A comparison of Rosseland-mean opacities from OP and OPAL

Abstract

Monochromatic opacities from the Opacity Project (OP) (Seaton et al.) have been augmented by hitherto missing inner-shell contributions (Badnell & Seaton). OP Rosseland-mean opacities are compared with results from OPAL (Iglesias & Rogers) for the elements H, He, C, O, S and Fe. Overall, there is good agreement between OP and OPAL Rosseland-mean opacities for the 6-elements, but there are some differences. In particular, recent work (Bahcall et al.) has shown that helioseismology measurements give a very accurate value for the depth of the solar convection zone and that solar models give agreement with that value only if opacities there are about 7% larger than OPAL values. For the 6-element mix, here, we obtain Rosseland-mean opacities to be larger than OPAL by 5%.