1. KIC 8840638: A Newly Discovered Eclipsing Binary with δ Scuti–Type Oscillations.
- Author
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Yang, Tao-Zhi, Zuo, Zhao-Yu, Liu, Jun-Hui, Jiang, Deng-Kai, Zhang, Zhi-Xiang, Tang, Qin-jie, and Hernández, Antonio García
- Subjects
STELLAR oscillations ,VARIABLE stars ,SUPERGIANT stars ,FREQUENCY spectra ,FOURIER transforms - Abstract
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 Δ ν = 36.5 ± 0.1 μ Hz 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. [ABSTRACT FROM AUTHOR]- Published
- 2024
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