We have made a new time-dependent calculation of the supernova production ratio of the long-lived isomeric state ${}^{180}\mathrm{Ta}$${}^m$. Such a time-dependent solution is crucial for understanding the production and survival of this isotope. We include the explicit linking between the isomer and all known excited states. We have also calculated the properties of possible links to a conjectured excited state that might decrease the final isomer residual ratio. We find that the explicit time evolution of the synthesis of ${}^{180}\mathrm{Ta}$ using the available nuclear data avoids the overproduction relative to ${}^{138}\mathrm{La}$ for a $\nu$-process neutrino temperature of 4 MeV.

• Received 28 May 2009

DOI:https://doi.org/10.1103/PhysRevC.81.052801