Modeling Keplerian Orbits of Stars, Brown Dwarfs, and Planets

Any companion object (Star, Brown Dwarf, or Planet) that orbits a star follows a Keplerian Orbit. The APO Galactic Evolution Experiment surveys (APOGEE-1 and APOGEE-II) in data release 15 took spectroscopy of 263,444 stars and produced stellar radial velocity data of order 100 m/s precision. The combined surveys cover a base line of over 6 years (~2000 days). In our project, we used a mock catalog of companions that was designed to mimic the APOGEE surveys. The goal of our project was to compare the effectiveness of Markov-Chain Monte Carlo (MCMC) techniques with more traditional orbital fitting methods for deriving correct companion orbits from APOGEE-like radial velocity data. We investigated not only how well we could recover orbital parameters as a function of parameter space, but we also investigated the practical limitations of each method. In particular, we focused on using these techniques with large data sets, and the trade-offs between precision and computational time