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Non-Local Convection Models for Stellar Atmospheres and Envelopes

Published online by Cambridge University Press:  26 May 2016

F. Kupka
F. Kupka*
Affiliation:
Astronomy Unit, School of Mathematical Sciences, Queen Mary, University of London, Mile End Road, London, El 4NS, U.K.

Abstract

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We present an overview of the concepts underlying advanced non-local Reynolds stress models of turbulent convection and review a comparison of this approach with a series of numerical simulations of fully compressible convection. We then discuss results from applications of the model to complete envelopes of A-type main sequence stars. The non-local model reproduces surface velocities in agreement with the lower limit of observed macro- and microturbulence velocities of A-star photospheres, the asymmetry of the surface velocity field as inferred from spectral line profiles, and the overall structure of the photospheric and subphotospheric convection zones, as predicted by the most recent numerical simulations available for these stars. Traditionally, local models of convection are unable to do so. We conclude with a brief survey of extensions of the model which are interesting for other applications such as atmospheres of solar type stars and overshooting below deep convective envelopes or above the core in massive stars.

Type
Session C. Convection
Information
Symposium - International Astronomical Union , Volume 210: Modelling of Stellar Atmospheres , 2003 , pp. 143 - 156
Copyright
Copyright © Astronomical Society of the Pacific 2003 

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