Runaway of Line-driven Winds toward Critical and Overloaded Solutions
Abstract
Line-driven winds from hot stars and accretion disks are thought to follow a unique, critical solution that corresponds to a maximum mass-loss rate and a particular velocity law. We show that in the presence of negative velocity gradients, radiative-acoustic (Abbott) waves can drive shallow wind solutions toward larger velocities and mass-loss rates. Perturbations that are introduced downstream from the critical point of the wind lead to a convergence toward the critical solution. By contrast, low-lying perturbations cause evolution toward a mass-overloaded solution, developing a broad deceleration region in the wind. Such a wind differs fundamentally from the critical solution. For sufficiently deep-seated perturbations, overloaded solutions become time-dependent and develop shocks and shells.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2000
- DOI:
- 10.1086/312577
- arXiv:
- arXiv:astro-ph/0002339
- Bibcode:
- 2000ApJ...532L.125F
- Keywords:
-
- ACCRETION;
- ACCRETION DISKS;
- GALAXIES: ACTIVE;
- HYDRODYNAMICS;
- STARS: NOVAE;
- CATACLYSMIC VARIABLES;
- STARS: MASS LOSS;
- STARS: WINDS;
- OUTFLOWS;
- Astrophysics
- E-Print:
- Latex, 2 postscript figures Astrophysical Journal Letters, in press