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Related papers: The Effects of Cooling on Boundary Layer Accretion

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Disk accretion onto a weakly magnetized central object, e.g. a star, is inevitably accompanied by the formation of a boundary layer near the surface, in which matter slows down from the highly supersonic orbital velocity of the disk to the…

Solar and Stellar Astrophysics · Physics 2015-06-05 Mikhail A. Belyaev , Roman R. Rafikov , James M. Stone

Disk accretion onto weakly magnetized objects possessing a material surface must proceed via the so-called boundary layer (BL) - a region at the inner edge of the disk, in which the velocity of accreting material abruptly decreases from its…

High Energy Astrophysical Phenomena · Physics 2021-10-20 Matthew S. B. Coleman , Roman R. Rafikov , Alexander A. Philippov

Disk accretion at high rate onto a white dwarf or a neutron star has been suggested to result in the formation of a spreading layer (SL) - a belt-like structure on the object's surface, in which the accreted matter steadily spreads in the…

Solar and Stellar Astrophysics · Physics 2016-01-27 Alexander A. Philippov , Roman R. Rafikov , James M. Stone

Disk accretion onto weakly magnetized astrophysical objects often proceeds via a boundary layer that forms near the object's surface, in which the rotation speed of the accreted gas changes rapidly. Here we study the initial stages of…

Solar and Stellar Astrophysics · Physics 2015-06-03 Mikhail Belyaev , Roman Rafikov

Astrophysical objects possessing a material surface (white dwarfs, young stars, etc.) may accrete gas from the disc through the so-called surface boundary layer (BL), in which the angular velocity of the accreting gas experiences a sharp…

High Energy Astrophysical Phenomena · Physics 2022-07-06 Matthew S. B. Coleman , Roman R. Rafikov , Alexander A. Philippov

The origin of the spins of giant planets is an open question in astrophysics. As planets and stars accrete from discs, if the specific angular momentum accreted corresponds to that of a Keplerian orbit at the surface of the object, it is…

Earth and Planetary Astrophysics · Physics 2021-09-29 Alexander J. Dittmann

In the initial formation stages young stars must acquire a significant fraction of their mass by accretion from a circumstellar disk that forms in the center of a collapsing protostellar cloud. Throughout this period mass accretion rates…

Astrophysics · Physics 2009-11-13 Roman Rafikov

For a slowly rotating non-magnetized white dwarf the accretion disk extends all the way to the star. Here the matter impacts and spreads towards the poles as new matter continuously piles up behind it. We have solved the 3d compressible…

Astrophysics · Physics 2015-08-06 Jacob Lund Fisker , Dinshaw S. Balsara , Tom Burger

Accretion disk outbursts, and their subsequent decline, offer a unique opportunity to constrain the physics of angular momentum transport in hot accretion disks. Recent work has centered on the claim by Cannizzo et al. that the exponential…

Astrophysics · Physics 2009-10-30 Ethan T. Vishniac

If a supermassive black hole resides in the centers of galaxies, there are several effects expected to be observed. It is likely that accretion disks are around the supermassive black hole. Stellar interactions with the accretion flows…

Astrophysics · Physics 2009-10-31 Heon-Young Chang

The physical modeling of the accretion disk boundary layer, the region where the disk meets the surface of the accreting star, usually relies on the assumption that angular momentum transport is opposite to the radial angular frequency…

High Energy Astrophysical Phenomena · Physics 2012-11-28 Chi-kwan Chan , Martin E. Pessah

Gravitational coupling between young planets and their parent disks is often explored using numerical simulations, which typically treat the disk thermodynamics in a highly simplified manner. In particular, many studies adopt the locally…

Earth and Planetary Astrophysics · Physics 2020-04-08 Ryan Miranda , Roman R. Rafikov

The nature of angular momentum transport in the boundary layers of accretion disks has been one of the central and long-standing issues of accretion disk theory. In this work we demonstrate that acoustic waves excited by supersonic shear in…

Solar and Stellar Astrophysics · Physics 2015-06-12 Mikhail A. Belyaev , Roman R. Rafikov , James M. Stone

We consider the effects of advection and radial gradients of pressure and radial drift velocity on the structure of accretion disks around black holes with proper description of optically thick/thin transitions. We concentrated our efforts…

Astrophysics · Physics 2009-11-10 Yu. V. Artemova , G. S. Bisnovatyi-Kogan , I. V. Igumenshchev , I. D. Novikov

Disc accretion onto astrophysical objects with a material surface proceeds through the boundary layer (BL) -- a radially narrow region in the inner disc where the incoming gas must slow down its rotation before settling onto the surface of…

High Energy Astrophysical Phenomena · Physics 2025-10-20 Samuel G. D. Turner , Roman R. Rafikov , Alexander A. Philippov

The existing disk instability model for dwarf nova eruptions is reviewed, in the light of recent progress in the understanding of angular momentum transport in accretion disks. It is proposed that the standard lower branch in the…

Astrophysics · Physics 2007-05-23 Mario Livio

Cooling flows in galaxy clusters and isolated elliptical galaxies are a source of mass for fueling accretion onto a central supermassive black hole. We calculate the dynamics of accreting matter in the combined gravitational potential of a…

Astrophysics · Physics 2009-10-31 Eliot Quataert , Ramesh Narayan

When the accretion disc around a weakly magnetised neutron star (NS) meets the stellar surface, it should brake down to match the rotation of the NS, forming a boundary layer. As the mechanisms potentially responsible for this braking are…

High Energy Astrophysical Phenomena · Physics 2020-07-01 Pavel Abolmasov , Joonas Nättilä , Juri Poutanen

Massive stars can form within or be captured by AGN disks, influencing both the thermal structure and metallicity of the disk environment. In a previous work, we investigated isotropic accretion onto massive stars from a gas-rich,…

High Energy Astrophysical Phenomena · Physics 2025-05-21 Yi-Xian Chen , Yan-Fei Jiang , Jeremy Goodman

Cold optically thick accretion disks with hot coronae and radial advection have been investigated. Within the framework of $\alpha$-viscosity models, we assume that all the mass accretion and angular momentum transport take place in the…

Astrophysics · Physics 2009-10-28 Xingming Chen
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