Encke races around the Sun every 3.3 years - the shortest period of any known comet - looping from inside Mercury’s orbit out to the asteroid belt. Thousands of close solar passes have baked away much of its ice, leaving a dim, crusted-over comet that shows us how comets age and fade.
Its 3.3-year orbit is the shortest of any known comet.
It has been observed at more returns than any other comet.
Its debris stream produces the slow, fireball-rich Taurid meteors each autumn.
Sunlight switches comets on
Far from the Sun a comet is an inert, frozen rock. Inside roughly 3 AU, sunlight becomes strong enough for water ice to sublimate - to jump straight from solid to gas - and the escaping vapour drags dust off the surface to build the coma and tails. Encke crosses that switch-on line every 3.3 years, and each firing spends a little more of its remaining ice; it is a comet slowly running out of fuel.
Physical characteristics
Diameter
4.8 km
Rotation period
11.1 h
Geometric albedo
0.05
Atmosphere and composition
Atmosphere
A weak coma near perihelion; after thousands of solar passes there is little ice left to boil off.
Composition
Ice-depleted rock and dust; repeated solar roasting has built a dark crust that chokes off most activity.
Orbit and activity
Perihelion distance
0.34 AU
Aphelion distance
4.09 AU
Origin
Jupiter-family comet from the Kuiper belt
Last perihelion
22 Oct 2023
Next perihelion
~Feb 2027
Associated meteor shower
Taurids (October-November)
Discovery
Discovered by
Pierre Méchain
Year
1786
How
its short period was computed in 1819 by Johann Franz Encke, whose name the comet now carries