Implications of solar wind measurements for solar models and composition

TL;DR

This paper critically evaluates claims that solar wind measurements suggest a high solar metallicity, finding that such models worsen helioseismological fits and overpredict neutrino fluxes, thus challenging their validity.

Contribution

It provides a comprehensive analysis showing that solar wind-based compositions do not improve solar models and are inconsistent with multiple observational constraints.

Findings

Solar wind-based models worsen helioseismological observables.

Predicted neutrino fluxes are inconsistent with measurements.

Astrophysical arguments favor spectroscopic abundances over solar wind data.

Abstract

We critically examine recent claims of a high solar metallicity by von Steiger \& Zurbuchen (2016) based on \textit{in situ} measurements of the solar wind, rather than the standard spectroscopically-inferred abundances (Asplund et al. 2009). We test the claim by Vagnozzi et al. (2016) that a composition based on the solar wind enables one to construct a standard solar model in agreement with helioseismological observations and thus solve the decades-old solar modelling problem. We show that, although some helioseismological observables are improved compared to models computed with spectroscopic abundances, most are in fact worse. The high abundance of refractory elements leads to an overproduction of neutrinos, with a predicted $^8$B flux that is nearly twice its observed value, and $^7$Be and CNO fluxes that are experimentally ruled out at high confidence. A combined likelihood analysis shows that models using the vSZ16 abundances fare worse than AGSS09 despite a higher metallicity. We also present astrophysical and spectroscopic arguments showing the vSZ16 composition to be an implausible representation of the solar interior, identifying the first ionisation potential effect in the outer solar atmosphere and wind as the likely culprit.