Density and temperature distributions used in this paper. These are from the models of d’Alessio et al. (2001), with ﹩\dot{M}=10^{-8}﹩ M_⊙ yr⁻¹, ﹩M_{*}=0.7﹩ M_⊙, ﹩T_{*}=4000﹩ K, and ﹩R_{*}=2.5﹩ R_⊙. The grain size distribution is given by ﹩n( a) \propto a^{-3.5}﹩ for ﹩0.005< a< 0.25﹩ μm, where a is the grain radius. The surface density ﹩\Sigma _{0}=25﹩ g cm⁻² at 10 AU and varies as ﹩1/ R﹩ for ﹩R> 10﹩ AU. The mass of the disk is 0.063 M_⊙ out to ﹩R=400﹩ AU.