Top: Frequency-power spectrum divided by the granulation background in the original (light) and uniformly smoothed (dark, window = 0.15 μHz). The vertical lines highlight the observed radial (ℓ = 0), dipole (ℓ = 1), and quadrupole (ℓ = 2) modes. Middle: Échelle diagram. The axes are flipped for illustration, showing observed radial ℓ = 0 and quadrupole ℓ = 2 frequencies and the best-fit frequencies from our reference radial mode fit. The heat-map data were uniformly smoothed with a window = 0.075 μHz. Bottom: Statistical significance of the O-C residuals relative to the measurement uncertainty σ. The marker-size was rescaled (in log₁₀) to demonstrate the statistical weight 1/σ² applied to each observed frequency in the asteroseismic inference.