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 evolutional history of the Centaurs, Kuiper belt, and Inner Oort cloud. This project will focus on the performing, analyzing, and interpreting observational data from optical ground-based telescopes to study the physical and orbital properties of these distant Solar System planetesimals as well as searching for cometary activity. The specific project can be tailored to the student’s interests. We expect that the project will focus on monitoring a sample of Centaurs for cometary activity with 1-8-m telescopes and exploring the color diversity within the Inner Oort cloud objects. There are likely to be opportunities with this project for follow-up observations at UK-supported telescopes and observatories around the world.
Our group are members of the Colours of the Outer Solar System Origins Survey (Col-OSSOS), a large program gathering near-simultaneous optical and near-infrared photometry with the Gemini North Telescope and the Canada-France-Hawaii Telescope of a well characterized sample of ~80 KBOs. Queen’s University Belfast is a member of both the ATLAS and Pan-STARRS wide-field surveys. We expect this project could involve a component of analyzing follow-up observations based on Col-OSSOS results. An additional component of this project could include mining photometry of Centaurs from the ATLAS survey and other ground-based optical datasets.