Absolute Properties of the Eclipsing γ Dor Star V404 Lyrae

Abstract

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 v ₁ 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 M ₁ = 2.17 ± 0.06 M _⊙, R ₁ = 1.91 ± 0.02 R _⊙, and L ₁ = 9.4 ± 0.8 L _⊙ for the primary, and M ₂ = 1.42 ± 0.04 M _⊙, R ₂ = 1.79 ± 0.02 R _⊙, and L ₂ = 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 l ₃ = 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 (f ₁ - f ₆, f ₉), their new pulsation constants, and the location in the Hertzsprung-Russell diagram indicate that the pulsating primary is a γ Dor-type variable star.