2021AJ....161..137H -
Astron. J., 161, 137-137 (2021/March-0)
The pre-He white dwarfs in eclipsing binaries. II. WASP 0843-11.
HONG K., LEE J.W., KOO J.-R., PARK J.-H., RITTIPRUK P., KIM H.-Y., KANJANASAKUL C. and HAN C.
Abstract (from CDS):
We present the Transiting Exoplanet Survey Satellite (TESS) photometry and our high-resolution spectra of the EL CVn-type star 1SWASP J084356.46-113327.5 (WASP 0843-11), which consists of an F-type main-sequence (MS) star and a hotter low-mass helium white dwarf precursor (pre-He WD). In a spectral analysis, double-lined radial velocities (RVs) were obtained for the first time. From a simultaneous analysis of the TESS light and RV curves, the masses, radii, and temperatures of each component were determined to be M1 = 1.733 ± 0.031 M☉, M2 = 0.220 ± 0.008 M☉, R1 = 2.094 ± 0.013 R☉, R2 = 0.331 ± 0.003 R☉, T1 = 6960 ± 120 K, and T2 =9870 ± 310 K, respectively. According to their physical properties, the primary and secondary stars are located on the instability strips of δ Sct/γ Dor hybrids and extremely low-mass WDs, respectively. We applied multiple frequency analyses to the residual light curve after subtracting the binarity effects and detected a total of four independent frequencies. A frequency of f3 = 1.6356 day–1 in the low-frequency region was reminiscent of γ Dor stars, while the other three frequencies of f2, f15, and f18 in the high-frequency region (150-196 day–1) are probably related to pre-He WD components. Our results demonstrate that the more massive MS primary star of WASP 0843-11 is a γ Dor pulsator, whereas the hotter secondary component is a pre-He WD with high-frequency pulsations.
Abstract Copyright:
© 2021. The American Astronomical Society. All rights reserved.
Journal keyword(s):
Eclipsing binary stars - Fundamental parameters of stars - Stellar oscillations - Spectroscopy - Multi-periodic pulsation - Asteroseismology - Stellar evolution - White dwarf stars
Simbad objects:
10
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