76 mas speckle-masking interferometry of IRC+10216 with the SAO 6m telescope: Evidence for a clumpy shell structure

TL;DR

This study presents a high-resolution K'-band image of IRC+10216 revealing a highly clumpy dust shell with five resolved clouds, providing evidence for inhomogeneous mass-loss likely caused by surface convection cells.

Contribution

First high-resolution image showing a clumpy dust shell structure of IRC+10216 with five resolved clouds, supporting models of inhomogeneous mass-loss in red giants.

Findings

Clumpy dust shell structure observed around IRC+10216.

Five individual clouds resolved within 210 mas radius.

Evidence suggests mass-loss driven by surface convection cells.

Abstract

We present the first K'-band image of the carbon star IRC+10216 with 76 mas resolution. The diffraction-limited image was reconstructed from 6m telescope speckle data using the speckle masking bispectrum method. The image shows that the dust shell of IRC+10216 is extremely clumpy. Five individual clouds within a 210 mas 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.