Oscillating classical Algol-type binary XZ Aql

•First comprehensive investigation of XZ Aql was carried out based on new CCD photometric data.•Oscillating behaviour of the primary component was determined for the first time.•Orbital period variations of the system were analysed and interpreted using possible mechanisms.•Absolute properties of the components were estimated.

New CCD photometric observations of the neglected classical Algol-type binary XZ Aql were obtained over 53 nights during the observing season of 2011. Photometric elements were determined from analysis of multi-colour light curves. This first comprehensive investigation of the system revealed that the system is in semi-detached configuration with a mass ratio of 0.204 ± 0.02 and a filling ratio of the primary of 50%. Absolute parameters of components and distance of the system were estimated. Based on all eclipse timings, the (O–C) variation indicating orbital period behaviour can be represented by a periodic term superimposed on an upward parabola. Secular increase with a rate of dP/dt   = 7.82 × 10−7−7 day yr−1−1 is due to mass transfer from the less massive to more massive component. A possible third body around the eclipsing pair and also magnetic activity of the late-type component were used to interpret cyclic variation in the orbital period. Short-period light variations out-of-eclipse imply that XZ Aql is an oscillating eclipsing binary with a pulsating, mass gainer component. From Fourier analysis, two frequencies were detected as 30.6325 c/d and 34.5009 c/d. Pulsational properties and estimated absolute parameters indicate that the primary component may be classified as a δ Scuti type variable.