a) Dipole mode visibility v₁ as a function of the large separation Δν. The color codes the mass determined with seismic scaling relations. Small symbols represent Kepler stars of the public data set; and larger symbols represent stars of the data set studied by Vrard et al. (2016). Diamonds with a dark center are stars showing depressed mixed modes. The dashed line represents the limit defining low visibilities. b) Radial mode width Γ₀ as a function of the large separation Δν of the data set studied by Vrard et al. (2016). The right y-axis provides the radial mode lifetime. c) Same as b) for the period spacings ΔΠ₁; and d) same as b) for the coupling factor q. The outlying value of q for KIC 6975038 is discussed in Sect. 5.4.