Petersen diagram with all evolutionary tracks and best-fit seismic models of the five HADS. The coloured solid evolutionary tracks show the stages from the zero-age MS to the post-MS evolutionary phase, with initial masses covering 1 M_⊙. The regions surrounded by the black rectangular boxes are selected to zoom in the best-fit seismic models, which are represented by the red stars. The coloured dashed lines present the evolutionary tracks with initial mass steps of 0.01 M_⊙.