Orbital Dynamics Of A Possible Second Planet In HD 17156

Abstract

In this letter we report the possible existence of a second planet in the transiting extrasolar planet system HD 17156 and its interactive dynamics with the previously known planet. The analysis is achieved through the \ optimization software which is based on a full integration of the system's multiple-body Newtonian equations of motion. The two-planet solution yields a significantly improved fit to the previously published radial velocities. The two planets are strongly interacting and exchange angular momentum in a 5:1 mean motion resonance, yet remain stable as they mutually excite orbital eccentricities and periastron advances.