The time interval between nucleosynthesis and formation of the earth

Abstract

The differences (δ_i) in the abundance ratios of the stable xenon isotopes in meteorites and in the earth's atmosphere indicate that the latter contains an excess of fissiogenic xenon. It is postulated that the “extinct” transuranium elements, such as Pu²⁴⁴ and Cm²⁴⁷, played important roles in the production of the fissiogenic xenon in the earth's atmosphere. The time interval (Ξ) between the nucleosynthesis and the formation of the earth has been calculated from the values of δ_i. If it is assumed that the contribution from the Cm²⁴⁷ spontaneous fission and the U²³⁵ neutron-induced fission was negligible, a value of Ξ = 4.8 × 10⁸ years is obtained for the single event model and a value of Ξ = 0.52 × 10⁸ years for the continuous synthesis model.