Estimate of solar radius from f-mode frequencies

TL;DR

This paper uses GONG data to analyze solar f-mode frequencies, finding they align with theoretical models and providing a refined estimate of the solar radius, which may impact existing solar models and rotation measurements.

Contribution

It offers the first observational estimate of the solar radius from f-mode frequencies that aligns with theoretical predictions, suggesting a smaller radius than previously used.

Findings

F-mode frequencies match theoretical models.

Estimated solar radius is about 0.03% less than standard models.

Provides an independent measure of near-surface solar rotation.

Abstract

Frequency and rotational splittings of the solar f-modes are estimated from the GONG data. Contrary to earlier observations the frequencies of f-modes are found to be close to the theoretically computed values for a standard solar model. The f-mode being essentially a surface mode is a valuable diagnostic probe of the properties of the solar surface, and also provides an independent measure of solar radius. The estimated solar radius is found to be about 0.03% less than what is traditionally used in construction of standard solar models. If this decrease in solar radius is confirmed then the current solar models as well as inversion results will need to be revised. The rotational splittings of the f-modes yield an independent measure of the rotation rate near the solar surface, which is compared with other measurements.