SOLAR WIND IMPLANTATION MODEL FOR 10Be IN CALCIUM-ALUMINUM INCLUSIONS

We propose a model for the incorporation of Be-10 within calcium-aluminum inclusions (CAIs) in primitive carbonaceous meteorites. In this model, Be-10 is produced by energetic particle reactions in the proto-solar atmosphere of a more active proto-Sun characterized by energetic particle fluxes higher than contemporary particle fluxes. This Be-10 is incorporated into the solar wind that is then implanted into CAI precursor material. This production mechanism is operational in the contemporary solar system implanting Be-10 in lunar materials. The contemporary production rate of Be-10 at the surface of the Sun is similar to 0.1 Be-10 cm(-2) s(-1). Scaling up the contemporary Be-10 production in the proto-Sun by a factor of 10(5) would increase the production rate to 10(4) Be-10 cm(-2) s(-1). Using this enhanced production value in conjunction with refractory mass inflow rates at 0.06 AU from the proto-Sun we model Be-10 concentrations in CAI precursors. We calculate the content of solar-wind-implanted Be-10 would have been of the order of 10(12) Be-10 g(-1) in CAIs, consistent with initial(10)Be content found from boron-beryllium isotopic systematics in CAIs.