Thatcher
A long-period comet on a roughly 415-year orbit, the parent body of the Lyrid meteor shower seen each April.
Orbit & physical parameters
Osculating orbit and physical parameters from the NASA JPL Small-Body Database · Comet · epoch 1861-05-25 (JD 2400920.5 TDB)
| Semi-major axis | 55.681887 au | NASA JPL · calculated |
| Eccentricity | 0.983465 | NASA JPL · calculated |
| Perihelion distance | 0.9207 au | NASA JPL · calculated |
| Aphelion distance | 110.443074 au | NASA JPL · calculated |
| Inclination | 79.7733 deg | NASA JPL · calculated |
| Longitude of ascending node | 31.8674 deg | NASA JPL · calculated |
| Argument of perihelion | 213.4496 deg | NASA JPL · calculated |
| Orbital period | 151,579 d | NASA JPL · calculated |
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 Oppolzer, 187 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 Oppolzer, 187 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 Oppolzer, 187 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 Oppolzer, 187 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 Oppolzer, 187 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 Oppolzer, 187 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 Oppolzer, 187 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 Oppolzer, 187 obs · retrieved 2026-07-11
Orbital elements are a calculated JPL orbit-determination fit, all referred to the single osculating epoch above (solution by Oppolzer); each carries its own uncertainty. Fields the database did not provide are omitted, never invented.
Classification & origin
Meteor shower: Parent of the annual Lyrid meteor shower.
Knowledge connections
- Member of groupLong-Period Comets
- Source reservoirOort Cloud
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.