Active asteroid · (7968) Elst–Pizarro
7968 Elst–Pizarro
The prototype main-belt comet — an object on an ordinary asteroid-belt orbit that repeatedly develops a comet-like tail, carrying both an asteroid number and a comet designation.
Comets
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 1.65646 au
| Semi-major axis | 3.163982 ± 1.0741e-8 au | NASA JPL · calculated |
| Eccentricity | 0.155212 ± 2.8525e-8 | NASA JPL · calculated |
| Perihelion distance | 2.672894 ± 8.8985e-8 au | NASA JPL · calculated |
| Aphelion distance | 3.65507 ± 1.2408e-8 au | NASA JPL · calculated |
| Inclination | 1.390016 ± 3.8160e-6 deg | NASA JPL · calculated |
| Longitude of ascending node | 160.085766 ± 0.000138 deg | NASA JPL · calculated |
| Argument of perihelion | 131.956307 ± 0.000139 deg | NASA JPL · calculated |
| Orbital period | 2,056 ± 1.0467e-5 d | NASA JPL · calculated |
| Diameter | 3.2 ± 0.2 km | NASA JPL · catalogued |
| Geometric albedo | 0.06 ± 0.02 | NASA JPL · estimated |
| Rotation period | 3.471 h | NASA JPL · catalogued |
| Absolute magnitude (H) | 15.65 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, 1096 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, 1096 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, 1096 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, 1096 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, 1096 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, 1096 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, 1096 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, 1096 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, 1096 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, 1096 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, 1096 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, 1096 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.
Classification & origin
Class:Main-Belt Comets
Knowledge connections
- Member of groupMain-Belt Comets
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.