The Evolution of Main Sequence Binary Star.

Abstract

In this thesis, we have reviewed the main properties of binary systems and the most important types of binary interactions, stable and unstable mass transfer, the role of mass loss, mass accretion and, in the most dramatic case, the merging of the two binary components. Kepler’s laws are just an approximation: we are treating the whole system as a collection of isolated two-body problems. A binary, shorthand for binary star system, is a pair of stars gravitationally bound together, in orbit around their mutual center of mass. The study of binary stars provides the key piece of information to understanding why main sequence stars have a range of properties from high luminosity to low luminosity. Binary stars have traditionally been the main source of accurate stellar masses and radii, and are employed to calibrate the mass-dependence of the main sequence (Andersen 1991). Most useful in this regard are the detached, double-lined, eclipsing systems. Here, one exploits both the radial velocity and light curves to obtain not only the masses of the individual components, but also their luminosities and effective temperatures. Orbital periods and orbital radii via Kepler’s Third Law yields the mass of stars. The masses and ages derived by placing stars on the tracks are fundamental data, not only for characterizing individual objects, but for assessing the mass distribution and history of formation activity within clusters and associations Close binary stars consisting of two compact stellar remnants (white dwarfs (WDs), neutron stars (NSs), or black holes (BHs)) are considered as primary targets of the forthcoming field of gravitational wave (GW) astronomy since their orbital evolution has entirely controlled by the emission of gravitational waves and leads to ultimate coalescence (merger) of the components.