Rediscussion of Eclipsing Binaries. Paper XXX. The Slightly Evolved F-type System BK Pegasi

TL;DR

This study precisely measures the physical properties of the BK Pegasi eclipsing binary system using TESS and previous data, confirming stellar models for a 2.65 Gyr age with high accuracy.

Contribution

It provides highly precise measurements of stellar masses and radii for BK Pegasi, validating theoretical models for a specific age and composition.

Findings

Masses of 1.411 and 1.254 solar masses with high precision.

Radii of 1.990 and 1.460 solar radii accurately determined.

Properties align with models for 2.65 Gyr old stars.

Abstract

BK Peg is a double-lined detached eclipsing binary containing two late-F stars in an orbit with small eccentricity. We use light curves from the Transiting Exoplanet Survey Satellite (TESS) and spectroscopic measurements from previous studies to measure the physical properties of the companions to a high precision. We obtain masses of $1.411 \pm 0.004$\Msun\ and $1.254 \pm 0.004$\Msun, and radii of $1.990 \pm 0.004$\Rsun\ and $1.460 \pm 0.004$\Rsun, which are among the most precise measurements made for these quantities in normal stars. These properties match theoretical stellar evolutionary models for a solar chemical composition and an age of 2.65~Gyr. We also present an updated ephemeris of the system, as a result of our TESS measurements and a collection of mid-eclipse times from previous studies.