$\gamma$ Doradus Pulsations in the Eclipsing Binary Star KIC 6048106

TL;DR

This study analyzes Kepler data of the eclipsing binary KIC 6048106, revealing gamma Doradus pulsations in the primary star and detailed system parameters, including starspots and pulsation modes, through light-curve synthesis and frequency analysis.

Contribution

First detailed analysis of gamma Dor pulsations in an eclipsing binary with comprehensive light-curve modeling and frequency identification.

Findings

Detected 30 pulsation frequencies with high S/N ratios.

Identified six high-order gravity-mode pulsations in the primary star.

Confirmed the primary as a gamma Doradus variable.

Abstract

We present the ${\it Kepler}$ 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 {\it 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 {\it 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 $\le n \le$ 25) low-degree ($\ell$ = 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 $\gamma$ Dor variable. The evolutionary status and the pulsation nature of KIC 6048106 are discussed.