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The radiation-dominated polar emitting region of an accreting X-ray pulsar is simulated numerically in the framework of a three-dimensional (geometrically two-dimensional) model. The radiative transfer within the emitting region and the…

High Energy Astrophysical Phenomena · Physics 2026-03-03 M. I. Gornostaev

(abridged) AIMS. We investigate the dynamics and stability of post-shock plasma streaming along nonuniform stellar magnetic fields at the impact region of accretion columns. We study how the magnetic field configuration and strength…

Solar and Stellar Astrophysics · Physics 2015-06-17 S. Orlando , R. Bonito , C. Argiroffi , F. Reale , G. Peres , M. Miceli , T. Matsakos , C. Stehlé , L. Ibgui , L. de Sá , J. P. Chièze , T. Lanz

Abridged: Recent simulations have explored different ways to form accretion disks around low-mass stars. We aim to present observables to differentiate a rotationally supported disk from an infalling rotating envelope toward deeply embedded…

Solar and Stellar Astrophysics · Physics 2015-04-29 Daniel Harsono , Ewine van Dishoeck , Simon Bruderer , Zhi-Yun Li , Jes Jorgensen

An approximate analytic one-dimensional model is constructed, for the accretion disk boundary layer surrounding a neutron star whose low magnetic field does not affect the process of accretion. A high luminosity model is considered, with…

High Energy Astrophysical Phenomena · Physics 2025-11-25 G. S. Bisnovatyi-Kogan

We present radiation hydrodynamics simulations of the collapse of massive pre-stellar cores. We treat frequency dependent radiative feedback from stellar evolution and accretion luminosity at a numerical resolution down to 1.27 AU. In the…

Solar and Stellar Astrophysics · Physics 2010-10-05 Rolf Kuiper , Hubert Klahr , Henrik Beuther , Thomas Henning

{It is necessary to understand the dynamics of the atomic gas to use complex modeling and to carry out detailed comparisons between theoretical models and observations.}{In a companion paper, we present high resolution bidimensional…

Astrophysics · Physics 2007-05-23 P. Hennebelle , E. Audit , M. -A Miville-Deschenes

Equilibrium models of differentially rotating nascent neutron stars are constructed, which represent the result of the accretion induced collapse of rapidly rotating white dwarfs. The models are built in a two-step procedure: (1) a rapidly…

Astrophysics · Physics 2008-11-26 Yuk Tung Liu , Lee Lindblom

The luminosity of X-ray pulsars is their key parameter determining the geometry and physical conditions of the accretion flow both on the spatial scales of a binary system and on much smaller scales of emitting regions located close to the…

High Energy Astrophysical Phenomena · Physics 2023-10-05 Ivan D. Markozov , Alexander A. Mushtukov

The dynamics and thermal structure of the surface layers of stars with outer convection zones can be studied in some detail by means of numerical simulations of time-dependent compressible convection. In an effort to investigate the…

Astrophysics · Physics 2007-05-23 Matthias Steffen

Neutron stars harbour extremely strong magnetic fields within their solid outer crust. The topology of this field strongly influences the surface temperature distribution, and hence the star's observational properties. In this work, we…

High Energy Astrophysical Phenomena · Physics 2020-11-04 Davide De Grandis , Roberto Turolla , Toby S. Wood , Silvia Zane , Roberto Taverna , Konstantinos N. Gourgouliatos

We present radiation hydrodynamics simulations of the collapse of massive pre-stellar cores. We treat frequency dependent radiative feedback from stellar evolution and accretion luminosity at a numerical resolution down to 1.27 AU. In the…

Solar and Stellar Astrophysics · Physics 2011-05-12 Rolf Kuiper , Hubert Klahr , Henrik Beuther , Thomas Henning

Recent observations of X-ray pulsars at low luminosities allow, for the first time, to compare theoretical models for the emission from highly magnetized neutron star atmospheres at low mass accretion rates ($\dot{M} \lesssim 10^{15}$ g…

Molecular dynamics simulation has been used to model pattern formation in three-dimensional Rayleigh--Benard convection at the discrete-particle level. Two examples are considered, one in which an almost perfect array of hexagonally-shaped…

Other Condensed Matter · Physics 2009-11-11 D. C. Rapaport

Radiation of X-ray pulsars is powered by accretion on the neutron star surface from a binary companion under the influence of a strong magnetic field. We study beaming of this radiation in the case of subcritical X-ray pulsars, where it is…

High Energy Astrophysical Phenomena · Physics 2026-05-06 I. D. Markozov , A. Y. Potekhin , A. D. Kaminker , A. A. Mushtukov

We investigate general aspects of molecular line formation under conditions which are typical of prestellar cores. Focusing on simple linear molecules, we study formation of their rotational lines by radiative transfer simulations. We…

Astrophysics · Physics 2009-11-13 Ya. Pavlyuchenkov , D. Wiebe , B. Shustov , Th. Henning , R. Launhardt , D. Semenov

Three-dimensional simulations of core-collapse supernovae are granting new insight into the as-yet uncertain mechanism that drives successful explosions. While there is still debate about whether explosions are obtained more easily in 3D…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Sean M. Couch , Evan P. O'Connor

Nonspherical mass motions are a generic feature of core-collapse supernovae, and hydrodynamic instabilities play a crucial role for the explosion mechanism. First successful neutrino-driven explosions could be obtained with self-consistent,…

Solar and Stellar Astrophysics · Physics 2016-11-23 H. -Thomas Janka , Tobias Melson , Alexander Summa

A three-dimensional numerical model for an accretion process investigation in the magnetosphere of a white dwarf in magnetic cataclysmic variables is developed. The model assumes that the white dwarf has a dipole magnetic field with its…

Solar and Stellar Astrophysics · Physics 2016-02-04 P. B. Isakova , A. G. Zhilkin , D. V. Bisikalo

I briefly review the theoretical models of radiatively efficient, geometrically thin and optically thick accretion disk spectra that currently exist for AGN. I then discuss three recent observational developments that have real potential to…

Astrophysics · Physics 2007-05-23 Omer Blaes

Current state-of-the-art computational modeling makes it possible to build realistic models of stellar convection zones and atmospheres that take into account chemical composition, radiative effects, ionization, and turbulence. The standard…

Solar and Stellar Astrophysics · Physics 2021-07-28 Irina N. Kitiashvili , Alan A. Wray