Electron Capture and Beta-Decay Rates for the Collapse of O+Ne+Mg Cores

Abstract. We present a new set of electron (e−) capture and β-decay rates that improves previous calculations by Takahara et al. and Oda et al. by: (a) incorporation of recent charge-exchange and β-decay data, (b) contributions of forbidden transitions, and (c) in-clusion of e − screening corrections. The experimental nuclear input is supplemented by theoretical data based on large-scale shell model calculations in the full sd-shell space using the USDB interaction. The impact of these new rates on the late-stage stellar evo-lution of 8.8M ⊙ star is demonstrated.