2020AJ....159...24L

We present the first high-resolution spectra for the eclipsing binary V404 Lyr showing γ Dor pulsations, which we use to study its absolute properties. By fitting models to the disentangling spectrum of the primary star, we found that it has an effective temperature of T_eff,1 = 7330 ± 150 K and a rotational velocity of v₁ sin i = 148 ± 18 km s^–1. The simultaneous analysis of our double-lined radial velocities and the pulsation-subtracted Kepler data gives us accurate stellar and system parameters of V404 Lyr. The masses, radii, and luminosities are M₁ = 2.17 ± 0.06 M_☉, R₁ = 1.91 ± 0.02 R_☉, and L₁ = 9.4 ± 0.8 L_☉ for the primary, and M₂ = 1.42 ± 0.04 M_☉, R₂ = 1.79 ± 0.02 R_☉, and L₂ = 2.9 ± 0.2 L_☉ for the secondary. The tertiary component orbiting the eclipsing pair has a mass of M_3b = 0.71 ± 0.15 M_☉ in an orbit of P_3b = 642 ± 3 days, e_3b = 0.21 ± 0.04, and a_3b = 509 ± 2 R_☉. The third light of l₃ = 4.1% ± 0.2% could be partly attributable to the K-type circumbinary object. By applying a multiple frequency analysis to the eclipse-subtracted light residuals, we detected 45 frequencies with signal-to-noise amplitude ratios larger than 4.0. Identified as independent pulsation modes, seven frequencies (f₁ - f₆, f₉), their new pulsation constants, and the location in the Hertzsprung-Russell diagram indicate that the pulsating primary is a γ Dor-type variable star.