SUPERNOVA NEUTRINO NUCLEOSYNTHESIS OF THE RADIOACTIVE ⁹² Nb OBSERVED IN PRIMITIVE METEORITES

Abstract

The isotope 92Nb decays to 92Zr with a half-life of 3.47 × 107 yr. Although this isotope does not exist in the current solar system, initial abundance ratios for 92Nb/93Nb at the time of solar system formation have been measured in primitive meteorites. The astrophysical origin of this material, however, has remained unknown. In this Letter, we present new calculations which demonstrate a novel origin for 92Nb via neutrino-induced reactions in core-collapse supernovae (ν-process). Our calculated result shows that the observed ratio of 92Nb/93Nb ∼ 10−5 can be explained by the ν-process.