Heavy element settling in the Sun and equation of state Available to Purchase

We study effect of heavy element settling on the equation of state in the standard solar model. The heavy element composition is an important source of uncertainty in the solar models; the uncertainty in Z itself comes from various sources, one of them being the element diffusion/settling. Z diffusion mostly affects opacities (iron is a very important source of opacity) but also touches equation of state. The settling rate depends on the ion mass and charge therefore different chemical elements have different settling velocities; the settling rates for O and Fe differ by 10% in our estimate. We study effect of 10% change in Z diffusion rate on the equation of state.