Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-12T11:52:05.748Z Has data issue: false hasContentIssue false
  • English
  • Français

Problems of Gas Dynamics in Planetary Nebulae

Published online by Cambridge University Press:  14 August 2015

F.D. Kahn
F.D. Kahn*
Affiliation:
Dept. of Astronomy, University of Manchester, England

Abstract

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 expansion of a typical planetary nebula is studied by means of a simple model, with spherical symmetry. It is shown that there is a build-up of radiation pressure, due to Lyman-α photons trapped in the nebula, and that this causes the initial acceleration outwards. After some 1·5 × 1011 sec the nebula will have a radius of the order of 1017 cm, and an expansion velocity of about 2 × 106 cm/sec. At roughly this time the dynamical effects of radiation pressure begin to be superseded by those of the recoil pressure at the ionization front, which continues to dominate until the nebula is fully ionized.

Finally some reasons are considered why most nebulae do not have spherically symmetrical shapes, but why so often they appear to be ring-like or butterfly-shaped.

Type
Session IV – Structure and Dynamics
Information
Symposium - International Astronomical Union , Volume 34: Planetary Nebulae , 1968 , pp. 236 - 248
Copyright
Copyright © Reidel 1968 

References

Aller, L.H. (1956) Gaseous Nebulae, Chapman and Hall, London, p. 74.Google Scholar
Axford, W.I. (1961) Phil. Trans. R. Soc. Lond., A253, 301.Google Scholar
Gebbie, K.B., Seaton, M.J. (1963) Nature, 199, 580.CrossRefGoogle Scholar
Harman, R.J., Seaton, M.J. (1966) Mon. Not. R. astr. Soc., 132, 15.Google Scholar
Henize, K.G. (1967) Astrophys. J. Suppl. Ser., No. 126.Google Scholar
Hjellming, R.M. (1966) Astrophys. J., 143, 420.Google Scholar
Khromov, G.S., Kohoutek, L. (1968) in the present volume, p. 227.Google Scholar
Mathews, W.G. (1965) Astrophys. J., 142, 1120.Google Scholar
Perek, L., Kohoutek, L. (1967) Catalogue of Galactic Planetary Nebulae, Academia, Prague.Google Scholar
Seaton, M.J. (1966) Mon. Not. R. astr. Soc., 132, 113.Google Scholar
Westerlund, B.E., Henize, K.G. (1967) Astrophys. J. Suppl. Ser., 126.Google Scholar