The E ect of Opacity on Parameters of the Convective Envelope in SolarModelsV

High-precision calculations of a series of standard models of the internal structure of the Sun using diierent opacity tables are presented. The models are compared on the basis of two key parameters-helium abundance and speciic entropy in the convection zone. The eeect of opacity on these two parameters in the radiative interior of the Sun is studied. Comparison of standard models calculated using diierent opacity tables shows that the speciic entropy in the envelope diminishes with growing opacity in the radiative zone, while helium abundance grows with increase in opacity in the core. Investigation of static nonevolutionary models with modiied opacities indicates a general connection between the speciic entropy in the envelope and opacity in the radiative zone, outside the region of energy release. INTRODUCTION The classical problem of modelling the internal structure of the Sun has not lost its urgency due, on the one hand, to continuous revision of theoretical ideas about the physics of high-temperature plasmas and, on the other hand, to the rapid development of helioseismology, which requires high-precision calculations of the distributions of physical quantities in the model. In the 1990s, a transition is taking place to a new generation of Solar models, distinguished most of all by their high internal mathematical consistency, which allows not only identiication and study of small eeects of diierent physical assumptions, but also analysis of internal relations between parameters in the problem of modelling the Solar interior. In this paper, we rst consider "standard" evolution ary Solar models , and remain within the framework of classical evolutionary ideas. This means that the basis of the calculation is the concept of equilibrium (ther-modynamic) evolution from an initial uniform state to a model with the present-day radius and luminosity for a given age. We assume mass conservation during the process of evolution (no accretion or mass loss) and the absence of any kind of mixing (diiusive or other) outside the convection