CN neutrinos and the Sun's primordial core metalicity

I discuss the use of neutrinos from the CN cycle and pp chain to constrain the primordial solar core abundances of C and N at an interesting level of precision. A comparison of the Sun's deep interior and surface compositions would test a key assumption of the standard solar model (SSM), a homogeneous zero-age Sun. It would also provide a cross-check on recent photospheric abundance determinations that have altered the once excellent agreement between the SSM and helioseismology. Motivated by the discrepancy between convective-zone abundances and helioseismology, I discuss the possibility that a two-zone Sun could emerge from late-stage metal differentiation in the solar nebula connected with formation of the gaseous giant planets.