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  • Print publication year: 2014
  • Online publication date: April 2014

11 - Some miscellaneous topics in stellar spectroscopy: individual stars of note, stellar chromospheres, interstellar lines and ultraviolet spectroscopy from space

Summary

Introduction

A miscellany of topics is covered in this final chapter. The first section discusses the spectra of a few individual peculiar stars of unusual interest, which appear not to be members of the broader groups of peculiar stars discussed under the headings of Chapter 9.1 A large number of stellar spectral idiosyncrasies could have been included here, but I have restricted the discussion to only a few objects. Several outstanding candidates were omitted, including β Lyrae (probably the star with the greatest number of spectroscopic references in the entire literature), because it has been referred to, albeit briefly, in earlier chapters; and also the spectroscopic binary and supergiant ζ Aurigae, with its atmospheric eclipses.

Secondly, two major topics of importance are treated which fell outside the headings in earlier chapters. The Wilson–Bappu effect encompasses the calcium emission lines from the chromospheres, or hot turbulent outer layers, of the cooler stars. The analysis of these lines has become a major method of determining stellar luminosities and distances.

In addition, the topic of interstellar absorption lines in stellar spectra is reviewed. This is an appropriate topic for a book on stellar spectroscopy, as it is the analysis of the starlight that reveals the presence of interstellar clouds along the line of sight to the star. Moreover, this subject played a big role in the advent of far ultraviolet spectroscopy from above the atmosphere.

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