On the composition of the solar interior - Rapporteur Paper I

Standard solar models, although they are free from the influence of much of the fluid motion that is bound to be present in the Sun, have been shown b y helioseismology to represent the spherically averaged structure of the Su n amazingly well. This state of affairs has come about after painstaking re finements by a great many people of the pertinent microphysics, including t hat which controls the equation of state, the opacity, the nuclear reaction rates and the diffusion that inhibits gravitational segregation of chemica l elements. It has instilled confidence in the modellers in being able to p redict the composition of the solar interior. But there are consequences of the how related particularly to redistribution of chemical species, that c an be difficult to identify observationally, yet which may degrade any infe rences we might make. Their potential presence must at least be acknowledge d by anyone who tries to asses the reliability of the models. This report s ummarizes the discussions in the preceding pages of this volume of the curr ent theoretical and observational status of the subject, pointing to many o f the caveats that have been raised, and attempting at the same time to put them into a seemingly coherent discourse in the context of our present und erstanding of the workings of the solar interior.