In 2003, I completed my D.Phil. thesis at the University of Oxford. Entitled "The Behaviour of Small Bodies in the Outer Solar System", it represented the most detailed analysis then carried out of the behaviour of objects known as the Centaurs, icy planetesimals which move on orbits that bring them closer to the Sun than the planet Neptune, while never allowing them to stray closer than the orbit of Jupiter.
The first Centaur, Chiron, was discovered in 1977, and the second, Pholus, in 1992. Since then ongoing surveys of the night sky have discovered over 100 of these inter-planetary wonderers - a number increasing year on year as telescopes become more sensative and surveys more thorough.
The abstract to my thesis read as follows...
"A study is made of the dynamical behaviour of the Centaur objects over time. In order to properly analyse the results of the study, a new classification scheme is developed which allows Centaurs with different orbital characteristics to be easily differentiated. The scheme also standardises the classification of cometary bodies in general, from the Edgeworth-Kuiper belt and other trans-Neptunian objects, to the short period comets. A variety of results are obtained for the Centaurs studied, including half-lives and transfer probabilities. A mathematical model to describe the changing populations of Centaurs is presented, and interesting possible behaviours displayed by individual Centaurs are highlighted by the study of ten individual cases. Also, an in-depth study of the biases which affect observations of comets is undertaken, and the results used to re-examine work on the possible existence of a tenth planet within the solar system."
The work itself led to five peer-reviewed papers in the journal Monthly Notices of the Royal Astronomical Society - four on the Centaurs, and one on the biases which affect the historical and ongoing discoveries of comets. That latter work looked in some depth into the question of whether there is a massive planetary body (perhaps three times the mass of Jupiter) buried in the Oort cloud - as had been proposed by a number of authors to explain observed asymmetries in the flux of dynamically new comets across the sky. Since our work, more comets have been discovered, and more research has been carried out, and it seems that the "Oort cloud planet" idea has taken a back seat to the idea that the asymmetries are a natural result of the effect of the galactic tide, which pulls and deforms the Oort cloud in much the same way as the gravitational pull of the moon pulls and deforms the Earth's oceans.
I recently managed to recover a version of my thesis as a .pdf. I haven't worked out whether it is the post- or pre-correction version (though I think it is the final one!) - but if you're interested, you're more than welcome to download it and have a read by clicking on this link.