The Sun's interior metallicity constrained by neutrinos




Observed solar neutrino fluxes are employed to constrain the interior composition of the Sun. Including the effects of neutrino flavour mixing, the results from Homestake, Sudbury and Gallium experiments constrain the Mg, Si and Fe abundances in the solar interior to be within a factor of 0.89 to 1.34 of the surface values with 68 per cent confidence. If the O and/or Ne abundances are increased in the interior to resolve helioseismic discrepancies with recent standard solar models, then the nominal interior Mg, Si and Fe abundances are constrained to a range of 0.83 to 1.24 relative to the surface. Additional research is needed to determine whether the Sun's interior is metal-poor relative to its surface.