INTERACTION OF A STELLAR WIND WITH CLUMPY STELLAR EJECTA IN A30

Clumpy, hydrogen-depleted material in the planetary nebula Abell 30 wa s ejected by its central star similar to 1000 yr ago. We present obser vations of Abell 30 showing compact, hydrogen-poor knots with wind-blo wn tails, obtained with the Wide Field Planetary Camera (WFPC2) on boa rd the Hubble Space Telescope, which offer an unprecedented view of th e interaction of a stellar wind with an ambient inhomogeneous medium. We can see how dense clumps of material, left within an expanding bubb le blown by a stellar wind, are being photoevaporated by the stellar r adiation and then swept back and accelerated by the wind. This acceler ated material mixes with the wind, slowing it and increasing its densi ty. The observed extent of this mass loading in Abell 30 supports clai ms that the mass-loading process is generally important in highly inho mogeneous astrophysical hows. In particular, mass loading of the magni tude observed in Abell 30 may explain the detection of X-ray-emitting gas in planetary nebulae.