A recent observational study suggests that the occurrence of hot Jupiters (HJs) around solar-type stars is correlated with stellar clustering. We study 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. Using semianalytical calculations of the effective ZLK inclination window, together with numerical simulations of stellar flybys, we obtain the analytic estimate for the HJ occurrence rate in this formation scenario. We find that 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.

最近的一项观测研究表明，太阳型恒星周围热木星 (HJ) 的出现与恒星聚集有关。我们研究了 HJ 形成的新场景，称为“飞越诱导的高电子迁移”，这可能有助于解释这种相关性。在这种情况下，恒星飞越会激发远距离（10-300 au）外伴星（巨行星、棕矮星或低质量恒星）的偏心率和倾斜度，然后触发内部冷木星的高辐射迁移（在几个天文单位）通过 von Zeipel-Lidov-Kozai (ZLK) 偏心率振荡和潮汐耗散的综合影响。使用有效 ZLK 倾角窗口的半解析计算，结合恒星飞越的数值模拟，我们获得了这种形成场景中 HJ 发生率的解析估计。