Revisiting the analysis of HW Virginis eclipse timing data: I. A frequentist data modeling approach and a dynamical stability analysis

Context. HW Vir is a short-period binary that presents eclipse timing variations. Circumbinary planets have been proposed as a possible explanation, although the properties of the planets differ in each new study.Aims. Our aim is to perform robust model selection methods for eclipse timing variations (ETV) and error calculation techniques based on a frequentist approach for the case of the HW Vir system.Methods. We initially performed simultaneous light and radial velocity curve analysis to derive the masses of the binary. We then analyzed the eclipse timing variation of the system by fitting multiple models. To select the best model, we searched the confidence levels for the best model by creating an chi(2) surface grid and bootstrap methods for each pair of parameters. We searched for stable orbital configurations for our adopted ETV model.Results. The masses of the binary are found as 0.413 +/- 0.008 M-circle dot and 0.128 +/- 0.004 M-circle dot. Under the assumption of two light time effects superimposed on a secular change, the minimum masses of the circumbinary objects are calculated as 25.0-2.2+3.5MJup and 13.9(-0.45)(+0.60)M(Jup)13.9-0.45+0.60MJup . The projected semi-major axes are found to be 7.8(-1.0)(+1.4) 7.8-1.0+1.4 and 4.56(-0.22)(+0.27)4.56-0.22+0.27 au in respective order. We find that this configuration is unstable within a 3 sigma range on the semi-major axis and eccentricity of the outer circumbinary object.

Automated summary

The study aims to analyze eclipse timing variations in the HW Vir system to determine the properties of circumbinary planets. By using robust model selection methods and error calculation techniques, the study found the masses of the binary system and the potential circumbinary objects' parameters, showing unstable orbital configurations for the outer circumbinary object.