Sub–Astronomical Unit Structure of the Near-Infrared Emission from AB Aurigae

We present near-infrared, long-baseline, interferometric observations of AB Aurigae, a well-known Herbig Ae/Be star, obtained with the Infrared Optical Telescope Array. The near-infrared emission from this source has been spatially resolved for the first time, and the observations indicate a characteristic diameter of 5 mas for the emission, corresponding to 0.7 AU at the distance of AB Aur. The data appear to be most consistent with models in which the circumstellar material around AB Aurigae lies in a flattened structure with a central large hole or optically thin region of radius about 0.3 AU.