Top panel: mode inertia (cf. Eq. (9)) for modes of degree l = 0 (solid line, circles), 1 (dashed line, triangles), and 2 (dot-dashed line, squares), in the ASTEC 1 M_⊙, 7 R_⊙ model. Bottom panel: separation between periods of adjacent modes with l = 1 in this model, plotted against frequency. The horizontal dashed line shows the asymptotic period spacing (cf. Eqs. (5) and (6)). The heavy vertical dotted lines show the frequency interval where power is half its maximum value, according to the fit of Mosser et al. (2012) (see also Appendix A.3).