KIC 8840638: A Newly Discovered Eclipsing Binary with δ Scuti–Type Oscillations Yang, Tao-Zhi Zuo, Zhao-Yu Liu, Jun-Hui Jiang, Deng-Kai Zhang, Zhi-Xiang Tang, Qin-jie García Hernández, Antonio In this paper, we analyze the light variation of KIC 8840638 using high-precision time-series data from the Kepler mission. The analysis reveals that this target is a new detached eclipsing binary system with a δ Scuti component, rather than a single δ Scuti star as previously known. The frequency analysis of short-cadence data reveals 95 significant frequencies, most of which lie in a frequency range of 23−32 day−1. Among them, seven independent frequencies are detected in the typical frequency range of δ Scuti stars, and they are identified as pressure modes. In addition, a possible large separation value of Δν = 36.5 ± 0.1 μHz is also detected with the Fourier transform (FT) and autocorrelation function (AC) analysis. The orbital frequency forb (= 0.320008 day−1) and its harmonics are also detected directly in the frequency spectrum. The binary modelings derived from PHOEBE indicate that this binary system is in detached configurations with a mass ratio of q 0.33 0.04 = -0.06 + , an inclination angle of 40.19 2.84 3.96 - + °. The derived parameters and binary evolutionary model suggest that the primary star is an object on the verge of leaving the main sequence with a temperature of ∼7600 K, while the secondary appears to be a cool component entering the giant branch with a temperature ∼3100 K lower than the primary. Moreover, this system may have undergone a mass ratio reversal, where the more massive star is the gainer component and the less massive one is the donor star. 2024-11-19T12:57:02Z 2024-11-19T12:57:02Z 2024-10-31 journal article Yang, T. et. al. The Astrophysical Journal, 975:171 (13pp), 2024 Nov 10. [https://doi.org/10.3847/1538-4357/ad7841] https://hdl.handle.net/10481/97104 10.3847/1538-4357/ad7841 eng http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional IOP Publishing