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Overshooting Motions from the Convection Zone and their Role in Atmospheric Heating

Published online by Cambridge University Press:  30 March 2016

Juri Toomre*
Affiliation:
Department of Astro-Geophysics and, Joint Institute for Laboratory Astrophysics, University of Coloradoand National Bureau of Standards, Boulder, CO 80309, U.S.A.

Extract

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Chromospheres and coronae in stars appear to require vigorous convection zones just below the surface. If we wish to understand how various dynamical instabilities contribute to the mechanical heating that is required to produce chromospheres, then we must be concerned both with fluid motions in the atmosphere and with the nature of their driving below the surface. One cannot really separate these two subjects. In order to emphasize this link, we will raise some basic questions about convective flows in a stellar envelope and of their penetration into the atmosphere. The significant puzzles between what is observed and what can be theoretically explained should serve to indicate some of the issues that need to be pursued. We will concentrate on the Sun in our discussions: the observations here are sufficiently detailed to provide the explicit challenges to theory unavailable in most other stars. However, we will also turn to A-type stars to illustrate a theoretical procedure for describing convection that may do better than the mixing-length approach in predicting the vertical structure in these flows.

Type
Joint Discussion
Copyright
Copyright © Cambridge University Press 1980

References

Canfield, R.C.: 1976, Solar Phys. 50, p. 239.Google Scholar
Graham, E.: 1975, J. Fluid Mech. 70, p. 689.CrossRefGoogle Scholar
Keil, S.L.,and Canfield, R.C.: 1978, Astron. Astrophys. 70, p. 169.Google Scholar
Latour, J., Spiegel, E.A., Toomre, J., and Zahn, J.-P.: 1976, Astrophys. J. 207, p. 233.CrossRefGoogle Scholar
Massaguer, J.M., and Zahn, J.-P.: 1979, Astron. Astrophys., submitted.Google Scholar
Mihalas, B.R.: 1979, Thesis, University of Colorado.Google Scholar
Nelson, G.D., and Musman, S.: 1977, Astrophys. J. 214, p. 312.CrossRefGoogle Scholar
Nelson, G.D., and Musman, S.: 1978, Astrophys. J. (Letters) 222, p. L69.CrossRefGoogle Scholar
Nordlund, A.: 1976, Astron. Astrophys. 50, p. 23.Google Scholar
November, L., Toomre, J., Gebbie, K.B. and Simon, G.W.: 1979a, Astrophys. J. 227, p. 600.Google Scholar
November, L., Toomre, J., Gebbie, K.B. and Simon, G.W.: 1979b, Astrophys. J. (Letters), submitted.Google Scholar
Savchenko, V.P., and Kozhevnikov, N.I.: 1978, Soviet Astron. 22, p. 459.Google Scholar
Simon, G.W., and Leighton, R.B.: 1964, Astrophys. J. 140, p. 1120.Google Scholar
Simon, G.W., and Weiss, N.O.: 1968, Z. Astrophys. 69, p. 435.Google Scholar
Spiegel, E.A.: 1966, Trans. IAU (Academic, N.Y.), Vol. 12B, p. 539.Google Scholar
Spiegel, E.A., Toomre, J., and Gough, D.O.: 1979, J. Fluid Mech. submitted.Google Scholar
Toomre, J., Zahn, J.-P., Latour, J., and Spiegel, E.A.: 1976, Astrophys. J. 207, p. 545.CrossRefGoogle Scholar
Toomre, J., Gough, D.O., and Spiegel, E.A.: 1977, J. Fluid Mech. 79, p. 1.Google Scholar
Zahn, J.-P., Toomre, J., and Latour, J.: 1979, Astrophys. J., submitted.Google Scholar