Dusty Disks Around Hot White Dwarfs: Rejuvenated Debris Disks or Remnant of Post-AGB Binary Disks?

Exoplanets and minor-body populations revealed as tenuous debris disks are commonly found around main-sequence (MS) stars of all masses. Theories have long predicted that planetary bodies can survive the ordeal of post-MS evolution as long as they resided more than a couple AU away from their MS host. As the white dwarf cools, asteroids and Kuiper-belt analogues that survived can repopulate the dust reservoir in the system, which can be readily detected as an infrared excess around the stellar corpse. The infrared emission characteristics such as dust temperatures and amount of emission provide insights into the nature of the dust reservoir. The infrared excess discovered around the Helix central star represents a prototype of a post-MS KBO-like disk in the earliest stage of white dwarf evolution. In this talk, I will give a general overview of other dusty disks around hot white dwarfs and discuss their physical properties in light of their possible origins.