Dr. Ben Zuckerman (UCLA)

University of Florida Astronomy Colloquium - Mar. 9th, 2015

The Nature of Rocky Exoplanets Via Study of White Dwarfs

The 2015 consensus view is that the presence of elements heavier than helium in the atmosphere of an isolated white dwarf is a signpost for a planetary system in orbit about that star. This interpretation was a long time in coming -- roughly 90 years! -- but by now the evidence is overwhelming. The relative elemental abundances in these otherwise-pristine stellar atmospheres reveal the bulk elemental composition of the building blocks of rocky planets. Using the Solar System as a model, one can deduce a past history of differentiation and collisions for some of these rocky exoplanet precursors, a history that can inform us about the origins of our own Solar System. Interpretation of the white dwarf data indicates the presence of closely-packed major planets around single main sequence stars and a history of gravitational interactions of such (complex) planetary systems with the secondaries in binary star systems.