Echelle diagrams for the best-fit model found for each set of evolutionary tracks calculated with α = 1.8. In this set of models, the surface effects are not included. The model frequencies (crosses) are compared to the observed frequencies, wich are represented as diamonds (ℓ = 0), asterisks (ℓ = 1), and triangles (ℓ = 2). To obtain these best fits, we had to shift the model frequencies by respectively (top left, top right, bottom left, bottom right) 27, 25, 24, and 22 μHz (see text).