Effects of Magnetic Field on Rotationally and Tidally Distorted White Dwarf Models of Stars

Abstract

In the present thesis, we have used the approach of Mohan, Saxena & Aggarwal along with the approach of Kopal to study the effects of magnetic field on Rotationally and tidally distorted White Dwarf Models of Stars. In Theoretical Models, Stars are often regarded as self-gravitating spheres composed mainly of gases. Theoretical Analysis is the determination of Equilibrium Structure (ES) of Stars. This involves studying the distribution of mass, pressure, temperature and density throughout a star’s interior. By accurately modelling these factors, scientists can gain insights into the physical processes that sustain a star’s stability and prevent its collapse. These studies have been beneficial to the understanding of the stellar structure, it’s evolution and its behaviour. Moreover, they are used to predict the properties of stars in different stages of their lifecycle. A binary star consists of two components that are gravitationally bonded to and orbit each other. These stars rotate about their own axis besides revolving around each other. Complex analytical studies have been used to understand the effect of rotation and tidal distortion stellar structure and evolution. While obtaining Roche equipotential surfaces effect of magnetic forces always have been neglected due to its minor effect as compared to centrifugal and gravitational forces. However, recent studies have suggested that magnetic forces should not be overlooked, as they can play a significant role in determining the shape of Roche equipotential surface of stars. By understanding the effects of magnetic field on rotationally and tidally distorted stars, this research has made a significant effort to both theoretically and computationally analyze the significant impacts of magnetic distortion on the ES of rotationally and tidally distorted gaseous spheres, further research is needed to gain a greater insight into stellar structure. This thesis consists of 3 Chapters. The First Chapter serves as an introduction to the topic. It consists of the brief explanation on how these binary stellar models can be used to study the effects of rotation, tidal forces and magnetic fields on the evolution of stars. Chapter two has a brief description about the binary stars thus reinforces the concept of Roche equipotential surfaces (EQS). Here we study the effect of magnetic field on mass transfer that takes place in a binary system and how it leads to significant decrease in the total stellar mass over time. It gives us a glimpse into the methodology used by Kippenhahn and Thomas to gain a deeper understanding of the stellar environment. In order to highlight the importance of inclusion of magnetic distortion on stellar grounds, where it was not thought to be to a significant level to be included in previous stellar studies, the phenomena of magnetic braking have been described. Chapter three is the last chapter of my thesis. It involves the numerical computations, approaches and procedures used to calculate the stellar parameters. On the basis of the current investigation, several conclusions have been drawn. The chapter comes to a close with a note on the importance of the current study, a discussion of the limitations of our methodology.