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A Revised Classification System in the Red for S Stars

Published online by Cambridge University Press:  14 August 2015

Thomas B. Ake
Thomas B. Ake*
Affiliation:
Warner and Swasey Observatory, Case Western Reserve University

Abstract

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A classification scheme in the red spectral region for the S stars is described. For those stars exhibiting both ZrO and TiO bands, a modified version of the Keenan (1954) system is used for the assignment of temperature subtypes. For the pure S stars, a new system is introduced utilizing ZrO band strengths and the sodium D lines. Comparisons between the revised types and photometric colors have been made. In addition a new abundance index is proposed based on the relative strength of YO compared to ZrO and TiO. The revised system provides a connecting link between the M and C systems so that all red giants may be classified consistently from the strengths of TiO, ZrO and Na D.

Type
Poster Session
Information
Symposium - International Astronomical Union , Volume 80: The HR Diagram , 1978 , pp. 409 - 412
Copyright
Copyright © Reidel 1978 

References

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