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The Wolf-Rayet Stars – The General Problems of Extended Atmospheres and Non-Classical Atmospheric Models

Published online by Cambridge University Press:  14 August 2015

Richard N. Thomas*
Affiliation:
Joint Institute for Laboratory Astrophysics, Boulder, Colo., U.S.A.

Extract

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The Organizers of this Symposium asked that I make some introductory remarks on the general problems of extended atmospheres, the degree of common behaviour among stars having such a feature, and how the Wolf-Rayet stars may contribute to the progress of our inference in this area. In a Symposium entitled Wolf-Rayet and High Temperature Stars, not ‘Stars With Extended Atmospheres’, the implication of your charge to me is clear. You are implicitly assuming that the Wolf-Rayet phenomenon is primarily one of extended atmospheres. I can indeed give you a succinct summary of my outlook on these three points under such an implicit assumption, elaborating in more detail only to the extent as is necessary in order to be specific. And, as I am sure you had planned, because my outlook is considerably contrary to this implicit assumption, at least my remarks will spark controversy from the outset of this Symposium. I would like to emphasize that it is the summary of outlook to which I attach most weight and which I think is correct. The more specific details may change as we develop the mosaic of the summary, which has two main points. First, when you ask the physical picture of the general structure of a stellar atmosphere, you will eventually reach the conclusion that part of this general structure is an extended atmosphere for all stars. A focus upon some class, or classes, of them as exhibiting ‘extended atmospheres’ simply reflects the degree to which particular observations focus upon a particular part of the atmosphere as a function of the particular characteristics of the considered star. Second, in this context, I think that the implication that the Wolf-Rayet phenomenon is primarily one of extended atmospheres is incorrect. You are confusing a single system with a more deep-seated disease. My emphasis will lie on the disease as a whole, and the Wolf-Rayet stars as a guide to its diagnostics. I want to emphasize that this outlook on the general model of an atmosphere has developed jointly with K. B. Gebbie, J-C. Pecker, and F. Praderie; so most of what I say simply reflects this joint work.

Type
Section I
Copyright
Copyright © Reidel 1973 

References

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