Helioseismic Tests of Radiative Opacities.

During the past fifteen years, thousands of solar acoustic oscillation modes have been measured to remarkable precision, in many cases to within 0.01%. These frequencies have been used to infer the interior structure of the sun and test the physical input to solar models. Here we summarize the procedures, input physics and assumptions for calculating a standard solar evolution model. We compare the observed and calculated sound speed profile and oscillation frequencies of solar models calibrated using the new Los Alamos LEDCOP and Livermore OPAL Rosseland mean opacities for the same element mixture. We show that solar oscillations are extremely sensitive to opacities, with opacity differences of only a few percent producing an easily detectable effect on the sound speed and predicted frequencies. The oscillation data indicate that agreement would be improved by an opacity increase of several percent below the convection zone for both the LEDCOP and OPAL opacities