Hartley 2
A small, hyperactive Jupiter-family comet flown past by NASA's EPOXI mission (the repurposed Deep Impact spacecraft) in 2010.
Imagery
Almost There at Comet Hartley 2
This close-up view of comet Hartley 2 was taken as NASA EPOXI mission approached the comet at 6:59 a.m.
2010
NASA/JPL-Caltech/UMD · NASA media (public domain)
Orbit & physical parameters
Osculating orbit and physical parameters from the NASA JPL Small-Body Database · Jupiter-family Comet · near-Earth · epoch 2015-05-10 (JD 2457152.5 TDB) · Earth MOID 0.0732373 au
| Semi-major axis | 3.475652 ± 2.1140e-7 au | NASA JPL · calculated |
| Eccentricity | 0.693598 ± 1.9437e-8 | NASA JPL · calculated |
| Perihelion distance | 1.064947 ± 3.8000e-8 au | NASA JPL · calculated |
| Aphelion distance | 5.886358 ± 3.5802e-7 au | NASA JPL · calculated |
| Inclination | 13.599468 ± 1.9866e-6 deg | NASA JPL · calculated |
| Longitude of ascending node | 219.742174 ± 9.2179e-6 deg | NASA JPL · calculated |
| Argument of perihelion | 181.321844 ± 9.5589e-6 deg | NASA JPL · calculated |
| Orbital period | 2,367 ± 0.000216 d | NASA JPL · calculated |
| Diameter | 1.6 km | NASA JPL · catalogued |
| Rotation period | 18.1 h | 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, 8768 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, 8768 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, 8768 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, 8768 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, 8768 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, 8768 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, 8768 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, 8768 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, 8768 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, 8768 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
Classification & origin
Knowledge connections
- Member of groupJupiter-Family Comets
- Source reservoirScattered Disc
- Visited byEPOXI
- Visited byEPOXI
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.