My new paper in Earth and Planetary Science Letters is out and available online. This paper on how iron isotopes fractionate during core formation follows up my first paper on the topic in Nature Geoscience by provided some additional experiments and also offer a model for why we see the isotopic behavior that we observe. In the paper, my co-authors and I propose that the shortening and stiffening of Fe bonds in Fe-rich core-like alloys causes an increase in the alloys preference for heavy Fe isotopes relative to molten silicate during core formation, which is what we observe in our experiments. We also model the fractionation behavior of Fe isotopes during planetary differentiation and conclude we do not see a clear signature of isotope fractionation by vaporization or volatile depletion.
