Exoplanet Magnetic Fields

By Keith Cowing
Status Report
April 27, 2024
Filed under ,
Exoplanet Magnetic Fields
(left) 2 GHz imaging of Jupiter’s inner electron radiation belts at different rotational phases. Jupiter’s dipole moment is offset from its rotation axis. Credit: NASA/JPL. (right) 8.4 GHz imaging of an electron radiation belt around the aurora-emitting ultracool dwarf LSR J1835+3259. Credit: Kao et al. (2023). — astro-ph.EP

Planetary magnetic fields are important indicators of planetary processes and evolution, from a planet’s outer core to its surface (if it possesses one) to its atmosphere and near-space environment.

Magnetic fields are most directly measured in situ, and determining whether distant planetary objects possess magnetic fields can be challenging. At present we have no unambiguous measurements of magnetic fields on exoplanets.

Nevertheless, it would be surprising if at least some exoplanets did not generate a magnetic field, like many planetary bodies in the solar system. This chapter provides an overview of the current understanding of exoplanetary magnetic fields and their consequences. In the next section we review the current understanding of planetary dynamo generation as it applies to solar system objects and discuss the implications for exoplanetary magnetic field generation.

Following this, we describe seven methods for determining the existence and strength of an exoplanetary magnetic field and discuss the near-term prospects for each method. We close by highlighting four main consequences of exoplanetary magnetic fields for a planet and its evolution.

David A. Brain, Melodie M. Kao, Joseph G. O’Rourke

Comments: Chapter 11 accepted for publication in the Reviews in Mineralogy and Geochemistry (RiMG) Volume 90 on “Exoplanets: Compositions, Mineralogy, and Evolution” edited by Natalie Hinkel, Keith Putirka, and Siyi Xu; 29 pages, 20 figures, 2 tables, and 12 equations
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR); Geophysics (physics.geo-ph); Space Physics (physics.space-ph)
Cite as: arXiv:2404.15429 [astro-ph.EP] (or arXiv:2404.15429v1 [astro-ph.EP] for this version)
Submission history
From: David Brain [via Natalie Hinkel as proxy]
[v1] Tue, 23 Apr 2024 18:19:23 UTC (5,724 KB)

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻