Minor planet · Trojan · (617) Patroclus
617 Patroclus
A binary Jupiter Trojan trailing Jupiter at the L5 'Trojan camp', and the final flyby target of NASA's Lucy mission.
Asteroidsbinary system
Orbit & physical parameters
Osculating orbit and physical parameters from the NASA JPL Small-Body Database · Jupiter Trojan · epoch 2026-06-09 (JD 2461200.5 TDB) · Earth MOID 3.52681 au
| Semi-major axis | 5.205975 ± 3.1680e-8 au | NASA JPL · calculated |
| Eccentricity | 0.139147 ± 1.4474e-8 | NASA JPL · calculated |
| Perihelion distance | 4.48158 ± 9.6721e-8 au | NASA JPL · calculated |
| Aphelion distance | 5.93037 ± 3.6089e-8 au | NASA JPL · calculated |
| Inclination | 22.063591 ± 9.1285e-7 deg | NASA JPL · calculated |
| Longitude of ascending node | 44.349689 ± 2.5054e-6 deg | NASA JPL · calculated |
| Argument of perihelion | 308.837726 ± 4.4823e-6 deg | NASA JPL · calculated |
| Orbital period | 4,339 ± 3.9603e-5 d | NASA JPL · calculated |
| Diameter | 140.362 ± 0.868 km | NASA JPL · catalogued |
| Geometric albedo | 0.047 ± 0.003 | NASA JPL · estimated |
| Rotation period | 102.8 h | NASA JPL · catalogued |
| Absolute magnitude (H) | 8.22 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 Davide Farnocchia, 6339 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 Davide Farnocchia, 6339 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 Davide Farnocchia, 6339 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 Davide Farnocchia, 6339 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 Davide Farnocchia, 6339 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 Davide Farnocchia, 6339 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 Davide Farnocchia, 6339 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 Davide Farnocchia, 6339 obs · retrieved 2026-07-11
- Diameter: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · phys_par · phys.diameter · catalogued value · JPL solution by Davide Farnocchia, 6339 obs · retrieved 2026-07-11
- Geometric albedo: Jet Propulsion Laboratory / Solar System Dynamics · JPL SBDB · phys_par · phys.albedo · Bayesian estimate · JPL solution by Davide Farnocchia, 6339 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 Davide Farnocchia, 6339 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 Davide Farnocchia, 6339 obs · retrieved 2026-07-11
Orbital elements are a calculated JPL orbit-determination fit, all referred to the single osculating epoch above (solution by Davide Farnocchia); each carries its own uncertainty. Fields the database did not provide are omitted, never invented.
Exploration
Targeted by:Lucy
Populations
Knowledge connections
- Member of groupTrojan Camp (L5)
- Member of groupJupiter Trojans
- In orbital resonance1:1 resonance with Jupiter
- TargetsLucy
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.