The traditional approximation of rotation for rapidly rotating stars and planets: I. The impact of strong deformation
| Autor: | H. Dhouib, Stéphane Mathis, T. Van Reeth, Vincent Prat |
|---|---|
| Přispěvatelé: | Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institute of Astronomy [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), European Project: 647383,H2020,ERC-2014-CoG,SPIRE(2015), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP) |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
010504 meteorology & atmospheric sciences
POLYTROPIC STARS CONVECTIVE CORE ASTEROSEISMIC MEASUREMENT GAMMA DORADUS PULSATORS Astrophysics Rotation 01 natural sciences rotation ACOUSTIC-OSCILLATIONS GRAVITY MODES stars: rotation Astrophysics::Solar and Stellar Astrophysics MAIN-SEQUENCE PERIOD SPACINGS 010303 astronomy & astrophysics Physics Earth and Planetary Astrophysics (astro-ph.EP) ANGULAR-MOMENTUM TRANSPORT Astrophysics::Instrumentation and Methods for Astrophysics Physics - Fluid Dynamics Mechanics INTERNAL-ROTATION Physics - Atmospheric and Oceanic Physics Astrophysics - Solar and Stellar Astrophysics Physical Sciences oscillations Astrophysics::Earth and Planetary Astrophysics stars: oscillations GRAVITO-INERTIAL WAVES stars GAMMA DORADUS STARS FOS: Physical sciences Context (language use) Angular velocity Astronomy & Astrophysics Asteroseismology TO-CORE ROTATION Computer Science::Digital Libraries Flattening methods methods: analytical methods: numerical numerical 0103 physical sciences waves Solar and Stellar Astrophysics (astro-ph.SR) 0105 earth and related environmental sciences Science & Technology TIDAL DISSIPATION Fluid Dynamics (physics.flu-dyn) Astronomy and Astrophysics Rotation matrix NONRADIAL OSCILLATIONS Prolate spheroidal coordinates Physics::History of Physics Stars Space and Planetary Science Atmospheric and Oceanic Physics (physics.ao-ph) hydrodynamics G-MODES analytical [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] Astrophysics - Earth and Planetary Astrophysics |
| Zdroj: | Astronomy and Astrophysics-A&A Astronomy and Astrophysics-A&A, 2021, 652, pp.A154. ⟨10.1051/0004-6361/202140615⟩ Astronomy and Astrophysics-A&A, EDP Sciences, 2021, 652, pp.A154. ⟨10.1051/0004-6361/202140615⟩ |
| ISSN: | 0004-6361 |
| DOI: | 10.1051/0004-6361/202140615⟩ |
| Popis: | The Traditional Approximation of Rotation (TAR) is a treatment of the hydrodynamic equations of rotating and stably stratified fluids in which the action of the Coriolis acceleration along the direction of the entropy and chemical stratifications is neglected because it is weak in comparison with the buoyancy force. The dependent variables in the equations for the dynamics of gravito-inertial waves (GIWs) then become separable into radial and horizontal parts as in the non-rotating case. The TAR is built on the assumptions that the star is spherical (i.e. its centrifugal deformation is neglected) and uniformly rotating. We study the feasibility of carrying out a generalisation of the TAR to account for the centrifugal acceleration in the case of strongly deformed uniformly and rapidly rotating stars (and planets), and to identify the validity domain of this approximation. We built analytically a complete formalism that allows the study of the dynamics of GIWs in spheroidal coordinates which take into account the flattening of rapidly rotating stars by assuming the hierarchies of frequencies adopted within the TAR in the spherical case and by deriving a generalised Laplace tidal equation for the horizontal eigenfunctions of the GIWs and their asymptotic wave periods, which can be used to probe the structure and dynamics of rotating deformed stars with asteroseismology. Using 2D ESTER stellar models, we determine the validity domain of the generalised TAR as a function of the rotation rate of the star normalised by its critical angular velocity and its pseudo-radius. This generalisation allows us to study the signature of the centrifugal effects on GIWs in rapidly rotating deformed stars. We found that the effects of the centrifugal acceleration in rapidly rotating early-type stars on GIWs are theoretically detectable in modern space photometry using observations from Kepler. Comment: 17 pages, 14 figures, 1 table, abstract shortened for arXiv. Accepted for publication in A&A |
| Databáze: | OpenAIRE |
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