Stellar interior models (the Henyey method)

This paper will describe the most common modern technique for treating stellar evolutionary problems (the Henyey technique) and will give a brief outline of the type of results obtained and of the current status of our understanding of stellar interiors. We will confine our attention to spherically symmetric stars in quasi-static equilibrium, i.e. we will exclude any stars which have magnetic fields, which are rotating, which are in close binary contact with other stars so that there are tidal effects, and also stars which are changing so rapidly that dynamic terms must be considered in the equations of their structure. All of these phenomena are treated (with varying degrees of approximation) in this branch of astrophysics, but their description here would involve us with a mass of astrophysical detail outside the scope of the present paper. (author)