Pulsating and Non-pulsating Components of Detached Eclipsing Binaries in the $δ$ Scuti instability strip

Abstract

Pulsating detached eclipsing binary systems are crucial for studying the internal structure of oscillating stars. These systems are advantageous because binary effects on pulsations are minimal, allowing for more accurate determinations of fundamental stellar parameters such as mass and radius. They serve as unique laboratories for detailed investigations of pulsating stars. In this study, we focused on four detached eclipsing binaries exhibiting $δ$ Scuti-type oscillations: HD 117476, 205 Dra, HY Vir, and V1031 Ori. Our preliminary investigation showed that all binary components of these targets lie within the $δ$ Scuti instability strip. Therefore, we aimed to determine which components are pulsating and which are not, and to explore the differences between them. To achieve this, we analyzed TESS photometric data and high-resolution spectra of the targets. Radial velocity variations were measured, and atmospheric parameters for each component were derived using spectral disentangling or synthetic composite spectra. We also modeled the binary light and radial velocity curves to determine the fundamental physical parameters of the components. Furthermore, we examined pulsation properties using three different approaches to identify the pulsating components. The evolutionary status of the targets was also assessed. Our analysis revealed that, in each system, only one component exhibits $δ$ Scuti-type pulsations, while the others are non-pulsating. Interestingly, we found that the key difference between pulsating and non-pulsating components within the same binary is metallicity: the metal-rich components were found to be non-pulsators, supporting theoretical studies on the effect of metallicity on $δ$ Scuti-type pulsations.