Nucleosynthesis during the Early History of the Solar System

摘要: Abundances in terrestrial and meteoritic matter indicate that the synthesis of D^2, Li^6, Li^7, Be^9, B^(10) B^(11) possibly C^(13) N^(15) occurred during an intermediate stage early history solar system. In this stage, planetary material had become largely separated, but not completely, from hydrogen which was main constituent primitive material. Appropriate physical conditions were satisfied by solid planetesimals dimensions 1 to 50 metres consisting silicates oxides metals embedded icy matrix. The through spallation neutron reactions simultaneously induced outer layers bombardment high energy charged particles, mostly protons, accelerated magnetic flares at surface condensing Sun. total particle approximately 10^(45) ergs while average close 500 MeV per nucleon. Recent studies abundance lithium young T Tauri stars serve as primary astronomical evidence for point view. observed abundances beryllium Sun are discussed terms nuclear considerations brought forward. The isotope ratios D^2/H^1 = 1.5 × 10^(−4), Li^6/L^i7 0.08, B^(10)/B^(11) 0.23 basic data leading requirement 10 cent terrestrial-meteoritic irradiated with a thermal flux 10^7 n/cm^2 s interval years. importance (n, α) on Li^6 is indicated relatively low these two nuclei. It shown sufficient produce radioactive Pd^(107) I^(129) necessary account radiogenic Ag^(107) Xe^(129) anomalies recently meteorites. short time interval, ∼ 6 years, required decays be effective applies between end nucleosynthesis system termination fractionation processes parent bodies postulate last event galactic formation large, nebula.