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Related papers: The core helium flash revisited: II. Two and three…

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Degenerate ignition of helium in low-mass stars at the end of the red giant branch phase leads to dynamic convection in their helium cores. One-dimensional (1D) stellar modeling of this intrinsically multi-dimensional dynamic event is…

Solar and Stellar Astrophysics · Physics 2015-05-18 Miroslav Mocak , Simon W. Campbell , Ewald Mueller , Konstantinos Kifonidis

We investigate the hydrodynamics of the core helium flash near its peak. Past research concerned with the dynamics of this event is inconclusive. However, the most recent multidimensional hydrodynamic studies suggest a quiescent behavior…

Astrophysics · Physics 2009-11-13 M. Mocak , E. Mueller , A. Weiss , K. Kifonidis

We describe and discuss hydrodynamic simulations of the core helium flash using an initial model of a 1.25 M_sol star with a metallicity of 0.02 near at its peak. Past research concerned with the dynamics of the core helium flash is…

Solar and Stellar Astrophysics · Physics 2009-05-01 M. Mocak , E. Mueller , A. Weiss , K. Kifonidis

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

Shell convection driven by nuclear burning in a stellar core is a common hydrodynamic event in the evolution of many types of stars. We encounter and simulate this convection (i) in the helium core of a low-mass red giant during core helium…

Solar and Stellar Astrophysics · Physics 2015-05-27 Miroslav Mocak , Ewald Muller , Lionel Siess

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

Our ability to predict the structure and evolution of stars is in part limited by complex, 3D hydrodynamic processes such as convective boundary mixing. Hydrodynamic simulations help us understand the dynamics of stellar convection and…

We present the first hydrodynamic, multi-dimensional simulations of He-shell flash convection. Specifically, we investigate the properties of shell convection at a time immediately before the He- luminosity peak during the 15th thermal…

Astrophysics · Physics 2009-11-11 Falk Herwig , Bernd Freytag , Robert M. Hueckstaedt , Francis X. Timmes

The treatment of convection remains a major weakness in the modelling of stellar evolution with one-dimensional (1D) codes. The ever increasing computing power makes now possible to simulate in 3D part of a star for a fraction of its life,…

Solar and Stellar Astrophysics · Physics 2024-06-03 C. Georgy , F. Rizzuti , R. Hirschi , V. Varma , W. D. Arnett , C. Meakin , M. Mocak , A. StJ. Murphy , T. Rauscher

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

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

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

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

Mixing processes in stars driven by composition gradients as a result of the Rayleigh-Taylor instability are not anticipated. They are supported only by hydrodynamic studies of stellar convection. We find that such mixing occurs below the…

Solar and Stellar Astrophysics · Physics 2015-03-17 Miroslav Mocak , Ewald Mueller

We present numerical results on three-dimensional (3D) hydrodynamic core-collapse simulations of an $11.2 M_{\odot}$ star. By comparing one-(1D) and two-dimensional(2D) results with those of 3D, we study how the increasing spacial…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Tomoya Takiwaki , Kei Kotake , Yudai Suwa

Extending our recent studies of two-dimensional stellar convection to 3D, we compare three-dimensional hydrodynamic simulations to identically set-up two-dimensional simulations, for a realistic pre-main sequence star. We compare…

Solar and Stellar Astrophysics · Physics 2020-07-01 J. Pratt , I. Baraffe , T. Goffrey , C. Geroux , T. Constantino , D. Folini , R. Walder

We have developed a multidimensional radiation hydrodynamics code to simulate the interaction of radial stellar pulsation and convection for full amplitude pulsating models. Convection is computed using large eddy simulations. Here we…

Solar and Stellar Astrophysics · Physics 2014-03-05 Christopher M. Geroux , Robert G. Deupree

The inner structure of core-helium burning (CHeB) stars remains uncertain due to the yet unknown nature of mixing at the boundary of their cores. Large convective cores beyond a bare Schwarzschild model are favoured both from theoretical…

Solar and Stellar Astrophysics · Physics 2023-11-21 Simon Blouin , Falk Herwig , Huaqing Mao , Pavel Denissenkov , Paul R. Woodward

We perform three dimensional radiation hydrodynamic simulations of the structure and dynamics of radiation dominated envelopes of massive stars at the location of the iron opacity peak. One dimensional hydrostatic calculations predict an…

Solar and Stellar Astrophysics · Physics 2015-11-04 Yan-Fei Jiang , Matteo Cantiello , Lars Bildsten , Eliot Quataert , Omer Blaes

The gravitational collapse, bounce, the explosion of an iron core of an 11.2 $M_{\odot}$ star is simulated by two-dimensional neutrino-radiation hydrodynamic code. The explosion is driven by the neutrino heating aided by multi-dimensional…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Yudai Suwa
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