Hubble Space Telescope space telescope imaging spectrograph coronagraphic imaging of the Herbig Ae star Ab Aurigae

We present the first broadband, coronagraphic Hubble Space Telescope images of the bright, optically visible, isolated Herbig Ae star AB Aurigae. The Space Telescope Imaging Spectrograph (STIS) images reveal extended circumst ellar nebulosity (r approximate to 1300 AU) covering the region of the mill imeter continuum and CO disk. The structure is observed in the disk on spat ial scales down to 0." 1 (14 AU) and exhibits a north-south asymmetry. A co mparison of the STIS data with scattering models for flared disks or disks + envelopes suggests that the disk inclination is i less than or equal to 4 5 degrees from the plane of the sky.