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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 non-local hydrodynamic moment equations for compressible convection are compared to numerical simulations. Convective and radiative flux typically deviate less than 20% from the 3D simulations, while mean thermodynamic quantities are…

Astrophysics · Physics 2009-10-31 F. Kupka

We analyze a three-dimensional smoothed particle hydrodynamics simulation of an evolving and later collapsing pre-stellar core. Using a three-dimensional continuum radiative transfer program, we generate images at 7 micron, 15 micron, 175…

Astrophysics · Physics 2009-11-10 J. Steinacker , B. Lang , A. Burkert , A. Bacmann , Th. Henning

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

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

We present the first three-dimensional (3D), hydrodynamic simulations of the core convection zone (CZ) and extended radiative zone spanning from 1% to 90% of the stellar radius of an intermediate mass (3 $\mathrm{M}_\odot$) star. This…

Solar and Stellar Astrophysics · Physics 2019-05-01 P. V. F. Edelmann , R. P. Ratnasingam , M. G. Pedersen , D. M. Bowman , V. Prat , T. M. Rogers

A toy model of the post-shock region of core-collapse supernovae is used to study the non-linear development of turbulent motions driven by convection in the presence of advection. Our numerical simulations indicate that buoyant…

Solar and Stellar Astrophysics · Physics 2018-07-18 Rémi Kazeroni , Brendan K. Krueger , Jérôme Guilet , Thierry Foglizzo , Daniel Pomarède

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 He-shell flash convection in AGB stars is the site for the high-temperature component of the s-process in low- and intermediate mass giants, driven by the Ne22 neutron source. [...] The upper convection boundary plays a critical role…

Solar and Stellar Astrophysics · Physics 2009-01-23 Paul R. Woodward , David H. Porter , Falk Herwig , Marco Pignatari , Jagan Jayaraj , Pei-Hung Lin

Three-dimensional (3D), time dependent numerical simulations, of flow of matter in stars, now have sufficient resolution to be fully turbulent. The late stages of the evolution of massive stars, leading up to core collapse to a neutron star…

Solar and Stellar Astrophysics · Physics 2014-01-30 W. David Arnett , Casey Meakin , Maxime Viallet

Based on multi-dimensional, multi-group, flux-limited-diffusion hydrodynamic simulations of core-collapse supernovae with the VULCAN/2D code, we study the physical conditions within and in the vicinity of the nascent protoneutron star…

Astrophysics · Physics 2009-11-13 L. Dessart , A. Burrows , E. Livne , C. D. Ott

We review our current understanding on the outer envelope structures of massive stars based on three dimensional (3D) radiation hydrodynamic simulations. We briefly summarize the fundamental issues to construct hydrostatic one dimensional…

Solar and Stellar Astrophysics · Physics 2023-10-16 Yan-Fei Jiang

1D and 2D supernova simulations for stars between 11 and 25 solar masses are presented, making use of the Prometheus/Vertex neutrino-hydrodynamics code, which employs a full spectral treatment of the neutrino transport. Multi-dimensional…

Astrophysics · Physics 2009-11-11 R. Buras , H. -Th. Janka , M. Rampp , K. Kifonidis

We present multidimensional modeling of convection and oscillations in main-sequence stars somewhat more massive than the Sun, using three separate approaches: 1) Using the 3-D planar StellarBox radiation hydrodynamics code to model the…

Solar and Stellar Astrophysics · Physics 2016-05-17 Joyce A. Guzik , T. H. Morgan , N. J. Nelson , C. Lovekin , K. Kosak , I. N. Kitiashvili , N. N. Mansour , A. Kosovichev

We use molecular dynamics simulations in two dimensions to investigate the possibility that a core-softened potential can reproduce static and dynamic anomalies found experimentally in liquid water: (i) the increase in specific volume upon…

Soft Condensed Matter · Physics 2009-10-31 A. Scala , M. Reza Sadr-Lahijany , N. Giovambattista , S. V. Buldyrev , H. E. Stanley

The extent of mixed regions around convective zones is one of the biggest uncertainties in stellar evolution. 1D overshooting descriptions introduce a free parameter ($f_{ov}$) that is in general not well constrained from observations.…

Solar and Stellar Astrophysics · Physics 2021-03-08 Johann Higl , Ewald Mueller , Achim Weiss

(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

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

We present a new scenario for the formation of cool cores in rich galaxy clusters based on results from recent high spatial dynamic range, adaptive mesh Eulerian hydrodynamic simulations of large-scale structure formation. We find that…

Astrophysics · Physics 2008-11-26 Patrick M. Motl , Jack O. Burns , Chris Loken , Michael L. Norman , Greg Bryan

This paper describes the first steps of development of a new multidimensional time implicit code devoted to the study of hydrodynamical processes in stellar interiors. The code solves the hydrodynamical equations in spherical geometry and…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 M. Viallet , I. Baraffe , R. Walder