Probing Exoplanetary Composition using White Dwarf Stars – Laura Rogers

Although exoplanets are ubiquitous across the Milky Way, determining their bulk composition remains a fundamental challenge in exoplanetary science. White dwarfs that exhibit atmospheric ‘pollution’ from accreted planetary material offer a unique solution. At least 30% of white dwarfs show heavy elements in their otherwise pristine hydrogen- or helium-dominated atmospheres. By analysing their spectra, we can perform detailed abundance studies of the accreted material. In this talk, I will discuss the mechanisms by which planetary material is delivered onto white dwarfs, key trends emerging from polluted white dwarf abundance studies, and how these systems inform our understanding of exoplanetary differentiation, mantle chemistry, and volatile retention. I will also explore whether exoplanetary material exhibits compositions similar to that of the Solar System and how these findings help to constrain models of planet formation and evolution.