Analytic and Computational Studies of Structures and Oscillations of Rotating Stars and Stars in Binary Systems

Abstract

Abstract In the present thesis an attempt has been made to extend the work of Mohan et al (108, 109) and Lal (70). This work relates to the analytic studies of the problems of computing the equilibrium structure and the periods of small adiabatic oscillations of rotating stars and stars in binary systems. While computing the effects of rotational and tidal distortions on the equilibrium structures and the eigenfrequencies of radial and nonradial modes of oscillations of rotating stars and stars in binary systems, Mohan and Saxena (99, 100) and Mohan et al (108, 109, 104, 107) did not explicitly account for the effect of Coriolis force and they analyze these problems in inertial frame of reference only. In the present study we have tried to investigate the effects of inclusion of Coriolis force on the equilibrium structures as well as periods of small adiabatic barotropic modes of oscillations of rotating stars and stars in binary systems. In the case of some of the observed rotating stars and stars in binary systems, rotation is not only expected to be uniform but also differential in which angular velocity of rotation varies from point to point. In this thesis we have also investigated the effect of Coriolis force on the equilibrium structures and periods of small adiabatic barotropic oscillations of differentially rotating stars. Thesis consists of seven chapters. Chapter I is introductory in nature. In this chapter we briefly discuss the astrophysical significance of the problem of determining the equilibrium structures and periods of small adiabatic oscillations of rotationally and tidally distorted stellar models of the stars. Mohan, Saxena and Agarwal (108, 109) approach of determining the effects of rotation and/or tidal distortions on the equilibrium structure and the eigenfrequencies of radial and nonradial modes of oscillations of the theoretical models of the stars is also discussed.