Abstract We present the first comprehensive spectroscopic and photometric analysis of the detached eclipsing binary KL Per, based on high-precision TESS light curves and mid-resolution spectra from DAO. The simultaneous modelling of the light and radial velocity curves yielded highly accurate absolute physical parameters, resulting in masses of M1 = 1.71 ± 0.02 M⊙ and M2 = 1.59 ± 0.03 M⊙, and radii of R1 = 2.49 ± 0.01 R⊙ and R2 = 2.08 ± 0.02 R⊙. To investigate the intrinsic variability, we analyzed the residual light curves obtained after subtracting the best-fitting binary model. A detailed frequency analysis reveals a dominant high-frequency signal at f1 ≈ 13.3 d−1, characteristic of δ Scuti type p-mode pulsations, along with an additional independent low-frequency signal at f2 ≈ 1.46 d−1, consistent with γ Doradus type g-mode oscillations. The high orbital inclination of the system (i ≈ 89○) results in a total secondary eclipse, providing a unique opportunity to identify the pulsating component. A phase-dependent analysis of the residuals and frequency spectra shows that the pulsation signal disappears during the secondary eclipse, while remaining clearly visible during the primary eclipse. This behavior provides direct empirical evidence that the secondary component is the source of the pulsations. The coexistence of p- and g-mode oscillations suggests that the secondary component exhibits hybrid δ Sct/γ Dor pulsational behavior. Given its detached configuration and well-constrained physical parameters, KL Per represents a valuable laboratory for testing stellar structure and evolution models of hybrid pulsators in binary systems.
Özavcı et al. (Thu,) studied this question.
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