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There is strong observational evidence that the convective cores of intermediate-mass and massive main sequence stars are substantially larger than those predicted by standard stellar-evolution models. However, it is unclear what physical…

Solar and Stellar Astrophysics · Physics 2024-08-20 R. Andrassy , G. Leidi , J. Higl , P. V. F. Edelmann , F. R. N. Schneider , F. K. Roepke

The advent of massively parallel supercomputing has begun to permit explicit 3--D simulations of turbulent convection occurring within the cores of early-type main sequence stars. Such studies should complement the stellar structure and…

Astrophysics · Physics 2007-05-23 Allan Sacha Brun , Matthew Browning , Juri Toomre

We present the results of 3--D simulations of core convection within A-type stars of 2 solar masses, at a range of rotation rates. We consider the inner 30% by radius of such stars, thereby encompassing the convective core and some of the…

Astrophysics · Physics 2008-11-26 Matthew Browning , Allan Sacha Brun , Juri Toomre

We perform two- (2D) and three-dimensional (3D) hydrodynamics simulations of convective oxygen shell-burning that takes place deep inside a massive progenitor star of a core-collapse supernova. Using one dimensional (1D) stellar evolution…

Solar and Stellar Astrophysics · Physics 2019-08-14 Takashi Yoshida , Tomoya Takiwaki , Kei Kotake , Koh Takahashi , Ko Nakamura , Hideyuki Umeda

We present the first detailed three-dimensional (3D) hydrodynamic implicit large eddy simulations of turbulent convection of carbon burning in massive stars. Simulations begin with radial profiles mapped from a carbon burning shell within a…

Solar and Stellar Astrophysics · Physics 2017-08-02 Andrea Cristini , Casey Meakin , Raphael Hirschi , David Arnett , Cyril Georgy , Maxime Viallet

(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 apply the mathematical formalism of vector spherical harmonics decomposition to convective stellar velocity fields from multi-dimensional hydrodynamics simulations, and show that the resulting power spectra furnish a robust and stable…

Solar and Stellar Astrophysics · Physics 2015-06-19 Emmanouil Chatzopoulos , Carlo Graziani , Sean M. Couch

We perform 2D, fully compressible, time-implicit simulations of convection in a solar-like model with the MUSIC code. Our main motivation is to explore the impact of a common tactic adopted in numerical simulations of convection that use…

Solar and Stellar Astrophysics · Physics 2021-10-27 I. Baraffe , J. Pratt , D. G. Vlaykov , T. Guillet , T. Goffrey , A. Le Saux , T. Constantino

Most stars host convection zones in which heat is transported directly by fluid motion, but the behavior of convective boundaries is not well understood. Here we present 3D numerical simulations which exhibit penetration zones: regions…

Solar and Stellar Astrophysics · Physics 2022-03-14 Evan H. Anders , Adam S. Jermyn , Daniel Lecoanet , Benjamin P. Brown

State-of-the-art one-dimensional (1D) stellar evolution codes rely on simplifying assumptions, such as mixing length theory, in order to describe superadiabatic convection. As a result, 1D stellar structure models do not correctly recover…

Solar and Stellar Astrophysics · Physics 2019-08-07 Andreas Christ Sølvsten Jørgensen , Achim Weiss

The dynamics and thermal structure of the surface layers of stars with outer convection zones can be studied in some detail by means of numerical simulations of time-dependent compressible convection. In an effort to investigate the…

Astrophysics · Physics 2007-05-23 Matthias Steffen

We present 3-D hydrodynamical simulations of core convection with a stably stratified envelope of a \unit{25}{\Msun} star in the early phase of the main-sequence. We use the explicit gas-dynamics code \code{PPMstar} which tracks two fluids…

Solar and Stellar Astrophysics · Physics 2024-08-13 Huaqing Mao , Paul Woodward , Falk Herwig , Pavel A. Denissenkov , Simon Blouin , William Thompson , Benjamin McDermott

We study the dynamics associated with the extension of turbulent convective motions from a convection zone (CZ) into a stable region (RZ) that lies below the latter. For that purpose, we have run a series of three-dimensional direct…

Solar and Stellar Astrophysics · Physics 2019-01-16 Lydia Korre , Pascale Garaud , Nicholas Brummell

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

We explore the effects of rotation on convective carbon, oxygen, and silicon shell burning during the late stages of evolution in a 20Msun star. Using the Modules for Experiments in Stellar Astrophysics (MESA) we construct 1D stellar models…

Solar and Stellar Astrophysics · Physics 2016-05-25 Emmanouil Chatzopoulos , Sean M. Couch , W. David Arnett , F. X. Timmes

Continued progress in observational stellar astrophysics requires a deep understanding of the underlying convection dynamics. We present results of realistic 3D radiative hydrodynamic simulations of the outer layers of a moderate mass star…

Solar and Stellar Astrophysics · Physics 2016-04-27 Irina N. Kitiashvili , Alexander G. Kosovichev , Nagi N. Mansour , Alan A. Wray

Theoretical descriptions of convective overshooting often rely on a one-dimensional parameterization of the flow called the filling factor for convection. Several definitions of the filling factor have been developed, based on: (1) the…

Solar and Stellar Astrophysics · Physics 2024-12-04 M. -G. Dethero , J. Pratt , D. G. Vlaykov , I. Baraffe , T. Guillet , T. Goffrey , A. Le Saux , A. Morison

In this paper we describe our convective hydrocodes for radial stellar pulsation. We adopt the Kuhfuss (1986) model of convection, reformulated for the use in stellar pulsation hydrocodes. Physical as well as numerical assumptions of the…

Astrophysics · Physics 2008-10-13 R. Smolec , P. Moskalik

Context. Mixing by convective overshooting has long been suggested to play an important role for the amount of hydrogen available to nuclear burning in convective cores of stars. The best way to model this effect is still debated. Aims. We…

Solar and Stellar Astrophysics · Physics 2022-11-16 F. Kupka , F. Ahlborn , A. Weiss

We study lithium depletion in low-mass and solar-like stars as a function of time, using a new diffusion coefficient describing extra-mixing taking place at the bottom of a convective envelope. This new form is motivated by…

Solar and Stellar Astrophysics · Physics 2017-08-16 I. Baraffe , J. Pratt , T. Goffrey , T. Constantino , D. Folini , M. V. Popov , R. Walder , M. Viallet