Program: GN-2014B-Q-6

A number of issues, such as high brightness contrast and large discrepancies in size and mass, make detection of main-sequence era exoplanets difficult. These challenges are all compounded with increasing stellar mass. One can more easily search for planets by looking at these systems in post-main sequence. Circumstellar dust around a white dwarf star is thought to originate from the tidal disruption of asteroid-like bodies and is thus used as a tracer for planetary systems. For Cycles 9 and 10 of the Spitzer mission we were awarded a total of 18.5 hours to search 100 white dwarfs from the SDSS in the 3.6 and 4.5 micron IRAC bands for excess emission in order to constrain the frequency of disks at massive WDs, and the frequency of planets at their massive progenitors, for the first time. Our sample is selected to have mass greater than 0.8 Msol (~3.5Msol progenitor mass) and Teff = 9500 - 22,500K. About half of the Cycle 10 data has been obtained. Near-infrared data is required, however, to rule out alternative sources of excess emission. We propose to use the NIRI instrument to obtain K-band observations of 6 massive WDs with a significant mid-IR excess.