Solar Models with Revised Abundances and Opacities

TL;DR

This paper develops solar models with revised abundances and opacities, incorporating rotational mixing and enhanced diffusion to better match helioseismic observations, though some discrepancies remain.

Contribution

It introduces a combined approach of revised opacities, diffusion, and rotational mixing to reconcile solar models with recent abundance measurements and helioseismic data.

Findings

Models with increased diffusion match sound speed and density profiles closely.

Rotational mixing improves surface helium abundance agreement.

Some model discrepancies with seismic data persist.

Abstract

Using reconstructed opacities, we construct solar models with low heavy-element abundance. Rotational mixing and enhanced diffusion of helium and heavy elements are used to reconcile the recently observed abundances with helioseismology. The sound speed and density of models where the relative and absolute diffusion coefficients for helium and heavy elements have been increased agree with seismically inferred values at better than the 0.005 and 0.02 fractional level respectively. However, the surface helium abundance of the enhanced diffusion model is too low. The low helium problem in the enhanced diffusion model can be solved to a great extent by rotational mixing. The surface helium and the convection zone depth of rotating model M04R3, which has a surface Z of 0.0154, agree with the seismic results at the levels of 1 $\sigma$ and 3 $\sigma$ respectively. M04R3 is almost as good as the standard model M98. Some discrepancies between the models constructed in accord with the new element abundances and seismic constraints can be solved individually, but it seems difficult to resolve them as a whole scenario.