Theoretical investigations suggest that magnetic fields may have played an important role in driving rapid stellar accretion rates and efficient planet formation in protoplanetary disks. Experimental constraints on magnetic field strengths throughout the solar nebula can test the occurrence of magnetically driven disk accretion and the effect of magnetic fields on planetary accretion. Here we conduct paleomagnetic experiments on chondrule samples from primitive CR (Renazzo type) chondrites GRA 95229 and LAP 02342, which likely originated in the outer solar system between 3 and 7 AU approximately 3.7 million years after calcium aluminum‐rich inclusion formation. By extracting and analyzing 18 chondrule subsamples that contain primary, igneous ferromagnetic minerals, we show that CR chondrules carry internally non‐unidirectional magnetization that requires formation in a nebular magnetic field of ≤8.0 ± 4.3 μT (2
Magnetic fields in the early solar system may have driven the inward accretion of the protoplanetary disk (PPD) and generated instabilities that led to the formation of planets and ring and gap structures. The Allende carbonaceous chondrite meteorite records a strong early solar system magnetic field that has been interpreted to have a PPD, dynamo, or impact‐generated origin. Using high‐resolution magnetic field imaging to isolate the magnetization of individual grain assemblages, we find that only Fe‐sulfides carry a coherent magnetization. Combined with rock magnetic analyses, we conclude that Allende carries a magnetization acquired during parent body chemical alteration at ~3.0–4.2 My after calcium aluminum‐rich inclusions in an >40 µT magnetic field. This early age strongly favors a magnetic field of nebular origin instead of dynamo or solar wind alternatives. When compared to other paleomagnetic data from meteorites, this strong intensity supports a central role for magnetic instabilities in disk accretion and the presence of temporal variations or spatial heterogeneities in the disk, such as ring and gap structures.
more » « less- Award ID(s):
- 1642268
- NSF-PAR ID:
- 10368060
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- AGU Advances
- Volume:
- 2
- Issue:
- 3
- ISSN:
- 2576-604X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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