Diffraction-limited Bispectrum Speckle Interferometry of the Carbon Star IRC +10 216 with the SAO 6 M telescope
Abstract
We present the first H- and K-band images of the carbon star IRC +10 216 with ~76 mas resolution. The images were reconstructed from 6 m telescope speckle data using the speckle masking bispectrum method. Several individual components of the circumstellar dust shell can be resolved at separations of approximately 100 to 200 mas from the central object. The dust clouds are located inside a larger nebulosity of a bipolar, X-shaped structure with an approximate NS polar axis. The high-resolution images as well as the SED of the object are compared with results of 2D radiative transfer calculations. The considerable brightness of one of the clouds can be explained if we assume that the central star is heavily obscured by circumstellar dust clouds. The radius of the central object was determined to be approximately 25 mas. Our high-resolution observations obtained at different epochs within the last 3 years suggest a dynamical evolution of the resolved structures caused by the expansion of the dust shell. For the interpretation of the resolved shell structures we compared our observations with time-dependent model calculations for carbon-rich circumstellar dust shells. The fragmentation of the dust shell can most likely be interpreted as direct evidence for a mass-loss process of extreme inhomogeneity, possibly caused by large-scale surface convection cells (supergranulation) of red giants discussed by Schwarzschild.
- Publication:
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Astronomische Gesellschaft Abstract Series
- Pub Date:
- 1998
- Bibcode:
- 1998AGAb...14..115O
- Keywords:
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- Carbon Stars: Speckle Interferometry;
- Carbon Stars: Circumstellar Dust