Four New Compact Triply Eclipsing Triples found with Gaia and TESS

TL;DR

This study identifies four new triply eclipsing triple star systems using Gaia and TESS data, and performs detailed photodynamical analysis to determine their orbital parameters and evolutionary states.

Contribution

The paper reports the discovery of four new compact triply eclipsing triples and provides the first detailed photodynamical analysis combining multiple data sources for these systems.

Findings

Four new triply eclipsing triples identified with Gaia and TESS.

Outer orbital periods range from 52.9 to 471 days.

Systems are very flat with mutual inclinations less than 4°.

Abstract

This paper presents a comprehensive analysis of four triply eclipsing triple star systems, namely TIC 88206187, TIC 14839347, TIC 298714297, and TIC 66893949. The four systems with third-body eclipses were found in the TESS lightcurves from among a sample of ~400 matches between known eclipsing binaries and the Gaia DR3 Non-Single Star (NSS; Gaia Collaboration 2022; Pourbaix et al. 2022) solution database. We combined photometric lightcurves, eclipse timing variations, archival spectral energy distributions, and theoretical evolution tracks in a robust photodynamical analysis to determine the orbital and system parameters. The triples have outer periods of 52.9, 85.5, 117, and 471 days, respectively. All dozen stars have masses $\lesssim$ 2.6 M$_\odot$. The systems are quite flat with mutual inclination angles between the inner and outer orbital planes that are all $\lesssim 4^\circ$. The outer mass ratios range from 0.39--0.76, consistent with our earlier collection of compact triply eclipsing triples. TIC 88206187 exhibits a fractional radius of the outer tertiary component $(r_B \equiv R_B/a_{\rm out})$ exceeding 0.1 (only the third such system known), and we consider its future evolution. Finally, we compare our photodynamical analysis results and the orbital parameters given in the Gaia DR3 NSS solutions, indicating decent agreement, but with the photodynamical results being more accurate.