The origin of $^{60}$Fe and other short-lived radionuclides in the early   solar system
  Establishing the origin of short-lived radionuclides (SLRs) with half-lives $\leq$ 100 Myr has important implications for the astrophysical context of our Sun's birth place. We review here the different origins proposed for the variety of SLRs present in the solar accretion disk 4.57 Ga ago. Special emphasis is given to an enhanced Galactic background origin for $^{60}$Fe which was inherited from several supernovae belonging to previous episodes of star formation, rather than from a nearby, contemporaneous supernova. 
Matthieu Gounelle, Anders Meibom