Adaptive optics imaging of GG Tauri: Optical detection of the circumbinary ring

High angular resolution images of GG Tau have been obtained in the I, J, H, and K bands with the University of Hawaii adaptive optics system. The close binary pair is found to be near periastron, and it rotates clockwise. It consists of a K7-M0 star with an M4 companion. Masses inferred from dynamical motion are larger than the spectral type suggest. The companion appears to be younger than the main star. Both stars seem to be surrounded with a warm unresolved disk. Images reveal a circumbinary ring also recently detected at millimetric wavelengths. The ring seems to be produced by light scattered by the edge of a cavity inside a much larger disk. At the cavity edge, the disk thickness is estimated to be one-tenth of the cavity radius. Light which illuminates this cavity edge appears to be reddened by absorption through the inner disks. Azimuthal variations of the illumination indicate that the inner disks must be lumpy.