Proto-planetary and transitional disks which are detected in scattered light provide a critical t... more Proto-planetary and transitional disks which are detected in scattered light provide a critical test of the interpretation of circumstellar disks based on the IR spectral energy distribution (SED) alone. The disk inclination to the line-of-sight, outter radius, and surface brightness (SB) maps or radial SB distributions provided by spatially resolved imaging remove most of the degeneracies inherent in fitting IR SEDs without such observational constraints. We have imaged the disk of SAO 206462 (HD 135344 B) in 1.1 and 1.6 mum scattered light with HST/NICMOS and can trace the essentially face-on disk out to 1.05''. The cavity detected in sub-mm observations lies entirely under the NICMOS coronagraphic spot, a result consistent with the SED fitting if the star is at d = 140 pc. The SED had previously been classified as a Meeus Group I SED and interpreted as arising in a flared disk. Neither the 1.1 nor the 1.6 mum radial surface brightness profiles are consistent with a flared disk. A FUSE FUV spectrum demonstrates the presence of excess light in this system, confirming the accretion rate estimated from Brgamma. Collectively, these data strengthen the interpretation of this system as a transitional disk.
Proto-planetary and transitional disks which are detected in scattered light provide a critical t... more Proto-planetary and transitional disks which are detected in scattered light provide a critical test of the interpretation of circumstellar disks based on the IR spectral energy distribution (SED) alone. The disk inclination to the line-of-sight, outter radius, and surface brightness (SB) maps or radial SB distributions provided by spatially resolved imaging remove most of the degeneracies inherent in fitting IR SEDs without such observational constraints. We have imaged the disk of SAO 206462 (HD 135344 B) in 1.1 and 1.6 mum scattered light with HST/NICMOS and can trace the essentially face-on disk out to 1.05''. The cavity detected in sub-mm observations lies entirely under the NICMOS coronagraphic spot, a result consistent with the SED fitting if the star is at d = 140 pc. The SED had previously been classified as a Meeus Group I SED and interpreted as arising in a flared disk. Neither the 1.1 nor the 1.6 mum radial surface brightness profiles are consistent with a flared disk. A FUSE FUV spectrum demonstrates the presence of excess light in this system, confirming the accretion rate estimated from Brgamma. Collectively, these data strengthen the interpretation of this system as a transitional disk.
Uploads