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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 660680.0, MPI für Astronomie / Publikationen_mpia
Bayesian analysis of exoplanet and binary orbits. Demonstrated using astrometric and radial-velocity data of Mizar A
Authors:Schulze-Hartung, T.; Launhardt, R.; Henning, T.
Date of Publication (YYYY-MM-DD):2012
Journal Abbrev.:Astronomy and Astrophysics
Start Page:id. A79
Audience:Not Specified
Abstract / Description:<BR /> Aims: We introduce BASE (Bayesian astrometric and spectroscopic exoplanet detection and characterisation tool), a novel program for the combined or separate Bayesian analysis of astrometric and radial-velocity measurements of potential exoplanet hosts and binary stars. The capabilities of BASE are demonstrated using all publicly available data of the binary Mizar A. <BR /> Methods: With the Bayesian approach to data analysis we can incorporate prior knowledge and draw extensive posterior inferences about model parameters and derived quantities. This was implemented in BASE by Markov chain Monte Carlo (MCMC) sampling, using a combination of the Metropolis-Hastings, hit-and-run, and parallel-tempering algorithms to explore the whole parameter space. Nonconvergence to the posterior was tested by means of the Gelman-Rubin statistic (potential scale reduction). The samples were used directly and transformed into marginal densities by means of kernel density estimation, a "smooth" alternative to histograms. We derived the relevant observable models from Newton's law of gravitation, showing that the motion of Earth and the target can be neglected. <BR /> Results: With our methods we can provide more detailed information about the parameters than a frequentist analysis does. Still, a comparison with the Mizar A literature shows that both approaches are compatible within the uncertainties. <BR /> Conclusions: We show that the Bayesian approach to inference has been implemented successfully in BASE, a flexible tool for analysing astrometric and radial-velocity data. BASE, the computer program introduced in this article, can be downloaded at <A href="http://www.mpia.de/homes/schulze/base.html">http://www.mpia.de/homes/schulze/base.html</A>.
Free Keywords:astrometry; celestial mechanics; methods: data analysis; methods: statistical; techniques: interferometric; techniques: radial velocities
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
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