Published in: ApJ, 449, 143
Clumpy, hydrogen-depleted material in the planetary nebula Abell 30 was ejected by its central star ~1000 yr ago. We present observations of Abell 30 showing compact, hydrogen-poor knots with wind-blown tails, obtained with the Wide Field Planetary Camera (WFPC2) on board the Hubble Space Telescope, which offer an unprecedented view of the interaction of a stellar wind with an ambient inhomogeneous medium. We can see how dense clumps of material, left within an expanding bubble blown by a stellar wind, are being photoevaporated by the stellar radiation and then swept back and accelerated by the wind. This accelerated material mixes with the wind, slowing it and increasing its density. The observed extent of this mass loading in Abell 30 supports claims that the mass-loading process is generally important in highly inhomogeneous astrophysical flows. In particular, mass loading of the magnitude observed in Abell 30 may explain the detection of X-ray--emitting gas in planetary nebulae.