Solar core rotation: low-degree solar p-mode rotational splitting results from BiSON

Abstract

In a recent paper (Elsworth et al.), we presented rotational splitting measurements of low-degree, low-frequency solar p modes, which, for the first time, show visually well-separated components at frequencies as low as similar to 1.5 mHz. At the present time, these data appear to rule out a rapidly rotating solar core. Here, we expand our analysis of these data to a full discussion of the statistical properties of the measured splittings. We have considered two fully independent Fourier spectra, generated from Doppler velocity residuals collected by the six-station Birmingham Solar-Oscillations Network (BiSON) between 1992 January 1 and 1994 August 23 (Fourier spectra 16A and 16C from Elsworth et al.). We present formal uncertainties from maximum-likelihood fits to the mode multiplets, analyse and compare the statistical properties of the sets, and search for possible trends in the splitting measures with n.