A Long‐Lived Planetesimal Dynamo Powered by Core Crystallization
Name
10.1029-2020GL091917.pdf
Size
850.35 KB
Format
Adobe PDF
Checksum (MD5)
31fb8d25a0bced60f7a0d998a923951f
Author(s)
Maurel, Clara
Bryson, James F. J.
Shah, Jay
Chopdekar, Rajesh V.
Elkins‐Tanton, Linda T.
Raymond, Carol A.
Weiss, Benjamin P.
Date Issued
February 11, 2021
Journal
Geophysical Research Letters
Publisher
American Geophysical Union (AGU)
Citation
Maurel, C., Bryson, J. F. J., Shah, J., Chopdekar, R. V., Elkins-Tanton, L. T., Raymond, C. A., & Weiss, B. P. (2021). A long-lived planetesimal dynamo powered by core crystallization. Geophysical Research Letters, 48, e2020GL091917.
Version
Author's final manuscript
Abstract
The existence of numerous iron meteorite groups indicates that some planetesimals underwent melting that led to metal-silicate segregation, sometimes producing metallic cores. Meteorite paleomagnetic records suggest that crystallization of these cores generated dynamo magnetic fields. Here we describe the magnetic history of the partially differentiated IIE iron meteorite parent body. This is the first planetesimal for which we have a time-resolved paleomagnetic record constrained by 40Ar/39Ar chronometry spanning several tens of million years (Ma). We find that the core of the IIE parent body generated a dynamo, likely powered by core crystallization, starting before 78 ± 13 Ma after solar system formation and lasting at least 80 Ma. Such extended core crystallization suggests that the core composed a substantial fraction of the body ( urn:x-wiley:00948276:media:grl61991:grl61991-math-0001 13%–19% core-to-body radius ratio depending on the body’s radius), indicating efficient core formation within some partially differentiated planetesimals.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
Creative Commons Attribution-Noncommercial-Share Alike
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1029/2020gl091917
