Rediscussion of eclipsing binaries. Paper XIX. The long-period solar-type system V454 Aurigae

TL;DR

This study combines TESS photometry and radial velocity data to precisely determine the masses, radii, and distance of the long-period eclipsing binary V454 Aurigae, revealing unusual stellar characteristics and providing new insights into such systems.

Contribution

First detailed mass and radius measurements of V454 Aurigae using combined TESS and spectroscopic data, highlighting its unique stellar configuration.

Findings

Masses of 1.034 and 1.161 solar masses for the stars.

Radii of 0.979 and 1.211 solar radii for the stars.

Distance measurement consistent with Gaia parallax.

Abstract

V454 Aur is an eclipsing binary system containing two solar-type stars on an orbit of relatively long period (P = 27.02 d) and large eccentricity (e = 0.381). Eclipses were detected using data from the Hipparcos satellite, and a high-quality double-lined spectroscopic orbit has been presented by Griffin (2001). The NASA Transiting Exoplanet Survey Satellite (TESS) has observed the system during eight sectors, capturing ten eclipses in their entirety. V454 Aur is unusual in that the primary star - the star eclipsed at the deeper minimum - is less massive, smaller \emph{and} cooler than its companion. This phenomenon can occur in certain configurations of eccentric orbits when the stars are closer together at the primary eclipse, causing a larger area to be eclipsed than at the secondary. We use the radial velocity measurements from Griffin and the light curves from TESS to determine the masses and radii of the component stars for the first time, finding masses of 1.034 +/- 0.006 Msun and 1.161 +/- 0.008 Msun, and radii of 0.979 +/- 0.003 Rsun and 1.211 +/- 0.003 Rsun. Our measurement of the distance to the system is consistent with that from the Gaia DR3 parallax. A detailed spectroscopic study to determine chemical abundances and more precise temperatures is encouraged. Finally, we present equations to derive the effective temperatures of the stars from the inferred temperature of the system as a whole, plus the ratio of the radii and either the surface brightness or light ratio of the stars.