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Article Dans Une Revue Astronomy and Astrophysics - A&A Année : 2013

The thermohaline, Richardson, Rayleigh-Taylor, Solberg–Høiland, and GSF criteria in rotating stars

A. Maeder
  • Fonction : Auteur
G. Meynet
  • Fonction : Auteur
N. Lagarde
Corinne Charbonnel
  • Fonction : Auteur

Résumé

Aims: We examine the interactions of various instabilities in rotating stars, which usually are considered as independent. Methods: An analytical study of the problem is performed accounting for radiative losses, μ-gradients, and horizontal turbulence. Results: The diffusion coefficient for an ensemble of instabilities is not given by the sum of the specific coefficients for each instability, but by the solution of a general equation. We find that thermohaline mixing is possible in low-mass red giants only if the horizontal turbulence is very weak. In rotating stars the Rayleigh-Taylor and the shear instabilities need simultaneous treating. This leads to rotation laws of the form 1/rα being predicted to be unstable for α > 1.6568, while the usual Rayleigh criterion only predicts instability for α > 2. Also, the shear instabilities are somehow reduced in main sequence stars by the effect of the Rayleigh-Taylor criterion. Various instability criteria should be expressed differently in rotating stars than in simplified geometries.

Dates et versions

hal-03025257 , version 1 (26-11-2020)

Identifiants

Citer

A. Maeder, G. Meynet, N. Lagarde, Corinne Charbonnel. The thermohaline, Richardson, Rayleigh-Taylor, Solberg–Høiland, and GSF criteria in rotating stars. Astronomy and Astrophysics - A&A, 2013, 553, pp.A1. ⟨10.1051/0004-6361/201220936⟩. ⟨hal-03025257⟩
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