COMPACT PROTOPLANETARY DISKS AROUND THE STARS OF A YOUNG BINARY-SYSTEM

Planet formation is believed to occur in the disks of gas and dust tha t surround young salar-type stars(1). Most stars, however, form in mul tiple systems(2-5), where the presence of a close companion could affe ct the structure of the disk(6-8) and perhaps interfere with planet fo rmation. It has been difficult to investigate this because of the reso lution needed Here we report interferometric observations (at a wavele ngth of 7 mm) of the core of the star-forming region L1551. We have ac hieved a linear resolution of seven astronomical units (less than the diameter of Jupiter's orbit). The core of L1551 contains two distinct disks, with a separation of 45 AU; these appear to be associated with a binary system. Both disks are spatially resolved, with semi-major ax es of about 10 AU, which is about a factor of ten smaller than disks a round isolated stars(9-12). The disk masses are of order 0.05 solar ma sses, which could be enough to form planetary systems like our own.