HD 178892 – a cool Ap star with extremely strong magnetic field

T. Ryabchikova; O. Kochukhov; D. Kudryavtsev; I. Romanyuk; E. Semenko; S. Bagnulo; G. Lo Curto; P. North; M. Sachkov

doi:10.1051/0004-6361:200500222

Home

All issues

Volume 445 / No 3 (January III 2006)

A&A, 445 3 (2006) L47-L50

Abstract

Free Access

Issue		A&A Volume 445, Number 3, January III 2006


Page(s)		L47 - L50
Section		Letters
DOI		https://doi.org/10.1051/0004-6361:200500222
Published online		03 January 2006

A&A 445, L47-L50 (2006)

Letter to the Editor

HD 178892 – a cool Ap star with extremely strong magnetic field

T. Ryabchikova¹^,2, O. Kochukhov³, D. Kudryavtsev⁴, I. Romanyuk⁴, E. Semenko⁴, S. Bagnulo⁵, G. Lo Curto⁵, P. North⁶ and M. Sachkov²

¹ Institute for Astronomy, University of Vienna, Türkenschanzstrasse 17, 1180 Wien, Austria e-mail: ryabchik@inasan.ru
² Institute of Astronomy, Russian Academy of Sciences, Pyatnitskaya 48, 109017 Moscow, Russia
³ Department of Astronomy and Space Physics, Uppsala University Box 515, 751 20 Uppsala, Sweden
⁴ Special Astrophysical Observatory of RAS, Nizhnij Arkhyz 369167, Russia
⁵ European Southern Observatory, Casilla 19001, Santiago 19, Chile
⁶ Laboratoire d'Astrophysique, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire, 1290 Sauverny, Switzerland

Received: 25 October 2005
Accepted: 29 November 2005

Abstract

We report a discovery of the Zeeman resolved spectral lines, corresponding to the extremely large magnetic field modulus $\langle B_{\rm s}\rangle$ = 17.5 kG, in the cool Ap star HD 178892. The mean longitudinal field of this star reaches 7.5 kG, and its rotational modulation implies the strength of the dipolar magnetic component $B_{\rm p}\ge$ 23 kG. We have revised rotation period of the star using the All Sky Automated Survey photometry and determined P = 8.2478 d. Rotation phases of the magnetic and photometric maxima of the star coincide with each other. We obtained Geneva photometric observation of HD 178892 and estimated T_eff = $7700\pm250$ K using photometry and the hydrogen Balmer lines. Preliminary abundance analysis reveals abundance pattern typical of rapidly oscillating Ap stars.

© ESO, 2006

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.