Nuclear Physics Seminar with Lee Sobotka and Ryan Ogliore on Cosmochronometers
The curious cases of two cosmochronometers: 26Al → 26Mg and 92Nb → 92Zr will be discussed. Ogliore will discuss some background on how radioactive isotopes are used to date events in the formative years of the Solar System, the cosmochemical and astrophysical evidence of their existence, the difficulties that arise from their use as choronometers, and their affect on the formation of habitable worlds.
Sobotka will present the decay feature, very short-lived isomers that do not decay to the long-lived ground state, these two decays have in common that is not present in well-established cosmochrometers. This feature generates concerns as how to validate these decays as cosmochronometers. For example, it is conceivable that the ground-state and excited (meta-stable) state are in equilibrium in hot stellar environments. This latter possibility presents a question that may intrigue theorists. While not the focus of this short presentation, the relevant reactions and a bit on the likely astrophysical setting that produce the parents will be mentioned.