13 - ³He transport and the solar neutrino problem

Summary

³He transport in the solar core has been suggested as a solution to the solar neutrino problem. I investigate the consequences of imposing a flow on the solar core and show that it is unlikely that a flow could exist that would reproduce the best-fit astrophysical solution to the experimental neutrino fluxes from Homestake, SAGE, GALLEX and SuperKamiokande.

Introduction

Before the announcement of the results from the Sudbury Neutrino Observatory (Ahmad et al. 2001), the measurements of the fluxes of neutrinos coming from nuclear reactions in the core of the sun were inconsistent with solar models. It has been argued that a so-called standard solar model can never be consistent with the experimental fluxes, and this has been used as an argument for the necessity of flavour transitions. However, non-standard solar models where ³He is burnt out of equilibrium have been suggested as astrophysical solutions to the neutrino problem (e.g. Dilke & Gough, 1972 and Gough, 1991), and Cumming & Haxton (1996) showed how a solar model with a redistribution of ³He in the core could overcome the problems of a standard solar model.

It was argued (Bahcall et al., 1997), using simple one-dimensional models with a mixed core, that Cumming and Haxton's model was inconsistent with helioseismology. As helioseismology had measured only a horizontal average of quantities in the solar interior, and as the suggested mechanism is fundamentally at least two-dimensional, the mechanism cannot be ruled out until a more realistic, two-dimensional model has been produced.