Presentation #108.06 in the session Poster Presentations.
Recent observational studies suggest that the occurrence of hot Jupiters (HJs) around solar-type stars is correlated with stellar clustering. We will present a new scenario for HJ formation, called “Flyby Induced High-e Migration”, that may help explain this correlation. In this scenario, stellar flybys excite the eccentricity and inclination of an outer companion (giant planet, brown dwarf, or low-mass star) at large distance (10–300 au), which then triggers high-e migration of an inner cold Jupiter (at a few astronomical units) through the combined effects of von Zeipel–Lidov–Kozai (ZLK) eccentricity oscillation and tidal dissipation. We will present the analytic estimate for the HJ occurrence rate in this formation scenario, that we obtained using semianalytical calculations of the effective ZLK inclination window, together with numerical simulations of stellar flybys. This “flyby induced high-e migration” could account for a significant fraction of the observed HJ population, although the result depends on several uncertain parameters, including the density and lifetime of birth stellar clusters, and the occurrence rate of the “cold Jupiter + outer companion” systems.