The complex fossil magnetic field of the $\delta$ Scuti star HD\,41641

TL;DR

This study reports the detection of a complex fossil magnetic field in the $ ext{delta}$ Scuti star HD 41641, expanding the limited sample of known magnetic $ ext{delta}$ Scuti stars and providing insights into their magnetic field structures.

Contribution

First detection of a complex fossil magnetic field in a $ ext{delta}$ Scuti star, highlighting its unique magnetic properties compared to typical stellar magnetic fields.

Findings

HD 41641 is the fourth known magnetic $ ext{delta}$ Scuti star.

The star's magnetic field is of fossil origin.

The magnetic field has a complex structure, not dipolar.

Abstract

Only three magnetic $\delta$ Scuti stars are known as of today. HD 41641 is a $\delta$ Scuti star showing chemical peculiarities and rotational modulation of its light-curve, making it a good magnetic candidate. We acquired spectropolarimetric observations of this star with Narval at TBL to search for the presence of a magnetic field and characterize it. We indeed clearly detect a magnetic field in HD 41641, making it the fourth known magnetic $\delta$ Scuti star. Our analysis shows that the field is of fossil origin, like magnetic OBA stars, but with a complex field structure rather than the much more usual dipolar structure.