Disk-instability model for outbursts of dwarf novae. II Full-disk calculations
Abstract
The time evolution of unstable accretion disks was calculated by solving full-disk equations in the nonthermal equilibrium situation. It is confirmed that instabilities based on a constant-alpha disk (where alpha is the standard viscosity parameter) yield only small amplitude continuous light variation and thus fail to reproduce the dwarf-nova outbursts. By assigning high alpha in hot state and low alpha in cool state, the basic feature of dwarf-nova outbursts can be reproduced by the disk-instability model. Numerical results are presented for two typical cases of outbursts, types A and B in Smak's (1984) notation. The local variations in the accretion disks and the global propagation of the transition waves are then discussed in detail. The propagation of transition waves is fairly complicated, particularly in the case when a heating wave propagating outward is reflected in the middle of the disk as a cooling wave.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- 1985
- Bibcode:
- 1985PASJ...37....1M
- Keywords:
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- Accretion Disks;
- Dwarf Novae;
- Stellar Mass Accretion;
- Stellar Radiation;
- Light Curve;
- Thermodynamic Equilibrium;
- Time Dependence;
- Wave Propagation;
- Astrophysics