Stis coronagraphic imaging of the Herbig Ae star: HD 163296

Coronagraphic imaging with the Space Telescope Imaging Spectrograph on boar d the Hubble Space Telescope reveals a similar to 450 AU radius circumstell ar disk around the Herbig Ae star HD 163296. A broadband (0.2-1.0 mum) refl ected light image shows the disk oriented at a position angle of 140 degree s +/- 5 degrees and inclined to our line of sight by similar to 60 degrees +/- 5 degrees. The disk includes an annulus of reduced scattering at 325 AU and exhibits a flat trend of surface brightness in to 180-122 AU (1."5-1 " ), consistent with a cleared central zone. For r greater than or equal to 3 70 AU the disk surface brightness drops as r to the approximately -3.5 powe r. The disk cannot: be traced beyond 450 AU in our data. The disk is accomp anied by a chain of nebulosities at P.A. = 42 degrees .5 +/- 3 degrees .5, compatible with detection of a Herbig-Haro flow. The HD 163296 disk most cl osely resembles the disk of HD 141569. As in the HD 141569 system, the dyna mical effects of a planet may be necessary to explain the structure in the outer disk.