Production Memory of the 225 Ra - 225 Ac Clock in Neutron-Star Merger Ejecta
The 225Ra–225Ac clock uses isotope ratios to test proposed source states from neutron-star mergers. By linking surviving isotope partitions to parent decay time, researchers established exact conditions for production age. This provides a consistency check for nuclear reaction networks and helps connect nucleosynthesis chronology to late-time kilonova emission.