Article
Astronomy & Astrophysics
Yingzhen Cui, Xiangcun Meng
Summary: The occurrence of optically thick wind in the single degenerate (SD) model for Type Ia supernovae progenitors is studied in this article. Hydrodynamical simulations with different accretion rates and white dwarf masses show that the optically thick wind occurs when neglecting interaction with accreted material, but its occurrence becomes dependent on the accretion rate when considering the interaction. The white dwarf mass also affects the occurrence of the optically thick wind.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
F. Ahlborn, F. Kupka, A. Weiss, M. Flaskamp
Summary: This study proposes an improved model for calculating the dissipation rate of turbulent kinetic energy, which can be used in 1D stellar evolution calculations. By analyzing the contributions of different factors to the dissipation rate and suggesting a new method to account for some of these physical mechanisms, the authors show that the new model allows for a more complete description of convective overshooting and mixing in stars.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
F. Kupka, F. Ahlborn, A. Weiss
Summary: In this study, an improved model for computing the dissipation rate of turbulent kinetic energy in non-local models of stellar convection is proposed. The new model allows for a more accurate description of convective overshooting and mixing in stars.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
F. Rizzuti, R. Hirschi, C. Georgy, W. D. Arnett, C. Meakin, A. St J. Murphy
Summary: This study reveals major flaws in the convective boundary mixing in 1D stellar models, calling for significant revisions in how these models are implemented.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Leandro G. Althaus, Maria E. Camisassa, Santiago Torres, Tiara Battich, Alejandro H. Corsico, Alberto Rebassa-Mansergas, Roberto Raddi
Summary: Investigation of the structural and evolutionary properties of ultra-massive white dwarfs considering the effects of general relativity.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Vishnu Varma, Bernhard Mueller
Summary: In the first 3D MHD simulation of convective oxygen and neon shell burning in a non-rotating star, magnetic fields in supernova progenitors were studied. The magnetic field approaches saturation levels in the oxygen shell, but does not reach kinetic equipartition.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Simon Blouin, Huaqing Mao, Falk Herwig, Pavel Denissenkov, Paul R. Woodward, William R. Thompson
Summary: We present the first 3D hydrodynamics simulations of the excitation and propagation of internal gravity waves (IGWs) in the radiative interiors of low-mass stars on the red giant branch (RGB). Our simulations show a rich, continuous spectrum of IGWs with a significant amount of total power contained at high wavenumbers. We observe weaker IGW mixing than predicted, and the efficiency of IGW mixing may be underestimated in our simulations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
N. Yokoi, Y. Masada, T. Takiwaki
Summary: This study investigates the mass, momentum, and heat transports in convective turbulence using the time-space double averaging procedure. By considering plumes as coherent fluctuations, a non-equilibrium model for convective turbulence is developed, which incorporates the change of turbulence characteristics along the mean stream into the expression of turbulent transport coefficients. The results demonstrate that incorporating plume motion into the turbulent transport model is an important extension of mean-field theory, and it successfully reproduces the enhanced and localized turbulent mass flux observed in surface cooling-driven convection.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Alejandro H. Corsico, S. Reece Boston, Leandro G. Althaus, Mukremin Kilic, S. O. Kepler, Maria E. Camisassa, Santiago Torres
Summary: Ultra-massive white dwarf stars, discovered at a considerable rate, likely play a major role in Type Ia supernova explosions. The interiors of these white dwarfs can be probed through asteroseismology, with general relativity potentially affecting their structure and pulsations.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
V. Prat, S. Mathis
Summary: This research investigates the impact of horizontal shear on the anisotropy of turbulent transport in stellar radiative zones, resulting in new theoretical scalings that enhance turbulent motions. These findings could lead to a more efficient transport of chemicals and angular momentum, aligning better with helio- and asteroseismic observations in the Hertzsprung-Russell diagram.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
R. Andrassy, J. Higl, H. Mao, M. Mocak, D. G. Vlaykov, W. D. Arnett, I Baraffe, S. W. Campbell, T. Constantino, P. V. F. Edelmann, T. Goffrey, T. Guillet, F. Herwig, R. Hirschi, L. Horst, G. Leidi, C. Meakin, J. Pratt, F. Rizzuti, F. K. Roepke, P. Woodward
Summary: Our ability to predict the structure and evolution of stars is limited by complex hydrodynamic processes. However, our simulations show that hydrodynamic simulations of flows in stellar interiors are reliable.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Ruskin Patel, Kaloyan Penev
Summary: The evolution of binary objects under tidal influence significantly impacts their observed properties. By studying eclipsing binary systems from the Kepler mission, constraints on tidal dissipation efficiency were found, and detailed simulations were performed to model the evolution of these systems. The analysis showed that a specific value of log(10) Q(*)' could reproduce the observed primary star spin in almost all systems in the sample.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
P. Eggenberger, F. D. Moyano, J. W. den Hartogh
Summary: This study investigates the impact of the magnetic Tayler instability on the angular momentum transport in stars, and tests different versions of the Tayler-Spruit dynamo by comparing them with asteroseismic measurements. It is found that the original TS dynamo provides insufficient coupling in certain cases, but a calibrated version can better reproduce the observed rotation rates of stars.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
L. Perot, N. Chamel
Summary: Space-based gravitational-wave detectors provide new possibilities for studying the crystallization of white dwarfs in binary systems by analyzing the tidal effects on the gravitational-wave signals. The elasticity of the crystallized core is found to reduce the tidal deformability, especially for low-mass stars. The relativistic correction to the observable tidal deformability becomes increasingly important for more massive white dwarfs.
Article
Astronomy & Astrophysics
L. J. A. Scott, R. Hirschi, C. Georgy, W. D. Arnett, C. Meakin, E. A. Kaiser, S. Ekstrom, N. Yusof
Summary: The study on the application of the entrainment law in 1D models reveals that the impact of mass and time on boundary penetrability varies, with the chemical gradient having a greater influence on time.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)