The Compact Triply Eclipsing Triple Star TIC 209409435 Discovered with TESS

Abstract

We report the discovery in $TESS$ Sectors 3 and 4 of a compact triply eclipsing triple star system. TIC 209409435 is a previously unknown eclipsing binary with a period of 5.717 days, and the presence of a third star in an outer eccentric orbit of 121.872 day period was found from two sets of third-body eclipses and from eclipse timing variations. The latter exhibit signatures of strong 3rd-body perturbations. After the discovery, we obtained follow-up ground-based photometric observations of several binary eclipses as well as another of the third-body eclipses. We carried out comprehensive analyses, including the simultaneous photodynamical modelling of $TESS$ and ground-based lightcurves (including both archival WASP data, and our own follow-up measurements), as well as eclipse timing variation curves. Also, we have included in the simultaneous fits multiple star spectral energy distribution data and theoretical PARSEC stellar isochrones. We find that the inner binary consists of near twin stars of mass 0.90 $M_{\odot }$ and radius 0.88 $R_{\odot }$. The third star is just 9% more massive and 18% larger in radius. The inner binary has a rather small eccentricity while the outer orbit has $e=0.40$. The inner binary and outer orbit have inclination angles within 0.1${}^{\circ }$ and 0.2${}^{\circ }$ of 90${}^{\circ }$, respectively. The mutual inclination angle is $\lesssim 1/4^{\circ }$. All of these results were obtained without radial velocity observations.

Accepted for publication in MNRAS

References in corpus (15)

• The Transiting Exoplanet Survey Satellite
• The K2 Mission: Characterization and Early results
• New Grids of ATLAS9 Model Atmospheres
• KOI-126: A Triply-Eclipsing Hierarchical Triple with Two Low-Mass Stars
• A fast hybrid algorithm for exoplanetary transit searches
• Eclipse Timing Variation Analyses of Eccentric Binaries with Close Tertiaries in the Kepler field
• YBC, a stellar bolometric corrections database with variable extinction coefficients: an application to PARSEC isochrones
• HD 181068: A Red Giant in a Triply-Eclipsing Compact Hierarchical Triple System
• Secular and tidal evolution of circumbinary systems
• TICs 167692429 and 220397947: The first compact hierarchical triple stars discovered with TESS
• EPIC 220204960: A Quadruple Star System Containing Two Strongly Interacting Eclipsing Binaries
• The compact multiple system HIP 41431
• A search for tight hierarchical triple systems amongst the eclipsing binaries in the CoRoT fields
• KIC 2856960: the impossible triple star
• LcTools: A Windows-Based Software System for Finding and Recording Signals in Lightcurves from NASA Space Missions

Cited by in corpus (18)

• TESS-Gaia Light Curve: a PSF-based TESS FFI light curve product
• Six New Compact Triply Eclipsing Triples Found With TESS
• Triply eclipsing triple stars in the northern TESS fields: TICs 193993801, 388459317 and 52041148
• A Study of Nine Triply Eclipsing Triples
• Von Zeipel - Lidov - Kozai cycles in action: $Kepler$ triples with eclipse depth variations: KICs 6964043, 5653126, 5731312 and 8023317
• Then and now: A new look at the eclipse timing variations of hierarchical triple star candidates in the primordial $Kepler$-field, revisited by TESS
• TIC 114936199: A Quadruple Star System with a 12-day Outer Orbit Eclipse
• Analytic Light Curve for Mutual Transits of Two Bodies Across a Limb-darkened Star
• The Value-Added Catalog of ASAS-SN Eclipsing Binaries II: Properties of Extra-Physics Systems
• Precision timing of eclipsing binaries from TESS full frame images. Method and performance
• Dynamical masses across the Hertzsprung-Russell diagram
• Ten new, ultracompact triply eclipsing triple star systems
• Spectroscopy of Eclipsing Compact Hierarchical Triples I
• Modeling Apsidal Motion in Eclipsing Binaries using ELC
• A differentiable N-body code for transit timing and dynamical modelling -- II. Photodynamics
• TIC 454140642: A Compact, Coplanar, Quadruple-lined Quadruple Star System Consisting of Two Eclipsing Binaries
• The Visual Survey Group: A Decade of Hunting Exoplanets and Unusual Stellar Events with Space-Based Telescopes
• A 2+1+1 quadruple star system containing the most eccentric, low-mass, short-period, eclipsing binary known