Where Do Hot Jupiters Come from? Revisiting Tidal Disruption and Ejection in High-eccentricity Migration

The origin of hot Jupiters remains a key open question. In the high-eccentricity migration scenario, traditional coreless models predict a strict tidal exclusion zone within ∼2.7 tidal radii r _t , in which giant planets are either fully disrupted or ejected. We revisit this limit using three-dimensional hydrodynamic simulations of giant planets with realistic dense cores (10–20 M _⊕ ). We find that even a few-percent-mass core fundamentally changes the outcome: no total disruptions occur within the previously suggested destruction zone (≲2.7 r _t ). For deep encounters (≲1.7 r _t ) planets suffer severe envelope stripping and are either progressively downsized to dense remnants or ejected after a few close encounters, possibly contributing to the free-floating planet population. In the intermediate regime (∼1.7–2.0, r _t ), planets experience significant partial mass loss over repeated encounters. For wider encounters (≳2.0 r _t ), mass loss is minimal, allowing the planets to gradually circularize into hot Jupiters. Furthermore, we show that for highly eccentric orbits ( e ≳ 0.9), the change in specific orbital energy Δ E _orb depends primarily on periastron distance r _p rather than semimajor axis a . This enables us to extrapolate our fixed- a results across a broad ( a , e ) parameter space and identify a well-defined tidal ejection zone whose sharp boundaries converge asymptotically. Our results highlight the crucial role of planetary internal structure in high-eccentricity migration and suggest that the survival and transformation of core-bearing giant planets are far more common than previously thought.