Probing exoplanetary magnetism via atomic alignment effect

TL;DR

This paper introduces a novel quantum-based method to detect weak magnetic fields of exoplanets through atomic alignment effects observed in transit spectra, offering a new way to study exoplanet magnetism.

Contribution

The work proposes a new observational technique leveraging atomic alignment to constrain exoplanet magnetic fields, sensitive to fields above approximately 0.001 G.

Findings

Potential to constrain exoplanet magnetic fields with current transit data.

Atomic alignment effect is sensitive to magnetic fields above ~0.001 G.

More precise measurements are needed for definitive results.

Abstract

The intrinsic magnetic fields of exoplanets affect the structure of their atmospheres and plasmaspheres and, therefore, the observational manifestations of transit absorptions. This work proposes a new method for constraining the presence or absence of relatively weak magnetic fields. The method is based on the quantum effect of atomic alignment of the lower energy level resulting in changing the absorption probabilities of individual transitions of multiplets from the equilibrium 2J+1 value. It appears to be sensitive to fields above ~0.001 G. We applied this method to some available transit observations of exoplanets and demonstrate that we indeed have the possibility to constrain the intrinsic magnetic field of some exoplanets right now. However, more precise and repetitive measurements, which might be available in near future, are needed for definite conclusions.