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Thermal convection in fluid layers heated from below are usually realized experimentally as well as treated theoretically with fixed boundaries on which conditions for the temperature and the velocity field are prescribed. The thermal and…

Fluid Dynamics · Physics 2011-02-08 R. D. Simitev , F. H. Busse

Both observations and numerical simulations show that stellar convective motions are composed of semi-regular flows of convective rolling cells and the fully developed turbulence. Although the convective rolling cells are crucial for the…

Solar and Stellar Astrophysics · Physics 2015-06-04 Yan Li

Recent hydrodynamical simulations of convection in a solar-like model suggest that penetrative convective flows at the boundary of the convective envelope modify the thermal background in the overshooting layer. Based on these results, we…

Solar and Stellar Astrophysics · Physics 2022-03-14 Baraffe I , Constantino T , Clarke J , Le Saux A , Goffrey T , Guillet T , Pratt J , Vlaykov D. G

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

As part of a larger program aimed at better quantifying the uncertainties in stellar computations, we attempt to calibrate the extent of convective overshooting in low to intermediate mass stars by means of eclipsing binary systems. We…

Solar and Stellar Astrophysics · Physics 2015-03-11 Richard J. Stancliffe , Luca Fossati , Jean-Claude Passy , Fabian R. N. Schneider

Modeling properly the interface between convective cores and radiative interiors is one the most challenging and important open questions in modern stellar physics. The rapid development of asteroseismology, with the advent of space…

Solar and Stellar Astrophysics · Physics 2020-01-14 S. Deheuvels

A model is developed for the transport of heat and solute in a system of double-diffusive layers under astrophysical conditions (viscosity and solute diffusivity low compared with the thermal diffusivity). The process of formation of the…

Solar and Stellar Astrophysics · Physics 2015-06-15 H. C. Spruit

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

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

In stars and planets natural processes heat convective flows in the bulk of a convective region rather than at hard boundaries. By characterizing how convective dynamics are determined by the strength of an internal heating source we can…

Fluid Dynamics · Physics 2024-04-16 Whitney T. Powers , Evan H. Anders , Benjamin P. Brown

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

The near-surface layers of cool main-sequence stars are structured by convective flows, which are overshooting into the atmosphere. The flows and the associated spatio-temporal variations of density and temperature affect spectral line…

Solar and Stellar Astrophysics · Physics 2013-08-27 Benjamin Beeck , Robert H. Cameron , Ansgar Reiners , Manfred Schüssler

We couple two-dimensional hydrodynamics to detailed one-dimensional multigroup flux-limited diffusion neutrino transport to investigate prompt convection in core collapse supernovae. Our initial conditions, time-dependent boundary…

The era of detailed asteroseismic analyses opened by space missions such as CoRoT and $\textit{Kepler}$ has highlighted the need for stellar models devoid of numerical inaccuracies, in order to be able to diagnose which physical aspects are…

Solar and Stellar Astrophysics · Physics 2014-09-24 Maurice Gabriel , Arlette Noels , Josefina Montalban , Andrea Miglio

Properties of semi-convection and core convective overshooting of stars with 15 $M_{\odot}$ and 30 $M_{\odot}$ are calculated in the present paper. New methods are used to deal with semi-convection. Different entropy gradient is used when…

Solar and Stellar Astrophysics · Physics 2015-06-18 Cai Yun Ding , Yan Li

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

We revisit a phenomenological description of turbulent thermal convection along the lines proposed by Gough (1977) in which eddies grow solely by extracting energy from the unstably stratified mean state and are subsequently destroyed by…

Solar and Stellar Astrophysics · Physics 2011-12-02 R. Smolec , G. Houdek , D. O. Gough

Our poor understanding of the boundaries of convective cores generates large uncertainties on the extent of these cores and thus on stellar ages. Our aim is to use asteroseismology to consistently measure the extent of convective cores in a…

Solar and Stellar Astrophysics · Physics 2016-04-20 S. Deheuvels , I. Brandão , V. Silva Aguirre , J. Ballot , E. Michel , M. S. Cunha , Y. Lebreton , T. Appourchaux

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

The uncertainties in the modelling of some important inputs of stellar evolution must be taken into account for a correct interpretation, both of the HR diagrams of individual stars, and of the integrated colors, of stellar clusters. After…

Astrophysics · Physics 2007-05-23 F. D'Antona