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Line and Continuous Spectra of Hydrogen and Helium

  • Lawrence H. Aller
Chapter
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Part of the Astrophysics and Space Science Library book series (ASSL, volume 112)

Abstract

In H II regions, planetary nebulae and perhaps radio galaxies, Seyfert galaxies and quasars, the H and He lines are produced by a process of photoionization followed by recombination and cascade. Expressions for calculating the rates of the various atomic processes, recapture and cascade (in this instance) are available. We should be able to calculate the population in each level and find the relative intensities of observable lines in the H and He spectrum. In particular, we should be able to compute the relative intensities of the Balmer lines, the so-called Balmer Decrement.

Keywords

Continuous Spectrum Optical Depth Brightness Temperature Optical Thickness Local Thermodynamic Equilibrium 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References to Chapter 4

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Copyright information

© D. Reidel Publishing Company, Dordrecht, Holland 1984

Authors and Affiliations

  • Lawrence H. Aller
    • 1
  1. 1.University of CaliforniaLos AngelesUSA

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