EDP Sciences
Free Access
Volume 446, Number 3, February II 2006
Page(s) 1089 - 1094
Section Stellar structure and evolution
DOI https://doi.org/10.1051/0004-6361:20053794
Published online 20 January 2006
A&A 446, 1089-1094 (2006)
DOI: 10.1051/0004-6361:20053794

Accurate magnetic field measurements of Vega-like stars and Herbig Ae/Be stars

S. Hubrig1, R. V. Yudin2, 3, M. Schöller1 and M. A. Pogodin2, 3

1  European Southern Observatory, Casilla 19001, Santiago 19, Chile
    e-mail: shubrig@eso.org
2  Central Astronomical Observatory of the Russian Academy of Sciences at Pulkovo, 196140 Saint-Petersburg, Russia
3  Isaac Newton Institute of Chile, St.-Petersburg Branch, Russia

(Received 8 July 2005 /Accepted 19 September 2005)

We obtained accurate circular spectropolarimetric observations of a sample of Vega-like and Herbig Ae/Be stars with FORS 1 at the VLT in an attempt to detect their magnetic fields. No magnetic field could be diagnosed in any Vega-like star. The most accurate determination of a magnetic field, at 2.6 $\sigma$ level, was performed for the Vega-like star $\iota$ Cen, for which we measured $\left<B_z\right>=-77\pm30$ G. In the prototype of Vega-like stars, the star $\beta$ Pictoris, which shows conspicuous signs of chromospheric activity, a longitudinal magnetic field is measured only at ~1.5 $\sigma$ level. We diagnosed a longitudinal magnetic field for the first time at a level higher than 3 $\sigma$ for the two Herbig Ae stars HD 31648 and HD 144432 and confirm the existence of a previously detected magnetic field in a third Herbig Ae star, HD 139614. Finally, we discuss the discovery of distinctive Zeeman features in the unusual Herbig Ae star HD 190073, where the $\ion{Ca}{ii}$ doublet displays several components in both H and K lines. From the measurement of circular polarization in all Balmer lines from H$_\beta$ to H8, we obtain $\left<B_z\right>=+26\pm34$ G. However, using only the $\ion{Ca}{ii}$ H and K lines for the measurement of circular polarization, we are able to diagnose a longitudinal magnetic field at 2.8 $\sigma$ level, $\left<B_z\right>=+84\pm30$ G.

Key words: stars: pre-main sequence -- stars: magnetic fields -- stars: individual: HD 31648 -- stars: individual: HD 139614 -- stars: individual: HD 144432 -- stars: individual: HD 190073

SIMBAD Objects

© 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.