Abstract

As the study of rocky exo-planets enters an era of characterisation, the ability to determine how similar a planet is to the Earth, and thus if it is potentially habitable, is fast approaching. An understanding of the geological processes which determine a rocky world’s bulk composition, geodynamics, and subsequent climate is of vital importance to this pursuit. Over the course of my PhD I have used the pollution of white dwarf stars by rocky exo-planetary material to gain insights into the bulk composition of rocky exo-planets, and thus, the geological processes which occur on them. I have created a model which reproduces the atmospheric metal abundances present in polluted white dwarf stars and generates constraints on the origin of the polluting material. Using this model I can constrain the mass of the polluting bodies, their formation temperature, and whether they experienced geochemical differentiation and formed iron-nickel cores and magnesium silicate mantles similar to the rocky worlds of the Solar System. In this talk I will outline the model and discuss the insights it provides into the origin and geology of rocky exo-planetary material. Additionally, I will discuss how polluted white dwarf systems may be used to constrain the interior compositions of exo-planets in an analogous manner to how the Solar System meteorite suites allowed the Earth’s interior to be constrained.