The dynamical evolution of the fragmented, bipolar dust shell around the   carbon star IRC +10216: Rapid changes of a PPN-like structure?
  We present high-resolution J-, H-, and K-band observations and the first H-K color image of the carbon star IRC +10216. The images were reconstructed from 6m telescope speckle interferograms using the bispectrum speckle interferometry method. The H and K images with resolutions between 70mas and 92mas consist of several compact components within a 0.2" radius and a fainter asymmetric nebula. The brightest four components are denoted with A to D in the order of decreasing brightness in the 1996 image. A comparison of our images from 1995, 1996, 1997, and 1998 gives - almost like a movie of five frames - insight into the dynamical evolution of the inner nebula. For instance, the separation of the two brightest components A and B increased from 191 mas in 1995 to 265 mas in 1998. At the same time, component B is fading and the components C and D become brighter. The X-shaped bipolar structure of the nebula, most prominently present in the J-band image, implies an asymmetric mass loss. Such asymmetries are often present in protoplanetary nebulae but are unexpected for AGB stars. IRC +10216 is thus likely to be very advanced in its AGB evolution, shortly before turning into a protoplanetary nebula. The cometary shapes of A in the H and J images and in the 0.79 micron and 1.06 micron HST images suggest that the core of A is not the central star, but the southern lobe of a bipolar structure. The position of the central star is probably at or near the position of component B, where the H-K color has a value of 4.2. If the star is at or near B, then the components A, C, and D are likely to be located at the inner boundary of the dust shell. 
R. Osterbart (1), Y. Balega (2), T. Bloecker (1), A. Men'shchikov (3),   and G. Weigelt (1) ((1) Max-Planck-Institut fuer Ra...