Analysis of the presence of small admixtures of heavy elements in the solar plasma by using the SAHA-S equation of state

The thermodynamic functions of a weakly nonideal plasma are extensively calculated for conditions typical of the depths of stars by using the SAHA-S equation of state. These calculations ensure precise analysis of the effect of the heavy-element content on adiabatic compressibility in the depths of the Sun. Comparison of model calculations with recent helioseismic data ensures more precise determination of solar-plasma composition. This comparison shows that the inclusion of additional components to the composition of heavy-element admixtures is a necessary condition for the theoretical equation of state and the results of analysis of solar oscillations to be consistent. (C) 2004 MAIK Nauka/Interperiodica.