Calculation of equilibrium polytropic and degenerate stellar configurations in binary systems
Abstract
Equilibrium polytropic and degenerate configurations of stars in binary systems are calculated for the case when one of the components fills its Roche lobe. For the case of the polytropic equation of state, the relationship is obtained between the mass of the primary component (filling its Roche lobe), the mass of the secondary component, the distance between the component centers, and the entropy constant K of the primary component. If in this case the three quantities are conserved in the mass exchange process, the total mass of the system, the total angular momentum, and the entropy constant K, then only one equilibrium configuration of the primary component, namely, the initial configuration, is shown to exist. In other words, if these three quantities are conserved, mass exchange cannot be thought as the sequence of equilibrium configurations of the primary component constantly filling its Roche lobe. In the case of the equation of state of a cool degenerate electron gas, the relation between the mass of the primary component (filling its Roche lobe), the mass of the secondary component, and the distance between the components centers is calculated. Only one equilibrium configuration of the primary component, the initial configuration, is proved to exist in the case when the following two quantities are conserved in the mass exchange process: the total mass and the total angular momentum of the system.
 Publication:

Astronomicheskii Zhurnal
 Pub Date:
 August 1995
 Bibcode:
 1995AZh....72..508K
 Keywords:

 Binary Stars;
 Polytropic Processes;
 Mass Transfer;
 Stellar Structure;
 Roche Limit;
 Stellar Mass Ejection;
 Stellar Systems;
 Astronomical Models;
 Stellar Mass Accretion;
 Astrophysics