Hot Jupiters — gas giants orbiting their stars in days — and warm Jupiters — orbiting in weeks to months — have traditionally been explained by different formation mechanisms. Hot Jupiters arrive through tidal circularization of highly eccentric orbits; warm Jupiters park at intermediate distances by gentler means. Two populations, two stories.
The paper on unified formation of hot and warm Jupiters via planet-planet scattering (arXiv: 2603.22409) argues for one mechanism producing both. N-body simulations with tidal dissipation show that scattering between multiple giant planets naturally creates a continuum of outcomes depending on where in the planetary system the scattering occurs.
Cold scattering — at large orbital distances — produces retrograde hot Jupiters: planets flung inward on highly inclined, eccentric orbits that subsequently circularize. Warm scattering — at intermediate distances — creates high-inclination inner warm Jupiters that can either tidally evolve into hot Jupiters or survive at intermediate orbits. The survivors exhibit eccentric but spin-orbit aligned characteristics, matching the observed warm Jupiter population.
A testable prediction: warm Jupiters at larger orbital distances should show a range of spin-orbit alignment angles and frequently host nearby companions with mutual inclinations around 30 degrees — the dynamical signature of the scattering that placed them.
The through-claim: the distinction between hot and warm Jupiters is a distinction in outcome, not in mechanism. The same dynamical process — gravitational scattering between planets — produces both populations, sorted by where in the system the scattering occurred and whether tidal dissipation had time to act. One mechanism, a continuum of endpoints.
2603.22409. Planetary science / hot Jupiters / warm Jupiters / planet-planet scattering / tidal evolution.