1995A&AS..113..477L

The δ Scuti variable star τ Pegasi was observed with the 60-cm telescope at Xinglong Station of Beijing Astronomical Observatory from 1991 to 1992.. Period analyses were made for the 1991-1992 data set and other avaliable data sets. Two pulsation frequencies (18.40567 and 18.0178 cycles/d) with visual amplitudes of 0.0116 and 0.0039mag were found. The observed frequencies indicate nonradial p₄ mode with l=1. The long-term variations in phasing of the first period is a value of dP/dt about 10^–9. The amplitude of the first frequency increased from 0.0067mag (1975-1979) to 0.0116mag (1991-1992). The amplitude of the second frequency increased from 0.0018mag (1975-1979) to 0.0039mag (1991-1992). The beating between the two frequencies can fit the 1991-1992 data to ±0.004mag. The number of frequencies detected, the long-term amplitude variability and the mode identification show that τ Peg is a typical nonradially pulsating δ Scuti star.