Expanding the Search for Accretion Luminosity in Disk-Polluted White Dwarfs

We propose an Xray survey of six nearby polluted white dwarfs to detecthighrate accretion states indicated by both optical data and recent theoreticalmodels of collisional cascades within their debris disks. The models predictthat the collisionally generated gas will be subject to high and low states ofaccretion, where the fraction of time spent in the high and detectable statesconstrains the size of bodies initiating the cascade. The proposed observationswill directly test these models, and thus provide valuable information on thenature of the (as yet unseen) parent bodies themselves. Only with Xrayobservations can we directly detect ongoing accretion, and provide an invaluableand independent determination of mass accretion rates. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]