Comet 67P/Churyumov–Gerasimenko
The rubber-duck-shaped comet that Rosetta orbited for two years and Philae landed on.
Key facts
- Designation
- 67P/Churyumov–Gerasimenko
- Type
- Jupiter-family comet
- Orbital period
- about 6.4 years
- Closest to the Sun
- 1.24 AU (about 185 million km)
- Farthest from the Sun
- 5.7 AU, near Jupiter's orbit
- Tilt of orbit
- about 7°
- Nucleus
- two lobes; the larger about 4.1 × 3.3 × 1.8 km, the smaller about 2.6 × 2.3 × 1.8 km
- Discovered
- on a photograph taken by Svetlana Gerasimenko in Alma-Ata on 11 September 1969; found on the plate by Klim Churyumov in Kyiv in October 1969
- Returns
- at perihelion in November 2021; next in 2028
Orbit
67P is a Jupiter-family comet with a period of six and a half years. Until 1959 it stayed farther out; on 4 February that year it passed close to Jupiter, which pulled its nearest point to the Sun in from about 2.7 AU to about 1.3 AU. That made it bright enough to discover ten years later.
Size and nature
Rosetta's cameras showed two lobes joined by a narrow neck, likely two bodies that touched gently long ago. Its density is only about half that of water, so the nucleus is about 70 per cent empty space: a loose pile of ice and dust. It turns every 12.4 hours. The surface has cliffs, pits, boulders and smooth plains of dust, and jets of gas switch on as each patch turns into sunlight.
History
Svetlana Gerasimenko photographed a different comet at Alma-Ata in September 1969. When Klim Churyumov examined the plates in Kyiv, he found another comet near the edge, the one now named after them both. In the 2000s it was chosen as Rosetta's new target after a launch delay meant the original target, 46P/Wirtanen, could no longer be reached.
Missions
Rosetta arrived on 6 August 2014 and orbited the comet for over two years, watching it wake as it neared the Sun and calm again as it left. On 12 November 2014 the lander Philae touched down, the first landing on a comet. It bounced, came to rest in shadow and ran out of power after about 60 hours, though not before sending data. Rosetta found water with about three times the deuterium of Earth's oceans, which makes comets like 67P unlikely to be the main source of Earth's water. It detected the amino acid glycine, phosphorus and a surprising amount of molecular oxygen. On 30 September 2016 Rosetta itself was set down on the comet, ending the mission.
Space missions
- Rosetta and Philae The first spacecraft to orbit a comet and to land on one.
Key dates
| Date | What happened |
|---|---|
| 11 September 1969 | Svetlana Gerasimenko took the photograph on which Comet 67P was later discovered. |
| 6 August 2014 | Rosetta arrived at Comet 67P/Churyumov–Gerasimenko. |
| 12 November 2014 | Philae landed on Comet 67P, the first landing on a comet. |
| 30 September 2016 | Rosetta ended its mission by descending onto Comet 67P. |
Did you know?
Philae was finally spotted in a crack in the comet's surface only a month before the mission ended.
67P's density is less than that of a pumice stone.
The dust grains Rosetta collected were fluffy aggregates, like the interplanetary dust particles caught in Earth's stratosphere.