Minor planet · Main belt · (221) Eos
221 Eos
The parent body of the Eos family, a large K-type asteroid in the outer main belt.
Asteroids
Orbit & physical parameters
Osculating orbit and physical parameters from the NASA JPL Small-Body Database · Main-belt Asteroid · epoch 2026-06-09 (JD 2461200.5 TDB) · Earth MOID 1.6975 au
| Semi-major axis | 3.011901 ± 3.9113e-9 au | NASA JPL · calculated |
| Eccentricity | 0.100888 ± 1.9040e-9 | NASA JPL · calculated |
| Perihelion distance | 2.708036 ± 8.2934e-9 au | NASA JPL · calculated |
| Aphelion distance | 3.315766 ± 4.3059e-9 au | NASA JPL · calculated |
| Inclination | 10.89072 ± 1.2692e-7 deg | NASA JPL · calculated |
| Longitude of ascending node | 141.711 ± 6.8853e-7 deg | NASA JPL · calculated |
| Argument of perihelion | 192.428955 ± 1.5550e-6 deg | NASA JPL · calculated |
| Orbital period | 1,909 ± 3.7190e-6 d | NASA JPL · calculated |
| Diameter | 95.469 ± 1.684 km | NASA JPL · catalogued |
| Geometric albedo | 0.166 ± 0.013 | NASA JPL · estimated |
| Rotation period | 10.443 h | NASA JPL · catalogued |
| Absolute magnitude (H) | 7.71 mag | NASA JPL · catalogued |
Full field-level provenance
- Semi-major axis: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · orbit.elements · a · JPL orbit determination (least-squares fit to the observation arc) · calculated · JPL solution by Otto Matic, 5689 obs · retrieved 2026-07-11
- Eccentricity: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · orbit.elements · e · JPL orbit determination (least-squares fit to the observation arc) · calculated · JPL solution by Otto Matic, 5689 obs · retrieved 2026-07-11
- Perihelion distance: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · orbit.elements · q · JPL orbit determination (least-squares fit to the observation arc) · calculated · JPL solution by Otto Matic, 5689 obs · retrieved 2026-07-11
- Aphelion distance: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · orbit.elements · ad · JPL orbit determination (least-squares fit to the observation arc) · calculated · JPL solution by Otto Matic, 5689 obs · retrieved 2026-07-11
- Inclination: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · orbit.elements · i · JPL orbit determination (least-squares fit to the observation arc) · calculated · JPL solution by Otto Matic, 5689 obs · retrieved 2026-07-11
- Longitude of ascending node: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · orbit.elements · om · JPL orbit determination (least-squares fit to the observation arc) · calculated · JPL solution by Otto Matic, 5689 obs · retrieved 2026-07-11
- Argument of perihelion: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · orbit.elements · w · JPL orbit determination (least-squares fit to the observation arc) · calculated · JPL solution by Otto Matic, 5689 obs · retrieved 2026-07-11
- Orbital period: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · orbit.elements · per · JPL orbit determination (least-squares fit to the observation arc) · calculated · JPL solution by Otto Matic, 5689 obs · retrieved 2026-07-11
- Diameter: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · phys_par · phys.diameter · catalogued value · JPL solution by Otto Matic, 5689 obs · retrieved 2026-07-11
- Geometric albedo: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · phys_par · phys.albedo · Bayesian estimate · JPL solution by Otto Matic, 5689 obs · retrieved 2026-07-11
- Rotation period: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · phys_par · phys.rot_per · catalogued value · JPL solution by Otto Matic, 5689 obs · retrieved 2026-07-11
- Absolute magnitude (H): Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · phys_par · phys.H · catalogued value · JPL solution by Otto Matic, 5689 obs · retrieved 2026-07-11
Orbital elements are a calculated JPL orbit-determination fit, all referred to the single osculating epoch above (solution by Otto Matic); each carries its own uncertainty. Fields the database did not provide are omitted, never invented.
Populations
Knowledge connections
- Member of familyEos family
- Member of groupMain Asteroid Belt
Sources
The primary and reference sources this topic draws on.
- 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.
- NASA JPLJet Propulsion Laboratory / Solar System Dynamics
Orbital data, ephemerides, and small-body parameters for planets, asteroids, and comets.