NEW ASTRONOMY, vol.46, pp.40-46, 2016 (SCI-Expanded)
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 x 10(-7) day yr(-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 delta Scuti type variable. (C) 2015 Elsevier B.V. All rights reserved.