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With the advent of dedicated photometric space missions, the ability to rapidly process huge catalogues of stars has become paramount. Bellinger and Angelou et al. (2016) recently introduced a new method based on machine learning for…

Solar and Stellar Astrophysics · Physics 2017-11-08 Earl P. Bellinger , George C. Angelou , Saskia Hekker , Sarbani Basu , Warrick H. Ball , Elisabeth Guggenberger

We analyze stellar convection with the aid of 3D hydrodynamic simulations, introducing the turbulent cascade into our theoretical analysis. We devise closures of the Reynolds-decomposed mean field equations by simple physical modeling of…

Astrophysics · Physics 2011-02-11 David Arnett , Casey Meakin , P. A. Young

Space-borne missions CoRoT and {\it Kepler} are providing a rich harvest of high-quality constraints on solar-like pulsators. Among the seismic parameters, mode damping rates remains poorly understood and thus barely used to infer physical…

Solar and Stellar Astrophysics · Physics 2012-04-03 K. Belkacem , M. A. Dupret , F. Baudin , T. Appourchaux , J. P. Marques , R. Samadi

We compute rotating 1D stellar evolution models that include a modified temperature gradient in convection zones and criterion for convective instability inspired by rotating 3D hydrodynamical simulations performed with the MUSIC code. In…

Solar and Stellar Astrophysics · Physics 2021-10-27 Thomas Constantino , Isabelle Baraffe , Thomas Goffrey , Jane Pratt , Thomas Guillet , Dimitar Vlaykov , Louis Amard

Asteroseismic modelling will be part of the pipeline of the PLATO mission and will play a key role in the mission precision requirements on stellar mass, radius and age. It is therefore crucial to compare how current modelling strategies…

We perform a calibration of the mixing length parameter at the bottom boundary of the convection zone for helium-dominated atmospheres of white dwarfs. This calibration is based on a grid of 3D DB (pure-helium) and DBA (helium-dominated…

Solar and Stellar Astrophysics · Physics 2019-09-25 Cukanovaite E. , P. -E. Tremblay , B. Freytag , H. -G. Ludwig , G. Fontaine , P. Brassard , O. Toloza , D. Koester

A calibration of the mixing-length parameter in the local mixing-length theory (MLT) is presented for the lower part of the convection zone in pure-hydrogen atmosphere white dwarfs. The parameterization is performed from a comparison of 3D…

Solar and Stellar Astrophysics · Physics 2015-06-23 P. -E. Tremblay , H. -G. Ludwig , B. Freytag , G. Fontaine , M. Steffen , P. Brassard

This paper describes the application of a laser diffraction technique to the study of electroconvection in nematic liquid crystal cells. It allows a real-time quantitative access to pattern wave lengths and amplitudes. The diffraction…

Strongly Correlated Electrons · Physics 2009-11-07 Th. John , U. Behn , R. Stannarius

Context. Mixing by convective overshooting has long been suggested to play an important role for the amount of hydrogen available to nuclear burning in convective cores of stars. The best way to model this effect is still debated. Aims. We…

Solar and Stellar Astrophysics · Physics 2022-11-16 F. Kupka , F. Ahlborn , A. Weiss

We investigate the relation between 1D atmosphere models that rely on the mixing length theory and models based on full 3D radiative hydrodynamic (RHD) calculations to describe convection in the envelopes of late-type stars. The adiabatic…

Solar and Stellar Astrophysics · Physics 2014-12-24 Zazralt Magic , Achim Weiss , Martin Asplund

Context. The surface structures and dynamics of cool stars are characterized by the presence of convective motions and turbulent flows which shape the emergent spectrum. Aims. We used realistic three-dimensional radiative hydrodynamical…

Solar and Stellar Astrophysics · Physics 2018-03-14 A. Chiavassa , L. Casagrande , R. Collet , Z. Magic , L. Bigot , F. Thevenin , M. Asplund

Based on detailed 2D numerical radiation hydrodynamics (RHD) calculations of time-dependent compressible convection, we have studied the dynamics and thermal structure of the convective surface layers of solar-type stars. The RHD models…

Astrophysics · Physics 2007-05-23 H. -G. Ludwig , B. Freytag , M. Steffen

The convective instability in a plane liquid layer with time-dependent temperature profile is investigated by means of a general method suitable for linear stability analysis of an unsteady basic flow. The method is based on a non-normal…

Fluid Dynamics · Physics 2015-05-14 F. Doumenc , T. Boeck , B. Guerrier , M. Rossi

Despite the fact that the initial helium abundance is an essential ingredient in modelling solar-type stars, its abundance in these stars remains a poorly constrained observational property. This is because the effective temperature in…

Solar and Stellar Astrophysics · Physics 2021-01-20 Nuno Moedas , Benard Nsamba , Miguel T. Clara

Standard 1D stellar evolution model has poor descriptions of the near-surface layers of stars, and this can be improved by using the atmosphere model computed from 3D hydrodynamical simulations. In this work, we validated the model…

Solar and Stellar Astrophysics · Physics 2025-12-02 Zhikai Li , Tanda Li , Yixiao Zhou , Shaolan Bi

We present a theoretical study of the effects and signatures of realistic velocity field and atmospheric inhomogeneities associated with convective motions at the surface of cool late-type stars on the emergent profiles of iron spectral…

Solar and Stellar Astrophysics · Physics 2014-03-26 Zazralt Magic , Remo Collet , Martin Asplund

Divergence and vorticity damping, which operate upon horizontal divergence and relative vorticity, are explicit diffusion mechanisms used in dynamical cores to ensure stability. To avoid numerical blow-up from excessively strong diffusion,…

Numerical Analysis · Mathematics 2026-02-19 Timothy C. Andrews , Christiane Jablonowski

In this paper, we calibrate the coefficients for the one-dimensional Reynolds stress model with the data generated from the three-dimensional numerical simulations of upward overshooting in turbulent compressible convection. It has been…

Solar and Stellar Astrophysics · Physics 2020-06-17 Tao Cai

Theoretical atmosphere models provide the basis for a variety of applications in astronomy. In simplified one-dimensional (1D) atmosphere models, convection is usually treated with the mixing length theory despite its well-known…

Solar and Stellar Astrophysics · Physics 2015-06-17 Zazralt Magic , Remo Collet , Martin Asplund

One of the largest sources of uncertainty in the computation of globular cluster isochrones and hence in the age determination of globular clusters is the lack of a rigorous description of convection. Therefore, we calibrated the…

Astrophysics · Physics 2009-10-31 Bernd Freytag , Maurizio Salaris