The study of triple systems V819 Her, V2388 Oph, and V1031 Ori

TL;DR

This paper presents a combined observational approach using interferometry and eclipse timing to analyze triple star systems, enabling detailed orbital parameter determination without spectroscopic data.

Contribution

It introduces a method combining interferometry and period variation analysis to study triple systems, avoiding the need for spectroscopic monitoring of long-period orbits.

Findings

Determined visual orbits for three triple systems.

Derived the distance to two systems independently.

Provided orbital parameters and eccentricities for the systems.

Abstract

The systems V819 Her, V2388 Oph, and V1031 Ori are triples comprised of an eclipsing binary orbiting with a distant visual component on a longer orbit. A detailed analysis of these interesting systems, combining the two observational techniques: interferometry and apparent period variation, was performed. The interferometric data for these three systems obtained during the last century determine the visual orbits of the distant components in the systems. The combined analysis of the positional measurements together with the analysis of apparent period changes of the eclipsing binary (using the minima timings) can be used to study these systems in a combined approach, resulting in a set of parameters otherwise unobtainable without the radial velocities. The main advantage of the technique presented here is the fact that one needs no spectroscopic monitoring of the visual orbits, which have rather long periods: 5.5 yr for V819 Her, 9.0 yr for V2388 Oph, and 31.3 yr for V1031 Ori, respectively. The eccentricities of the outer orbits are 0.69, 0.33, and 0.92, respectively. Moreover, the use of minima timings of the eclipsing pairs help us to derive the orientation of the orbit in space with no ambiguity around the celestial plane. And finally, the combined analysis yielded also an independent determination of the distance of V819 Her (68.7 +/- 1.8 pc), and V2388 Oph (70.6 +/- 8.9 pc). We also present a list of similar systems, which would be suitable for a combined analysis like this one.