 au. Centaurs are cometary precursors that have recently diffused out of the Kuiper belt. These bodies are a transitory population on relatively short-lived chaotic orbits between Neptune and Jupiter that cross one or more of the giant-planets. The Inner Oort cloud on the other hand consists of dynamically excited and detached orbits from Neptune, with semimajor axes greater than ~ 250 au, likely scattered on to their orbits by a giant planet beyond Neptune or by a passing star. By studying the ensemble properties (shapes, sizes, compositions, orbits, and other physical characteristics) of these small icy planetesimals, we can probe the giant planets' early dynamical history, explore the compositional structure of the Solar System's primordial planetesimal disk, and study the evolution of the outer Solar System over time. The majority of these objects are too faint for spectroscopy with ground-based telescopes, but by measuring broad-band colors in different optical and near-infrared filters, we obtain a proxy for a planetesimal's surface composition. By measuring the brightness of a planetesimal over time, we can estimate shape and measure rotation rates. With deep optical imaging, we can look for faint features associated with comet-like activity and explore how often these objects experience outgassing of water ice and other volatile species.The main aim of this project is to explore the connection and evolutionary history of the Centaurs, Kuiper belt, and Inner Oort cloud. The project will focus on two main avenues for exploring these Solar System populations. The first will be through the study of light curves, phase curves, and the cometary activity histories of a sample of KBOs and Centaurs utilising observations from 1-8-m telescopes and the Asteroid Terrestrial-impact Last Alert System (ATLAS). The second avenue will consist of a search for distant inner Oort Cloud objects with the ATLAS survey in order to constrain the size and bright-end magnitude distribution of this distant population of bodies.