Open AccessA Bayesian Kepler periodogram detects a second planet in HD 208487
Author(s) -
Gregory P. C.
Publication year - 2007
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2006.11240.x
Subject(s) - physics , markov chain monte carlo , planet , eccentricity (behavior) , radial velocity , astrophysics , parallel tempering , kepler , periodogram , computation , monte carlo method , bayesian probability , algorithm , stars , statistics , hybrid monte carlo , computer science , mathematics , law , political science
An automatic Bayesian Kepler periodogram has been developed for identifying and characterizing multiple planetary orbits in precision radial velocity data. The periodogram is powered by a parallel tempering Markov chain Monte Carlo (MCMC) algorithm which is capable of efficiently exploring a multiplanet model parameter space. The periodogram employs an alternative method for converting the time of an observation to true anomaly that enables it to handle much larger data sets without a significant increase in computation time. Improvements in the periodogram and further tests using data from HD 208487 have resulted in the detection of a second planet with a period of 909 82 −92 d, an eccentricity of 0.37 0.26 −0.20 , a semimajor axis of 1.87 0.13 −0.14 au and an M sin i = 0.45 +0.11 −0.13 M J . The revised parameters of the first planet are period = 129.8 ± 0.4 d, eccentricity = 0.20 ± 0.09, semimajor axis = 0.51 ± 0.02 au and M sin i = 0.41 ± 0.05 M J . Particular attention is paid to several methods for calculating the model marginal likelihood which is used to compare the probabilities of models with different numbers of planets.