Encke-type comet

Encke-type comet

At the shorter orbital period extreme, Encke's Comet has an orbit that does not reach the orbit of Jupiter, and is known as an Encke-type comet. They have aphelion less than 4 AU. Short-period comets with orbital periods less than 20 years and low inclinations (up to 30 degrees) to the ecliptic are called traditional Jupiter-family comets (JFCs). Those like Halley, with orbital periods of between 20 and 200 years and inclinations extending from zero to more than 90 degrees, are called Halley-type comets (HTCs). As of July 2025 there are 74 known Encke-type comets (six of which are classified as near-Earth objects (NEOs)), 109 HTCs (36 of which are NEOs), and 815 JFCs (153 of which are NEOs).