Instability in the red star of semidetached binary systems
Abstract
The solution of the linear adiabatic wave equation has been found for a range of evolutionary models in both singlestar and binary (lineofcentres) gravitational potentials, with Eulerian and Lagrangian surface pressure boundary conditions. The eigenvalues determining the stability of the envelope from different boundary conditions converge onto the same dynamically unstable value as the stellar surface approaches the L_{1} point. The properties of this instability are shown to be well correlated with the position and existence of the hydrogen/helium I ionization zone. Offlineofcentres calculations show that the instability patch about the L_{1} point is approximately 15 scaleheights in radius for a typical 1 M_sun; mainsequence star.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 February 1985
 DOI:
 10.1093/mnras/212.3.623
 Bibcode:
 1985MNRAS.212..623E
 Keywords:

 Binary Stars;
 Companion Stars;
 Stellar Evolution;
 Stellar Models;
 Adiabatic Conditions;
 Eigenvalues;
 Helium;
 Hydrogen;
 Linear Equations;
 Roche Limit;
 Astrophysics