Institute for Advanced Study Informal Astrophysics Seminar

ABSTRACT: As a low- or intermediate-mass star evolve to the final white dwarf stage, it often loses more than 50% of its original mass. Consequently, its planetary system expands, and the collision rates among the subplanetary bodies, such as asteroids and comets, would increase. While no planets have been convincingly detected around white dwarfs, dust disks produced by tidally disrupted asteroids or collisions among comets have been reported. We have conducted a Spitzer MIPS 24 micron survey of hot white dwarfs, and archival Spitzer IRAC/MIPS surveys of white dwarfs and central stars of planetary nebulae. IR excesses indicative of dust disks have been found in many cases. I will report these results and discuss their implications on planetary systems.