  We conduct a multiplicity survey of members of the rho Ophiuchus cloud
complex with high resolution imaging to characterize the multiple star
population of this nearby star forming region and investigate the relation
between stellar multiplicity and star and planet formation. Our aperture
masking survey reveals the presence of 5 new stellar companions beyond the
reach of previous studies, but does not result in the detection of any new
substellar companions. We find that 43+/-6% of the 114 stars in our survey have
stellar mass companions between 1.3-780AU, while 7 (+8 -5)% host brown dwarf
companions in the same interval. By combining this information with knowledge
of disk-hosting stars, we show that the presence of a close binary companion
(separation < 40 AU) significantly influences the lifetime of protoplanetary
disks, a phenomenon previously seen in older star forming regions. At the
~1-2Myr age of our Ophiuchus members ~2/3 of close binary systems have lost
their disks, compared to only ~30% of single stars and wide binaries. This has
significant impact on the formation of giant planets, which are expected to
require much longer than 1 Myr to form via core accretion and thus planets
formed via this pathway should be rare in close binary systems.
