We investigate $^{ 60}$Fe in massive stars and core-collapse supernovae focussing on uncertainties that influence its production in 15, 20 and 25 $M_\odot$ stars at solar metallicity. We find that the $^{ 60}$Fe yield is a monotonic increasing function of the uncertain $^{ 59}$Fe$(n,\gamma)^{ 60}$Fe cross section and that a factor of 10 reduction in the reaction rate results in a factor 8-10 reduction in the $^{ 60}$Fe yield; while a factor of 10 increase in the rate increases the yield by a factor 4-7. We find that none of the 189 simulations we have performed are consistent with a core-collapse supernova triggering the formation of the Solar System, and that only models using $^{ 59}$Fe$(n,\gamma)^{ 60}$Fe cross section that is less than or equal to that from NON-SMOKER can reproduce the observed $^{ 60}$Fe/$^{ 26}$Al line flux ratio in the diffuse ISM. We examine the prospects of detecting old core-collapse supernova remnants (SNRs) in the Milky Way from their $\gamma$-ray emission from the decay of $^{ 60}$Fe, finding that the next generation of gamma-ray missions could be able to discover up to $\sim100$ such old SNRs as well as measure the $^{ 60}$Fe yields of a handful of known Galactic SNRs. We also predict the X-ray spectrum that is produced by atomic transitions in $^{ 60}$Co following its ionization by internal conversion and give theoretical X-ray line fluxes as a function of remnant age as well as the Doppler and fine-structure line broadening effects. The X-ray emission presents an interesting prospect for addressing the missing SNR problem with future X-ray missions.
Categories: astro-ph.SR astro-ph.HE