TY - CHAP

T1 - Low-frequency oscillations in rotating stars

AU - Lee, Umin

N1 - Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2013

Y1 - 2013

N2 - We review the properties of low-frequency oscillations in uniformly rotating stars. Rotation not only yields a new class of modes, like inertial modes and r-modes, but also significantly modifies the properties of low-frequency g-modes. For slow rotation rates where |Ω/ω| ≪ 1, we can treat the rotation frequency Ω as a small parameter for perturbation analysis, but for |Ω/ω| ≮< 1, we have to properly solve the oscillation equation given as a set of partial differential equations, taking account of the effects of the Coriolis force and the centrifugal force, where ω stands for the oscillation frequency observed in the corotating frame of the star. The Coriolis force couples modes having different spherical harmonic degrees l, and the centrifugal force deforms the equilibrium structure. Rapid rotation affects the stability and the frequency of low-frequency modes. We discuss perturbation theory, the traditional approximation, linear mode coupling, series expansion methods, and weakly nonlinear calculations, which are applied to low-frequency modes in rotating stars.

AB - We review the properties of low-frequency oscillations in uniformly rotating stars. Rotation not only yields a new class of modes, like inertial modes and r-modes, but also significantly modifies the properties of low-frequency g-modes. For slow rotation rates where |Ω/ω| ≪ 1, we can treat the rotation frequency Ω as a small parameter for perturbation analysis, but for |Ω/ω| ≮< 1, we have to properly solve the oscillation equation given as a set of partial differential equations, taking account of the effects of the Coriolis force and the centrifugal force, where ω stands for the oscillation frequency observed in the corotating frame of the star. The Coriolis force couples modes having different spherical harmonic degrees l, and the centrifugal force deforms the equilibrium structure. Rapid rotation affects the stability and the frequency of low-frequency modes. We discuss perturbation theory, the traditional approximation, linear mode coupling, series expansion methods, and weakly nonlinear calculations, which are applied to low-frequency modes in rotating stars.

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U2 - 10.1007/978-3-642-33380-4_7

DO - 10.1007/978-3-642-33380-4_7

M3 - Chapter

AN - SCOPUS:84893121608

SN - 9783642333798

T3 - Lecture Notes in Physics

SP - 133

EP - 157

BT - Studying Stellar Rotation and Convection

PB - Springer Verlag

ER -