A study of nine compact triply eclipsing triples

In this work, we report the independent discovery and analysis of nine new compact triply eclipsing triple star systems found with the Transiting Exoplanet Survey Satellite (TESS) mission: TICs 47151245, 81525800, 99013269, 229785001, 276162169, 280883908, 294803663, 332521671, and 356324779. Each of these nine systems exhibits distinct third-body eclipses where the third ('tertiary') star occults the inner eclipsing binary (EB), or vice versa. We utilize a photodynamical analysis of the TESS photometry, archival photometric data, TESS eclipse timing variations of the EBs, available archival spectral energy distribution (SED) curves, and, in some cases, newly acquired radial velocity observations, to solve for the parameters of all three stars, as well as most of the orbital elements. From these analyses we find that the outer orbits of all nine systems are viewed nearly edge on (i.e. within less than or similar to 4 degrees), and six of the systems are coplanar to within 5 degrees; the others have mutual inclination angles of 20 degrees, 41 degrees, and possibly 179 degrees (i.e. a retrograde outer orbit). The outer orbital periods range from 47.8 to 604 d, with eccentricities spanning 0.004-0.61. The masses of all 18 EB stars are in the range of 0.9-2.6 M-circle dot and are mostly situated near the main sequence. By contrast, the masses and radii of the tertiary stars range from 1.4 to 2.8 M-circle dot and 1.5 to 13 R-circle dot, respectively. We make use of the system parameters from these nine systems, plus those from a comparable number of compact triply eclipsing triples published previously, to gain some statistical insight into their properties.

Automated summary

We report the independent discovery and analysis of nine new compact triply eclipsing triple star systems using TESS mission data. Each system exhibits distinct third-body eclipses where the third star occults the inner eclipsing binary or vice versa. By utilizing photodynamical analysis and additional observational data, we were able to determine the parameters and orbital elements of all three stars. Statistical insights into the properties of these systems were gained by comparing them with a comparable number of previously published compact triply eclipsing triples.