Through detailed radiative transfer modeling , we present a disk+cavity model to simultaneously explain both the spectral energy distribution ( SED ) and Subaru H -band polarized light imaging for the pre-transitional protoplanetary disk PDS 70 .
In particular , we are able to match not only the radial dependence , but also the absolute scale , of the surface brightness of the scattered light .
Our disk model has a cavity 65 AU in radius , which is heavily depleted of sub-micron-sized dust grains , and a small residual inner disk that produces a weak but still optically thick Near-IR excess in the SED .
To explain the contrast of the cavity ’ s edge in the Subaru image , a factor of \sim 1000 depletion for the sub-micron-sized dust inside the cavity is required .
The total dust mass of the disk may be on the order of 10 ^ { -4 } M _ { \odot } , only weakly constrained due to the lack of long wavelength observations and the uncertainties in the dust model .
The scale height of the sub-micron-sized dust is \sim 6 AU at the cavity edge , and the cavity wall is optically thick in the vertical direction at H -band .
PDS 70 is not a member of the class of ( pre- ) transitional disks identified by Dong et al. , whose members only show evidence of the cavity in the millimeter-sized dust but not the sub-micron-sized dust in resolved images .
The two classes of ( pre- ) transitional disks may form through different mechanisms , or they may simply be at different evolution stages in the disk clearing process .