Hostname: page-component-586b7cd67f-2plfb Total loading time: 0 Render date: 2024-11-28T22:50:33.895Z Has data issue: false hasContentIssue false
  • English
  • Français

Short-Term Wind and Photospheric Activity in Be Stars Deduced from Campaigns with the IUE Spacecraft

Published online by Cambridge University Press:  12 April 2016

Geraldine J. Peters  and
Douglas R. Gies
Geraldine J. Peters
Affiliation:
Space Sciences Center, University of Southern California, Los Angeles, CA 90089-1341, USA
Douglas R. Gies
Affiliation:
Center for High Angular Resolution Astronomy, Department of Physics & Astronomy, Georgia State University, Atlanta, GA 30303-3083, 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.

From 1985–96 twelve multiwavelength campaigns on 15 Be stars were carried through using data from the IUE spacecraft to study the phenomenon of short-term spectroscopic and photometric variability. Highlights from recent work on this database are presented here. Three classes of variability have been identified: 1) The FUV flux and wind strength are correlated, 2) The FUV flux varies cyclically but wind variability if present does not correlate with the flux, and 3) The wind strength cyclically varies but does not correlate with light variations. For Class 1 the period is usually less than the star’s expected rotational period, but for Classes 2 & 3, the period is sometimes close to Prot. We have employed a cross-correlation technique to extract information on the nature of the line profile variability (lpv). Evidence for nonradial pulsations (NRP) in low-order modes is found for objects in Classes 1 & 2, the light variations appear to be caused by a modulation of the star's photospheric temperature, and the hot crest of the NRP wave is in front when the star is bright. For Class 1 stars the wind is enhanced over the hot crest. The mass loss in Class 3 may originate from a localized active region on the star and the importance of NRP in these stars remains unknown.

Type
5. Campaigns
Information
International Astronomical Union Colloquium , Volume 175: The Be Phenomenon in Early-Type Stars , 2000 , pp. 372 - 383
Copyright
Copyright © Astronomical Society of the Pacific 2000

References

Baade, D. 1982, in Be Stars, ed. Jaschek, M. & Groth, H.-G. (Dordrecht: Reidel), 167 Google Scholar
Baade, D., Balona, L.A. 1994, in Pulsation, Rotation, and Mass Loss in Early-Type Stars, ed. Balona, L.A., Henrichs, H.F., & Le Contel, J.M. (Dordrecht: Kluwer), 311 Google Scholar
Balona, L.A., Englebrecht, C.A. 1986, MNRAS, 219, 131 Google Scholar
Bolton, C.T. 1982, in Be Stars, ed. Jaschek, M. & Groth, H.-G. (Dordrecht: Reidel), 181 Google Scholar
Doazan, V., et al. 1985, A&A, 152, 182 Google Scholar
Gies, D.R. 1994, in Pulsation, Rotation, and Mass Loss in Early-Type Stars, ed. Balona, L., Henrichs, H., & Le Contel, J. (Dordrecht: Kluwer), 89 Google Scholar
Gies, D.R. 1996, in Stellar Surface Structure, ed. Strassmeier, K.G. & Linsky, J.L. (Dordrecht: Kluwer), 121 Google Scholar
Gies, D.R., Kullavanijaya, A. 1988, ApJ, 326, 813 Google Scholar
Gies, D.R., et al. 1999, ApJ, 525, in pressGoogle Scholar
Hahula, M.E., Gies, D.R. 1994, in Pulsation, Rotation, and Mass Loss in Early-Type Stars, ed. Balona, L.A., Henrichs, H.F., LeContel, J.M. (Dordrecht: Kluwer), 100 Google Scholar
Holberg, J.B., Sandel, B., Drake, V., Peters, G.J. 1999, in preparationGoogle Scholar
Kurucz, R.L. 1993, SYNTHE Spectrum Synthesis Programs and Line Data, Kurucz CD-ROM 18 (ambridge: SAO)Google Scholar
Kurucz, R.L. 1994, Solar Abundance Model Atmospheres for 0, 1, 2, 4, 8, km s−1 , Kurucz CD-ROM 19 (Cambridge: SAO)Google Scholar
Penny, L.R. 1996, ApJ, 463, 737 Google Scholar
Percy, J.R. 1987, in Physics of Be Stars, ed. Slettebak, A. & Snow, T.P. (Cambridge: Cambridge Univ. Press), 49 Google Scholar
Peters, G.J. 1994, in Pulsation, Rotation, and Mass Loss in Early-Type Stars, ed. Balona, L., H.Henrichs, , Le Contel, J. (Dordrecht: Kluwer), 284 CrossRefGoogle Scholar
Peters, G.J. 1998, in ESO Astrophys. Symp., Cyclical Variations in Stellar Winds, ed Kaper, L. & Fullerton, A. (Berlin: Springer), 127 Google Scholar
Peters, G.J., Penrod, G.D. 1988, in A Decade of UV Astronomy with the IUE Satellite ESA SP-281, Vol. 2, 117 Google Scholar
Slettebak, A. 1982, ApJS, 50, 55 Google Scholar
Slettebak, A., & Snow, T.P., eds. 1987, Physics of Be Stars (Cambridge: Cambridge Univ. Press)Google Scholar
Smith, M.A., Polidan, R.S. 1993, ApJ, 408, 323 Google Scholar
Smith, M.A., Robinson, R.D., Hatzes, A.P. 1998, ApJ, 507, 945 Google Scholar
Sonneborn, G., Grady, C.A., Wu, C.-C., Hayes, D.P., Guinan, E.F., Barker, P.K., Henrichs, H.F. 1988, ApJ, 325, 784 Google Scholar