Hostname: page-component-586b7cd67f-g8jcs Total loading time: 0 Render date: 2024-11-27T15:41:10.107Z Has data issue: false hasContentIssue false
  • English
  • Français

Theory of Intrinsic Variability in Hot-Star Winds

Published online by Cambridge University Press:  03 August 2017

Stanley P. Owocki
Stanley P. Owocki*
Affiliation:
Bartol Research Institute University of Delaware Newark, DE 19716 USA

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The winds of the hot, luminous, O, B, and WR stars are driven by the line-scattering of the star's continuum radiation flux. Several kinds of observational evidence indicate that such winds are highly structured and variable, and it seems likely that a root cause of this variability is the known strong instability of the line-driving mechanism. Initial dynamical models of the nonlinear evolution of this instability confirm that the wind indeed becomes highly structured, with large amplitude (~500 – 1000 km/s) shocks that separate high-speed rarefied flow from lower speed, dense shells. Remarkably, such variability can often have an intrinsic character, persisting even in the absence of explicit perturbation, and it now appears that this is a direct consequence of a degeneracy in the steady-state solutions for such models. However, recent work indicates that including scattering effects, which have so far been ignored in these pure-absorption models, might reduce or even break this steady-state solution degeneracy; through the “line-drag” effect, scattering can also reduce the strength of the instability, possibly rendering it an advective character for which wind variability now requires explicit perturbation from below. This review will examine the consequences of these ideas for understanding the likely nature of wind variability among the various kinds of early-type stars.

Type
Session III. Intrinsic Variability
Information
Symposium - International Astronomical Union , Volume 143: Wolf–Rayet Stars and Interrelations with other Massive Stars in Galaxies , 1991 , pp. 155 - 166
Copyright
Copyright © Kluwer 1991 

References

Abbott, D. C. 1980, Ap. J., 242, 1183.CrossRefGoogle Scholar
Abbott, D. C. 1988, in Solar Wind VI, ed. Pizzo, V. J., Holzer, T. E., and Sime, D. G. (Boulder: NCAR/TN-306), p.149.Google Scholar
Abbott, D. C., Bieging, J. H., and Churchwell, E. 1984, Ap. J., 280, 671.Google Scholar
Baade, D. 1988, in O Stars and Wolf-Rayet Stars, ed. Conti, P. S. and Underhill, A. B. (NASA SP-497), p.137.Google Scholar
Bers, A. 1983, in Handbook of Plasma Physics, Vol. 1: Basic Plasma Physics I, ed. Galeev, A. A. and Sudan, R. N. (Amsterdam: North-Holland), p. 451.Google Scholar
Carlberg, R. G. 1980, Ap. J., 241, 1131.CrossRefGoogle Scholar
Cassinelli, J. P., and Swank, J. H. 1983, Ap. J., 271, 681.Google Scholar
Castor, J. I. 1987, in Instabilities in Luminous Early Type Stars, ed. Lamers, H. J. G. L. M. and de Loore, C. W. H., (Dordrecht: Reidel), p. 159.Google Scholar
Castor, J. I., Abbott, D. C., and Klein, R. I. 1975, Ap. J., 195, 157. (CAK) Google Scholar
Fullerton, A. W. 1990, Ph.D. Thesis, University of Toronto.Google Scholar
Harnden, F. R. et al. 1979, Ap. J. (Letters), 234, L51.Google Scholar
Henrichs, H. F., Kaper, L., and Zwarthoed, G. A. A. 1988, in A Decade of UV Astronomy with the IUE Satellite, Vol. 2, ed. by Rolfe, E. J. (Paris: ESA), p.145.Google Scholar
Krolik, J. H., and Raymond, J. C. 1985, Ap. J., 298, 660.CrossRefGoogle Scholar
Kudritzki, R. P., and Hummer, D. G. 1990, Ann. Rev. Astr. Ap., 28, in press.Google Scholar
Lamers, H. J. G. L. M., and Morton, D. C. 1976, Ap. J. Suppl., 32, 715.Google Scholar
Lucy, L. B. 1982a, Ap. J., 255, 278.Google Scholar
Lucy, L. B. 1982b, Ap. J., 255, 286.Google Scholar
Lucy, L. B. 1984, Ap. J., 284, 351.CrossRefGoogle Scholar
Lucy, L. B., and Solomon, P. M. 1970, Ap. J., 159, 879.Google Scholar
MacFarlane, J. J., and Cassinelli, J. P. 1989, Ap. J., 347, 1090.Google Scholar
MacGregor, K. B., Hartmann, L., and Raymond, J. C. 1979, Ap. J., 231, 514.CrossRefGoogle Scholar
Mullan, D. J. 1984, Ap. J., 283, 303.Google Scholar
Mullan, D. J. 1985, Astr. Ap., 165, 157.Google Scholar
Olson, G. L., Auer, L. H., and Buchler, J. R., J. Q. R. S. T., 35, 431.Google Scholar
Owocki, S. P. 1990, Reviews of Modern Astronomy, 3, (Berlin: Springer), in press.Google Scholar
Owocki, S. P., and Rybicki, G. B. 1984, Ap. J., 284, 337.Google Scholar
Owocki, S. P., and Rybicki, G. B. 1985, Ap. J., 299, 265.CrossRefGoogle Scholar
Owocki, S. P., and Rybicki, G. B. 1986, Ap. J., 309, 127.Google Scholar
Owocki, S. P., and Rybicki, G. B. 1990, Ap. J., submitted.Google Scholar
Owocki, S. P., Castor, J. I., and Rybicki, G. B. 1988, Ap. J., 335, 914. (OCR) Google Scholar
Owocki, S. P., Poe, C. H., and Castor, J. I. 1990, in Properties of Hot Luminous Stars, Garmany, C. D., ed. (San Francisco: ASP), p.283.Google Scholar
Owocki, S. P., and Zank, G. P. 1990, Ap. J., submitted.Google Scholar
Parker, E. N. 1963, Interplanetary Dynamical Processes, (New York: Interscience).Google Scholar
Pauldrach, A., Puls, J., and Kudritzki, R. P. 1986, Astr. Ap., 164, 86.Google Scholar
Poe, C. H., Owocki, S. P., and Castor, J. I. 1990, Ap. J., 355, in press. (POC) Google Scholar
Prinja, R. K., and Howarth, I. D. 1988, M. N. R. A. S., 233, 123.Google Scholar
Robert, C., and Moffat, A. F. J. 1990, in Properties of Hot Luminous Stars, Garmany, C. D., ed. (San Francisco: ASP), p.271.Google Scholar
Rybicki, G. B. 1987, in Instabilities in Luminous Early Type Stars, ed. Lamers, H. J. G. L. M. and de Loore, C. W. H., (Dordrecht: Reidel), p. 175.Google Scholar
Sobolev, V. V. 1960, Moving Envelopes of Stars, (Cambridge: Harvard University Press).Google Scholar
Willson, L. A., and Hill, S. J. 1979, Ap. J., 228, 854.Google Scholar