Hostname: page-component-669899f699-chc8l Total loading time: 0 Render date: 2025-04-29T06:34:00.577Z Has data issue: false hasContentIssue false
  • English
  • Français

Modelling the expansion of NGC 7027

Published online by Cambridge University Press:  25 May 2016

J. R. Walsh ,
G. Dudziak  and
N. A. Walton
J. R. Walsh
Affiliation:
1European Southern Observatory
G. Dudziak
Affiliation:
1European Southern Observatory
N. A. Walton
Affiliation:
2Royal Greenwich Observatory, La Palma

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The high angular resolution and dynamic range of VLA radio continuum mapping of planetary nebulae has raised expansion parallax measurement to the most sensitive method for determining PN distances (Hajian et al 1995). In order to derive the distance, the proper motion in the plane of the sky must be compared to the expansion velocity measured from emission line profiles. For a spherical PN with a measured line of sight expansion velocity, the comparison is simple. However most PN are not spherical, and their axisymmetric structures may be tilted to the line of sight; the line of sight expansion velocity cannot therefore be used for distance estimation from expansion proper motion. 3-D kinematic modelling is required in order to determine the expansion velocity in the plane of the sky.

Type
IV. Envelopes
Information
Symposium - International Astronomical Union , Volume 180: Planetary Nebulae , 1997 , pp. 286
Copyright
Copyright © Kluwer 1997 

References

Hajian, A. R., Terzian, Y., Bignell, C., 1993, AJ, 106, 1965.Google Scholar
Hajian, A. R., Terzian, Y., Bignell, C., 1995, AJ, 109, 2600.Google Scholar
Masson, C. R., 1989, ApJ, 336, 294.CrossRefGoogle Scholar
Middlemass, D., 1990, MNRAS, 244, 294.Google Scholar
Roelfsema, P. R., Goss, W. M., Pottasch, S. R., Zijlstra, A. A., 1991, A&A, 251, 611.Google Scholar
Walton, N. A., Walsh, J. R., Sahu, K. C., 1990, A&A, 230, 445.Google Scholar