Bound (Elliptical) Orbit
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.
Definition
Eccentricity below 1 — a closed, repeating orbit; the object is bound to the Sun.
The eccentricity ladder
Orbits run from bound and elliptical, through the parabolic boundary, to the strongly hyperbolic trajectories of interstellar objects.
Sources
The primary and reference sources this topic draws on.
- NASA JPLJet Propulsion Laboratory / Solar System Dynamics
Orbital data, ephemerides, and small-body parameters for planets, asteroids, and comets.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.