Exploring remnant exo-planetary material with white dwarf stars

Amy Steele ( Université McGill )

Less than 1% of white dwarfs (WDs) show evidence of circumstellar gas disks formed through the tidal shredding and subsequent sublimation of remnant exo-asteroids. Yet, these ~30 WDs with emission features that reveal the elemental building blocks of rocky bodies can be used to probe the bulk compositions of the remnant leftovers of exoplanet formation. In this talk, I give a broad overview of these types of "polluted" WDs, describe what we have learned from them thus far, and highlight current efforts to build a database of models for these types of systems that includes a new set of optical constants motivated by the elements present in polluted WD spectra.