X-rays from Planetary Nebulae: a Decade of Insight from Chandra

Planetary nebulae (PNe) represent very late stages in the lives of stars of initial mass 1--8 M_⊙. As such, PNe serve as proving grounds for theories concerning a wide range of astrophysical phenomena, from stellar nucleosynthesis to wind interactions to the impact of binarity on stellar evolution and the ultimate fates of binary (and, perhaps, exoplanet) systems. In the era of Chandra and XMM-Newton, the detection (or nondetection) of diffuse and/or point-like X-ray sources within PNe yields important, unique information concerning the evolutionary state of PN central star(s) and wind interactions as nebular shaping agents. Diffuse X-ray sources allow us to probe the energetic shocks within PN wind interaction regions, whether in the form of wind-blown bubbles or fast, collimated outflows impinging on PN progenitor ejecta. Chandra X-ray gratings spectroscopy of the superheated plasma in such a wind-shock region -- within the PN BD +303639 -- has yielded unparalleled insight into the crucial, late stages of nucleosynthesis within this PN's progenitor star. At the same time, searches for X-ray point sources within PNe provide a novel means to detect binary companions at PN cores, thereby constraining models in which the formation and shaping of PNe is directly linked to central star binarity and, perhaps, the presence of planetary-mass companions. I present highlights within each of these areas from among the X-ray results for PNe accumulated by Chandra and XMM-Newton over the past decade, and I discuss the pressing, unsolved questions in PN research that these X-ray observatories can best address in the coming years.