中文
相关论文

相关论文: Calibration of the Mixing-Length Theory for Convec…

200 篇论文

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…

太阳与恒星天体物理 · 物理学 2019-09-25 Cukanovaite E. , P. -E. Tremblay , B. Freytag , H. -G. Ludwig , G. Fontaine , P. Brassard , O. Toloza , D. Koester

We present results of a fully non-local model of convection for white dwarf envelopes. We show that this model is able to reproduce the results of numerical simulations for convective efficiencies ranging from very inefficient to moderately…

天体物理学 · 物理学 2016-08-30 M. H. Montgomery , F. Kupka

We present the first grid of mean three-dimensional (3D) spectra for pure-hydrogen (DA) white dwarfs based on 3D model atmospheres. We use CO5BOLD radiation-hydrodynamics 3D simulations instead of the mixing-length theory for the treatment…

太阳与恒星天体物理 · 物理学 2015-06-17 P. -E. Tremblay , H. -G. Ludwig , M. Steffen , B. Freytag

The CoRoT and Kepler missions provided a wealth of high-quality data for solar-like oscillations. To make the best of such data for seismic inferences, we need theoretical models with precise near-surface structure, which has significant…

太阳与恒星天体物理 · 物理学 2019-01-16 T. Sonoi , H. -G. Ludwig , M. -A. Dupret , J. Montalbán , R. Samadi , K. Belkacem , E. Caffau , M. -J. Goupil

A sequence of pure-hydrogen CO5BOLD 3D model atmospheres of DA white dwarfs is presented for a surface gravity of log g = 8 and effective temperatures from 6000 to 13,000 K. We show that convective properties, such as flow velocities,…

太阳与恒星天体物理 · 物理学 2015-06-15 P. -E. Tremblay , H. -G. Ludwig , M. Steffen , B. Freytag

Main sequence, solar-like stars (M < 1.5 Msun) have outer convective envelopes that are sufficiently thick to affect significantly their overall structure. The radii of these stars, in particular, are sensitive to the details of…

太阳与恒星天体物理 · 物理学 2018-12-26 F. Spada , P. Demarque , S. Basu , J. D. Tanner

We perform a calibration of the mixing length of convection in stellar structure models against realistic 3D radiation-coupled hydrodynamics (RHD) simulations of convection in stellar surface layers, determining the adiabat deep in…

太阳与恒星天体物理 · 物理学 2015-06-23 Regner Trampedach , Robert F. Stein , Jørgen Christensen-Dalsgaard , Åke Nordlund , Martin Asplund

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…

太阳与恒星天体物理 · 物理学 2014-12-24 Zazralt Magic , Achim Weiss , Martin Asplund

We review the application of the one-dimensional Mixing Length Theory (MLT) model of convection in stellar interiors and low-mass stellar evolution. We summarize the history of MLT, present a derivation of MLT in the context of the 1D…

太阳与恒星天体物理 · 物理学 2023-06-01 Meridith Joyce , Jamie Tayar

We present a theoretical description of macroscopic diffusion caused by convective overshoot in pure-hydrogen DA white dwarfs using three-dimensional (3D), closed-bottom, radiation hydrodynamics CO$^5$BOLD simulations. We rely on a new grid…

太阳与恒星天体物理 · 物理学 2019-07-10 Tim Cunningham , Pier-Emmanuel Tremblay , Bernd Freytag , Hans-Günther Ludwig , Detlev Koester

The surface gravities of cool (Teff < 13,000 K) hydrogen-atmosphere DA white dwarfs, determined from spectroscopic analyses, are found to be significantly higher than the canonical value of log g ~ 8 expected for these stars. It was…

太阳与恒星天体物理 · 物理学 2015-05-28 P. -E. Tremblay , H. -G. Ludwig , M. Steffen , P. Bergeron , B. Freytag

We investigate crystallization-driven convection in carbon-oxygen white dwarfs. We present a version of the mixing length theory (MLT) that self-consistently includes the effects of thermal diffusion and composition gradients, and provides…

太阳与恒星天体物理 · 物理学 2024-07-01 Matias Castro-Tapia , Andrew Cumming , J. R. Fuentes

We present results of a large, high resolution 3D hydrodynamical simulation of the surface layers of a DA white dwarf (WD) with $T_{\rm eff}=11800$ K and $\log(g)=8$ using the ANTARES code, the widest and deepest such simulation to date.…

太阳与恒星天体物理 · 物理学 2017-12-05 F. Kupka , F. Zaussinger , M. H. Montgomery

As a step toward a complete theoretical integration of 3D compressible hydrodynamic simulations into stellar evolution, convection at the surface and sub-surface layers of the Sun is re-examined, from a restricted point of view, in the…

太阳与恒星天体物理 · 物理学 2014-11-20 W. David Arnett , Casey Meakin , Patrick A. Young

We present an extended grid of mean three-dimensional (3D) spectra for low-mass, pure-hydrogen atmosphere DA white dwarfs (WDs). We use CO5BOLD radiation-hydrodynamics 3D simulations covering Teff = 6000-11,500 K and logg = 5-6.5 (cgs…

太阳与恒星天体物理 · 物理学 2015-08-26 P. -E. Tremblay , A. Gianninas , M. Kilic , H. -G. Ludwig , M. Steffen , B. Freytag , J. J. Hermes

In this study we compute the structure and evolution of carbon-oxygen DA white dwarfs by means of a detailed and updated evolutionary code. We treat the energy transport by convection within the formalism of the full spectrum turbulence…

天体物理学 · 物理学 2016-08-30 L. G. Althaus , O. G. Benvenuto

We present the first radiation magnetohydrodynamics simulations of the atmosphere of white dwarf stars. We demonstrate that convective energy transfer is seriously impeded by magnetic fields when the plasma-beta parameter, the thermal to…

太阳与恒星天体物理 · 物理学 2015-10-14 P. -E. Tremblay , G. Fontaine , B. Freytag , O. Steiner , H. -G. Ludwig , M. Steffen , S. Wedemeyer , P. Brassard

Convective overshooting in super asymptotic giant branch stars has been suggested to lead to the formation of hybrid white dwarfs with carbon-oxygen cores and oxygen-neon mantles. As the white dwarf cools, this core-mantle configuration…

太阳与恒星天体物理 · 物理学 2019-05-01 Josiah Schwab , Pascale Garaud

(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…

天体物理学 · 物理学 2011-02-11 Casey A. Meakin , David Arnett

Based on detailed 2D and 3D numerical radiation-hydrodynamics (RHD) simulations of time-dependent compressible convection, we have studied the dynamics and thermal structure of the convective surface layers of a prototypical late-type…

天体物理学 · 物理学 2009-11-07 H. -G. Ludwig , F. Allard , P. H. Hauschildt
‹ 上一页 1 2 3 10 下一页 ›