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Paper: Variable P Cygni: from UV to radio
Volume: 233, P Cygni 2000: 400 Years of Progress
Page: 83
Authors: Kolka, I.
Abstract: The observed variability of P Cygni at different wavelength regions will be reviewed. Starting with optical spectroscopic measurements we point to the main characteristic time-scale ~100 days and to other possible scales (from 17 to several hundred days) extracted by different authors from this type of data. We show the consistency of IUE spectroscopic data on P Cygni with the results in the optical region. The time-scales found in photometric, polarimetric and radio-flux time series of P Cygni will be compared with spectroscopic ones. It is stressed that the obvious time delay between variability cycles of many measurable quantities of P Cygni makes it difficult to search for reliable correlations among them. The most plausible explanation to the variability should be the changes in the stellar-wind structure of P Cygni - both at the base of the wind and in the outer wind regions. Structured (non-smooth) wind models for P Cygni are still lacking. There is an obvious need for such models to explain, on the one hand, the persistent spectroscopic features and, on the other hand, the different kinds of variability patterns.
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