An Integrative Analysis of the HD 219134 Planetary System and the Inner solar system: Extending DYNAMITE with Enhanced Orbital Dynamical Stability Criteria

Abstract

Planetary architectures remain unexplored for the vast majority of exoplanetary systems, even among the closest ones, with potentially hundreds of planets still "hidden"from our knowledge. Dynamite is a powerful software package that can predict the presence and properties of these yet-undiscovered planets. We have significantly expanded the integrative capabilities of Dynamite, which now allows for (i) planets of unknown inclinations alongside planets of known inclinations, (ii) population statistics and model distributions for the eccentricity of planetary orbits, and (iii) three different dynamical stability criteria. We demonstrate the new capabilities with a study of the HD 219134 exoplanet system consisting of four confirmed planets and two likely candidates, where five of the likely planets and candiates are Neptune-sized or below with orbital periods less than 100 days. By integrating the known data for the HD 219134 planetary system with contextual and statistical exoplanet population information, we tested different system architecture hypotheses to determine their likely dynamical stability. Our results provide support for the planet candidates, and we predict at least two additional planets in this system. We also deploy Dynamite on analogs of the inner solar system by excluding Venus or Earth from the input parameters to test Dynamite's predictive power. Our analysis finds that the system remains stable while also recovering the excluded planets, demonstrating the increasing capability of Dynamite to accurately and precisely model the parameters of additional planets in multiplanet systems. © 2022. The Author(s). Published by the American Astronomical Society.