Determining Orbital Elements of Extrasolar Planets by Evolution Strategies

After the detection of the first extrasolar planet (exoplanet) more than one decade ago we currently know about more than 200 planets around other stars and there are about twenty multi-planet systems. Today’s most commonly used technique for identifying such exoplanets is based on radial velocity measurements of the star. Due to the increasing time span and accuracy of the respective observations, the measured data samples will more and more contain indications of multiple planetary companions. Unfortunately, especially in multi-planet systems, the determination of these exoplanets’ orbital elements is a rather complex and computationally expensive data analysis task. It is usually formulated as an optimization problem in which the orbital parameters yielding minimal residues w.r.t. the measured data are to be found. Very likely, improved algorithms for (approximately) solving this problem will enable the detection of more complex systems. In this paper we describe a specialized evolution strategy for approaching this problem.