LIGHT-ELEMENT NUCLEOSYNTHESIS IN A MOLECULAR CLOUD INTERACTING WITH A SUPERNOVA REMNANT AND THE ORIGIN OF BERYLLIUM-10 IN THE PROTOSOLAR NEBULA

The presence of short-lived radionuclides (t sub(1/2) < 10 Myr) in the early solar system provides important information about the astrophysical environment in which the solar system formed. In this paper, we investigate various astrophysical contexts for the nonthermal nucleosynthesis of super(10)Be by cosmic-ray-induced reactions. We first show that the super(10)Be recorded in FUN-CAIs cannot have been produced in situ by irradiation of the FUN-CAIs themselves. We then show that trapping of Galactic cosmic rays (GCRs) in the collapsing presolar cloud core induced a negligible super(10)Be contamination of the protosolar nebula, the inferred super(10)Be/ super(9)Be ratio being at least 40 times lower than that recorded in FUN-CAIs ( super(10)Be/ super(9)Be ~3x 10 super(-4)). This model naturally provides an explanation for the injection of other short-lived radionuclides of stellar origin into the cold presolar molecular cloud ( super(26)Al, super(41)Ca, and super(36)Cl) and is in agreement with the solar system originating from the collapse of a molecular cloud shocked by a supernova blast wave.