Hot Jupiters are asynchronous rotators

Fuente: arXiv
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Autori principali: Wazny, Marek, Menou, Kristen
Natura: Preprint
Pubblicazione: 2024
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author Wazny, Marek
Menou, Kristen
author_facet Wazny, Marek
Menou, Kristen
contents Hot Jupiters are typically assumed to be synchronously rotating, from tidal locking. Their thermally-driven atmospheric winds experience Lorentz drag on the planetary magnetic field anchored at depth. We find that the magnetic torque does not integrate to zero over the entire atmosphere. The resulting angular momentum feedback on the bulk interior can thus drive the planet away from synchronous rotation. Using a toy tidal-ohmic model and atmospheric GCM outputs for HD189733b, HD209458b and Kepler7b, we establish that off-synchronous rotation can be substantial at tidal-ohmic equilibrium for sufficiently hot and/or magnetized hot Jupiters. Potential consequences of asynchronous rotation for hot Jupiter phenomenology motivate follow-up work on the tidal-ohmic scenario with approaches that go beyond our toy model.
format Preprint
id arxiv_https___arxiv_org_abs_2409_07651
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Hot Jupiters are asynchronous rotators
Wazny, Marek
Menou, Kristen
Earth and Planetary Astrophysics
Hot Jupiters are typically assumed to be synchronously rotating, from tidal locking. Their thermally-driven atmospheric winds experience Lorentz drag on the planetary magnetic field anchored at depth. We find that the magnetic torque does not integrate to zero over the entire atmosphere. The resulting angular momentum feedback on the bulk interior can thus drive the planet away from synchronous rotation. Using a toy tidal-ohmic model and atmospheric GCM outputs for HD189733b, HD209458b and Kepler7b, we establish that off-synchronous rotation can be substantial at tidal-ohmic equilibrium for sufficiently hot and/or magnetized hot Jupiters. Potential consequences of asynchronous rotation for hot Jupiter phenomenology motivate follow-up work on the tidal-ohmic scenario with approaches that go beyond our toy model.
title Hot Jupiters are asynchronous rotators
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2409.07651