Abstract

Defying the notion of the silent graveyard, planetary systems refuse to die quietly. Instead, a significant fraction show one or more signs of dynamical reanimation, with strong indications of general mayhem during the last stages of stellar evolution. I will give a brief tour of these evolved and active planetary systems, which provide major insights into rocky planetary bodies in particular. These descendants of intermediate mass stars reveal characteristics of their former planetary systems in ways unattainable by conventional methods using main sequence stars. In particular, the metal pollution observed in white dwarf stars reveals the bulk chemistry of entire planetesimals or planetary fragments, including compelling evidence for Earth-like chemistry, planetary differentiation, and believe it or not, water. This talk will cover some of the highlights of the active planetary graveyard, including variability and transient behavior.