Exploring the Impact of Tilted Magnetic Dipoles on the Atmospheric Dynamics of Hot Jupiters: Towards an Improved Magnetohydrodynamic Framework

TL;DR

This study investigates how tilted magnetic dipoles affect hot Jupiter atmospheres, revealing asymmetries in temperature and wind patterns, and impacts on observable phase curves, using advanced 3D GCM simulations.

Contribution

It extends existing models by incorporating tilted magnetic dipoles into 3D GCMs, providing new insights into magnetic influence on atmospheric dynamics.

Findings

Tilted dipoles cause north-south asymmetries in temperature profiles.

Stronger magnetic fields increase phase curve amplitude.

Magnetic field orientation affects hot spot locations and wind deflections.

Abstract

The atmospheres of hot Jupiters lie in a dynamical regime without a solar system analogue. The strongly irradiated daysides reach temperatures sufficiently hot for substantial thermal ionization of atmospheric species, resulting in flows that can interact with the planetary magnetic field. These magnetic effects can significantly impact wind speeds, atmospheric temperatures, and large-scale circulation patterns. Previous work combining 3D atmospheric models and magnetic prescriptions has shown the impact of magnetic effects on temperature and velocity profiles are dependent on local atmospheric properties as well as the set of assumptions employed by the magnetic prescription. In this work, we examine a commonly employed magnetic model--a perfectly aligned dipole--in 3D General Circulation Models (GCMs) and extend this framework to allow for tilting of the deep-seated internal magnetic dipole field relative to the axis of rotation. We find that the inclusion of a tilted dipole introduces pronounced north-south asymmetries into the temperature profile leading to latitudinally shifted hotpots and deflection of winds that would otherwise be axially symmetric. We additionally simulate JWST/NIRSpec phase curves. We find that the strength of the magnetic field has the most significant effect on the simulated phase curves, with stronger magnetic fields increasing the amplitude of the phase curve and reducing the hot spot offset. Our model can provide qualitative insight into how the magnetic dipole strength or orientation may influence the large scale atmospheric dynamics and represents one of the most sophisticated incorporations of magnetic effects in GCMs for hot Jupiter atmospheres to date.