A Long‐Lived Planetesimal Dynamo Powered by Core Crystallization
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...
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| Format: | Article |
| Language: | English |
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Wiley
2021-03-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1029/2020GL091917 |
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| author | Clara Maurel James F. J. Bryson Jay Shah Rajesh V. Chopdekar Linda T. Elkins‐Tanton Carol A. Raymond Benjamin P. Weiss |
| author_facet | Clara Maurel James F. J. Bryson Jay Shah Rajesh V. Chopdekar Linda T. Elkins‐Tanton Carol A. Raymond Benjamin P. Weiss |
| author_sort | Clara Maurel |
| collection | DOAJ |
| description | 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 ( ≳ 13%–19% core‐to‐body radius ratio depending on the body’s radius), indicating efficient core formation within some partially differentiated planetesimals. |
| format | Article |
| id | doaj-art-4fdc7adeaeb844ee969c499ce5fc8608 |
| institution | Kabale University |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2021-03-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-4fdc7adeaeb844ee969c499ce5fc86082025-08-20T03:48:43ZengWileyGeophysical Research Letters0094-82761944-80072021-03-01486n/an/a10.1029/2020GL091917A Long‐Lived Planetesimal Dynamo Powered by Core CrystallizationClara Maurel0James F. J. Bryson1Jay Shah2Rajesh V. Chopdekar3Linda T. Elkins‐Tanton4Carol A. Raymond5Benjamin P. Weiss6Department of Earth, Atmospheric, and Planetary Sciences Massachusetts Institute of Technology Cambridge MA USADepartment of Earth Sciences University of Oxford Oxford UKDepartment of Earth, Atmospheric, and Planetary Sciences Massachusetts Institute of Technology Cambridge MA USAAdvanced Light Source Lawrence Berkeley National Laboratory Berkeley CA USASchool Of Earth and Space Exploration Arizona State University Phoenix AZ USAJet Propulsion Laboratory California Institute of Technology Pasadena CA USADepartment of Earth, Atmospheric, and Planetary Sciences Massachusetts Institute of Technology Cambridge MA USAAbstract 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 ( ≳ 13%–19% core‐to‐body radius ratio depending on the body’s radius), indicating efficient core formation within some partially differentiated planetesimals.https://doi.org/10.1029/2020GL091917core crystallizationdynamoiron meteoritesmagnetic fieldplanetesimal |
| spellingShingle | Clara Maurel James F. J. Bryson Jay Shah Rajesh V. Chopdekar Linda T. Elkins‐Tanton Carol A. Raymond Benjamin P. Weiss A Long‐Lived Planetesimal Dynamo Powered by Core Crystallization Geophysical Research Letters core crystallization dynamo iron meteorites magnetic field planetesimal |
| title | A Long‐Lived Planetesimal Dynamo Powered by Core Crystallization |
| title_full | A Long‐Lived Planetesimal Dynamo Powered by Core Crystallization |
| title_fullStr | A Long‐Lived Planetesimal Dynamo Powered by Core Crystallization |
| title_full_unstemmed | A Long‐Lived Planetesimal Dynamo Powered by Core Crystallization |
| title_short | A Long‐Lived Planetesimal Dynamo Powered by Core Crystallization |
| title_sort | long lived planetesimal dynamo powered by core crystallization |
| topic | core crystallization dynamo iron meteorites magnetic field planetesimal |
| url | https://doi.org/10.1029/2020GL091917 |
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