Electron capture of iron-group nuclei in magnetars

Using the theory of relativity in superstrong magnetic fields (SMFs) and a nuclear shell model, we carry out an estimation of electron capture (EC) rates on iron-group nuclei in SMFs. The rates of change of electronic abundance (RCEA) due to EC are also investigated in SMFs. It is concluded that the EC rates of most iron-group nuclides are increased greatly by SMFs, by an amount sometimes even exceeding nine orders of magnitude. On the other hand, RCEA is influenced greatly by SMFs and reduced by more than eight orders of magnitude in the EC reaction. We also compare our results with those of Fuller et al. (FFN) and Aufderheide et al. (AUFD) in cases with and without SMFs. The results show that our results are in good agreement with AUFD's, but FFN's rates are close to one order of magnitude higher than ours in the case without SMFs. In contrast, our calculated rates for most nuclides in SMFs are increased and even exceed FFN's and AUFD's results, which is in the case without SMFs, by as much as nine and eight orders of magnitude, respectively.