Hostname: page-component-5cf477f64f-n7lw4 Total loading time: 0 Render date: 2025-04-05T05:23:12.077Z Has data issue: false hasContentIssue false
  • English
  • Français

Model Atmospheres and Spectra: The Role of Dust

Published online by Cambridge University Press:  26 May 2016

France Allard ,
Tristan Guillot ,
Hans-Günter Ludwig ,
Peter H Hauschildt ,
Andreas Schweitzer ,
David R. Alexander  and
Jason W. Ferguson
France Allard
Affiliation:
CRAL-ENS, 46 Allée d'Italie, 69364 Lyon Cedex 07, France
Tristan Guillot
Affiliation:
Observatoire de la Côte d'Azur, BP 4229, 06304 Nice Cedex 04, France
Hans-Günter Ludwig
Affiliation:
Lund Observatory, Box 43, 22100 Lund, Sweden
Peter H Hauschildt
Affiliation:
Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany
Andreas Schweitzer
Affiliation:
Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany
David R. Alexander
Affiliation:
Dept. of Physics, Wichita State University, Wichita, KS 67260–0032, USA
Jason W. Ferguson
Affiliation:
Dept. of Physics, Wichita State University, Wichita, KS 67260–0032, 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.

Brown dwarf atmospheres form molecules, then high temperature condensates (corundum, titanates, silicates, and iron compounds), and then low temperature condensates (ices) as they cool down over time. These produce large opacities which govern entirely their spectral energy distribution. Just as it is important to know molecular opacities (TiO, H2O, CH4, etc.) with accuracy, it is imperative to understand the interplay of processes (e.g. condensation, sedimentation, coagulation, convection) that determines the radial and size distribution of grains. Limiting case models have shown that young, hot brown (L) dwarfs form dust mostly in equilibrium, while at much cooler stages (late T dwarfs) all high temperature condensates have sedimented out of their photospheres. But this process is gradual and all intermediate classes of brown dwarfs can partly be understood in terms of partial sedimentation of dust. With new models accounting for these processes, we describe the effects they may have upon brown dwarf spectral properties.

Type
Part 7. Atmospheres and Internal Structure
Information
Symposium - International Astronomical Union , Volume 211: Brown Dwarfs , 2003 , pp. 325 - 332
Copyright
Copyright © Astronomical Society of the Pacific 2001 

References

Ackerman, A. S., & Marley, M. S. 2001, ApJ, 556, 872 CrossRefGoogle Scholar
Allard, F., Hauschildt, P. H., Alexander, D. R., Tamanai, A., & Schweitzer, A. 2001, ApJ, 556, 357 CrossRefGoogle Scholar
Burgasser, A. J., Marley, M. S., Ackerman, A. S., Saumon, D., Lodders, K., Dahn, C. C., Harris, H. C., & Kirkpatrick, J. D. 2002, ApJ, 571, L151 CrossRefGoogle Scholar
Chabrier, G., Baraffe, I., Allard, F., & Hauschildt, P.H. 2000, ApJ, 542, 464 CrossRefGoogle Scholar
Dahn, C. C., Harris, H. C., Vrba, F. J., Guetter, H. H., Canzian, B., Henden, A. A., Levine, S. E., Luginbuhl, C. B., Monet, A. K. B., Monet, D. G., Pier, J. R., Stone, R. C., Walker, R. L., Burgasser, A. J., Gizis, J. E., Kirkpatrick, J. D., Liebert, J., & Reid, I. N. 2002, AJ, in press Google Scholar
Els, S. G., Sterzik, M. F., Marchis, F., Pantin, E., Endl, M., & Kürster, M. 2001, A&A, 370, L1 Google Scholar
Helling, C., Oevermann, M., Lüttke, M. J. H., Klein, R., & Sedlmayr, E. 2001, A&A, 376, 194 Google Scholar
Leggett, S. K., Allard, F., Dahn, C., Hauschildt, P. H., Kerr, T. H., & Rayner, J. 2000, ApJ, 535, 965 CrossRefGoogle Scholar
Leggett, S. K., Golimowski, D. A., Fan, X., Geballe, T. R., Knapp, G. R., Brinkmann, J., Csabai, I., Gunn, J. E., Hawley, S. L., Henry, T. J., Hindsley, R., Ivezić, Ž., Lupton, R. H., Pier, J. R., Schneider, D. P., Smith, J. A., Strauss, M. A., Uomoto, A., & York, D. G. 2002, ApJ, 564, 452 CrossRefGoogle Scholar
Ludwig, H.-G., Allard, F., & Hauschildt, P. H. 2002, A&A, in press Google Scholar
Marley, M. S., Seager, S., Saumon, D., Lodders, K., Ackerman, A. S., Freedman, R. S., Fan, X., ApJ, 568, 335 CrossRefGoogle Scholar
Rossow, W. B. 1978, Icarus, 36, 1 CrossRefGoogle Scholar
Schweitzer, A., Gizis, J. E., Hauschildt, P. H., Allard, F., & Reid, I. N. 2001, ApJ, 555, 368 CrossRefGoogle Scholar
Tsuji, T., Ohnaka, K., Aoki, W., & Nakajima, T. 1996, ApJ, A&A, 308, 29 Google Scholar