Short-Lived Radioisotope Tc-98 Synthesized by the Supernova Neutrino Process

Abstract

The isotope Tc-98 decays to Ru-98 with a half-life of 4.2 x 10(6) yr and could have been present in the early Solar System. In this Letter, we report on the first calculations of the production of Tc-98 by neutrino-induced reactions in core-collapse supernovae (the v process). Our predicted Tc-98 abundance at the time of solar system formation is not much lower than the current measured upper limit raising the possibility for its detection in the not too distant future. We show that, if the initial abundance were to be precisely measured, the Tc-98 nuclear cosmochronometer could be used to evaluate a much more precise value of the duration time from the last core-collapse supernova to the formation of the solar system. Moreover, a unique and novel feature of the Tc-98 v-process nucleosynthesis is the large contribution (similar to 20%) from charged current reactions with electron antineutrinos. This means that Tc-98 becomes a unique new v-process probe of the temperature of the electron antineutrinos.