Jupiter-family comet
Comet Hartley 2
A small but hyperactive comet whose peanut-shaped nucleus, spewing jets of carbon dioxide, was visited by Deep Impact in 2010.
- Distance from Earth today
- 1.03 billion km6.865 AU · light: 57 min 6 s
- Distance from the Sun today
- 878.6 million km5.873 AU
- As of
- 2 November 2026position from NASA/JPL orbital elements
Where it is today
Top view of the plane of Earth’s orbit, compressed distance scale. Open on the big map with the time slider →
Facts
- Diameter
- 1.60 km
- Rotation period
- 18.1 h
- Semi-major axis
- 3.477 AU (520.1 million km)
- Perihelion
- 1.067 AU
- Aphelion
- 5.886 AU
- Orbital period
- 6.48 years
- Orbital eccentricity
- 0.693
- Orbital inclination
- 13.6°
- Last perihelion
- 11 October 2023
- Next perihelion
- 5 April 2030
- Minimum orbit distance from Earth’s orbit (MOID)
- 0.073 AU (10.96 million km)
Source of the figures: JPL Small-Body Database (public domain).
Discovery: 1986 – Malcolm Hartley
Description
Hartley 2 was discovered by Malcolm Hartley at Siding Spring Observatory in Australia in 1986. In November 2010 the Deep Impact spacecraft, reused for its EPOXI extended mission, flew past it and found a small, peanut-shaped nucleus that was unusually active for its size. Jets driven by carbon dioxide ice were dragging chunks of water ice off the surface, creating a cloud of icy debris around the nucleus. Observations from the Herschel Space Observatory showed that its water has a hydrogen isotope ratio similar to Earth's oceans, reviving the debate over whether comets helped supply Earth's water.