Live Iron-60 in the Early Solar System

Abstract

Isotopic analyses of nickel in samples from the differentiated meteorite Chervony Kut revealed the presence of relative excesses of ⁶⁰Ni ranging from 2.4 up to 50 parts per 10⁴. These isotopic excesses are from the decay of the now extinct short-lived nuclide ⁶⁰Fe and provide clear evidence for the existence of ⁶⁰Fe over large scales in the early solar system. Not only was ⁶⁰Fe present at the time of melting and differentiation (that is, Fe-Ni fractionation) of the parent body of Chervony Kut but also later at the time when basaltic magma solidified at or near the surface of the planetesimal. The inferred abundance of ⁶⁰Fe suggests that its decay alone could have provided sufficient heat to melt small (diameters of several hundred kilometers) planetary bodies shortly after their accretion.