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Related papers: 3D Convective Urca Process in a Simmering White Dw…

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Convection is one of the most important mixing processes in stellar interiors. Hydrodynamic mass entrainment can bring fresh fuel from neighboring stable layers into a convection zone, modifying the structure and evolution of the star.…

Solar and Stellar Astrophysics · Physics 2023-11-29 G. Leidi , R. Andrassy , J. Higl , P. V. F. Edelmann , F. K. Röpke

Polluted white dwarfs (WDs) with small surface convection zones deposit significant concentrations of heavy elements to the underlying radiative interior, presumably driving thermohaline convection. Current models of polluted WDs frequently…

Solar and Stellar Astrophysics · Physics 2025-03-28 Imogen G. Cresswell , Adrian E. Fraser , Evan B. Bauer , Evan H. Anders , Benjamin P. Brown

The process referred to as "semi-convection" in astrophysics and "double-diffusive convection in the diffusive regime" in Earth and planetary sciences, occurs in stellar and planetary interiors in regions which are stable according to the…

Solar and Stellar Astrophysics · Physics 2015-06-03 Giovanni M. Mirouh , Pascale Garaud , Stephan Stellmach , Adrienne L. Traxler , Toby S. Wood

We construct time-dependent one-dimensional (vertically averaged) models of accretion disks produced by the tidal disruption of a white dwarf (WD) by a binary neutron star (NS) companion. Nuclear reactions in the disk midplane burn the WD…

High Energy Astrophysical Phenomena · Physics 2016-09-16 Ben Margalit , Brian D. Metzger

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

We investigate neutrino-driven convection in core collapse supernovae and its ramifications for the explosion mechanism. We begin with an ``optimistic'' 15 solar mass precollapse model, which is representative of the class of stars with…

We report on the three-dimensional (3D) hydrodynamic evolution to iron core-collapse of a rapidly rotating 16 $M_{\odot}$ star. For the first time, we follow the 3D evolution of the angular momentum (AM) distribution in the iron core and…

Solar and Stellar Astrophysics · Physics 2022-01-19 C. E. Fields

A major weakness in one-dimensional (1D) stellar structure and evolution modeling is the simplified treatment of convection, which leads to erroneous near-surface stratification and considerable uncertainties in predicted effective…

Multi-dimensional fluid flow plays a paramount role in the explosions of massive stars as core-collapse supernovae. In recent years, three-dimensional (3D) simulations of these phenomena have matured significantly. Considerable progress has…

Solar and Stellar Astrophysics · Physics 2020-06-11 B. Müller

The evolution of the first generations of stars at zero or extremly low metallicity, and especially some crucial properties like the primary N14 production, is charactarized by convective-reactive mixing events that are mostly absent from…

Astrophysics · Physics 2009-06-23 Paul Woodward , Falk Herwig , David Porter , Tyler Fuchs , Anthony Nowatzki , Marco Pignatari

The final stages of the evolution of electron--degenerate ONe cores, resulting from carbon burning in ``heavy weight'' intermediate--mass stars ($8 M_{\sun}\la M \la 11 M_{\sun}$) and growing in mass, either from carbon burning in a shell…

Astrophysics · Physics 2009-11-10 J. L. Gutierrez , R. Canal , E. Garcia-Berro

Hydrodynamic simulations of neutron star mergers rely on the clear separation between the strong-interaction, weak-interaction, and hydrodynamic timescales. In this effective framework, weak Urca interactions are typically the slowest…

High Energy Astrophysical Phenomena · Physics 2026-03-17 Jamie M. Karthein , Maneesha Sushama Pradeep , Rachel Steinhorst

Observationally, spectra of brown dwarfs indicate the presence of dust in their atmospheres while theoretically it is not clear what prevents the dust from settling and disappearing from the regions of spectrum formation. Consequently,…

Solar and Stellar Astrophysics · Physics 2015-05-18 Bernd Freytag , France Allard , Hans-Guenter Ludwig , Derek Homeier , Matthias Steffen

Condensable species are crucial in shaping planetary climate. A wide range of planetary climate systems involve understanding non-dilute condensable substances and their influence on climate dynamics. There has been progress on large-scale…

Earth and Planetary Astrophysics · Physics 2021-12-22 Xianyu Tan , Maxence Lefevre , Raymond Pierrehumbert

Mixing in the convective core is quite uncertain in core helium burning stars. In order to explore the overshooting mixing beyond the convective core, we incorporated the $k$-$\omega$ proposed by Li (2012, 2017) into MESA, and investigated…

Solar and Stellar Astrophysics · Physics 2018-08-15 Yan Li , Xing-hao Chen , He-ran Xiong , Jun-jun Guo , Xue-fei Chen , Zhan-wen Han

In this paper we address the theory of Type Ia supernovae from the moment of carbon runaway up to several hours after the explosion. We have concentrated on the boiling-pot model: a deflagration characterized by the (nearly-) simultaneous…

Astrophysics · Physics 2009-11-10 D. Garcia-Senz , E. Bravo

Context. Classical novae are thermonuclear explosions hosted by accreting white dwarfs in stellar binary systems. Material piles up on top of the white dwarf star under mildly degenerate conditions, driving a thermonuclear runaway. The…

Solar and Stellar Astrophysics · Physics 2018-05-23 Joana Figueira , Jordi Jose , Enrique Garcia-Berro , Simon W. Campbell , Domingo Garcia-Senz , Shazrene Mohamed

We study mass ejection from accretion disks formed in the merger of a white dwarf with a neutron star or black hole. These disks are mostly radiatively-inefficient and support nuclear fusion reactions, with ensuing outflows and…

High Energy Astrophysical Phenomena · Physics 2019-07-10 Rodrigo Fernández , Ben Margalit , Brian D. Metzger

We present three-dimensional numerical simulations of turbulent combustion converting a neutron star into a quark star. Hadronic matter, described by a micro-physical finite-temperature equation of state, is converted into strange quark…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Matthias Herzog , Friedrich K. Roepke

A ubiquitous arrangement in nature is a free-flowing fluid coupled to a porous medium, for example a river or lake lying above a porous bed. Depending on the environmental conditions, thermal convection can occur and may be confined to the…

Fluid Dynamics · Physics 2022-12-21 Matthew McCurdy , Nicholas J. Moore , Xiaoming Wang