INJECTION OF FRESHLY SYNTHESIZED CA-41 IN THE EARLY SOLAR NEBULA BY AN ASYMPTOTIC GIANT BRANCH STAR

We show that ejecta from the envelope of one asymptotic giant branch s tar of M similar to 3 M. may account for many of the short-lived nucle i in the early solar system and also for the recent evidence of the pr esence of Ca-41 (<(tau)over bar>(41) = 1.50 x 10(5) yr) in early solar nebular condensates. This would require that the injection into the p rotosolar molecular cloud took place within a narrow time interval of( 5-7) x 10(5) yr before the formation of the solar system. If true, thi s places extremely tight constraints on the whole process of injection mixing and collapse. The timescales for both Ca-41 and Al-26 require that the placental medium be a dense molecular cloud (2 x 10(3)-8 x 10 (3) H cm(-3)). If the observed residual Ca-41 is instead produced by a proton bombardment mechanism within the early solar system, similar t o what appears necessary to explain Mn-53, then the time interval is r elaxed but would still be (1-2) x 10(6) yr from consideration of Al-26 .