See caption of Fig. 18 for details. Left: our isochrone (black) with an age of 1.1 Ga and [M/H] = 0.16 dex for the stars N77-210, N77-255, N77-325, and N77-342 (top to bottom). The scattered red, green and blue points represent the LT error of stars for E(B−V)_bkg = 0.24, 0.29, and 0.34 mag, respectively. Right: observed frequencies (grey) and the corresponding pulsation models are shown for the two stars.