Dynamical and Observational Constraints on Additional Planets in Highly Eccentric Planetary Systems

TL;DR

This study examines highly eccentric exoplanet systems using updated radial velocity data and simulations to identify potential additional planets and establish detection limits, revealing possible stable regions and ruling out smaller planets in some systems.

Contribution

It provides new orbital solutions, dynamical stability analyses, and detection limits for six highly eccentric planetary systems, enhancing understanding of their potential to host additional planets.

Findings

Short-period planets could exist in HD 45350 and 16 Cyg B.

Detection limits rule out additional planets down to a few Neptune masses in three systems.

Dynamical simulations identify stable regions for potential additional planets.

Abstract

Long time coverage and high radial velocity precision have allowed for the discovery of additional objects in known planetary systems. Many of the extrasolar planets detected have highly eccentric orbits, which raises the question of how likely those systems are to host additional planets. We investigate six systems which contain a very eccentric (e>0.6) planet: HD 3651, HD 37605, HD 45350, HD 80606, HD 89744, and 16 Cyg B. We present updated radial-velocity observations and orbital solutions, search for additional planets, and perform test particle simulations to find regions of dynamical stability. The dynamical simulations show that short-period planets could exist in the HD 45350 and 16 Cyg B systems, and we use the observational data to set tight detection limits, which rule out additional planets down to a few Neptune masses in the HD 3651, HD 45350, and 16 Cyg B systems.