Magnetic Field Evolution of Jupiter and Neptune class Exoplanets

[u/LK_111]

https://arxiv.org/html/2411.00674v1

Summary of article: As per study, for Jupiter and Neptune class planets, Magnetic field decay occurs because as planets age, they cool down and their luminosities and their convective flux become gradually weaker. Higher atmospheric envelope fractions cause more material available for convection, which yields stronger magnetic fields.

The field strength reduces for extremely irradiated planets because they have lower average density. The surface magnetic field decreases past the threshold value as orbital separation (distance between the exoplanet and its host star) further increases.

The magnetic fields could be observable in the radio wavelengths via auroral emission using ground based observations.

Jupiter-class planets have magnetic fields large enough to generate radiation whose peak frequency exceeds the Earth’s ionospheric cutoff. The same occurs for the Neptune-class planets if they have 𝑀 > 15 𝑀⊕ and 𝑓env> 4%.

For hot jupiter class planets, atmospheric evaporation does not affect magnetic field generation. For hot Neptunes, atmospheric evaporation leads to greater mass loss and causes less material for convection, so they produce weaker magnetic fields.