Blowing in the Wind: II, Creation and Redistribution of Refractory Inclusions in a Turbulent Protoplanetary Nebula

摘要: Abstract Ca–Al rich refractory mineral inclusions (CAIs) found at 1–6% mass fraction in primitive chondrites appear to be 1–3 million years older than the dominant (chondrule) components which were accreted into same parent bodies. A prevalent concern is that it difficult retain CAIs for this long against gas-drag-induced radial drift Sun. We reassess situation terms of a hot inner (turbulent) nebula context CAI formation, using analytical models evolution and particle diffusion. show outward diffusion weakly turbulent can overcome inward drift, prevent significant numbers CAI-size particles from being lost Sun times on order 10 6 years. form early, when was hot, persist sufficient abundance incorporated planetesimals much later time. Small (≲0.1 mm diameter) longer large (≳5 mm ones. To obtain quantitative match observed volume fractions chondrites, another process must allowed for: substantial enhancement silicate-forming material, we suggest caused by rapid meter-sized objects. This early history, drifting rubble would have carbon content probably an magnitude larger even most (CI) carbonaceous chondrites. Abundant evaporating material help keep oxygen fugacity low, plausibly solar, as inferred formation environment CAIs. The associated production canonical amount CO 2 might also play role mass-independent fractionation isotopes, leaving gas 16 O other high temperature condensates.