Abstract

I will give a few highlights of an evolving field that didn’t exist until 2005 or so, and one that I hope has broad interest for those interested in the physics of accretion disks, as well as planetary rings. We know now that white dwarf stars are often surrounded by rings or disks of planetary debris, where in all cases the stellar atmosphere is polluted by this material. Photospheric measurements demonstrate this material is strinkingly Earth-like, with evidence for disrupted bodies that are chemically analogous to planetary crusts, cores, and even evidence for water (but not other volatiles). This is all very exciting, and transiting events have been seen in one case, but the truth is we know very little about how these disks form, how they evolve, and how the material actually accretes onto the star. I’ll present observational highlights with an eye towards areas where theoretical work can have a large impact.