30-50% of all WDs are metal polluted when look in UV (Koester et al. 2014) – WD debris is comparable to bulk Earth (dominated by Fe, O, S, Mg) – Some of this debris is water-rich! (Farihi et al. 2013) WDs Directly Measure Exoplanet Compositions Abundances of rocks falling on 10 different white dwarfs: Xu et al. 2014 Bulk Earth Comet Halley
2-3 solar- mass ZAMS stars. 2. As the host evolves, the orbits of surviving planets expand. Objects destabilize, some scatter in. 3. Ancient solar systems have leftover debris. We can see it if it pollutes a pristine white dwarf.
rocks Few dozen show IR excess from dusty debris Less than a dozen show gas emission (Ca II) One (WD1145+017) shows transiting rocky debris No surviving, in-tact planets yet discovered: Gaia end-of-mission astrometry beckons!