Mixing and Transport in Protoplanetary Disks: Chondrites and Crystalline Silicates
          Alan Boss, Carnegie Institution

          Transport of refractory inclusions from the inner solar nebula out to asteroidal distances seems to be required in order to assemble chondrules, refractory inclusions, and matrix grains into the chondritic meteorites. In a gaseous disk capable of forming Jupiter by either core accretion or disk instability, the disk must have been marginally gravitationally unstable at and beyond Jupiter's orbit. Three dimensional, gravitational hydrodynamical models with radiative transfer and full thermodynamics are used to study mixing and transport in such a disk. The models show that gas and dust can be transported so rapidly (roughly 1 AU per 100 years) that mm- to cm-sized solids will remain effectively tied to the gas and will not be lost by monotonic inward drift caused by gas drag. In addition, the models show that a marginally gravitationally unstable disk drives spiral shock fronts at asteroidal distances strong enough to lead to flash heating of chondrule precursors. Mixing and transport of solids in such a disk results in a unified scenario linking chondrite production with gas giant planet formation. Furthermore, amorphous solids can be transported inward to be thermally annealed and then back outward to the edge of the disk, as seems to be required to explain observations of thermally processed, crystalline silicates in comets and protoplanetary disks.