Nonradial thermal instabilities in the solar core, revisited

Mechanisms which produce a mixing in the solar core, based on the original idea of the “solar spoon” (Dilke & Gough 1972), for explaining the neutrino problem have recently been ruled out by Bahcall & Kumar (1993). We therefore revisit the original work of Rosenbluth & Bahcall (1973) on the nonspherical thermal instabilities in the solar core, introducing some improvements. The authors found that their solar model was stable against these perturbations and they concluded that the turbulence in the solar core appeared unlikely to be the explanation of the lack of solar neutrinos. Our analysis is motived by the fact that the updated standard solar models are sensibly different from those used in the 70’s, and therefore instabilities of the kind postulated by Rosenbluth & Bahcall might be excited. However our results fully confirm the previous ones that the present Sun is stable against nonradial thermal disturbances, at least in the linear analysis, therefore no solutions for growing thermal modes are possible. The confirmation of the stability of the solar core against the mixing and the impressive agreement of the standard solar models with helioseismic data indicate that the present neutrino problem is not astrophysical in origin but it relies upon non standard neutrino properties.