It Takes Two to Tango: Searching for Companion Planets in Hot Jupiter Systems

The formation and migration of warm and hot Jupiters remains an open problem in planetary science. Core accretion models suggest these gas giants form beyond the frost line, yet their presence at <1 AU requires significant orbital evolution. Dynamical pathways such as high-eccentricity migration, driven by gravitational interactions with additional planetary companions, offer a likely explanation. We analyzed radial velocity data from the TESS-Keck Survey to search for such companions in known warm and hot Jupiter systems. By fitting Keplerian models to the radial velocity time series, we searched for periodic signals that would indicate outer perturbers capable of driving migration. Evidence of companions would support high-eccentricity migration as a dominant pathway, while nondetections would offer equally important constraints on alternative migration mechanisms such as disk interactions. Our results contribute to constraining the dominant pathways for giant planet evolution and the dynamical architectures of planetary systems.