Understanding the relationship between long-period giant planets and multiple smaller short-period planets is critical for formulating a complete picture of planet formation. This work characterizes three such systems. We present Kepler-65, a system with an eccentric (e=0.28+/-0.07) giant planet companion discovered via radial velocities (RVs) exterior to a compact, multiply-transiting system of sub-Neptune planets. We also use precision RVs to improve mass and radius constraints on two other systems with similar architectures, Kepler-25 and Kepler-68. In Kepler-68 we propose a second exterior giant planet candidate. Finally, we consider the implications of these systems for planet formation models, particularly that the moderate eccentricity in Kepler-65's exterior giant planet did not disrupt its inner system.
@article{arxiv.1903.07186,
title = {Long-Period Giant Companions to Three Compact, Multiplanet Systems},
author = {Sean M. Mills and Andrew W. Howard and Lauren M. Weiss and Jason H. Steffen and Howard Isaacson and Benjamin J. Fulton and Erik A. Petigura and Molly R. Kosiarek and Lea A. Hirsch and John H. Boisvert},
journal= {arXiv preprint arXiv:1903.07186},
year = {2019}
}