Comet Encke
Comet Encke photographed from the Kitt Peak Observatory on 5 January 1994. | |
| Discovery | |
|---|---|
| Discovered by |
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| Discovery date | 17 January 1786 |
| Designations | |
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| Orbital characteristics | |
| Epoch | 5 May 2025 (JD 2460800.5) |
| Observation arc | 239.45 years |
| Number of observations | 6,016 |
| Aphelion | 4.097 AU |
| Perihelion | 0.339 AU |
| Semi-major axis | 2.218 AU |
| Eccentricity | 0.84711 |
| Orbital period | 3.304 years |
| Max. orbital speed | 69.5 km/s (250,000 km/h) |
| Inclination | 11.344° |
| 334.01° | |
| Argument of periapsis | 187.28° |
| Mean anomaly | 167.19° |
| Last perihelion | 22 October 2023 |
| Next perihelion | 10 February 2027 |
| TJupiter | 3.022 |
| Earth MOID | 0.168 AU |
| Jupiter MOID | 0.907 AU |
| Physical characteristics | |
Mean diameter | 4.86 km (3.02 mi) |
| 11.083±0.003 hours | |
| 0.046 | |
| (V–R) = 0.44±0.06 | |
| Comet total magnitude (M1) | 15.6 |
Comet Encke /ˈɛŋki/, or Encke's Comet (official designation: 2P/Encke), is a periodic comet that completes an orbit of the Sun once every 3.3 years. (This is the shortest period of a reasonably bright comet; the faint main-belt comet 311P/PanSTARRS has a period of 3.2 years.) Encke was first recorded by Pierre Méchain on 17 January 1786, but it was not recognized as a periodic comet until 1819 when its orbit was computed by Johann Franz Encke. Like Halley's Comet, it is unusual in its being named after the calculator of its orbit rather than its discoverer. Like most comets, it has a very low albedo, reflecting only 4.6% of the light its nucleus receives, although comets generate a large coma and tail that can make them much more visible during their perihelion (closest approach to the Sun). The diameter of the nucleus of Encke's Comet is 4.86 km (3.02 mi).