  We present the results of adaptive optics nulling interferometric
observations of two Herbig Ae stars, AB Aur and V892 Tau. Our observations at
10.3 microns show resolved circumstellar emission from both sources. Further
analysis of the AB Aur emission suggests that there is an inclined disk
surrounding the star. The diameter of the disk is derived to be 24 to 30 AU
with an inclination of 45 to 65 degrees from face-on, and a major-axis PA of 30
+/- 15 degrees (E of N). Differences in the physical characteristics between
the mid-IR emission and emission at other wavelengths (near-IR and millimeter),
found in previous studies, suggest a complex structure for AB Aur's
circumstellar environment, which may not be explained by a disk alone. The
similarity in the observed size of AB Aur's resolved emission and that of
another Herbig Ae star, HD 100546, is likely coincidental, as their respective
evolutionary states and spectral energy distributions suggest significantly
different circumstellar environments.
