Evolution of the helium glitch amplitude A_He with the surface helium abundance Y_f. Each track corresponds to a given mass, written in the legend. The dot-dashed line represents the amplitude for a 1.052 M_⊙ model of which the frequencies have been corrected for surface effects as in Kjeldsen et al. (2008). Every model has an initial heavy elements abundance of (Z/X)₀ = 0.022. Each point has been computed with the same large separation to remain at the same evolutionary stage.