Abstract

Planets are formed from the same material as their host stars and as such, the star indicates the composition of the material available to form planets. However, the process of planet formation could alter the composition of exoplanets, and some key questions remain to understand the interior composition of rocky exoplanets: Do planetary bodies retain their refractory elements? Are volatile elements lost due to the high temperatures in the disc? I will discuss how we can use polluted white dwarfs in wide binary systems to constrain the composition of rocky exoplanets and find how closely the planet’s composition resembles that of their host star. We compare the abundances of a polluted white dwarf, indicative of the composition of the planetary material, with the abundances of its main-sequence wide binary companion, which will work as a proxy for the composition of the host star. By doing this, we can find signatures of the planet formation process, such as loss of moderate refractories.