SIMBAD references

Recent observations at the NOT telescope clearly show that PG 1618+563 is a new member of the EC14026 class of sdB pulsating stars (Kilkenny et al. 1997, O'Donoghue et al. 1999). The very good quality of the non-filtered data allows to detect an amplitude modulation effect with a beat period of about 1.2 hours, which is consistent with the presence in the temporal spectrum of two close frequencies at 6.95 and 7.14 mHz (∼ 144 and 140 s). The amplitudes are very low: between 1 and 2 mma. Moreover, from UBV data we find amplitude (and phase) differences, that could be useful for mode identification.