ABSTRACT
This chapter discusses the structure of compact stars, namely white dwarfs and neutron stars, which are significantly more compact than an ordinary star like the Sun. Compact stars form at the end point of the evolution of sufficiently massive main-sequence stars. In order to understand how these objects can form, the chapter briefly describes the main steps of stellar evolution. Stars are formed by the fragmentation of primordial hydrogen clouds. It focuses on the study of white dwarfs. Since these objects have masses of the order of that of the Sun and radii of the order of 5000 km, their compactness is very small. A more accurate description of white dwarfs should take into account other effects, like for example electrostatic corrections due to the fact that the positive charges are concentrated in individual nuclei rather than being uniformly distributed.
