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The development of 2D and 3D simulations of solar convection has lead to a picture of convection quite unlike the usually assumed Kolmogorov spectrum turbulent flow. We investigate the impact of this changed structure on the dissipation…

Astrophysics · Physics 2012-05-14 Kaloyan Penev , Dimitar Sasselov , Frank Robinson , Pierre Demarque

The current understanding of the turbulent dissipation in stellar convective zones is based on the assumption that the turbulence follows Kolmogorov scaling. This assumption is valid for some cases in which the time frequency of the…

Astrophysics · Physics 2012-05-14 Kaloyan Penev , Joseph Barranco , Dimitar Sasselov

Turbulent convection is thought to act as an effective viscosity ($\nu_E$) in damping tidal flows in stars and giant planets. However, the efficiency of this mechanism has long been debated, particularly in the regime of fast tides, when…

Earth and Planetary Astrophysics · Physics 2020-07-27 Craig D. Duguid , Adrian J. Barker , Chris A. Jones

The convective collapse of thin magnetic flux tubes in the photospheres of sun-like stars is investigated using realistic models of the superadiabatic upper convection zone layers of these stars. The strengths of convectively stable flux…

Astrophysics · Physics 2009-11-07 S. P. Rajaguru , R. L. Kurucz , S. S. Hasan

Convection is thought to act as a turbulent viscosity in damping tidal flows and in driving spin and orbital evolution in close convective binary systems. This turbulent viscosity should be reduced, compared to mixing-length predictions,…

Solar and Stellar Astrophysics · Physics 2020-07-28 Jérémie Vidal , Adrian J. Barker

Although the dependence of convective core overshooting on mass has attracted much attention, no corresponding work exists for overshooting below a convective envelope. We aim to quantify this relationship for pre-main sequence stars of…

Solar and Stellar Astrophysics · Physics 2025-09-24 J. Pratt , I. Baraffe , M. -G. Dethero , M. Stuck , D. G. Vlaykov , T. Goffrey

The value of the effective convective viscosity, in the framework of the mixing length theory (MLT), is 2 orders of magnitude too small compared to that required by the observational data. Moreover, the reduction of the effective viscosity…

Astrophysics · Physics 2011-08-31 Itzhak Goldman

Subsurface convection zones are ubiquitous in early-type stars. Driven by narrow opacity peaks, these thin convective regions transport little heat but play an important role in setting the magnetic properties and surface variability of…

Solar and Stellar Astrophysics · Physics 2022-03-09 Adam S. Jermyn , Evan H. Anders , Matteo Cantiello

We investigate the pulsational stability of massive (M >~ 120 Msun) main sequence stars of a range of metallicities, including primordial, Population III stars. We include a formulation of convective damping motivated by numerical…

Solar and Stellar Astrophysics · Physics 2015-06-04 Joshua H. Shiode , Eliot Quataert , Phil Arras

Turbulent convection is thought to act as an effective viscosity in damping equilibrium tidal flows, driving spin and orbital evolution in close convective binary systems. Compared to mixing-length predictions, this viscosity ought to be…

Solar and Stellar Astrophysics · Physics 2020-09-01 Jérémie Vidal , Adrian J. Barker

The subsurface convective zones (CZs) of massive stars significantly influences many of their key characteristics. Previous studies have paid little attention to the impact of rotation on the subsurface convective zone (CZ), so we aim to…

Solar and Stellar Astrophysics · Physics 2025-01-23 Xiao-long He , Guo-liang Lv , Chun-hua Zhu , Lin Li , He-lei Liu , Su-fen Guo , Xi-zhen Lu , Lei Li , Hao Wang

We have adapted the anelastic spectral code of Barranco & Marcus (2006) to simulate a turbulent convective layer with the intention of studying the effectiveness of turbulent eddies in dissipating external shear (e.g. tides). We derive the…

Astrophysics · Physics 2015-05-13 Kaloyan Penev , Joseph Barranco , Dimitar Sasselov

There is strong observational evidence that the convective cores of intermediate-mass and massive main sequence stars are substantially larger than those predicted by standard stellar-evolution models. However, it is unclear what physical…

Solar and Stellar Astrophysics · Physics 2024-08-20 R. Andrassy , G. Leidi , J. Higl , P. V. F. Edelmann , F. R. N. Schneider , F. K. Roepke

We study the convection zones in the outer envelope of hot massive stars which are caused by opacity peaks associated with iron and helium ionization. We determine the occurrence and properties of these convection zones as function of the…

Solar and Stellar Astrophysics · Physics 2015-05-13 M. Cantiello , N. Langer , I. Brott , A. de Koter , S. N. Shore , J. S. Vink , A. Voegler , D. J. Lennon , S. -C. Yoon

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

In recent years, observers have found that the fraction of M-stars demonstrating significant magnetic activity transitions sharply from roughly $10\%$ for main-sequence stars earlier (more massive) than spectral type M3.5 (0.35 M$_\odot$)…

Solar and Stellar Astrophysics · Physics 2020-04-23 Connor P. Bice , Juri Toomre

During their main sequence evolution, massive stars can develop convective regions very close to their surface. These regions are caused by an opacity peak associated with iron ionization. Cantiello et al. (2009) found a possible connection…

Solar and Stellar Astrophysics · Physics 2011-08-26 Matteo Cantiello , Jonathan Braithwaite , Axel Brandenburg , Fabio Del Sordo , Petri Käpylä , Norbert Langer

Tidal dissipation in star-planet systems can occur through various mechanisms, among which is the elliptical instability. This acts on elliptically deformed equilibrium tidal flows in rotating fluid planets and stars, and excites inertial…

Earth and Planetary Astrophysics · Physics 2023-07-12 Nils B. de Vries , Adrian J. Barker , Rainer Hollerbach

Context. Synthetic model atmosphere calculations are still the most commonly used tool when determining precise stellar parameters and stellar chemical compositions. Besides three-dimensional models that consistently solve for hydrodynamic…

Solar and Stellar Astrophysics · Physics 2015-05-20 X. S. Wu , S. Alexeeva , L. Mashonkina , L. Wang , G. Zhao , F. Grupp

Analytic estimates of the viscous time-scale due to cloud-cloud collisions have been as high as thousands of Gyr. Consequently, cloud collisions are widely ignored as a source of viscosity in galactic disks. However, capturing the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 David J. Williamson , Rob J. Thacker
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