Iron-60 is an iron isotope with a half-life of 2.6 million years, but was thought until 2009 to have a half-life of 1.5 million years. It undergoes beta decay to cobalt-60.
In phases of the meteorites Semarkona and Chervony Kut a correlation between the concentration of 60Ni, the granddaughter isotope of 60Fe, and the abundance of the stable iron isotopes could be found which is evidence for the existence of 60Fe at the time of formation of the solar system. Possibly the energy released by the decay of 60Fe contributed, together with the energy released by decay of the radionuclide 26Al, to the remelting and differentiation of asteroids after their formation 4.6 billion years ago. The abundance of 60Ni present in extraterrestrial material may also provide further insight into the origin of the solar system and its early history.
Standard atomic mass: 55.845(2) u
Read more about this topic: Isotopes Of Iron