V456 Cyg: An eclipsing binary with tidally perturbed g-mode pulsations

Abstract

Context. Many well-known bright stars have been observed by the ongoing Transiting Exoplanet Survey Satellite (TESS) space mission. For several of them, these new data reveal previously unobserved variability, such as tidally perturbed pulsations in close binary stars. Aims. Using newly detected gravity-mode (g-mode) pulsations in V456 Cyg, we aim to determine the global stellar properties of this short-period eclipsing binary and evaluate the interaction between these pulsations and the tides. Methods. We model the binary orbit and determine the physical properties of the component stars using the TESS photometry and published spectroscopy. We then measure the pulsation frequencies from the residuals of the light curve fit using iterative prewhitening, and analyse them to determine the global asteroseismic stellar parameters. We evaluate the pulsation parameters as a function of the orbital phase. Results. We find that the pulsations belong to the secondary component of V456 Cyg and that this star likely has a uniform radial rotation profile, synchronous (${\nu }_{\mathrm{rot}}=1.113(14){\mathrm{d}}^{-1}$) with the binary orbit (${\nu }_{\mathrm{orb}}=1.122091(8){\mathrm{d}}^{-1}$). The observed g modes are amplified by almost a factor three in the stellar hemisphere facing the primary. We present evidence that this is caused by tidal perturbation of the pulsations, with the mode coupling being strongly affected. Conclusions. V456 Cyg is only the second object for which tidally perturbed high-order g-mode pulsations are identified, after ${\pi }^5$ Ori. This opens up new opportunities for tidal g-mode asteroseismology, as it demonstrates another avenue in which g modes and tides can interact with each other.

8 pages, 6 figures, 3 tables. Accepted for publication in Astronomy & Astrophysics on 12 January 2022

References in corpus (29)

• Array Programming with NumPy
• The Transiting Exoplanet Survey Satellite
• Binary interaction dominates the evolution of massive stars
• Homogeneous studies of transiting extrasolar planets. I. Light curve analyses
• Probing the properties of convective cores through g modes: high-order g modes in SPB and gamma Doradus stars
• The interior rotation of a sample of gamma Doradus stars from ensemble modelling of their gravity mode period spacings
• {\em Gaia}-derived luminosities of {\em Kepler} A/F stars and the pulsator fraction across the δ Scuti instability strip
• Heartbeat Stars, Tidally Excited Oscillations, and Resonance Locking
• Asteroseismic masses, ages, and core properties of $\gamma$ Doradus stars using gravito-inertial dipole modes and spectroscopy
• Rotation of the convective core in $\gamma$ Dor stars measured by dips in period spacings of g modes coupled with inertial modes
• First evidence of inertial modes in $\gamma$ Doradus stars: The core rotation revealed
• Period spacings of gravity modes in rapidly rotating magnetic stars I. Axisymmetric fossil field with poloidal and toroidal components
• The single-sided pulsator CO~Camelopardalis
• Asteroseismic inference of the near-core magnetic field strength in the main sequence B star HD 43317
• KIC 8164262: a Heartbeat Star Showing Tidally Induced Pulsations with Resonant Locking
• Discovery of $\beta$ Cep pulsations in the eclipsing binary V453 Cygni
• Variability of newly identified B-type stars observed by Kepler
• Deriving the orbital properties of pulsators in binary systems through their light arrival time delays
• Tidally Trapped Pulsations in Binary Stars
• Tidally Induced Pulsations in Kepler Eclipsing Binary KIC 3230227
• Nonconservative Mass Transfer in Massive Binaries and the Formation of Wolf-Rayet+O Binaries
• Asteroseismic modeling of gravity modes in slowly rotating A/F stars with radiative levitation
• A beta Cephei pulsator and a changing orbital inclination in the high-mass eclipsing binary system VV Orionis
• A comparison of the dynamical and model-derived parameters of the pulsating eclipsing binary KIC9850387
• Tidally perturbed pulsations in the pre-main sequence $\delta$ Scuti binary RS Cha
• The effect of the centrifugal acceleration on period spacings of gravito-inertial modes in intermediate-mass stars
• Mass transfer and tidally tilted pulsation in the Algol-type system TZ Dra
• BRITE-Constellation photometry of $\bpi^5$ Orionis, an ellipsoidal SPB variable
• Study of Eclipsing Binary and Multiple Systems in OB Associations II. The Cygnus OB Region: V443 Cyg, V456 Cyg and V2107 Cyg