Title: Insights into exoplanet compositions from polluted white dwarfs
Speaker: Isabella Trierweiler (Yale)
Abstract:
Polluted white dwarfs offer the rare chance to directly measure the bulk compositions of exoplanetary material. These stars show evidence of recent accretion of rocky bodies in the form of metal lines in their spectra, which tell us about the relative elemental abundances of the accreted material. In this talk I will discuss some of the key characteristics of the exoplanetary material polluting white dwarfs. I will show that most pollution is similar in composition to CI chondrites, the assumed primitive material in our own solar system. I will also demonstrate that oxygen abundances in polluted white dwarfs are consistent with water contents ranging from dry, Earth-like bodies to water-rich objects akin to icy moons in the solar system. Finally, I will show that the bulk objects causing pollution are likely massive, on the order of Vesta or Ceres, the largest objects in our asteroid belt.
