Fricção dinâmica e aplicações para os problemas do decaimento dos aglomerados globulares em núcleos galáticos.

Abstract

Dynamical Friction (DF) developed by Chandrasekhar in the mid-20th century and in the context of the theory of galaxy dynamics is an important gravitational phenomenon involving stellar encounters or gravitational interactions between stars in the galactic field and a perturber of greater mass, such as a Globular Cluster (GA). This Final Course Work (TCC) aims to describe, understand, analyze and apply succinctly the DF theory originally proposed and developed by S. Chandrasekhar in the 1940s. On another front, an application of this mechanism will be developed for the problem involving the orbital decay of some massive objects, such as GAs in galactic nuclei. Using a purely theoretical approach, the primary objective is to describe how the idea of stellar encounters or gravitational interactions between a massive object of mass M and the stars of mass m in the galactic field produce a constant deceleration, producing profound physical implications for the motion of such a body within the galaxy. This means that the present mechanism, popularly known as Chandrasekhar's FD, plays an important role in the theory of stellar systems and galaxy dynamics, influencing the dynamics, evolution, structure and trajectory of GAs, Supermassive Black Holes and Satellite Galaxies. Following the Chandrasekhar formalism, an application of this basic mechanism will be presented to describe the decay of the orbits of GAs in galactic nuclei, especially for the case in which the velocity distribution of the stars in the galactic field can be modeled by a Maxwellian, with the distribution of matter in the galaxy assuming the profile of an isothermal singular sphere. Finally, we will show that the time scale, usually known as friction time, which is the time for which a GA can decay in the center of the galaxy, is of the order of 2 to 3 billion years, although other more realistic predictions will also be discussed.