76 MAS SPECKLE-MASKING INTERFEROMETRY OF IRC- EVIDENCE FOR A CLUMPY SHELL STRUCTURE(10216 WITH THE SAO 6 M TELESCOPE )

We present the first K'-band image of the carbon star IRC +10 216 with 76 mas resolution. The diffraction-limited image was reconstructed fr om 6 m telescope speckle data using the speckle masking bispectrum met hod. The image shows that the dust shell of IRC +10 216 is extremely c lumpy. Five individual clouds within a 0.'' 21 radius of the central s tar have been resolved for the first time. On the basis of consistent theoretical models we argue that these structures are produced by circ umstellar dust formation. The fragmentation of the shell structure giv es most likely direct evidence for an inhomogeneous mass-loss process which may be interpreted in terms of large-scale surface convection-ce lls (Schwarzschild 1975) being a common phenomenon for red giants.