Rediscussion of eclipsing binaries. Paper XXVII. The totally-eclipsing system UZ Draconis

TL;DR

This study precisely models the totally-eclipsing binary UZ Draconis using extensive TESS data, determining stellar properties, rotation, and distance, and confirming consistency with theoretical models and Gaia measurements.

Contribution

The paper provides high-precision measurements of stellar parameters for UZ Draconis using TESS data and models, including the first detailed radius measurements enabled by total eclipses.

Findings

Stellar masses are 1.291 and 1.193 solar masses.

Radii are 1.278 and 1.122 solar radii.

Distance measured at 185.7 pc, matching Gaia data.

Abstract

UZ Dra is a detached and totally-eclipsing binary containing two late-F stars in a circular orbit of period 3.261 d. It has been observed by the Transiting Exoplanet Survey Satellite in 41 sectors, yielding a total of 664,809 high-quality flux measurements. We model these data and published radial velocities to determine the physical properties of the system to high precision. The masses of the stars are 1.291 +/- 0.012 Msun and 1.193 +/- 0.009 Msun, and their radii are 1.278 +/- 0.004 Rsun and 1.122 +/- 0.003 Rsun. The high precision of the radius measurements is made possible by the (previously unrecorded) total eclipses and the extraordinary amount of data available. The light curves show spot modulation at the orbital period, and both stars rotate synchronously. Our determination of the distance to the system, 185.7 +/- 2.4 pc, agrees very well with the parallax distance of 185.39 +/- 0.39 pc from Gaia DR3. The properties of the system are consistent with theoretical predictions for an age of 600 +/- 200 Myr and a slightly super-solar metallicity.