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By direct hydrodynamic simulation, using the Piecewise Parabolic Method (PPM) code PROMETHEUS, we study the properties of a convective oxygen burning shell in a SN 1987A progenitor star prior to collapse. The convection is too heterogeneous…

Astrophysics · Physics 2009-10-30 Grant Bazán , David Arnett

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

The convective envelopes of solar-type stars and the convective cores of intermediate- and high-mass stars share boundaries with stable radiative zones. Through a host of processes we collectively refer to as "convective boundary mixing"…

Solar and Stellar Astrophysics · Physics 2023-04-18 Evan H. Anders , May G. Pedersen

Two dimensional hydrodynamical simulations of convective oxygen burning shell in the presupernova evolution of a 20 solar-mass star are extended to later times. We used the VULCAN code to simulate longer evolution times than previously…

Astrophysics · Physics 2009-10-31 S. M. Asida , David Arnett

Massive star formation requires the accretion of gas at high rate while the star is already bright. Its actual luminosity depends sensitively on the stellar structure. We compute pre-main-sequence tracks for massive and intermediate-mass…

Solar and Stellar Astrophysics · Physics 2016-03-23 Lionel Haemmerlé , Thomas Peters

We performed 3D hydrodynamic simulations of the inner $\approx 50\%$ radial extent of a $25\ \mathrm{M_\odot}$ star in the early phase of the main sequence and investigate core convection and internal gravity waves in the core-envelope…

Solar and Stellar Astrophysics · Physics 2023-07-21 Falk Herwig , Paul R. Woodward , Huaqing Mao , William R. Thompson , Pavel Denissenkov , Josh Lau , Simon Blouin , Robert Andrassy , Adam Paul

Supermassive stars are Population III stars with masses exceeding $10^4\,M_{\odot}$ that could be the progenitors of the first supermassive black holes. Their interiors are in a regime where radiation pressure dominates the equation of…

Solar and Stellar Astrophysics · Physics 2023-03-29 Simon Blouin , Huaqing Mao , Tyrone E. Woods , Pavel Denissenkov , Paul R. Woodward , Falk Herwig

Main-sequence intermediate-mass stars present a radiative envelope that supports internal gravity waves (IGWs). Excited at the boundary with the convective core, IGWs propagate towards the stellar surface and are suspected to impact…

Solar and Stellar Astrophysics · Physics 2023-04-26 A. Le Saux , I. Baraffe , T. Guillet , D. G. Vlaykov , A. Morison , J. Pratt , T. Constantino , T. Goffrey

We investigate simulated turbulent flow within thermally driven stellar convection zones. Different driving sources are studied, including cooling at the top of the convectively unstable region, as occurs in surface convection zones; and…

Solar and Stellar Astrophysics · Physics 2015-05-18 Casey Meakin , David Arnett

Turbulent convection is certainly one of the most important and thorny issues in stellar physics. Our deficient knowledge of this crucial physical process introduces a fairly large uncertainty concerning the internal structure and evolution…

Solar and Stellar Astrophysics · Physics 2018-04-25 M. Gabriel , K. Belkacem

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

Although the dependence of convective core overshooting on mass has attracted much attention, no corresponding work exists for overshooting below a convective envelope. We aim to quantify this relationship for pre-main sequence stars of…

Solar and Stellar Astrophysics · Physics 2025-09-24 J. Pratt , I. Baraffe , M. -G. Dethero , M. Stuck , D. G. Vlaykov , T. Goffrey

Context. Recent, nonlinear simulations of wave generation and propagation in full-star models have been carried out in the anelastic approximation using spectral methods. Although it makes long time steps possible, this approach excludes…

Solar and Stellar Astrophysics · Physics 2020-09-15 L. Horst , P. V. F. Edelmann , R. Andrassy , F. K. Roepke , D. M. Bowman , C. Aerts , R. P. Ratnasingam

Our knowledge of stellar evolution is driven by one-dimensional (1D) simulations. 1D models, however, are severely limited by uncertainties on the exact behaviour of many multi-dimensional phenomena occurring inside stars, affecting their…

Solar and Stellar Astrophysics · Physics 2023-05-26 F. Rizzuti , R. Hirschi , W. D. Arnett , C. Georgy , C. Meakin , A. StJ. Murphy , T. Rauscher , V. Varma

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 the first detailed three-dimensional hydrodynamic implicit large eddy simulations of turbulent convection for carbon burning. The simulations start with an initial radial profile mapped from a carbon burning shell within a 15…

Solar and Stellar Astrophysics · Physics 2017-12-20 Andrea Cristini , Casey Meakin , Raphael Hirschi , David Arnett , Cyril Georgy , Maxime Viallet

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

Context. The one-dimensional treatment of turbulent convection had large successes until the early 2000s. However, the recent abundance and precision of observational data shows that this problem is far from solved. A modern approach should…

Solar and Stellar Astrophysics · Physics 2025-07-16 Gábor B. Kovács , R. Szabó , J. Nuspl

We perform the first multidimensional fluid simulations of thermonuclear helium ignition underneath a hydrogen-rich shell. This situation is relevant to Type I X-ray bursts on neutron stars that accrete from a hydrogen-rich companion. Using…

High Energy Astrophysical Phenomena · Physics 2024-11-21 Simon Guichandut , Michael Zingale , Andrew Cumming

The injection of hydrogen into the convection shell powered by helium burning during the core helium flash is commonly encountered during the evolution of metal-free and extremely metal-poor low-mass stars. With specifically designed…

Solar and Stellar Astrophysics · Physics 2015-05-28 Miroslav Mocak , Lionel Siess , Ewald Muller