Nonlinear Oscillations of Thermally Unstable Slim Accretion Disks around a Neutron Star or a Black Hole
Abstract
Numerical simulations were performed in order to examine the time evolution of thermally unstable accretion disks which surround a black hole or a weakly magnetized neutron star. Optically thick, slim transonic accretion disk models are used. The radialazimuthal component of a viscous stress tensor is assumed to have the form alpha beta (q) P, where beta is the ratio of the gas pressure to the total pressure, P, with constants alpha and q. Three cases (q = 0, 0.25, and 0.5) are examined. For q = 0, the disks exhibit burstlike oscillations. For q = 0.25, in comparison with the case of q = 0, the amplitude of the oscillations is much smaller and their period much shorter. For q = 0.5, the disks are stable.
 Publication:

Publications of the Astronomical Society of Japan
 Pub Date:
 February 1991
 Bibcode:
 1991PASJ...43..147H
 Keywords:

 Accretion Disks;
 Black Holes (Astronomy);
 Neutron Stars;
 Stellar Mass Accretion;
 Oscillations;
 Stellar Models;
 Thermal Stability;
 Astrophysics;
 ALPHADISKS;
 NUMERICAL SIMULATIONS;
 SLIM DISKS;
 THERMAL INSTABILITY