BINARY SEARCH AMONG X-RAY ACTIVE STARS SOUTH OF THE TAURUS MOLECULAR CLOUD

We have conducted an R-band imaging survey of a ROSAT x-ray selected s ample of 99 stars south of the Taurus-Auriga association using the WIY N 3.5 m telescope under subarcsec seeing conditions (typically similar to 0''.7). Recent optical spectroscopic identifications show that thi s sample contains 17 Pleiades-like stars, 17 emission-line stars, 32 a ctive corona stars, and 32 stars judged to be younger than the Pleiade s by the strength of their lithium absorption. A considerable fraction of these young Li-rich stars are probably weak-line T Tauri stars (TT S). In total, we resolve 21 binary stars, 3 of them having separations less than 1''.0. Within the young Li-rich subsample, we find 9 compan ions in the separation range between 0''.6 and 14''.0. The visual bina ry fractions among the young and active stars within the sample are si milar and compatible with expectations from main-sequence field stars in the solar neighborhood. We discuss some implications of these resul ts for understanding the nature of the widespread, X-ray active, young stellar population recently identified around nearby star forming reg ions. (C) 1997 American Astronomical Society.