The null result of a search for pulsational variations of the surface magnetic field in the roAp star gamma Equulei

TL;DR

This study conducted high-resolution spectroscopic measurements of gamma Equ to detect pulsational variations in its surface magnetic field but found no evidence of such variability, setting an upper limit of 5-10 G.

Contribution

The paper provides the first high-resolution, high S/N spectroscopic analysis to search for magnetic pulsational variations in gamma Equ, challenging previous reports.

Findings

No magnetic variability detected with pulsation phase

Upper limit of 5-10 G for magnetic modulation

Contradicts recent reports of magnetic pulsations

Abstract

We describe an analysis of the time-resolved measurements of the surface magnetic field in the roAp star gamma Equ. We have obtained a high-resolution and high S/N spectroscopic time-series, and the magnetic field was determined using Zeeman resolved profiles of the Fe II 6149.25 A and Fe I 6173.34 A lines. Contrary to recent reports we do not find any evidence of magnetic variability with pulsation phase, and derive an upper limit of 5-10 G for pulsational modulation of the surface magnetic field in gamma Equ.