Investigating the role of opacity in reconciling the Standard Solar Model and Helioseismology

Over the last 20 years, advances in determining the chemical composition of the Sun have adversely affected the agreement between Standard Solar Models (SSMs) and helioseismology, to the point where SSMs can no longer be made to agree with helioseismic constraints. Agreement with helioseismology could be restored by either increasing atomic opacity at the bottom of the convection zone and decreasing it towards the solar center by 30%, or by returning to older, higher metal abundances. The accuracy of seismic results has highlighted the importance of verifying opacity calculations in order to reconcile the SSM, helioseismology, and solar neutrino fluxes. The goal of this work is to investigate the effect of increasing the Fe opacity on SSMs assuming the most recent chemical composition by Magg et al. (2022), to calibrate models computed with different opacity tables from the OPAL and TOPS projects, and to estimate the Fe opacity values that best reproduce the helioseismic constraints. A correction factor is applied to Fe monochromatic opacity prior the computation of the Rosseland mean opacity, and an MCMC technique is used to calibrate SSMs and obtain the best value of this correction factor.