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Astron. Astrophys. 336, 980-985 (1998)


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How thin B[e] supergiant disks can be?

Ph. Stee

Observatoire de la Côte d'Azur, Département FRESNEL, CNRS UMR 6528, 2130, route de l'Observatoire, Caussols, F-06460 St. Vallier de Thiey, France

Received 29 January 1998 / Accepted 4 June 1998

Abstract

We investigate the shape of the envelope around B[e] supergiant stars using a model developed by Stee & Araùjo (1994) for Be stars. We obtain mass loss rates [FORMULA] between [FORMULA] and [FORMULA] [FORMULA]yr-1 depending on mass flux variation from polar to equatorial regions. We find that winds from B[e] stars can be so dense that they become optically thick in the continuum, masking the photosphere of the central star. For mass loss rates larger than [FORMULA][FORMULA]yr-1 it is not possible to see the stellar photosphere even for pole-on B[e] stars. Using a two-component wind model driven by optically thin lines in the equatorial regions and optically thick lines in the polar regions, we obtain a relation between the geometry of the envelope and the total mass loss. We also put limits on the inclination angle ([FORMULA]) beyond which the stellar photosphere is masked. Finally, this study seems to discard "wind-compressed disks" (WCD) models as a possible senario for B[e] supergiant envelopes.

Key words: circumstellar matter – stars: emission-line, Be – stars: mass-loss – stars: supergiants

Send offprint requests to: stee@obs-nice.fr

© European Southern Observatory (ESO) 1998

Online publication: July 27, 1998

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