EDP Sciences
Free access
Issue
A&A
Volume 428, Number 1, December II 2004
Page(s) L13 - L16
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:200400095


A&A 428, L13-L16 (2004)
DOI: 10.1051/0004-6361:200400095

Letter

First detection of dust clouds around R CrB variable stars

P. de Laverny and D. Mékarnia

Observatoire de la Côte d'Azur, Dpt Cassiopée, CNRS - UMR 6202, BP 4229, 06304 Nice Cedex 4, France
    e-mail: [laverny;mekarnia]@obs-nice.fr

(Received 6 September 2004 / Accepted 23 October 2004 )

Abstract
From VLT/NACO diffraction-limited images of RY Sgr, we report the first direct detection of heterogeneities in the circumstellar envelope of a R Coronae Borealis variable star. Several bright and very large dust clouds are seen in various directions at several hundred stellar radii from RY Sgr, revealing high activity for the ejection of stellar material by R CrB variables. These observations do support the current interpretation that optically thick dust clouds are formed around the surface of this type of variable stars and, when passing between the star and the observer, produce the huge and sudden declines characterizing these objects in visible light. This is the first direct confirmation of a scenario proposed about 70 years ago.


Key words: stars: AGB and post-AGB -- stars: variables: general -- stars: individual: RY Sgr -- stars: mass-loss -- stars: circumstellar matter -- techniques: high angular resolution

SIMBAD Objects



© ESO 2004