Orbital Dynamics Of A Possible Second Planet In HD 17156

TL;DR

This paper investigates the potential existence of a second planet in the HD 17156 system, analyzing its orbital dynamics and stability through numerical simulations, revealing a resonant interaction that improves data fit.

Contribution

It introduces a two-planet model for HD 17156 using full Newtonian simulations, demonstrating a stable 5:1 resonance and better fit to observational data.

Findings

Two planets are in a 5:1 mean motion resonance.

The two-planet system remains dynamically stable.

The model improves the fit to radial velocity data.

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 \POFP\ 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.