Updated pulsation period relations of gamma Dor-type stars in eclipsing binaries: the case of KIC 2557430

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 calculatemasses and radii of the primary and the secondary components as M-1 = 1.69 +/- 0.03 M-circle dot, M-2 = 1.35 +/- 0.02 M-circle dot and R-1 = 1.88 +/- 0.02 R-circle dot, R-2 = 1.23 +/- 0.03 R-circle dot, respectively. Position of the primary component in the HR diagram is in the region of gamma Doradus-type pulsators and the residuals from light curve modelling exhibit additional light variation with a dominant period of similar to 0.5 d(-1). These are clear evidence of the gamma Doradus-type pulsations on the primary component. Focusing on the gamma 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 gamma Dor-type pulsations.