Fresh insights on the structure of the solar core

TL;DR

This paper uses new low-degree p mode frequencies from the BiSON network to refine the solar core's structure, revealing a slightly larger sound speed and smaller density differences compared to previous models, with improved uncertainties.

Contribution

It introduces new solar core structure results based on expanded low-degree mode data, showing improved accuracy and consistency with solar models.

Findings

Solar sound speed in the core is slightly larger than previous estimates.

Density differences between models and the Sun are smaller with new data.

Uncertainties in the inversion results are significantly reduced.

Abstract

We present new results on the structure of the solar core, obtained with new sets of frequencies of solar low-degree p modes obtained from the BiSON network. We find that different methods used in extracting the different sets of frequencies cause shifts in frequencies, but the shifts are not large enough to affect solar structure results. We find that the BiSON frequencies show that the solar sound speed in the core is slightly larger than that inferred from data from MDI low-degree modes, and the uncertainties on the inversion results are smaller. Density results also change by a larger amount, and we find that solar models now tend to show smaller differences in density compared to the Sun. The result is seen at all radii, a result of the fact that conservation of mass implies that density differences in one region have to cancel out density differences in others, since our models are constructed to have the same mass as the Sun. The uncertainties on the density results are much smaller too. We attribute the change in results to having more, and lower frequency, low-degree mode frequencies available. These modes provide greater sensitivity to conditions in the core.