Inflating Hot Jupiters With Ohmic Dissipation

TL;DR

This paper proposes a magnetohydrodynamic mechanism where atmospheric winds interacting with planetary magnetic fields induce currents that cause Ohmic heating, potentially explaining the inflated radii of hot Jupiters.

Contribution

It introduces an analytical model for Ohmic dissipation in hot Jupiters, linking atmospheric winds and magnetic fields to planetary radius inflation, a novel approach to a long-standing problem.

Findings

Model predicts sufficient Ohmic heating to explain observed radii

Application to specific exoplanets supports the mechanism's plausibility

Provides a new theoretical framework for understanding hot Jupiter inflation

Abstract

We present a new, magnetohydrodynamic mechanism for inflation of close-in giant extrasolar planets. The idea behind the mechanism is that current, which is induced through interaction of atmospheric winds and the planetary magnetic field, results in significant Ohmic dissipation of energy in the interior. We develop an analytical model for computation of interior Ohmic dissipation, with a simplified treatment of the atmosphere. We apply our model to HD209458b, Tres-4b and HD189733b. With conservative assumptions for wind speed and field strength, our model predicts a generated power that appears to be large enough to maintain the transit radii, opening an unexplored avenue towards solving a decade-old puzzle of extrasolar gas giant radius anomalies.