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C.A. Grady, D. Devine (AURA/NOAO, GSFC), B. Woodgate, R. Kimble (NASA/GSFC), F.C. Bruhweiler, A. Boggess (CUA), J.L. Linsky (JILA and NIST, U. Colorado, Boulder), P. Plait (ACC), M. Clampin, P. Kalas (STScI)
Coronagraphic imaging with STIS on the HST reveals an ~450 AU circumstellar disk around the 4-10 Myr old Herbig Ae star HD 163296. A broad-band (0.2-1.1 micron) reflected light image shows the disk oriented with its semi-major axis at PA=140+/-5 degrees, and inclination of ~ 60+/-5 degrees. The disk includes an annulus of depleted material at 325 AU, and a flat trend of surface brightness in to 1-1.5", consistent with a partially cleared zone extending from 300 to 180-122 AU. For radii r > 370 AU the disk surface brightness distribution drops as r-3.5. The disk cannot be traced beyond 450 AU in our data. The disk is accompanied by a chain of HH knots at PA=42.5+/-3.5 degrees. The dynamical effects of more than one planet appear necessary to explain the outer disk morphology and the apparent central clearing. HD 163296 is the third A star under t < 10 Myr with disk structure indicating that planet formation has occurred, and is present at larger radii than expected based on theoretical modelling of gas giant planet formation. The STIS data favor early formation of massive planets.
Support for this study was provided by HST STIS GTO funding through support to the NOAO, in response to NASA A/O OSSA -4-84 through the Hubble Space Telescope Project at GSFC. NOAO is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under cooperative agreement with the National Science Foundation. Data analysis facilities were provided by the Laboratory for Astronomy & Solar Physics, NASA/GSFC.
The author(s) of this abstract have provided an email address for comments about the abstract: cgrady@echelle.gsfc.nasa.gov