Mathieu 9417195 This is a two part project to study pre-main sequence binaries with orbital periods of a few years or less. The first is a high precision radial velocity survey of about 400 of these stars using the new Wisconsin-Indiana-Yale-NOAO (WIYN) 3.5m telescope and multi-object spectrograph. It is expected that about 50 binaries with periods of less than 1000 days, triple the present number, will be found. The second is an enlargement of a previous successful survey for submillimeter continuum emission from protostellar disks associated with these binary stars using the new submillimeter array detector at the JC Maxwell Telescope. The results will be accurate enough to resolve whether the reduced continuum emission from 5-50 AU separation binaries, those embedded in disks, are due to the binary formation processes or from dynamical torques later clearing gaps in the disks. ***
