FX UMa: A New Heartbeat Binary System with Linear and Non-linear Tidal Oscillations and delta Sct Pulsations

• Main Authors: Wang, Kun, Ren, Anbing, Andersen, Mads Fredslund, Grundahl, Frank, Chen, Tao, Palle, Pere L
• Format: Journal Article
• Language: English
• Published: 03-06-2023
• Subjects: Physics - Solar and Stellar Astrophysics
• DOI: 10.48550/arxiv.2212.04639

We present a detailed analysis of an eclipsing double-lined binary FX UMa
based on TESS photometry and newly acquired spectroscopic observations. The
radial velocities and atmospheric parameters for each component star are
obtained from the SONG high-resolution spectra. Combined with the
radial-velocity measurements, our light-curve modeling yields absolute masses
and radii of the two components. The Fourier amplitude spectrum of the residual
light curve reveals a total of 103 frequencies with signal-to-noise ratio (S/N)
> 4, including 12 independent frequencies, 17 multiples of the orbital
frequency (Nforb), and 74 combination frequencies. Ten Nforb peaks with S/N >
10 have very high amplitudes and are likely due to tidally excited oscillations
(TEOs). The remaining Nforb peaks (4 < S/N < 10) may be originated from the
imperfect removal, or they are actually real TEOs. Four anharmonic frequencies
can pair up and sum to give exact harmonics of the orbital frequency,
suggesting the existence of non-linear tidal processes in the eccentric binary
system FX UMa. Eight independent frequencies in the range of 20 to 32
day$^{-1}$ are typical low-order pressure modes of delta Scuti pulsators.