ABSTRACT Differentiated planetesimals delivered iron-rich material to the Earth and Moon in high-velocity collisions at the end stages of accretion. The physical process of accreting this

late material has implications for the geochemical evolution of the Earth–Moon system and the timing of Earth’s core formation1,2,3. However, the fraction of a planetesimal’s iron core that

is vaporized by an impact is not well constrained as a result of iron’s poorly understood equation of state. Here we determine the entropy in the shock state of iron using a recently

developed shock-and-release experimental technique implemented at the Sandia National Laboratory Z-Machine. We find that the shock pressure required to vaporize iron is 507 (+65, −85) GPa,

siderophile elements in the lunar mantle and crust5,6,7,8 can be explained by the retention of a smaller fraction of vaporized planetesimal iron on the Moon, as compared with Earth, due to

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our FAQs * Contact customer support SIMILAR CONTENT BEING VIEWED BY OTHERS THE DISSIPATION OF THE SOLAR NEBULA CONSTRAINED BY IMPACTS AND CORE COOLING IN PLANETESIMALS Article 23 May 2022

EVIDENCE OF HYDROGEN−HELIUM IMMISCIBILITY AT JUPITER-INTERIOR CONDITIONS Article 26 May 2021 CONTEMPORARY FORMATION OF EARLY SOLAR SYSTEM PLANETESIMALS AT TWO DISTINCT RADIAL LOCATIONS

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Google Scholar  Download references ACKNOWLEDGEMENTS Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of

Lockheed Martin Corporation, for the US Department of Energy’s National Nuclear Securities Administration under Contract No. DE-AC04-94AL85000. This work was conducted under the Sandia Z

Fundamental Science Program and supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001804. This work was improved by helpful discussions

with R. Walker, D. Flicker, D. Swift, M. Knudson and M. Desjarlais. We thank S. Raymond, K. Walsh and D. O’Brien for the impact data from their N-body simulations. Iron samples were provided

by B. Jensen of Los Alamos National Laboratory. AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge,

Massachusetts 02138, USA Richard G. Kraus, Sarah T. Stewart & Stein B. Jacobsen * Shock Physics Group, Lawrence Livermore National Laboratory, PO Box 808, L-487, Livermore, California

94551-0808, USA Richard G. Kraus * Dynamic Material Properties Group, Sandia National Laboratory, PO Box 5800, Albuquerque, New Mexico 87185-1195, USA Seth Root * High Energy Density Physics

Theory, Sandia National Laboratory, PO Box 5800, Albuquerque, New Mexico 87185-1189, USA Raymond W. Lemke & Thomas R. Mattsson * Department of Earth and Planetary Sciences, UC Davis,

One Shields Avenue, Davis, California 95616, USA Sarah T. Stewart Authors * Richard G. Kraus View author publications You can also search for this author inPubMed Google Scholar * Seth Root

View author publications You can also search for this author inPubMed Google Scholar * Raymond W. Lemke View author publications You can also search for this author inPubMed Google Scholar *

Sarah T. Stewart View author publications You can also search for this author inPubMed Google Scholar * Stein B. Jacobsen View author publications You can also search for this author

inPubMed Google Scholar * Thomas R. Mattsson View author publications You can also search for this author inPubMed Google Scholar CONTRIBUTIONS R.G.K. conceived the experimental technique.

R.G.K., S.T.S., S.B.J. and T.R.M. prepared the proposal for experimental time. S.R., R.W.L. and R.G.K. designed and conducted the experiments. R.G.K. analysed the data. R.G.K. and S.T.S.

wrote the paper and all authors provided comments on the manuscript. CORRESPONDING AUTHOR Correspondence to Richard G. Kraus. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no

competing financial interests. SUPPLEMENTARY INFORMATION SUPPLEMENTARY INFORMATION Supplementary Information (PDF 6476 kb) RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE

CITE THIS ARTICLE Kraus, R., Root, S., Lemke, R. _et al._ Impact vaporization of planetesimal cores in the late stages of planet formation. _Nature Geosci_ 8, 269–272 (2015).

https://doi.org/10.1038/ngeo2369 Download citation * Received: 22 September 2014 * Accepted: 19 January 2015 * Published: 02 March 2015 * Issue Date: April 2015 * DOI:

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