TIC 114936199: A Quadruple Star System with a 12-day Outer Orbit Eclipse

TL;DR

This paper reports the discovery and detailed analysis of a unique quadruple star system with a 12-day outer eclipse duration, combining multiple observational methods to determine the properties and orbits of all four stars.

Contribution

The study presents the first detailed spectro-photodynamical analysis of a quadruple star system with an unprecedented 12-day outer eclipse, revealing its complex orbital configuration and stellar properties.

Findings

Longest outer eclipse duration among known systems (~12 days)

Precise stellar masses and orbital parameters for all four stars

Identification of a 2+1+1 quadruple star configuration

Abstract

We report the discovery with TESS of a remarkable quadruple star system with a 2+1+1 configuration. The two unique characteristics of this system are that (i) the inner eclipsing binary (stars Aa and Ab) eclipses the star in the outermost orbit (star C), and (ii) these outer 4th body eclipses last for $\sim$12 days, the longest of any such system known. The three orbital periods are $\sim$3.3 days, $\sim$51 days, and $\sim$2100 days. The extremely long duration of the outer eclipses is due to the fact that star B slows binary A down on the sky relative to star C. We combine TESS photometric data, ground-based photometric observations, eclipse timing points, radial velocity measurements, the composite spectral energy distribution, and stellar isochones in a spectro-photodynamical analysis to deduce all of the basic properties of the four stars (mass, radius, $T_{\rm eff}$, and age), as well as the orbital parameters for all three orbits. The four masses are $M_{\rm Aa} =0.382$M$_\odot$, $M_{\rm Ab} =0.300$M$_\odot$, $M_{\rm B} =0.540$M$_\odot$ and $M_{\rm C} =0.615$M$_\odot$, with a typical uncertainty of 0.015 M$_\odot$.