Γ Doradus Pulsations in the Eclipsing Binary Star Kic 6048106

Abstract

We present the Kepler photometry of KIC 6048106 exhibiting O'Connell effect and multiperiodic pulsations. Including a starspot on either of the components, light-curve synthesis indicates that this system is a semi-detached Algol with a mass ratio of 0.211, an orbital inclination of 73.9 deg, and a large temperature difference of 2,534 K. To examine in detail both spot variations and pulsations, we separately analyzed the Kepler time-series data at the interval of an orbital period by an iterative way. The results reveal that the variable asymmetries of the light maxima can be interpreted as the changes of a magnetic cool spot on the secondary component with time. Multiple frequency analyses were performed in the outside-eclipse light residuals after removal of the binarity effects from the observed Kepler data. We detected 30 frequencies with signal to noise amplitude ratios larger than 4.0, of which six (f 2 -f 6 and f 10 ) can be identified as high-order (17 ≤ n ≤ 25) low-degree (ℓ = 2) gravity-mode pulsations that were stable during the observing run of 200 d. In contrast, the other frequencies may be harmonic and combination terms. For the six frequencies, the pulsation periods and pulsation constants are in the ranges of 0.352−0.506 d and 0.232−0.333 d, respectively. These values and the position on the HR diagram demonstrate that the primary star is a γ Dor variable. The evolutionary status and the pulsation nature of KIC 6048106 are discussed.

Eclipsing Systems with Pulsating Components (Types β Cep, δ Sct, γ Dor or Red Giant) in the Era of High-Accuracy Space Data

“…Among the low frequencies, 1.9764 d −1 is most dominant. Seven independent g modes with a mean ∆P of 0.0176 d were found, six of which were already reported by Lee [45]. The corresponding period-échelle diagram shows that the g modes follow a single ridge with some wiggles.…”

“…It should be noted that the maximum amplitude in the acoustic regime is about ten times smaller than that in the gravity regime. This is one of the reasons why Lee [45] did not detect them. Five regular multiplets with a mean frequency spacing of 0.64113 ± 0.00027 d −1 (in perfect agreement with f orb = 0.64143 ± 0.00015 d −1 ) were identified, including 25 p modes equidistantly split by the orbital frequency.…”

Absolute Properties of the Eclipsing γ Dor Star V404 Lyrae

“…In the Hertzsprung-Russell diagram (cf. Lee et al 2016), the primary component is located close to the blue edge of the γ Dor instability strip inside the main-sequence band, while the lobe-filling secondary lies above this band.…”

The effect of tides on near-core rotation: analysis of 35 Kepler γ Doradus stars in eclipsing and spectroscopic binaries

“…The known γ Dor binaries whose period spacings were not previously measured are: KIC 3228863 (Lee et al 2019(Lee et al , 2014; KIC 4150611 (Hełminiak et al 2017); KIC 6048106 (Lee 2016;Samadi Ghadim, Lampens & Jassur 2018); KIC 6206751 (Lee & Park 2018); KIC 8569819 (Kurtz et al 2015); KIC 9236858 (Kjurkchieva & Atanasova 2016); and KIC 9851944 (Guo et al 2016). These works focused mainly on the dynamics of the binary systems, hence they did not measure the period spacings of g modes.…”