Stability Analysis of the Accretion Line
Abstract
The stability of the flow along the accretion line in the BondiHoyleLyttletontype accretion flow is studied. The WKB approximation is used to analyze short wavelength linear perturbations of the axisymmetric steady state flow. The viscosity terms in the gasdynamical equations are included in the analysis. The radial modes are studied both in two and threedimensional accretion flow. Since a displaced accretion line cannot be defined in threedimensional flow, the tangential modes are only analyzed in the twodimensional flow. The analysis of the perturbed gasdynamical equations are made simpler as a result of the radial and tangential modes being decoupled in the linear regime. As was shown before, the threedimensional accretion flow is unstable against radial modes. The twodimensional accretion flow is found to be unstable against tangential modes, as well as against radial modes. Using typical numerical parameters which are in common use, the wavelength which gives the maximum growth rate of a small perturbation is found to be about 0.5 r(a), where r(a) is the accretion radius.
 Publication:

The Astrophysical Journal
 Pub Date:
 August 1990
 DOI:
 10.1086/169007
 Bibcode:
 1990ApJ...358..545S
 Keywords:

 Flow Stability;
 Gas Dynamics;
 Stellar Mass Accretion;
 Three Dimensional Flow;
 WentzelKramerBrillouin Method;
 Perturbation Theory;
 Steady State;
 Viscosity;
 Astrophysics;
 HYDRODYNAMICS;
 STARS: ACCRETION;
 STARS: BINARIES