LOCALIZED, HIGH-SPEED FLOWS WITHIN THE HYDROGEN-DEFICIENT PLANETARY-NEBULA ABELL-78

The remarkable velocity structure of the different components of the h ydrogen-deficient planetary nebula Abell 78 have been revealed by obta ining spatially resolved profiles of the [O III] 5007 Angstrom line wi th the Manchester echelle spectrometer combined with the 2.1 m San Ped ro Martir telescope. The outer, diffuse, hydrogen-rich, 124'' diameter shell is expanding radially at 40 km s(-1) The irregular, knotty, hyd rogen-deficient 89'' x 52'' inner shell has a similar overall expansio n velocity but more complex kinematical structure. Similar to A 30, ve locity 'spikes' are found in the position-velocity arrays of [O III] 5 007 Angstrom. profiles from the inner shell. These extend to a further -140 km s(-1) than the radial velocity of the approaching side of thi s inner shell. The [O III] 5007 Angstrom bright, hydrogen-deficient co re knots are distributed throughout an elongated disk expanding at app roximate to 25 km s(-1). There is kinematical evidence that 'polar bul lets' are being ejected perpendicularly to this central feature at 380 km s(-1). Altogether 'velocity spikes' and other high-speed knots in the pv arrays of [O III] 5007 Angstrom profiles are found over a 455 k m s(-1) range of radial velocities. Many of the kinematical phenomena are considered to be a consequence of the mass-loaded, shocked, wind f rom the central star.