REDISCUSSION OF ECLIPSING BINARIES. PAPER 3: THE INTERFEROMETRIC, SPECTROSCOPIC, AND ECLIPSING BINARY V1022 CASSIOPEIAE

摘要

V1022 Cas has been known as a spectroscopic binary for a century. It was found to be eclipsing based on photometry from the Hipparcos satellite, and an astrometric orbit was recently obtained from near-infrared interferometry. We present the first high-precision measurement of the radii of the stars based on light-curves obtained by the TESS satellite. Combined with published radial velocities from high-resolution spectra, we measure the masses of the stars to be 1-626 ± 0.001 M_⊙ and 1-609 ± 0.001 M_⊙, and the radii to be 2.591 ± 0.026 R_⊙ and 2.472 ± 0.027 R_⊙.The 12~d.16 orbit is eccentric and the stars rotate sub-synchronously, so the system is tidally unevolved. A good match to these masses and radii, and published temperatures of the stars, is found for several sets of theoretical stellar evolutionary models, for a solar metallicity and an age of approximately 2 Gyr. Four separate distance determinations to the system are available, and are in good agreement. The distances are based on surface- brightness calibrations, theoretical bolometric corrections, the Gaia parallax, and the angular size of the astrometric orbit. A detailed spectroscopic analysis of the system to measure chemical abundances and more precise temperatures would be helpful.