Resolve the Solar Modelling Problem

Resolve the Solar Modelling Problem by developing a comprehensive solar model that simultaneously accounts for the solar chemical composition, helioseismic constraints, lithium and beryllium depletion, and the measured solar neutrino fluxes.

Background

The paper explains that modern spectroscopic determinations yield lower solar metal-to-hydrogen ratios than the Standard Solar Composition used in successful models of the 1990s. Standard Solar Models built with these lower abundances fail to reproduce key helioseismic observables, including the helium abundance in the convective envelope, the sound-speed profile, and the depth of the convection zone.

Additional macroscopic mixing can improve the treatment of lithium and beryllium depletion and some helioseismic constraints, but it produces discrepancies with measured beryllium, boron, and CNO neutrino fluxes. The authors therefore identify a broader modelling problem involving potentially incomplete treatments of macroscopic transport, radiative opacities, nuclear reaction rates, and other microphysics. A comprehensive solution that satisfies the full set of observational constraints remains unresolved.

References

As already stated above, it thus appears as though the problem is not with the abundances, and we are rather faced with a much more complex Solar Modelling Problem for which a comprehensive solution still eludes us (Buldgen et al., 2025a).

— Solar chemical composition  (2608.23155 - Amarsi et al., 24 Aug 2026) in Section 4.3, “The Solar Modelling Problem”