{"dataset":{"slug":"trajectory-classes","title":"Trajectory Classes","description":"Orbital-trajectory classes by eccentricity — bound, near-parabolic, hyperbolic, and interstellar.","version":"1.0.0","lastGenerated":"2026-06-29","license":"CC BY-SA 4.0","entityCount":4,"sources":["jpl","nasa"]},"entities":[{"id":"trajectory_class:bound-orbit","name":"Bound (Elliptical) Orbit","type":"trajectory_class","domain":"science","description":"An orbit with eccentricity below 1: the object is gravitationally bound to the Sun and returns. Planets, asteroids, and periodic comets all follow bound elliptical orbits. A bound orbit is the baseline against which unbound, hyperbolic trajectories are recognised.","entryPath":"/interstellar-objects/trajectory/bound-orbit"},{"id":"trajectory_class:hyperbolic-ejection","name":"Hyperbolic Orbit (Solar-System Origin)","type":"trajectory_class","domain":"science","description":"An orbit with eccentricity just above 1, produced when a Solar-System comet is perturbed by a planet (usually Jupiter) onto an escape trajectory. The object is leaving the Solar System, but it formed here — the small excess over e = 1 is a slingshot effect, not evidence of an interstellar origin.","entryPath":"/interstellar-objects/trajectory/hyperbolic-ejection"},{"id":"trajectory_class:interstellar-hyperbolic","name":"Interstellar Hyperbolic Trajectory","type":"trajectory_class","domain":"science","description":"A strongly hyperbolic trajectory — eccentricity well above 1 with a large excess velocity relative to the Sun — that cannot be produced by planetary perturbations. This is the signature of an interstellar object: a body that entered the Solar System already unbound, from another star system, and will leave on the same path. 1I/ʻOumuamua, 2I/Borisov, and 3I/ATLAS all follow such trajectories.","entryPath":"/interstellar-objects/trajectory/interstellar-hyperbolic"},{"id":"trajectory_class:near-parabolic","name":"Near-Parabolic Orbit","type":"trajectory_class","domain":"science","description":"An orbit with eccentricity very close to 1 — the boundary between bound and unbound. Long-period comets falling in from the Oort cloud on their first passage follow near-parabolic orbits. A near-parabolic orbit signals a distant Solar-System origin, not an interstellar one.","entryPath":"/interstellar-objects/trajectory/near-parabolic"}]}