Letter to the Editor

No magnetic field variation with pulsation phase in the roAp star γ Equulei

¹ Institut für Astronomie, Universität Wien, Türkenschanzstraße 17, 1180 Wien, Austria
² Institute of Astronomy, Russian Academy of Sciences, Pyatnitskaya 48, 109017 Moscow, Russia
³ Uppsala Astronomical Observatory, Box 515, 751 20 Uppsala, Sweden

Corresponding author: O. Kochukhov, kochukhov@astro.univie.ac.at

Received: 26 November 2003
Accepted: 5 January 2004

Abstract

We present an analysis of 210 high-resolution time-resolved spectropolarimetric observations of the roAp star γ Equ obtained over three nights in August and September 2003. Radial velocity variations due to p-mode non-radial pulsations are clearly detected in the lines of rare-earth elements, in particular , and . In contrast, we find absolutely no evidence for the variation of the mean longitudinal magnetic field over the pulsation period in γ Equ at the level of 110–240 G which was recently reported by Leone & Kurtz ([CITE]). Our investigation of the variability of circularly polarized profiles of 13  lines demonstrates that, at the 3σ confidence level, no magnetic field variation with an amplitude above ≈ G was present in γ Equ during our monitoring of this star.