Hostname: page-component-586b7cd67f-dsjbd Total loading time: 0 Render date: 2024-11-23T21:28:27.870Z Has data issue: false hasContentIssue false
  • English
  • Français

X-ray Emission from O Stars

Published online by Cambridge University Press:  01 December 2007

David H. Cohen
David H. Cohen*
Affiliation:
Swarthmore College, Department of Physics and Astronomy, 500 College Ave., Swarthmore, Pennsylvania 19081, USA
Rights & Permissions [Opens in a new window]

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.

Young O stars are strong, hard, and variable X-ray sources; properties that strongly affect their circumstellar and galactic environments. After ≈ 1 Myr, these stars settle down to become steady sources of soft X-rays. I will use high-resolution X-ray spectroscopy and MHD modeling to show that young O stars like θ1 Ori C are well explained by the magnetically channeled wind shock scenario. After their magnetic fields dissipate, older O stars produce X-rays via shock heating in their unstable stellar winds. Here too I will use X-ray spectroscopy and numerical modeling to confirm this scenario. In addition to elucidating the nature and cause of the O star X-ray emission, modeling of the high-resolution X-ray spectra of O supergiants provides strong evidence that mass-loss rates of these O stars have been overestimated.

Keywords

hydrodynamics – instabilities – line: profiles – magnetic fields – MHD – shock waves – stars: early type – stars: mass loss – stars: windsoutflows – X-rays: stars
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 3 , Symposium S250: Massive Stars as Cosmic Engines , December 2007 , pp. 17 - 24
Copyright
Copyright © International Astronomical Union 2008

References

Babel, J. & Montmerle, T. 1997, ApJ, 485, L29CrossRefGoogle Scholar
Cohen, D. H., Leutenegger, M., & Townsend, R. H. D. 2008, in: Hamann, W.-R., Feldmeier, A., Oskinova, L. M. (eds.), Clumping in Hot Star Winds (Potsdam: Universitäts-Verlag)Google Scholar
Dessart, L. & Owocki, S. P. 2005, ApJ, 437, 657Google Scholar
Feldmeier, A., Puls, J., & Pauldrach, 1997, A&A, 322, 878Google Scholar
Gagné, M., Oksala, M., Cohen, D. H., et al. 2005, ApJ, 628, 986CrossRefGoogle Scholar
Oskinova, L. M., Feldmeier, A., & Hamann, W.-R. 2006, MNRAS, 372, 313CrossRefGoogle Scholar
Owocki, S. P. & Cohen, D. H. 2001, ApJ, 559, 1108CrossRefGoogle Scholar
Owocki, S. P. & Cohen, D. H. 2006, ApJ, 648, 565CrossRefGoogle Scholar
Puls, J., Kudritzki, R.-P., Herrero, A., et al. 1996, A&A, 305, 171Google Scholar
Wojdowski, P. & Schulz, N. S. 2005, ApJ, 627, 953CrossRefGoogle Scholar