On Finding Exoplanets

Well over 100 exoplanets (planets outside our Solar system) have been 
detected by the gravitational influence they have on their companion
stars.  Variations in a star's radial velocity, measureable by Doppler 
shift in the star's spectrum, may indicate one or more orbiting
planets, or may simply be the result of measurement errors.  
Bayes may be a useful tool for separating planets from noise, 
but multimodality in several dimensions makes it difficult to 
estimate parameter values for a given model, and model selection 
is more difficult still.  In this talk we look at some real and 
simulated data and consider possible ways to tackle the problem 
of multimodality.