Electron capture and beta-decay rates for the collapse of O+Ne+Mg cores

We present a new set of electron (e − ) capture and �-decay rates that improves previous calculations by Takahara et al. and Oda et al. by: (a) incorporation of recent charge-exchange and �-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 8.8Mstar is demonstrated.