  We present the results of a Spitzer photometric investigation into the IR
excesses of close binary systems. In a sample of 10 objects, excesses in IRAC
and MIPS24 bands implying the presence of warm dust are found for 3. For 2
objects we do not find excesses reported in earlier IRAS studies. We discuss
the results in the context of the scenario suggested by Rhee and co-workers, in
which warm dust is continuously created by destructive collisions between
planetary bodies. A simple numerical model for the steady-state distribution of
dust in one IR excess system shows a central clearing of radius 0.22 AU caused
by dynamical perturbations from the binary star. This is consistent with the
size of the central clearing derived from the Spitzer spectral energy
distribution. We conclude that close binaries could be efficient "destroyers of
worlds", lead to destabilize the orbits of their planetary progeny by
magnetically-driven angular momentum loss and secular shrinkage of the binary
separation.
