2017/04/30 by Z. Guo, Zhao Guo, Douglas R. Gies +3 · 40 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Binary number #Binary star #Dipole #Envelope (radar) #Light curve #Orbital elements #Orbital period #Rotation (mathematics) #Stars #Stellar rotation #Stellar, planetary, and galactic studies #astro-ph.SR
paper · pdf · doi:10.3847/1538-4357/aa978c
published in The Astrophysical Journal 851(1), 39 (IOP Publishing) · ApJ accepted. We have added the following discussions: (a) the evidence of Am stars in the spectra; (b)two examples of the effect of mass-transfer on stellar oscillations;(c) the evolution of unstable frequency range of p-modes in Figure 7. We have corrected a mistake in the labeling of effective temperatures in Table 1
openalex created_date 2017/06/05 · arxiv created 2017/10/31 · openalex publication_date 2017/12/08 · arxiv updated 2017/12/20 · openalex updated_date 2026/08/05
Abstract We report the discovery of a post-mass-transfer Gamma Doradus/Delta Scuti hybrid pulsator in the eclipsing binary KIC 9592855. This binary has a circular orbit, an orbital period of 1.2 days, and contains two stars of almost identical masses ( ). However, the cooler secondary star is more evolved ( ), while the hotter primary is still on the zero-age-main-sequence ( ). Coeval models from single-star evolution cannot explain the observed masses and radii, and binary evolution with mass-transfer needs to be invoked. After subtracting the binary light curve, the Fourier spectrum shows low-order pressure-mode pulsations, and more dominantly, a cluster of low-frequency gravity modes at about 2 day −1 . These g-modes are nearly equally spaced in period, and the period spacing pattern has a negative slope. We identify these g-modes as prograde dipole modes and find that they stem from the secondary star. The frequency range of unstable p-modes also agrees with that of the secondary. We derive the internal rotation rate of the convective core and the asymptotic period spacing from the observed g-modes. The resulting values suggest that the core and envelope rotate nearly uniformly, i.e., their rotation rates are both similar to the orbital frequency of this synchronized binary.