strongly constrain the grain properties and size distribution. We fit the data with a blackbody model, and then compare the data with several “realistic” grain models .

In fitting a blackbody we account for inefficient grain emission at long wavelengths by including parameters $\lambda_0$ and $\beta$, where the blackbody is modified by a factor $\left( \lambda_0/\lambda \right)^\beta$ for wavelengths longer than $\lambda_0$. The best fitting model has a temperature of 49K and fractional luminosity $L_{\rm
  disk}/L_\star = 1.4 \times 10^{-5}$. The SPIRE data are near the confusion limit of about 6mJy, so the parameters $\beta$ and $\lambda_0$ are unconstrained within reasonable limits by the data (based on previous sub-mm detections for other disks we fix them to $\lambda_0=210 \mu$m and $\beta=1$ in Figure \[fig:sed\] [@2007ApJ...663..365W]).

Assuming that grains absorb and emit like blackbodies, the radial dust distance implied by 49K is 45AU. Because the disk is observed at a radius of 120AU (i.e. is warmer than expected for blackbodies at 120AU), the dust emission has at least some contribution from grains small enough to emit inefficiently in the 70-350$\mu$m wavelength range. Because the SED alone is consistent with a pure blackbody (i.e. with $\beta=0$), we cannot make such a statement 