2020MNRAS.491.5980H

We employ optical spectroscopy and Kepler photometry to derive the physical properties and pulsational characteristics of the detached system KIC 2557430. We find that the system is formed by F-type components. Combining results from the analysis of spectroscopic data and Kepler photometry, we calculate masses and radii of the primary and the secondary components as M1 = 1.69 ± 0.03 M☉, M2 = 1.35 ± 0.02 M☉ and R1 = 1.88 ± 0.02 R☉, R2 = 1.23 ± 0.03 R☉, respectively. Position of the primary component in the HR diagram is in the region of γ Doradus-type pulsators and the residuals from light curve modelling exhibit additional light variation with a dominant period of ∼0.5 d-1. These are clear evidence of the γ Doradus-type pulsations on the primary component. Focusing on the γ Dor primaries, with their currently known numbers in eclipsing binaries to compare against, we probe the role binary stars might play, to understand the nature of γ Dor-type pulsations.