BD+47 378: An Eclipsing Binary Containing a δ Sct Pulsating Star

Abstract

New high-resolution spectra of the eclipsing binary BD+47 378 were obtained on five nights between 2020 and 2021 with the Bohyunsan Observatory Echelle Spectrograph in Korea. We collected the TESS light curve of the system obtained from Sectors 17 to 18, which shows a flat bottom at the secondary eclipse, an O’Connell effect, and oscillation features. From the spectral analysis, the radial velocities (RVs) of the primary and secondary stars were obtained, and the temperature of the brighter and more massive primary component was determined to be 7140 ± 100 K. According to a simultaneous analysis of the double-lined RVs and TESS light curves, the masses and radii of both components are M 1 = 1.69 ± 0.03 M ⊙, M 2 = 0.80 ± 0.02 M ⊙, R 1 = 2.01 ± 0.01 R ⊙, and R 2 = 0.79 ± 0.01 R ⊙, respectively. The primary component of the system is located on the δ Sct and γ Dor instability strips. After subtracting the theoretical light curve from the TESS data, a total of four independent frequencies (5.7235 day−1, 6.2577 day−1, 6.9588 day−1, and 14.7675 day−1) were detected using the multiple frequency analysis. These frequencies are typical of a δ Sct pulsator. The results reveal that BD+47 378 is a detached system consisting of two main-sequence stars with a δ Sct type primary component.