First solar models with OPAS opacity tables

TL;DR

This paper investigates the impact of new OPAS opacity tables on solar models, showing improvements in matching helioseismic data compared to traditional OPAL and OP tables, thus addressing longstanding discrepancies.

Contribution

It introduces the use of OPAS opacity tables in solar modeling and demonstrates their positive effects on helioseismic agreement, a novel application in this context.

Findings

Improved location of the base of the convective zone.

Better match of solar radiative zone profiles with helioseismic data.

OPAS tables lead to less than 6% difference in Rosseland mean opacity.

Abstract

Stellar seismology appears more and more as a powerful tool for a better determination of the fundamental properties of solar-type stars. However the particular case of Sun is still challenging. The helioseismic sound speed determination continues to disagree with the Standard Solar Model (SSM) prediction for about a decade, questioning the reliability of this model. One of the sources of uncertainty could be in the treatment of the transport of radiation from the solar core to the surface. In this letter, we use the new OPAS opacity tables, recently available for solar modelling, to address this issue. We discuss first the peculiarities of these tables, then we quantify their impact on the solar sound speed and density profiles using the reduced OPAS tables taken on the grids of the OPAL ones. We use the two evolution codes MESA and CLES that led to similar conclusions in the solar radiative zone. In comparison to commonly used OPAL opacity tables, the new solar models computed, for the most recent photospheric composition, with OPAS tables present improvements in the location of the base of the convective zone and in the description of the solar radiative zone in comparison to the helioseismic observations, even if the differences in the Rosseland mean opacity do not exceed 6 %. We finally carry out a comparison to a solar model computed with the OP opacity tables.