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arXiv · 2504.16817

Rediscussion of eclipsing binaries. Paper XXIII. The F-type twin system RZ Chamaeleontis

John Southworth
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Abstract

RZ Cha is a detached eclipsing binary containing two slightly evolved F5 stars in a circular orbit of period 2.832 d. We use new light curves from the Transiting Exoplanet Survey Satellite (TESS) and spectroscopic orbits from Gaia DR3 to measure the physical properties of the component stars. We obtain masses of 1.488 +/- 0.011 Msun and 1.482 +/- 0.011 Msun, and radii of 2.150 +/- 0.006 Rsun and 2.271 +/- 0.006 Rsun. An orbital ephemeris from the TESS data does not match published times of mid-eclipse from the 1970s, suggesting the period is not constant. We measure a distance to the system of 176.7 +/- 3.7 pc, which agrees with the Gaia DR3 value. A comparison with theoretical models finds agreement for metal abundances of Z = 0.014 and Z = 0.017 and an age of 2.3 Gyr. No evidence for pulsations was found in the light curves. Future data from TESS and Gaia will provide more precise masses and constraints on any changes in orbital period.

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John Southworth. 2025-04-23. Rediscussion of eclipsing binaries. Paper XXIII. The F-type twin system RZ Chamaeleontis. https://arxiv.org/abs/2504.16817

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