Transitional Disks Associated With Intermediate-mass Stars: Results of the SEEDS YSO survey

As part of the Strategic Exploration of Exoplanets and Disks with Subaru YSO survey, we have surveyed a number of Herbig B-F stars at H-band using Polarimetric Differential Imaging+Angular differential imaging. Historically, Herbig stars have been sorted based on their IR SEDs into those with SEDS which can be fit by powerlaws over 1-200 μm (Meeus et al. 2001, group II), and those which can be interpreted as a powerlaw + a blackbody component (Meeus group I) or powerlaw+missing warm thermal emission, which is one of the criteria for identification of gapped or transitional disks. Meeus group II disks, when imaged with HiCIAO show featureless disks with depolarization along the projection of the disk semi-minor axis (Kusakabe et al. 2012). This is what we had expected to see for the Meeus group I disks, except for the addition of wide gaps or central cavities. Instead we find wild diversity, suggesting that transitional disks are highly perturbed compared to Meeus group II disks.