Peer-Reviewed Journal Details
Mandatory Fields
Meaburn, J.,Lopez, J. A.,Bryce, M.,Redman, M. P.
1998
Unknown
Astronomy & Astrophysics
Localised, high-speed flows within the hydrogen-deficient planetary nebula Abell 78
Published
()
Optional Fields
334
670
677
The remarkable velocity structure of the different components of the hydrogen-deficient planetary nebula Abell 78 have been revealed by obtaining spatially resolved profiles of the [O i] 6300 Angstromsii\ line with the Manchester echelle spectrometer combined with the 2.1 m San Pedro Martir telescope. The outer, diffuse, hydrogen-rich, 124'' diameter shell is expanding radially at 40 km s^{-1}$. The irregular, knotty, hydrogen-deficient 89arcsec \times 52arcsec \ inner shell has a similar overall expansion velocity but more complex kinematical structure. Similar to A 30, velocity spikes' are found in the position-velocity arrays of [O {sc i}] 6300 Angstromsii\ profiles from the inner shell. These extend to a further -140 km s^{-1} than the radial velocity of the approaching side of this inner shell. The [O {sc i}] 6300 Angstromsii\ bright, hydrogen-deficient core knots are distributed throughout an elongated disk expanding at \approx 25 km s^{-1}. There is kinematical evidence that polar bullets' are being ejected perpendicularly to this central feature at 380 km s^{-1}. Altogether velocity spikes' and other high-speed knots in the pv arrays of [O {sc i}] 6300 Angstromsii\ profiles are found over a 455 km s^{-1}$ range of radial velocities. Many of the kinematical phenomena are considered to be a consequence of the mass-loaded, shocked, wind from the central star.The remarkable velocity structure of the different components of the hydrogen-deficient planetary nebula Abell 78 have been revealed by obtaining spatially resolved profiles of the [O i] 6300 Angstromsii\ line with the Manchester echelle spectrometer combined with the 2.1 m San Pedro Martir telescope. The outer, diffuse, hydrogen-rich, 124'' diameter shell is expanding radially at 40 km s^{-1}$. The irregular, knotty, hydrogen-deficient 89arcsec \times 52arcsec \ inner shell has a similar overall expansion velocity but more complex kinematical structure. Similar to A 30, velocity spikes' are found in the position-velocity arrays of [O {sc i}] 6300 Angstromsii\ profiles from the inner shell. These extend to a further -140 km s^{-1} than the radial velocity of the approaching side of this inner shell. The [O {sc i}] 6300 Angstromsii\ bright, hydrogen-deficient core knots are distributed throughout an elongated disk expanding at \approx 25 km s^{-1}. There is kinematical evidence that polar bullets' are being ejected perpendicularly to this central feature at 380 km s^{-1}. Altogether velocity spikes' and other high-speed knots in the pv arrays of [O {sc i}] 6300 Angstromsii\ profiles are found over a 455 km s^{-1}$ range of radial velocities. Many of the kinematical phenomena are considered to be a consequence of the mass-loaded, shocked, wind from the central star.
0004-63610004-6361