SOLAR WIND IMPLANTATION MODEL FOR10Be IN CALCIUM–ALUMINUM INCLUSIONS

Abstract

We propose a model for the incorporation of 10 Be within calcium–aluminum inclusions (CAIs) in primitive carbonaceous meteorites. In this model, 10 Be 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 10 Be 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 10 Be in lunar materials. The contemporary production rate of 10 Be at the surface of the Sun is ∼0.1 10 Be cm −2 s −1 . Scaling up the contemporary 10 Be production in the protoSun by a factor of 10 5 would increase the production rate to 10 41 0 Be 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 10 Be concentrations in CAI precursors. We calculate the content of solar-wind-implanted 10 Be would have been of the order of 10 12 10 Be g −1 in CAIs, consistent with initial 10 Be content found from boron–beryllium isotopic systematics in CAIs.