Primordial Circumstellar Disks in Binary Systems: Evidence for Reduced
  Lifetimes
  We combine the results from several multiplicity surveys of pre-main-sequence
stars located in four nearby star-forming regions with Spitzer data from three
different Legacy Projects. This allows us to construct a sample of 349 targets,
including 125 binaries, which we use to to investigate the effect of companions
on the evolution of circumstellar disks. We find that the distribution of
projected separations of systems with Spitzer excesses is significantly
different (P ~2.4e-5, according to the KS test for binaries with separations <
400 AU) from that of systems lacking evidence for a disk. As expected, systems
with projected separations < 40 AU are half as likely to retain at least one
disk than are systems with projected separations in the 40-400 AU range. These
results represent the first statistically significant evidence for a
correlation between binary separation and the presence of an inner disk (r ~ 1
AU). Several factors (e.g., the incompleteness of the census of close binaries,
the use of unresolved disk indicators, and projection effects) have previously
masked this correlation in smaller samples. We discuss the implications of our
findings for circumstellar disk lifetimes and the formation of planets in
multiple systems.
