The challenge of measuring magnetic fields in strongly pulsating stars: the case of HD 96446

TL;DR

This paper investigates the magnetic field geometry of the pulsating He-rich Bp star HD 96446 by utilizing new spectropolarimetric data and an accurate rotation period, addressing previous measurement challenges caused by pulsations.

Contribution

It introduces a refined analysis method for magnetic field measurements in pulsating stars, incorporating detailed pulsation effects and a new rotation period for HD 96446.

Findings

Improved magnetic field geometry model for HD 96446

Enhanced understanding of pulsation impact on magnetic measurements

Reliable rotation period determination for the star

Abstract

Among the early B-type stars, He-rich Bp stars exhibit the strongest large-scale organized magnetic fields with a predominant dipole contribution. The presence of $\beta$ Cep-like pulsations in the typical magnetic early Bp-type star HD 96446 was announced a few years ago, but the analysis of the magnetic field geometry was hampered by the absence of a reliable rotation period and a sophisticated procedure for accounting for the impact of pulsations on the magnetic field measurements. Using new spectropolarimetric observations and a recently determined rotation period based on an extensive spectroscopic time series, we investigate the magnetic field model parameters of this star under more detailed considerations of the pulsation behaviour of the line profiles.