Log−log scale plot of the S index (top) and range index (bottom) as a function of the small frequency separation δν₀₂. The orange solid line indicates the resulting Bayesian fits to Eqs. (1) and (2), respectively, while the open symbols are the measured quantities, with corresponding error bars overlaid on both axes. The Sun symbol for the range index corresponds to the value adopted by Basri et al. (2010).