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The Ionisation Equilibrium for Heavy Elements

Published online by Cambridge University Press:  14 August 2015

D.R. Flower
D.R. Flower*
Affiliation:
Dept. of Physics, University College London, England

Abstract

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Calculations are being made of the distribution of the ions of heavy elements in planetary nebulae. Initial work has been concentrated on the central or He2+ zone of planetaries. The optical depths of ions of C, N, O, and Ne have been computed using ground state ionisation cross-sections and using approximations which should be substantially better than hydrogenic. A comparison has been made between the combined optical depth of the heavy elements and the optical depth of He+ in the far ultraviolet. The optical depths of the heavy elements in this spectral region may become significant, but a reasonable first approximation to the radiation field may be obtained by neglecting the absorption of all ions except He+. The distribution of the ions of the heavy elements has been calculated on this assumption.

Type
Session III – Physical Processes
Information
Symposium - International Astronomical Union , Volume 34: Planetary Nebulae , 1968 , pp. 205 - 208
Copyright
Copyright © Reidel 1968 

References

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