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O and Of Stars

Published online by Cambridge University Press:  14 August 2015

Peter S. Conti
Peter S. Conti*
Affiliation:
Lick Observatory, University of California, Santa Cruz, Calif., U.S.A.

Extract

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My intention here is to discuss the ‘high temperature’ portion of this symposium and call attention to those stars that are called Of. There are some similarities in spectral appearance to WR stars, e.g. emission lines. I should first like to define what I think are the essential differences among four groups of hot stars;

O stars: Stars that have only absorption lines in the visible spectrum. Type O is distinguished from type B by the presence of He ii 4541 at MK dispersion. It may be that some (supergiants) O stars will have emission lines in the rocket UV region but this description will be primarily concerned with ground based observations.

Of stars: These are O type stars that also have λλ 4634,40 N iii in emission above the continuum. In addition to normal O star absorption lines and N iii emission, they may also have other lines in emission. I will discuss this further below.

Oe stars: These are O type stars that have emission in the hydrogen lines (or at least at Hα), but with no emission in N iii or in other lines. I personally think that this small class of objects is related to the Be stars in their evolutionary status and in their emission mechanism.

WR stars: These stars are primarily characterized by emission lines. The only absorption lines seen are violet shifted (P Cyg type). Although in some cases emission lines appear which are similar to those found in some Of stars, the latter types always have some unshifted absorption lines present. Several Of stars have P Cyg profiles in some lines.

Type
Section IV
Information
Symposium - International Astronomical Union , Volume 49: Wolf-Rayet and High Temperature Stars , 1973 , pp. 93 - 107
Copyright
Copyright © Reidel 1973 

References

Abt, H., Meinel, A. B., Morgan, W. W., and Tapscott, J. W.: 1968, Atlas of Low Dispersion Grating Stellar Spectra, Kitt Peak National Observatory, Tucson.Google Scholar
Auer, L. H. and Mihalas, D.: 1972, Astrophys. J. Suppl. 24, 193.CrossRefGoogle Scholar
Castor, J. I. and Nussbaumer, H.: 1972, Monthly Notices Roy. Astron. Soc. 155, 293.CrossRefGoogle Scholar
Conti, P. S. and Alschuler, W. R.: 1971, Astrophys. J. 170, 325.CrossRefGoogle Scholar
Mihalas, D.: 1971, Astrophys. J. 170, 541.CrossRefGoogle Scholar
Morton, D. C.: 1969, Astrophys. J. 158, 629.CrossRefGoogle Scholar
Simpson, E.: 1971, Astrophys. J. 165, 295.CrossRefGoogle Scholar
Walborn, N.: 1971, Astrophys. J. Letters 167, L31.CrossRefGoogle Scholar
Wolff, R. J.: 1963, Publ. Astron. Soc. Pacific 74, 485.CrossRefGoogle Scholar