Allowed Gamow-Teller strength distributions and stellar electron capture rates on odd-A nuclei

Abstract

The allowed Gamow-Teller (GT) strength distributions and associated weak interaction rates on fp-shell nuclei play crucial role in several astrophysical processes, particularly in nucleosynthesis, stellar evolution and supernova explosions. Results from simulation show that the electron capture (EC) rates on medium-heavy nuclei have a significant impact on decreasing the electron-to-baryon ratio of the stellar matter during the late stages of star formation. In this work we present the computation of allowed charge-changing transitions for odd-A fp-shell nuclei by using the deformed pn-QRPA model. The calculated GT strength distributions are compared with previous calculations (including shell and other QRPA models) and measured charge-changing reaction results. The associated EC rates are computed in stellar environment and are compared with previous theoretical results. It is concluded that our results are in good accordance with measured data. For [Formula: see text]Sc, [Formula: see text]V and [Formula: see text]Co, at high stellar temperatures, our calculated EC rates are bigger than the independent-particle and shell model rates. For [Formula: see text]Mn we generally calculate smaller EC rates than previous calculations. The differences with previous calculations may have consequences for supernovae simulators.