EDP Sciences
Free access
Volume 402, Number 2, May I 2003
Page(s) 729 - 731
Section Stellar atmospheres
DOI http://dx.doi.org/10.1051/0004-6361:20030283

A&A 402, 729-731 (2003)
DOI: 10.1051/0004-6361:20030283

Magnetic field measurements of Ap stars

Discovery of a strong magnetic field in HD 18610
Ch. Stütz1, T. Ryabchikova1, 2 and W. W. Weiss1

1  Institute for Astronomy (IfA), University of Vienna, Türkenschanzstrasse 17, 1180 Wien, Austria
2  Institute of Astronomy, Russian Academy of Sciences, Pyatnitskaya 48, 109017 Moscow, Russia

(Received 5 July 2002 / Accepted 12 February 2003)

HD 18610 was included in our project on abundance determination of rapidly oscillating (roAp) and non-oscillating (noAp) cool chemically peculiar stars. Already a preliminary investigation of the raw spectra indicated the presence of an intense magnetic field which was confirmed by a more detailed analysis.

To determine the magnetic field strength we primarily used the Fe II line at 6149.26 Å, a strong line which is split in a anomalous Zeeman doublet. HD 18610 is a Cr-Eu-Sr non-pulsating Ap star with a $T_{\rm eff}$ and $\log g$ typical for roAp stars. The classification of this star as a CP2 star (Preston 1974) was confirmed with $\Delta$a photometry by Maitzen & Vogt (1983). In the present investigation we derived a mean magnetic field modulus of $\vert\vec{B}\vert=5\,700 \pm 200\,$G.

Key words: stars: individual: HD 18610 -- stars: magnetic fields -- stars: chemically peculiar

Offprint request: Ch. Stütz, stuetz@tycho.astro.univie.ac.at

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