Solar models with new low-metal abundances

TL;DR

This paper explores solar models with new low-metal abundances, incorporating rotation, magnetic fields, and overshoot to reconcile models with helioseismic data and neutrino observations, highlighting the strengths and limitations of different approaches.

Contribution

It introduces the AGSM magnetic model that improves agreement with helioseismic data and neutrino fluxes compared to previous models with low-metal abundances.

Findings

AGSR reproduces sound-speed and density profiles.

AGSM improves surface helium abundance prediction.

Neutrino fluxes from AGSM align with observations.

Abstract

In the last decade, the photospheric abundances of the Sun had been revised several times by many observers. The standard solar models (SSM) constructed with the new low-metal abundances disagree with helioseismic results and detected neutrino fluxes. The solar model problem has been puzzled some stellar physicists for more than ten years. Rotation, enhanced diffusion, convection overshoot, and magnetic fields are used to reconcile the new abundances with helioseismology. The \textbf{too} low-helium \textbf{subsurface abundance} in enhanced diffusion models can be improved by the mixing caused by rotation and magnetic fields. The problem of the depth of the convective zone in rotating models can be resolved by convection overshoot. Consequently the Asplund-Grevesse-Sauval rotation model including overshooting (AGSR) reproduces the seismically inferred sound-speed and density profiles, and the convection zone depth as well as the Grevesse and Sauval (GS98) model computed before. But this model fails to reproduce the surface helium abundance which is 0.2393 ($2.6$ $\sigma$ away from the seismic value) and neutrino fluxes. The magnetic model called AGSM keeps the agreement of the AGSR and improves the prediction of the surface helium abundance. The observed separation ratios $r_{02}$ and $r_{13}$ are reasonably reproduced by AGSM. Moreover, neutrino fluxes calculated by this model are not far from the detected neutrino fluxes and the predictions of previous works.