2003ApJ...591..267C

Using the Keck I telescope, we have obtained 11.7 and 18.7 µm images of the circumstellar dust emission from AB Aur, a Herbig Ae star. We find that AB Aur is probably resolved at 18.7 µm with an angular diameter of 1".2 at a surface brightness of 3.5 Jy.arcsec^–2. Most of the dust mass detected at millimeter wavelengths does not contribute to the 18.7 µm emission, which is plausibly explained if the system possesses a relatively cold, massive disk. We find that models with an optically thick, geometrically thin disk surrounded by an optically thin spherical envelope fit the data somewhat better than flared disk models.