This image shows a snapshot from a hydrodynamics simulation movie by Vincent Icke at http://www.strw.leidenuniv.nl/~icke/html/VincentScience.html. Colour channels are coded as follows: red is the gas density, green the gas pressure, and blue is the absolute value of the velocity. This image is a logarithmic rendering of the actual flow, in order to improve the dynamic range. Superimposed on the plot is an image of the shape of the original disk, before the wind from the central object blew it up. Note the antisymmetric or `point-symmetric' structure of the resulting nebula: the shape is symmetric under inversion through the central star.

The GFDL license on Prof Icke's homepage releases this image under a GFDL license.

Image by Vincent Icke

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