HR diagram showing the five models listed in the upper part of Table 2 as crosses on their evolutionary track (full lines). These models have excited oscillation modes whose frequencies match all the observed ones, except for the frequency 8.77 d ^-1, which fits but is predicted to be stable. The 38 dotted tracks each contain one model with excited oscillation frequencies matching the observed ones, except for the two modes with frequency above 8 d ^-1, which are predicted to be stable.