Helioseismic bounds in the central temperature of the Sun

Abstract

The information concerning the variation of sound speed and density inside the Sun as inferred from helioseismic inversion is employed to constrain the temperature and composition profiles in the solar core. The usual thermal transport and energy generation equations governing stellar structure are adopted to demonstrate that in order to reduce the chlorine neutrino flux to match the observed values, the opacity needs to be reduced by a factor upwards of 1.5. Further, assuming that the uncertainties in the tabulated OPAL opacity values are no longer than 20% in the core, the central temperature is bounded by 15.2×10⁶ ≲ T_c ≲ 16.1×10⁶ K. In order to get a temperature profile which is consistent with the observed solar luminosity and the helioseismic data, it appears that the nuclear energy generation rates will need to be revised upward by a few percent, although the estimates of the central temperature is not particularly affected by these uncertainties. With the current OPAL opacities, the central temperature is found to be (15.6±0.40) ×10⁶ K.