Échelle diagram of a typical RGB star (KIC 6144777) as a function of ν/Δν − (n_p + ε). The radial order n_p is indicated on the y-axis. Radial modes (highlighted in red) are centered on 0, quadrupole modes (highlighted in green), near − 0.12 (with a radial order n_p − 1), and ℓ = 3 modes, sometimes observed, (highlighted in light blue) near 0.20. Dipole mixed modes are identified with the frequency given by the asymptotic relation of mixed modes, in μHz. The fit is based on peaks showing a height larger than eight times the mean background value (grey dashed lines).