Asteroseismology reveals the near-core magnetic field strength in the early-B star HD 43317

TL;DR

This study uses asteroseismology and magneto-hydrodynamical modeling to estimate the near-core magnetic field strength in the early-B star HD 43317, providing new insights into internal stellar magnetism.

Contribution

It introduces a novel magneto-asteroseismology approach to measure magnetic fields inside massive stars, which were previously inaccessible.

Findings

Magnetic field strength near the core is approximately 5×10^5 G.

The method constrains internal magnetic fields using gravity-mode pulsations.

This approach opens new avenues for studying stellar magnetism inside massive stars.

Abstract

Spectropolarimetic campaigns have established that large-scale magnetic fields are present at the surfaces of approximately 10% of massive dwarf stars. However, there is a dearth of magnetic field measurements for their deep interiors. Asteroseismology of gravity-mode pulsations combined with rotating magneto-hydrodynamical calculations of the early-B main-sequence star HD 43317 constrain its magnetic field strength to be approximately $5\times10^{5}$ G just outside its convective core. This proof-of-concept study for magneto-asteroseismology opens a new window into the observational characterisation of magnetic fields inside massive stars.