V907 Sco Switched to the Eclipsing Mode Again

Abstract

V907 Scorpii is a unique triple system in which the inner binary component has been reported to have switched on and off eclipses several times in modern history. In spite of its peculiarity, observational data on this system are surprisingly scarce. Here we make use of the recent Transiting Exoplanet Survey Satellite observations, as well as our own photometric and spectroscopic data, to expand the overall data set and study the V907 Sco system in more detail. Our analysis provides both new and improved values for several of its fundamental parameters: (i) the masses of the stars in the eclipsing binary are 2.74 ± 0.02 M ⊙ and 2.56 ± 0.02 M ⊙; and (ii) the third component is a solar-type star with mass 1.06 − 0.10 + 0.11 M ⊙ (90% C.L.), orbiting the binary on an elongated orbit with an eccentricity of 0.47 ± 0.02 and a period of 142.01 ± 0.05 days. The intermittent intervals of time when eclipses of the inner binary are switched on and off are caused by a mutual 26 .° 2 − 2.2 + 2.6 inclination of the inner- and outer-orbit planes, and a favorable inclination of about 71° of the total angular momentum of the system. The nodal precession period is P ν = 63.5 − 2.6 + 3.3 yr. The inner binary will remain eclipsing for another ≃26 yr, offering an opportunity to significantly improve the parameters of the model. This is especially true during the next decade when the inner-orbit inclination will increase to nearly 90°. Further spectroscopic observations are also desirable, as they can help to improve constraints on the system’s orbital architecture and its physical parameters.

Detached Eclipsing Binaries in Compact Hierarchical Triples: Triple-lined systems BD+44 2258 and KIC 06525196

“…There is a subset of these triples, called Compact Hierarchical Triples (CHT), which offer more potential for observational astrophysics (Borkovits 2022). The timescale of the changes due to these interactions is short in CHT and can be observed easily over a few years, e.g., vanishing eclipses of HS Hya (Zasche & Paschke 2012) or re-appearing eclipses of V907 Sco (Zasche et al 2023). These are triples with the outer orbit period shorter than 1000 days.…”