Activity and Magnetic Field Structure of the Sun-Like Planet Hosting Star HD 1237

TL;DR

This study analyzes the magnetic activity and surface magnetic field structure of the Sun-like star HD 1237, revealing a stable, complex magnetic topology with a 7-day rotation period, using spectro-polarimetric data and advanced Zeeman Doppler Imaging techniques.

Contribution

The paper introduces a new fit-stopping criterion based on information content and demonstrates the impact of local line profile modeling on magnetic field reconstruction.

Findings

Detected a 7-day rotational modulation of magnetic field.

Revealed a strong azimuthal magnetic ring and complex radial fields.

Magnetic maps are consistent over five months.

Abstract

We analyse the magnetic activity characteristics of the planet hosting Sun-like star, HD 1237, using HARPS spectro-polarimetric time-series data. We find evidence of rotational modulation of the magnetic longitudinal field measurements consistent with our ZDI analysis, with a period of 7 days. We investigate the effect of customising the LSD mask to the line depths of the observed spectrum and find that it has a minimal effect on shape of the extracted Stokes V profile but does result in a small increase in the S/N ($\sim$ 7%). We find that using a Milne-Eddington solution to describe the local line profile provides a better fit to the LSD profiles in this slowly rotating star, which also impacts the recovered ZDI field distribution. We also introduce a fit-stopping criterion based on the information content (entropy) of the ZDI maps solution set. The recovered magnetic field maps show a strong (+90 G) ring-like azimuthal field distribution and a complex radial field dominating at mid latitudes ($\sim$45 degrees). Similar magnetic field maps are recovered from data acquired five months apart. Future work will investigate how this surface magnetic field distribution impacts the coronal magnetic field and extended environment around this planet-hosting star.