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Pole-On Cataclysmic Variables as Be Stars

Published online by Cambridge University Press:  23 September 2016

R. F. Garrison*
Affiliation:
David Dunlap Observatory, University of Toronto, Box 360, Richmond Hill, Ontario, Canada L4C 4Y6

Extract

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Cataclysmic-variable stars (CVs) are technically Be stars, since Balmer emission lines appear in their spectra. In general, CV spectra are so unusual that they are easily recognized. The main features are extremely broad, shallow hydrogen lines with broad, faint emission cores. The Balmer emission decrement is very slow, more like that of an H II region than that of a normal Be star. The Balmer decrement in cataclysmic variable stars has been discussed by Elitzur, et al.

If a CV were viewed pole-on, the spectrum might be quite different. It could exhibit a smooth continuum or may even resemble a normal Be star, except for the Balmer decrement. In this case, there may be a bright cataclysmic variable lurking in the Be star class. A possible example is the star NS 274-67, an 03e star described by Conti et al. (1986), which has Balmer emission from H-beta to H-ep-silon, but no nebular emission at [0 II] or [0 III].

Type
IV. Models
Copyright
Copyright © Cambridge University Press 1987

References

Conti, P., Garmany, C., and Massey, P. 1986, A. J. 92, 48.Google Scholar
Elitzur, M., Ferland, G., Matthews, W., and Shields, G. 1983, Ap.J. 272, L55.CrossRefGoogle Scholar
Garrison, R.F., Hiltner, W.A., and Schild, R.E. 1977, Ap.J.Suppl. 35, 111.CrossRefGoogle Scholar