@article{11cf5667d96a43499956a2bd981c0847,
title = "Weak Magnetic Fields in the Outer Solar Nebula Recorded in CR Chondrites",
abstract = "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 (2σ). These weak magnetic fields may be due to the secular decay of nebular magnetic fields by 3.7 million years after calcium aluminum-rich inclusions, spatial heterogeneities in the nebular magnetic field, or a combination of both effects. The possible inferred existence of spatial variations in the nebular magnetic field would be consistent with a prominent role for disk magnetism in the formation of density structures leading to gaps and planet formation.",
keywords = "meteoritics, paleomagnetism, planet formation",
author = "Fu, {Roger R.} and Pauli Kehayias and Weiss, {Benjamin P.} and Schrader, {Devin L.} and Bai, {Xue Ning} and Simon, {Jacob B.}",
note = "Funding Information: We thank A. J. Brearley, A. N. Krot, and B. Zanda for discussions related to sample selection and petrography of the CR chondrites. We also thank K. Righter and C. E. Satterwhite for help sampling the two CR chondrites at the JSC Antarctic meteorites curation facility. We are grateful to J. F. D. F. Araujo and E. A. Lima for help with LAP 02342 data acquisition. Finally, we thank H. Wang and an anonymous reviewer for comments that improved the manuscript. This work was supported by NASA Emerging Worlds Program Grant NNX15AH72G to B. P. W. This work was performed in part at the Harvard Center for Nanoscale Systems (CNS), which is supported by the National Science Foundation under NSF Award 1541959. All demagnetization data reported in this study are available in the MagIC Database under Contribution 16701. All demagnetization data and raw images from the QDM and SQUID microscope are available in the Harvard Dataverse (Fu et al., 2020 ). Funding Information: We thank A. J. Brearley, A. N. Krot, and B. Zanda for discussions related to sample selection and petrography of the CR chondrites. We also thank K. Righter and C. E. Satterwhite for help sampling the two CR chondrites at the JSC Antarctic meteorites curation facility. We are grateful to J. F. D. F. Araujo and E. A. Lima for help with LAP 02342 data acquisition. Finally, we thank H. Wang and an anonymous reviewer for comments that improved the manuscript. This work was supported by NASA Emerging Worlds Program Grant NNX15AH72G to B. P. W. This work was performed in part at the Harvard Center for Nanoscale Systems (CNS), which is supported by the National Science Foundation under NSF Award 1541959. All demagnetization data reported in this study are available in the MagIC Database under Contribution 16701. All demagnetization data and raw images from the QDM and SQUID microscope are available in the Harvard Dataverse (Fu et al.,?2020). Publisher Copyright: {\textcopyright}2020. American Geophysical Union. All Rights Reserved.",
year = "2020",
month = may,
day = "1",
doi = "10.1029/2019JE006260",
language = "English (US)",
volume = "125",
journal = "Journal of Geophysical Research: Planets",
issn = "2169-9097",
publisher = "Wiley-Blackwell Publishing Ltd",
number = "5",
}