Angular momentum transport by internal gravity waves

Pantillon, Florian; Talon, Suzanne; Charbonnel, C.

doi:10.1051/0004-6361:20078078

Cited by 51 publications

(64 citation statements)

References 27 publications

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“…Just as in the terrestrial atmosphere and in laboratory experiments, this turbulence acts to reduce its cause, namely the gradients of angular velocity and of chemical composition. This explains why its effect may be described as a diffusion process Maeder 2003;Talon 2007, and references therein).…”

Section: The Impact Of Rotation On Stellar Evolutionmentioning

confidence: 99%

“…Furthermore, internal gravity waves and gravito-inertial waves that are excited at the edge of the convection zones may also contribute to the transport of angular momentum. They propagate inside radiative zones and extract or deposit angular momentum in the region where they are damped, thus modifying the angular velocity profile and the vertical distribution of chemicals (Press 1981;Schatzman 1993;Talon et al 2002;, 2008Rogers & Glatzmaier 2005;Pantillon et al 2007;Mathis et al 2008).…”

Section: The Impact Of Rotation On Stellar Evolutionmentioning

confidence: 99%

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Diagnoses to unravel secular hydrodynamical processes in rotating main sequence stars

Decressin

Mathis

Palacios

et al. 2008

A&A

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118

138

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Context. Recent progress and constraints brought by helio and asteroseismology call for a better description of stellar interiors and an accurate description of rotation-driven mechanisms in stars. Aims. We present a detailed analysis of the main physical processes responsible for the transport of angular momentum and chemical species in the radiative regions of rotating stars. We focus on cases where meridional circulation and shear-induced turbulence all that are included in the simulations (i.e., no either internal gravity waves nor magnetic fields). We put special emphasis on analysing the angular momentum transport loop and on identifying the contribution of each of the physical process involved. Methods. We develop a variety of diagnostic tools designed to help disentangle the role of the various transport mechanisms. Our analysis is based on a 2-D representation of the secular hydrodynamics, which is treated using expansions in spherical harmonics. By taking appropriate horizontal averages, the problem reduces to one dimension, making it implementable in a 1D stellar evolution code, while preserving the advective character of angular momentum transport. We present a full reconstruction of the meridional circulation and of the associated fluctuations of temperature and mean molecular weight, along with diagnosis for the transport of angular momentum, heat, and chemicals. In the present paper these tools are used to validate the analysis of two main sequence stellar models of 1.5 and 20 M , for which the hydrodynamics has previously been extensively studied in the literature. Results. We obtain a clear visualisation and a precise estimation of the different terms entering the angular momentum and heat transport equations in radiative zones of rotating stars. This enables us to corroborate the main results obtained over the past decade by Zahn, Maeder, and collaborators concerning the secular hydrodynamics of such objects. We focus on the meridional circulation driven by angular momentum losses and structural readjustments. We confirm quantitatively for the first time through detailed computations and separation of the various components that the advection of entropy by this circulation is balanced very well by the barotropic effects and the thermal relaxation during most of the main sequence evolution. This enables us to simplify for the thermal relaxation on this phase. The meridional currents in turn advect heat and generate temperature fluctuations that induce differential rotation through thermal wind, thus closing the transport loop. We plan to make use of our refined diagnosis tools in forthcoming studies of secular (magneto-)hydrodynamics of stars at various evolutionary stages.

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Section: The Impact Of Rotation On Stellar Evolutionmentioning

confidence: 99%

Section: The Impact Of Rotation On Stellar Evolutionmentioning

confidence: 99%

Diagnoses to unravel secular hydrodynamical processes in rotating main sequence stars

Decressin

Mathis

Palacios

et al. 2008

A&A

Self Cite

118

138

View full text Add to dashboard Cite

show abstract

“…The convective kinetic energy is then transmitted less efficiently to the internal waves in the radiative envelope. The associated transport is consequently decreased (see Pantillon et al 2007;Mathis et al 2008). -Next, because of the Coriolis acceleration, internal waves are damped through thermal diffusion closer to the excitation region than in the slowly rotating case (i.e.…”

Section: Internal Wavesmentioning

confidence: 99%

“…-Next, because of the Coriolis acceleration, internal waves are damped through thermal diffusion closer to the excitation region than in the slowly rotating case (i.e. close to the convective core) and just below the surface (see again Pantillon et al 2007;Mathis et al 2008). …”

Section: Internal Wavesmentioning

confidence: 99%

Seismic modelling of the late Be stars HD 181231 and HD 175869 observed with CoRoT: a laboratory for mixing processes

Neiner

Mathis

Saio

et al. 2012

A&A

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Context. HD 181231 and HD 175869 are two late rapidly rotating Be stars, which have been observed using high-precision photometry with the CoRoT satellite during about five consecutive months and 27 consecutive days, respectively. An analysis of their light curves, by Neiner and collaborators and Gutiérrez-Soto and collaborators respectively, showed that several independent pulsation g-modes are present in these stars. Fundamental parameters have also been determined by these authors using spectroscopy. Aims. We aim to model these results to infer seismic properties of HD 181231 and HD 175869, and constrain internal transport processes of rapidly rotating massive stars. Methods. We used an adiabatic (NRO) and a non-adiabatic (Tohoku) oscillation code that accounts for the combined action of Coriolis and centrifugal accelerations on stellar pulsations as needed for rapid rotator modelling. We coupled these codes with a 2D (ROTORC) stellar structure model to take the rotational deformation of the star into account. The action of transport processes was parametrised with the mixing parameter α ov , which represents the "non-standard" extension of the convective core, and determined by matching observed pulsation frequencies assuming a single star evolution scenario. In a second step, we used (Geneva) evolution models to evaluate the contribution of the secular rotational transport and mixing processes in the radiative envelope. A Monte Carlo analysis of spectropolarimetric data was also performed to examine the role of a potential fossil magnetic field. Finally, based on state-of-the-art modelling of penetrative convection and internal waves, we unravelled their respective contribution to the needed "non-standard" mixing.Results. We find that extra mixing of α ov = 0.3−0.35H p is needed in HD 181231 and HD 175869 to match the observed frequencies with those of prograde sectoral g-modes. We also detect the possible presence of r-modes. We investigated the respective contributions of several transport processes to this mixing: the hydrodynamical processes in particular the meridional circulation and shear-induced turbulence caused by the radiative envelope differential rotation, the possible magnetic field, the penetrative convection at the top of the convective core, and the transport by internal waves. Conclusions. We showed that the extension of the convective core needed to match observations and models may be explained by mixing induced by the penetrative movements at the bottom of the radiative envelope and by the secular hydrodynamical transport processes induced by the rotation in the envelope. We showed how asteroseismology opens a new door to probe transport processes in stellar interiors.

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“…In the non-magnetic case (Λ E = 0), the result obtained in Pantillon et al (2007) and Mathis et al (2008) is recovered.…”

Section: The Transport Of Angular Momentummentioning

confidence: 53%

Low-frequency internal waves in magnetized rotating stellar radiation zones

Mathis

Brye

2012

A&A

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Angular momentum transport by internal gravity waves

Cited by 51 publications

References 27 publications

Diagnoses to unravel secular hydrodynamical processes in rotating main sequence stars

Diagnoses to unravel secular hydrodynamical processes in rotating main sequence stars

Seismic modelling of the late Be stars HD 181231 and HD 175869 observed with CoRoT: a laboratory for mixing processes

Low-frequency internal waves in magnetized rotating stellar radiation zones

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