Hostname: page-component-586b7cd67f-t8hqh Total loading time: 0 Render date: 2024-12-01T04:41:54.775Z Has data issue: false hasContentIssue false
  • English
  • Français

The Influence of Alfvén Ionization on Exoplanetary Atmospheres

Published online by Cambridge University Press:  06 January 2014

Craig R. Stark ,
Christiane Helling  and
Declan A. Diver
Craig R. Stark
Affiliation:
SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS, UK email: [email protected]
Christiane Helling
Affiliation:
SUPA, School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS, UK email: [email protected]
Declan A. Diver
Affiliation:
SUPA, School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
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.

Observations of radio emission from exoplanets and brown dwarfs suggest that such objects harbour atmospheric magnetized plasmas. However, the degree of thermal ionization for such substellar objects is insufficient to qualify the ionized component as a plasma, posing the question: what ionization processes can efficiently produce the required plasma? We propose Alfvén ionization as a mechanism for producing localized pockets of ionized gas in the atmosphere, having sufficient degrees of ionization (≥10−7) that they constitute plasmas. We outline the criteria required for Alfvén ionization to occur and justify its applicability in substellar atmospheres. For the model atmospheres considered here, our results show that degrees of ionization ranging from 10−6−1 can be obtained.

Keywords

plasmasstars: atmospheresstars: low-massbrown dwarfs
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 8 , Symposium S299: Exploring the Formation and Evolution of Planetary Systems , June 2013 , pp. 384 - 385
Copyright
Copyright © International Astronomical Union 2013 

References

Alfvén, H. 1960, Rev. Mod. Phys. 32 4, 710CrossRefGoogle Scholar
Hallinan, G., et al. 2007, ApJ 663 L25–L28Google Scholar
Helling, Ch., Jardine, M., Witte, S., & Diver, D. A. 2011, ApJ, 727, 4CrossRefGoogle Scholar
Helling, Ch., Jardine, M., Stark, C. R., & Diver, D. A. 2013, ApJ, 767, 136.CrossRefGoogle Scholar
Helling, Ch., et al. 2008, MNRAS, 391, 1854CrossRefGoogle Scholar
Helling, Ch., Woitke, P., & Thi, W.-F. 2008b, A&A, 485, 547Google Scholar
Rimmer, P. B. & Helling, Ch. 2013, ApJ, 774, 108CrossRefGoogle Scholar
Route, M. & Wolszczan, A. 2012, ApJ, 747, L22CrossRefGoogle Scholar
Stark, C. R., et al. 2013, ApJ, 776, 11CrossRefGoogle Scholar
Witte, S., Helling, Ch., Hauschildt, P. H. 2009, A&A, 506, 1367.Google Scholar
Witte, S., Helling, Ch., Barman, T., Heidrich, N. & Hauschildt, P. H. 2011, A&A 529 A44.Google Scholar
Woitke, P. & Helling, Ch. 2003, A&A, 399, 297Google Scholar