Astron. Astrophys. 333, L51-L54 (1998)

Letter to the Editor

76 mas speckle-masking interferometry of IRC +10 216 with the SAO 6 m telescope: Evidence for a clumpy shell structure

G. Weigelt ¹, Y. Balega ², T. Blöcker ¹, A.J. Fleischer ³, R. Osterbart ¹ and J.M. Winters <sup>3

1</sup> Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany
² Special Astrophysical Observatory, Nizhnij Arkhyz, Zelenchuk region, 35147 Karachai-Cherkesia, Russia
³ Technische Universität Berlin, Institut für Astronomie und Astrophysik, Sekr. PN 8-1, Hardenbergstrasse 36, D-10623 Berlin, Germany

Received 18 December 1997 / Accepted 10 March 1998

Abstract

We present the first -band image of the carbon star IRC +10 216 with 76 mas resolution. The diffraction-limited image was reconstructed from 6 m telescope speckle data using the speckle masking bispectrum method. The image shows that the dust shell of IRC +10 216 is extremely clumpy. Five individual clouds within a radius of the central star have been resolved for the first time. On the basis of consistent theoretical models we argue that these structures are produced by circumstellar dust formation. The fragmentation of the shell structure gives most likely direct evidence for an inhomogeneous mass-loss process which may be interpreted in terms of large-scale surface convection-cells (Schwarzschild 1975) being a common phenomenon for red giants.

Key words: techniques: image processing stars: carbon circumstellar matter stars: individual: IRC +10 216 stars: mass-loss stars: AGB, post-AGB

Send offprint requests to: G. Weigelt
Correspondence to: weigelt@mpifr-bonn.mpg.de

SIMBAD Objects

Contents

• 1. Introduction
• 2. Observations and speckle masking results
• 3. Discussion
  • 3.1. Evolutionary status
  • 3.2. Discrete dust layers
  • 3.3. Inhomogeneuos mass loss
• 4. Conclusion
• Acknowledgements
• References

© European Southern Observatory (ESO) 1998

Online publication: April 20, 1998
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