Study of CoRoT 105415473: A Heartbeat Star with δ Scuti Oscillations

Abstract

We study the light curves of CoRoT 105415473 with the CoRoT satellite photometric data of 144 days. The light curves consist of two types of temporal variations: periodic brightening and pulsational. The periodic brightening suggests that the variations are from a binary system without eclipsing, with an orbital period of 2.6 days. The frequency analysis of the periodic brightening reveals six modes, which correspond to the orbital frequency and five consecutive harmonics. If the contribution to the periodic brightening comes mainly from the tidal interaction between two stars, a fit of the pulsation-free light curves to the tidal interaction model by Kumar et al. yields to an estimation of three binary orbital parameters: eccentricity e = 0.21 ± 0.01, inclination angle i = 39.°3 ± 0.°8, and angle of periastron ω = -3.°3 ± 0.°6. The pulsation is likely from a δ Scuti star, based on its spectral type and the range of its frequencies. The frequency analysis with Period04 gives 95 frequencies with a signal-to-noise ratio greater than 4. Among them, 42 frequencies are, according to the resolution of the data, the combination of another pulsation frequency and a harmonic of the orbital frequency.