Hostname: page-component-8448b6f56d-dnltx Total loading time: 0 Render date: 2024-04-19T20:55:37.626Z Has data issue: false hasContentIssue false
  • English
  • Français

Time-dependent Turbulence in Stars

Published online by Cambridge University Press:  12 August 2011

W. David Arnett  and
Casey Meakin
W. David Arnett
Affiliation:
Steward Observatory, University of Arizona, Tucson AZ 85721, USA email: wdarnett@gmail.com
Casey Meakin
Affiliation:
Steward Observatory, University of Arizona, Tucson AZ 85721, USA email: wdarnett@gmail.com
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.

Three-dimensional (3D) hydrodynamic simulations of shell oxygen burning by Meakin & Arnett (2007b) exhibit bursty, recurrent fluctuations in turbulent kinetic energy. These are shown to be due to a global instability in the convective region, which has been suppressed in simulations of stellar evolution which use mixing-length theory (MLT). Quantitatively similar behavior occurs in the model of a convective roll (cell) of Lorenz (1963), which is known to have a strange attractor that gives rise to random fluctuations in time. An extension of the Lorenz model, which includes Kolmogorov damping and nuclear burning, is shown to exhibit bursty, recurrent fluctuations like those seen in the 3D simulations. A simple model of a convective layer (composed of multiple Lorenz cells) gives luminosity fluctuations which are suggestive of irregular variables (red giants and supergiants, see Schwarzschild (1975). Details and additional discussion may be found in Arnett & Meakin (2011).

Apparent inconsistencies between Arnett, Meakin, & Young (2009) and Nordlund, Stein, & Asplund (2009) on the nature of convective driving have been resolved, and are discussed.

Keywords

turbulenceirregular variablesconvection
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 6 , Symposium S271: Astrophysical Dynamics: From Stars to Galaxies , June 2010 , pp. 205 - 212
Copyright
Copyright © International Astronomical Union 2011

References

Arnett, W. D., Meakin, C., & Young, P. A., 2009, ApJ, 690, 1715CrossRefGoogle Scholar
Arnett, W. D., Meakin, C., & Young, P. A., 2010, ApJ, 710, 1619CrossRefGoogle Scholar
Arnett, W. D. & Meakin, D., 2011, submitted.Google Scholar
Böhm-Vitense, E., 1958, Zeit. für Ap., 46, 108Google Scholar
Chandrasekhar, S. 1961, Hydrodynamic and Hydromagnetic Instability, Oxford University Press, LondonGoogle Scholar
Chiavassa, A., Haubois, X., Young, J. S., Plez, B., Josselin, E., Perrin, G., & Freytag, B., 2010, A&A, in pressGoogle Scholar
Cvitanović, P., Universality in Chaos, Adam Hilger, Bristol and New YorkGoogle Scholar
Davidson, P. A., 2004, Turbulence, Oxford University Press, OxfordGoogle Scholar
Gleick, J., 1987, Chaos: Making a New Science, Penguin Books, New YorkGoogle Scholar
Goldberg, L., 1984, Publ. Astron. Soc. Pacific, 96, 366CrossRefGoogle Scholar
Kiss, L. L., Szabo, Gy. M., & Bedding, T. R., 2006, MNRAS, 372, 1721CrossRefGoogle Scholar
Kjeldsen, H. & Bedding, T. R., 1995, A&A, 293, 87Google Scholar
Landau, L. D. & Lifshitz, E. M. 1959, Fluid Mechanics, Pergamon Press, LondonGoogle Scholar
Ledoux, P., 1941, ApJ, 94, 537CrossRefGoogle Scholar
Ledoux, P. & Walraven, Th., 1958, in Handbuch der Physik, 51, ed. Flugge, S., (Springer-Verlag, Berlin), p. 353Google Scholar
Lorenz, E. N., 1963, Journal of Atmospheric Sciences, 20, 1302.0.CO;2>CrossRefGoogle Scholar
Meakin, C. & Arnett, D., 2007b, ApJ, 667, 448CrossRefGoogle Scholar
Meakin, C. & Arnett, D., 2010 ApJ, submittedGoogle Scholar
Nordlund, A., Stein, R., & Asplund, M., 2009, Living Reviews in Solar Physics, 6, 2 {http://www.livingreviews.org/lrsp-2009-2}CrossRefGoogle Scholar
Schwarzschild, M., 1975, ApJ, 195, 137CrossRefGoogle Scholar
Stein, R. F. & Nordlund, A., 1998, ApJ, 499, 914CrossRefGoogle Scholar
Thompson, J. M. T. & Stewart, H. B., 1986, Nonlinear Dynamics and Chaos, John Wiley and Sons, New YorkGoogle Scholar
Unno, W., Osaki, Y., Ando, H., Saio, H., & Shibahashi, H., 1989, Nonradial Oscillations of Stars, 2nd. ed., University of Tokyo Press, TokyoGoogle Scholar