Modelling Binary Orbits in the WIYN Open Cluster Survey - The alternative evolutionary tracks for binary stars.
Date:
Abstract: Blue Straggler Stars (BSS) are believed to have originated from binary star interactions. Therefore, modeling binary orbits is crucial for understanding their formation and evolution. In this study, we applied The Joker (a Monte Carlo rejection sampler) to model binary orbits in the WIYN Open Cluster Survey (WOCS). Our objective was to evaluate The Joker’s efficacy on binaries with ample radial-velocity data (RVD). Exploring the potential usage of The Joker, designed for sparsely measured radial velocities, we applied it to known single-lined binary orbits in M67 and NGC 188. With 70+ binary systems, we compared our Joker orbital parameters among binaries having a diverse array of period-eccentricity combinations (Geller et al. 2021). We found 5-7 RVD start to meaningfully constrain orbital parameters, and 8-10 RVD are required for unimodal period solutions with eccentricities converging to previous studies’ solutions. Additionally, we explored the possibility of devising observing plans having limited prior measurements with The Joker predicting possible periastron approach times to constrain eccentricity. This work enables us to estimate binary orbital solutions with fewer RVD and to enhance our understanding of the alternative evolutionary tracks of binary systems.
We acknowledge the support of the National Science Foundation through the award NSF AST-1714506 and the Wisconsin Alumni Research Fund.