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Advances in modeling of Wolf-Rayet stars

Published online by Cambridge University Press:  26 May 2016

D. John Hillier
D. John Hillier*
Affiliation:
Department of Physics and Astronomy, University of Pittsburgh, 3941 O'Hara Street, Pittsburgh, PA 15260, USA

Abstract

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Due to advances in computer power and numerical techniques non-LTE line-blanketing calculations for Wolf-Rayet (WR) stars are now routine. The incorporation of blanketing has led to significant improvements in spectral analyses, and to a systematic increase in the derived WR luminosities. To make further progress we need to understand the distribution, structure, and strength of inhomogeneities in the stellar wind, and in turn, how these influence diagnostics of WR stellar parameters, and radiative driving. Further, we need to understand the physical process that initiates mass loss in WR stars. Problems with existing wind calculations are examined, and the difficulty of observationally determining the shape of the velocity law around the sonic point is discussed. To determine the wind dynamics around the sonic point, it is essential to include ions with ionization potentials in excess of 300 eV. A recent study of the 07 Iaf+ star AV 83 is discussed. The analysis indicates the existence of a clumped wind, and a relatively slow wind acceleration with the velocity law characterized by β = 2. The importance of extreme Of stars, for understanding both WR and O-type star winds, is stressed. Spectra of such stars show numerous photospheric and wind features, allowing the entire wind to be probed observationally.

Type
Part 1. Atmospheres of Massive Stars
Information
Symposium - International Astronomical Union , Volume 212: A Massive Star Odyssey: From Main Sequence to Supernova , 2003 , pp. 70 - 79
Copyright
Copyright © Astronomical Society of the Pacific 2003 

References

Abbott, D.C., Bieging, J.H., Churchwell, E. 1981, ApJ 250, 645.CrossRefGoogle Scholar
Antokhin, I.I., Cherepashchuk, A.M. 2001, Astron. Zh. 78, 313 (= Astron. Reports 45, 269).Google Scholar
Barlow, M.J., Storey, P.J. 1993, in: Weinberger, R. & Acker, A. (eds.), Planetary Nebulae, Proc. IAU Symp. No. 155 (Dordrecht: Kluwer), p. 105.Google Scholar
Cardelli, J.A., Clayton, G.C., Mathis, J.S. 1988, ApJ (Letters) 329, L33.CrossRefGoogle Scholar
Crowther, P.A., Pasquali, A., De Marco, O., et al. 1999, A&A 350, 1007.Google Scholar
Crowther, P.A., Dessart, L., Hillier, D.J., et al. 2002a, A&A 392, 653.Google Scholar
Crowther, P.A., Hillier, D.J. Evans, C.J., et al. 2002b, ApJ 579, 774.CrossRefGoogle Scholar
De Marco, O., Barlow, M.J., Storey, P.J. 1997a, MNRAS 292, 86.Google Scholar
De Marco, O., Storey, P.J., Barlow, M.J. 1997b, MNRAS 297, 999.Google Scholar
De Marco, O., Crowther, P.A. 1998, MNRAS 296, 419.Google Scholar
Dessart, L., Owocki, S.P. 2002, A&A 383, 1112.Google Scholar
Gayley, K.G., Owocki, S.P., Cranmer, S.R. 1995, ApJ 442, 296.Google Scholar
Gräfener, G., Koesterke, L., Hamann, W.-R. 2002, A&A 387, 244.Google Scholar
Hamann, W.-R., Schwarz, E. 1992, A&A 261, 523.Google Scholar
Hamann, W.-R., Koesterke, L. 2000, A&A 360, 647.Google Scholar
Herald, J.E., Hillier, D.J., Schulte-Ladbeck, R.E. 2001, ApJ 548, 932.Google Scholar
Hillier, D. J. 1991a, in: Crivellari, L., Hubeny, I. & Hummer, D. G. (eds.), Stellar Atmospheres: Beyond Classical Models, NATO ASI Ser. Vol. 341 (Dordrecht: Kluwer), p. 317.CrossRefGoogle Scholar
Hillier, D.J. 1991b, A&A 247, 455.Google Scholar
Hillier, D.J. 1996, in: Vreux, J.-M., Detal, A., Fraipont-Caro, D., Gosset, E. & Rauw, G. (eds.), Wolf-Rayet Stars in the Framework of Stellar Evolution, Proc. 33rd Liege Int. Astrophys. Coll. (Liége:Université de Liége), p. 509.Google Scholar
Hillier, D.J. 1999, in: van der Hucht, K.A., Koenigsberger, G. & Eenens, P.R.J. (eds.), Wolf-Rayet Phenomena in Massive Stars and Starburst Galaxies, proc. IAU Symp. No. 193 (San Francisco: ASP), p. 129.Google Scholar
Hillier, D.J., Miller, D.L. 1998, ApJ 496, 407.Google Scholar
Hillier, D.J., Miller, D.L. 1999, ApJ 519, 354.Google Scholar
Hillier, D.J., Lanz, T. 2001, in: Ferland, G. & Savin, D.W. (eds.), Spectroscopic Challenges of Photoionized Plasmas, ASP-CS 247, 343.Google Scholar
Hillier, D.J., Lanz, T., Heap, S.R., et al. 2003, ApJ in press.Google Scholar
Hummer, D.G., Berrington, K.A., Eissner, A., et al. 1993, A&A 279, 298.Google Scholar
Iglesias, C.A., Rogers, F.J., 1996, ApJ 464, 943.Google Scholar
Koesterke, L, Hamann, W.-R., Urrutia, T. 2001, A&A 379, 224.Google Scholar
Kurosawa, R., Hillier, D.J., Pittard, J.M. 2002, A&A 388, 957.Google Scholar
Kurucz, R.L. 1993, cd-rom 22, Atomic Data for Fe and Ni (Cambridge: SAO)Google Scholar
Lamers, H., Waters, L.B.F.M. 1984, A&A 138, 25.Google Scholar
Lépine, S., Moffat, A.F.J., Henriksen, R.N. 1996, ApJ 466, 392.CrossRefGoogle Scholar
Lépine, S., Moffat, A.F.J. 1999, ApJ 514, 909.CrossRefGoogle Scholar
Lucy, L.B., Abbott, D.C. 1993, ApJ 405, 738.Google Scholar
Nugis, T., Crowther, P.A., Willis, A.J. 1998 A&A 333, 956.Google Scholar
Nugis, T., Lamers, H. 2002, A&A 389, 162.Google Scholar
Owocki, S.P., Castor, J.I., Rybicki, G.B. 1988, ApJ 335, 914.Google Scholar
Owocki, S.P., Gayley, K.G. 1999, in: van der Hucht, K.A., Koenigsberger, G. & Eenens, P.R.J. (eds.), Wolf-Rayet Phenomena in Massive Stars and Starburst Galaxies, IAU Symp. No. 193 (San Francisco: ASP), p 157.Google Scholar
Robert, C. 1994, in: Moffat, A.F.J., Owocki, S.P., Fullerton, A.W., St-Louis, N. (eds.), Instability and Variability of Hot-Star Winds, Ap&SS 221, 137.Google Scholar
Schmutz, W. 1997, A&A 321, 268.Google Scholar
Seaton, M.J. 1979, MNRAS (Letters) 187, 73P.Google Scholar
Seaton, M.J. 1987, J. Phys. B. 20, 6363.Google Scholar
Springmann, U. 1994, A&A 289, 505.Google Scholar
Williams, R.E. 1992, ApJ 392, 99.CrossRefGoogle Scholar