The semi-detached binary system IU Per and its intrinsic oscillation

Abstract

We present a long-term time-resolved photometry of the short-period eclipsing binary IU Per. It confirms the intrinsic δ Scuti-like pulsation of the system reported by Kim et al. With the obtained data, an orbital period study and an eclipsing light curve synthesis based on the Wilson–Devinney method were carried out. The photometric solution reveals a semi-detached configuration with the less-massive component filling its own Roche-lobe. By subtracting the eclipsing light changes from the data, we obtained the pure pulsating light curve of the mass-accreting primary component. A Fourier analysis reveals four pulsation modes with confidence larger than 99%. A mode identification based on the results of the photometric solution was made. It suggests that the star may be in radial pulsation with a fundamental period of about 0.0628 d. A brief discussion concerning the evolutionary status and the pulsation nature is finally given.