Convective overshoot mixing in stellar interior models

Abstract

The convective overshoot mixing plays an important role in stellar structure and evolution. However, the overshoot mixing is a long standing problem. The uncertainty of the overshoot mixing is one of the most uncertain factors in stellar physics. As it is well known, the convective and overshoot mixing is determined by the radial chemical component flux. In this paper, a local model of the radial chemical component flux is established based on the hydrodynamic equations and some model assumptions. The model is tested in stellar models. The main conclusions are as follows. (i) The local model shows that the convective and overshoot mixing could be regarded as a diffusion process, and the diffusion coefficient for different chemical element is the same. However, if the non-local terms, i.e., the turbulent convective transport of radial chemical component flux, are taken into account, the diffusion coefficient for each chemical element should be in general different. (ii) The diffusion coefficient of convective / overshoot mixing shows different behaviors in convection zone and in overshoot region because the characteristic length scale of the mixing is large in the convection zone and small in the overshoot region. The overshoot mixing should be regarded as a weak mixing process. (iii) The result of the diffusion coefficient of mixing is tested in stellar models. It is found that a single choice of our central mixing parameter leads to consistent results for a solar convective envelope model as well as for core convection models of stars with mass from 2M to 10M.

9 pages, 2 figures, accepted for publication in ApJS

References in corpus (3)

• Fresh insights on the structure of the solar core
• Sound-speed inversion of the Sun using a nonlocal statistical convection theory
• Testing the core overshooting mixing described by the turbulent convection model on the eclipsing binary star HY Vir

Cited by in corpus (23)

• Sub-Inertial Gravity Modes in the B8V Star KIC 7760680 Reveal Moderate Core Overshooting and Low Vertical Diffusive Mixing
• On the proper use of the Schwarzschild and Ledoux criteria in stellar evolution computations
• Binary Asteroseismic Modelling: isochrone-cloud methodology and application to Kepler gravity-mode pulsators
• Matter Mixing in Aspherical Core-collapse Supernovae: Three-dimensional Simulations with Single Star and Binary Merger Progenitor Models for SN 1987A
• How accurate are stellar ages based on stellar models ? I. The impact of stellar models uncertainties
• Solar models with convective overshoot, the solar-wind mass loss, and a PMS disk accretion: helioseismic quantities, Li depletion and neutrino fluxes
• Extreme value statistics for two-dimensional convective penetration in a pre-Main Sequence star
• Thermonuclear Bursts with Short Recurrence Times from Neutron Stars Explained by Opacity-Driven Convection
• Overshooting in simulations of compressible convection
• Significant uncertainties from calibrating overshooting with eclipsing binary systems
• Black hole - black hole total merger mass and the origin of LIGO/Virgo sources
• Overshooting calibration and age determination from evolved binary system
• Applications of the $k$-$\omega$ model in stellar evolutionary models
• Calibrating the updated overshoot mixing model on eclipsing binary stars: HY Vir, YZ Cas, X2 Hya & VV Crv
• Asteroseismic analysis of the CoRoT target HD49933
• The solar abundance problem: the effect of the turbulent kinetic flux on the solar envelope model
• The YNEV stellar evolution and oscillation code
• Exploring the helium core of the delta Scuti star CoRoT 102749568 with asteroseismology
• A simple scheme to implement a nonlocal turbulent convection model for the convective overshoot mixing
• Asteroseismic investigation on KIC 10526294 to probe convective core overshoot mixing
• Core overshoot constrained by the absence of a solar convective core and some solar-like stars
• Convective shells in the interior of Cepheid variable stars: overshooting models based on hydrodynamic simulations
• On the shape of core overshooting in stellar model computations, and asteroseismic tests