Comet Encke

2P/Encke

Discovery
Discovered by	Pierre Méchain; Johann Franz Encke (recognition of periodicity)
Discovery date	17 January 1786[1]
Designations
Alternative designations	1786 I; 1795; 1805; 1819 I; 1822 II; 1825 III; 1829; 1832 I; 1835 II; 1838; 1842 I; 1845 IV
Orbital characteristics
Epoch	2023 September 13[1]
Aphelion	4.098 AU
Perihelion	0.33960 AU
Semi-major axis	2.2187 AU
Eccentricity	0.8469
Orbital period	3.30 yr 3y 3m 27d (perihelion to perihelion)
Max. orbital speed	69.5 km/s (250,000 km/h)[2]
Inclination	11.34°
Argument of periapsis	187.3°
Last perihelion	22 October 2023[2]
Next perihelion	9 February 2027[citation needed]
TJupiter	3.025[1]
Earth MOID	0.17 AU (25 million km)[1]
Physical characteristics
Dimensions	4.8 km[1]

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,^[3] 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 4.8 km.^[1]