2002ApJ...580L.167M

We present near-infrared high-resolution observations of the young binary system Z Canis Majoris using the adaptive optics system at the Keck II telescope. Both components are unresolved at 1.25 and 1.65 µm, although high dynamic range images reveal a previously unknown jetlike feature in the circumstellar environment. We argue that this feature probably arises from light scattered off the walls of a jet-blown cavity, and proper-motion studies of this feature can probe the dynamics of the bipolar outflow. Potentially, the morphology of the dust-laden cavity walls offers a new probe of the momentum profile and collimation of bipolar winds from young stellar objects. We also derive high-precision binary parameters, which when combined with historical data have allowed the first detection of orbital motion. Finally, our observations confirm the high degree of flux variability in the system; the northwest binary component is dominant at the H band, in contrast to all previous observations.