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(Abridged) We describe the results of three-dimensional (3D) numerical simulations designed to study turbulent convection in the stellar interiors, and compare them to stellar mixing-length theory (MLT). Simulations in 2D are significantly…

Astrophysics · Physics 2011-02-11 Casey A. Meakin , David Arnett

We analyze stellar convection with the aid of 3D hydrodynamic simulations, introducing the turbulent cascade into our theoretical analysis. We devise closures of the Reynolds-decomposed mean field equations by simple physical modeling of…

Astrophysics · Physics 2011-02-11 David Arnett , Casey Meakin , P. A. Young

As a step toward a complete theoretical integration of 3D compressible hydrodynamic simulations into stellar evolution, convection at the surface and sub-surface layers of the Sun is re-examined, from a restricted point of view, in the…

Solar and Stellar Astrophysics · Physics 2014-11-20 W. David Arnett , Casey Meakin , Patrick A. Young

We examine the physical basis for algorithms to replace mixing-length theory (MLT) in stellar evolutionary computations. Our 321D procedure is based on numerical solutions of the Navier-Stokes equations. These implicit large eddy…

Solar and Stellar Astrophysics · Physics 2015-08-19 W. David Arnett , Casey Meakin , Maxime Viallet , Simon W. Campbell , John Lattanzio , Miroslav Mocák

Stellar evolution models of massive stars are important for many areas of astrophysics, for example nucleosynthesis yields, supernova progenitor models and understanding physics under extreme conditions. Turbulence occurs in stars primarily…

Solar and Stellar Astrophysics · Physics 2016-03-23 Andréa Cristini , Casey Meakin , Raphael Hirschi , David Arnett , Cyril Georgy , Maxime Viallet

We review the application of the one-dimensional Mixing Length Theory (MLT) model of convection in stellar interiors and low-mass stellar evolution. We summarize the history of MLT, present a derivation of MLT in the context of the 1D…

Solar and Stellar Astrophysics · Physics 2023-06-01 Meridith Joyce , Jamie Tayar

A program is outlined, and first results described, in which fully three-dimensional, time dependent simulations of hydrodynamic turbulence are used as a basis for theoretical investigation of the physics of turbulence in stars. The…

Solar and Stellar Astrophysics · Physics 2015-05-14 W. David Arnett , Casey Meakin

During the various steps of stellar evolution are formed convectives zones that alter the chemical stratification in stars. Usually, in astrophysics is used the Mixing Length Theory (MLT) for modeling the convective movement and, in…

Solar and Stellar Astrophysics · Physics 2024-12-18 M. M. Ocampo , M. M. Miller Bertolami , L. G. Althaus , F. C Wachlin

Convective overshoot mixing is a critical ingredient of stellar structure models, but is treated in most cases by ad hoc extensions of the mixing-length theory for convection. Advanced theories which are both more physical and numerically…

Solar and Stellar Astrophysics · Physics 2022-11-16 Felix Ahlborn , Friedrich Kupka , Achim Weiss , Martin Flaskamp

The understanding of transport processes inside the stars is one of the main goals of asteroseismology. Chemical turbulent mixing can affect the internal distribution of \mu near the energy generating core, having an effect on the…

Astrophysics · Physics 2015-05-13 J. Montalban , A. Miglio , P. Eggenberger , A. Noels

Double-diffusive convection refers to mixing where the effects of thermal and composition gradients compete to determine the stability of a fluid. In addition to the familiar fast convective instability, such fluids exhibit the slow, direct…

Astrophysics · Physics 2015-06-24 Scott A. Grossman , Ronald E. Taam

Asteroseismology of non-radial pulsations in Hot B Subdwarfs (sdB stars) offers a unique view into the interior of core-helium-burning stars. Ground-based and space-borne high precision light curves allow for the analysis of pressure and…

Solar and Stellar Astrophysics · Physics 2017-11-08 J. -T. Schindler , Elizabeth M. Green , W. David Arnett

The numerical simulation of turbulence in stars has led to a rich set of possibilities regarding stellar pulsations, asteroseismology, thermonuclear yields, and formation of neutron stars and black holes. The breaking of symmetry by…

Solar and Stellar Astrophysics · Physics 2016-10-05 W. David Arnett , Casey Meakin

The effects of turbulence on the mixing of gases and dust in the outer Solar nebula are examined using 3-D MHD calculations in the shearing-box approximation with vertical stratification. The turbulence is driven by the magneto-rotational…

Astrophysics · Physics 2009-11-13 N. J. Turner , K. Willacy , G. Bryden , H. W. Yorke

Our understanding of stellar structure and evolution coming from one-dimensional (1D) stellar models is limited by uncertainties related to multi-dimensional processes taking place in stellar interiors. 1D models, however, can now be tested…

Solar and Stellar Astrophysics · Physics 2022-08-17 F. Rizzuti , R. Hirschi , C. Georgy , W. D. Arnett , C. Meakin , A. StJ. Murphy

The turbulent burning of nuclei is a common phenomenon in the evolution of stars. Here we examine a challenging case: the merging of the neon and oxygen burning shells in a 23 M$_{\odot}$ star. A previously unknown quasi-steady state is…

Solar and Stellar Astrophysics · Physics 2018-09-12 Miroslav Mocák , Casey Meakin , Simon Wattana Campbell , David Arnett

Stellar models utilising one-dimensional (1D), heuristic theories of convection fail to adequately describe the energy transport in superadiabatic layers. The improper modelling leads to well-known discrepancies between observed and…

Solar and Stellar Astrophysics · Physics 2019-10-23 Andreas Christ Sølvsten Jørgensen , George C. Angelou

Three-dimensional (3D) hydrodynamic simulations of shell oxygen burning (Meakin and Arnett 2007) exhibit bursty, recurrent fluctuations in turbulent kinetic energy. These are shown to be due to a global instability in the convective region,…

Solar and Stellar Astrophysics · Physics 2015-05-20 W. David Arnett , Casey Meakin

Convective boundary mixing is one of the major uncertainties in stellar evolution. In order to study its dependence on boundary properties and turbulence strength in a controlled way, we computed a series of 3D hydrodynamical simulations of…

Solar and Stellar Astrophysics · Physics 2019-02-13 A. Cristini , R. Hirschi , C. Meakin , D. Arnett , C. Georgy , I. Walkington

Convection and rotation are both key processes in stellar evolution modelling. While standard mixing-length theory (MLT) provides a widely used modelling of convection, it neglects the effects of rotation on convective transport. We…

Solar and Stellar Astrophysics · Physics 2026-04-02 Poojan Agrawal , Aaron Dotter , Conny Aerts , Leïla Bessila , Stéphane Mathis
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