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2000ApJ...541..918B - Astrophys. J., 541, 918-923 (2000/October-1)
Hypercritical advection-dominated accretion flow.
BROWN G.E., LEE C.-H. and BETHE H.A.
Abstract (from CDS):
In order to raise the temperature high enough that the disk might cool by neutrino emission, Chevalier found a small value of the α-parameter, where the kinematic coefficient of shear viscosity is ν=αcsH, with cs the velocity of sound and H the disk height; namely, α∼10–6 was necessary for gas pressure to dominate. He also considered results with higher values of α, pointing out that radiation pressure would then predominate. With these larger α-values, the temperatures of the accreting material are much lower, ≳0.35 MeV. The result is that neutrino cooling during the flow is negligible, satisfying very well the advection-dominating conditions.
The low temperature of the accreting material means that it cannot get rid of its energy rapidly by neutrino emission, so it piles up, pushing its way through the accretion disk. An accretion shock is formed, far beyond the neutron star, at a radius ≲108 cm, much as in the earlier spherically symmetric calculation, but in rotation. Two-dimensional numerical simulation shows that an accretion disk is reformed inside of the accretion shock, allowing matter to accrete onto the neutron star with pressure high enough so that neutrinos can carry off the energy.
Abstract Copyright: ∼
Journal keyword(s): Accretion, Accretion Disks - Stars: Binaries: Close - Black Hole Physics - Stars: Evolution - Stars: Neutron
Simbad objects: 2
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