Abstract
The multiple system V505 Sagittarii is composed of at least three stars: a compact eclipsing pair and a distant component, whose orbit is measured directly using speckle interferometry. In order to explain the observed orbit of the third body in V505 Sagittarii and also other observable quantities, namely the minima timings of the eclipsing binary and three different radial velocities (RVs) detected in the spectrum, we thoroughly test a fourth-body hypothesis—a perturbation by a dim, yet-unobserved object.
We use an N-body numerical integrator to simulate future and past orbital evolution of three or four components in this system. We construct a suitable χ2 metric from all available speckle-interferometry, minima-timings, and RV data and we scan a part of a parameter space to get at least some of the possible solutions.