SIMBAD references

All available light curves and times of minima of OO Aql from the literature have been used to study the light curve and period variation of the system. Both the light curve and photometric period were found variable, but no simple correlation in between could be revealed. The present (O-C) data covering ∼45000 cycles of orbital period is equally well represented by two sloping straight lines or a large amplitude (A=0.0455d) sinusoidal wave (with P≃89y). The sinusoidal variation, if real, predicts an unseen third star with a minimum mass of 0.8M_☉ ; in the system. The systematic deviations of the data from the best representations have an amplitude of about 10^–6d which may be caused by fluctuations in the mass transfer (or loss) rate, or magnetic activity variations of the component stars.