The R-process and nucleochronology

摘要: Abstract The r-process of nucleosynthesis is the process which responsible for synthesis approximately half nuclear species in nature that are more massive than iron. This heavy-element involves progressive buildup heavier isotopes via neut ron captures proceeding on neutron-rich isotopes, interspersed by beta decays. Its abudance features clearly reflect propeties — maxima related to magic neutron numbers N = 50, 82 and 126. It probes our knowledge properties nuclei far from region stability, even through position drip line. also forms important long-lived chronometers 232Th, 238U 235U utilized dating Galaxy. While astrophysical site foprocess not yet identified, its association with stars undergoing type II supernova events strongly suggested. can be deduced observation already present oldest most metal-deficient stars, tracers chemical evolution become supernovae evolve fastest contribute their ejecta interstellar medium at earliest beginnings When utilizing production ratios chronometer nuclei, observed primitive meteorites (limited) star formation throughout galactic evolution, one put limits duration nucleosynthesis, age Galaxy universe. latter has a large uncertainty but comparable ages estimated globular clusters cosmology. paper will provide review basic physics underlying r-process, operation mechanisms possible sites, time models, inferred