View in EDS

Magnetization of Iron Meteorites up to the Meter in Size as Possible Analogs for Asteroid Psyche.

Saved in:
Bibliographic Details
Title: Magnetization of Iron Meteorites up to the Meter in Size as Possible Analogs for Asteroid Psyche.
Authors: Maurel, Clara1,2 (AUTHOR) cmaurel@cerege.fr, Clavé, Elise1,3 (AUTHOR), Gattacecca, Jérôme2 (AUTHOR), Uehara, Minoru2 (AUTHOR), Mansbach, Elias N.1 (AUTHOR), McCoy, Timothy J.4 (AUTHOR), Weiss, Benjamin P.1 (AUTHOR)
Source: Journal of Geophysical Research. Planets. Apr2025, Vol. 130 Issue 4, p1-13. 13p.
Subject Terms: Iron meteorites, Remanence, Magnetic measurements, Magnetic fields, Meteorites, Asteroids
Abstract: Meteorite paleomagnetic studies indicate planetesimal generated magnetic fields, but spacecraft magnetic measurements have yet to identify asteroidal natural remanent magnetization (NRM). This apparent discrepancy is of particular interest in the context of the NASA Psyche mission, which will search for evidence of past magnetic activity of the metal‐rich asteroid (16) Psyche. Here, we aim to test whether the NRM of meteorites inevitably drops below detectable values as specimen size increases, which could explain why asteroidal NRMs could never be detected. We focus on iron meteorites as possible analogs to (16) Psyche's constituent material. To do so, we measure the remanent magnetic field and estimate the NRM of samples of four iron meteorites with volumes between mm3 and m3. We find that their estimated NRMs decrease with increasing sample size but appear to plateau. These data are compatible with the idea that the bulk NRM of increasingly large objects becomes dominated by the fraction of this NRM produced by assemblages of magnetic minerals sharing a common magnetization direction. Moreover, all m3‐sized meteorites carry NRMs that are two orders of magnitude above the detectability limit of the Psyche Magnetometer, three of which are possibly pre‐terrestrial. These data, acquired on some of the largest masses of iron meteorites available on Earth, support the range of plausible NRM values for km‐size regions of (16) Psyche, used to establish the spacecraft Magnetometer's performance requirements. Nevertheless, large‐scale events such as brecciation of the asteroid following magnetization acquisition could always lower the asteroid's NRM below the detectability limit. Plain Language Summary: Asteroids and meteorites are fragments of planetesimals, the building blocks of planetary bodies. Laboratory studies of meteorite samples have shown that they contain remanent magnetization acquired in past magnetic fields. This indicates that, like the Earth, some planetesimals formed liquid metallic cores that generated these fields. In contrast, none of the seven spacecraft magnetic investigations at comets or asteroids have found reliable evidence for remanent magnetization. Searching for evidence of an ancient magnetic field is one of the objectives of the NASA Psyche mission that will orbit the metal‐rich asteroid Psyche beginning 2029. Solving the apparent discrepancy between laboratory and spacecraft measurements is important for interpretation of the mission's future data. Here, we analyze the correlation between magnetization and sample size up to the meter‐scale for iron meteorites, which are possible analogs of Psyche's constituent materials. Our data are compatible with the idea that, if the meteorite contains a fraction of magnetic minerals sharing a common magnetization direction, the bulk remanent magnetization of increasingly large specimens of this meteorite should reach a constant value. If asteroid Psyche is made of materials like known iron meteorites, it may therefore carry a magnetization detectable with the Psyche spacecraft Magnetometer. Key Points: The remanent magnetization of samples of individual iron meteorites decreases with size up to m3 volumes, trending to a plateau valueThis plateau may correspond to the fraction of total magnetization due to minerals sharing a preferential magnetization direction, if anyThe remanent magnetization of asteroid (16) Psyche may be detectable depending on the magnitude of such a unidirectional component [ABSTRACT FROM AUTHOR]
Copyright of Journal of Geophysical Research. Planets is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: GreenFILE
Description
Abstract:Meteorite paleomagnetic studies indicate planetesimal generated magnetic fields, but spacecraft magnetic measurements have yet to identify asteroidal natural remanent magnetization (NRM). This apparent discrepancy is of particular interest in the context of the NASA Psyche mission, which will search for evidence of past magnetic activity of the metal‐rich asteroid (16) Psyche. Here, we aim to test whether the NRM of meteorites inevitably drops below detectable values as specimen size increases, which could explain why asteroidal NRMs could never be detected. We focus on iron meteorites as possible analogs to (16) Psyche's constituent material. To do so, we measure the remanent magnetic field and estimate the NRM of samples of four iron meteorites with volumes between mm3 and m3. We find that their estimated NRMs decrease with increasing sample size but appear to plateau. These data are compatible with the idea that the bulk NRM of increasingly large objects becomes dominated by the fraction of this NRM produced by assemblages of magnetic minerals sharing a common magnetization direction. Moreover, all m3‐sized meteorites carry NRMs that are two orders of magnitude above the detectability limit of the Psyche Magnetometer, three of which are possibly pre‐terrestrial. These data, acquired on some of the largest masses of iron meteorites available on Earth, support the range of plausible NRM values for km‐size regions of (16) Psyche, used to establish the spacecraft Magnetometer's performance requirements. Nevertheless, large‐scale events such as brecciation of the asteroid following magnetization acquisition could always lower the asteroid's NRM below the detectability limit. Plain Language Summary: Asteroids and meteorites are fragments of planetesimals, the building blocks of planetary bodies. Laboratory studies of meteorite samples have shown that they contain remanent magnetization acquired in past magnetic fields. This indicates that, like the Earth, some planetesimals formed liquid metallic cores that generated these fields. In contrast, none of the seven spacecraft magnetic investigations at comets or asteroids have found reliable evidence for remanent magnetization. Searching for evidence of an ancient magnetic field is one of the objectives of the NASA Psyche mission that will orbit the metal‐rich asteroid Psyche beginning 2029. Solving the apparent discrepancy between laboratory and spacecraft measurements is important for interpretation of the mission's future data. Here, we analyze the correlation between magnetization and sample size up to the meter‐scale for iron meteorites, which are possible analogs of Psyche's constituent materials. Our data are compatible with the idea that, if the meteorite contains a fraction of magnetic minerals sharing a common magnetization direction, the bulk remanent magnetization of increasingly large specimens of this meteorite should reach a constant value. If asteroid Psyche is made of materials like known iron meteorites, it may therefore carry a magnetization detectable with the Psyche spacecraft Magnetometer. Key Points: The remanent magnetization of samples of individual iron meteorites decreases with size up to m3 volumes, trending to a plateau valueThis plateau may correspond to the fraction of total magnetization due to minerals sharing a preferential magnetization direction, if anyThe remanent magnetization of asteroid (16) Psyche may be detectable depending on the magnitude of such a unidirectional component [ABSTRACT FROM AUTHOR]
ISSN:21699097
DOI:10.1029/2024JE008810