| Object type | Jupiter-family comet; contact binary (two lobes joined by a neck)[4] |
|---|---|
| Discovered | Oct. 22, 1969 — Klim Churyumov, on a photographic plate by Svetlana Gerasimenko[1] |
| Size | ≈ 4.3 × 4.1 km at its longest and widest[4] |
| Mass | ≈ 10 billion tonnes[4] |
| Density | ≈ 0.53 g/cm³ — about half the density of water[3] |
| Rotation period | ≈ 12.4 hours (12.76 h before 2009)[4] |
| Orbital period | ≈ 6.4 years[3] |
| Distance from Sun | ≈ 1.24 AU (perihelion) to 5.68 AU (aphelion)[3] |
| Orbital inclination | ≈ 7.0°[3] |
| Next perihelion | April 9, 2028[4] |
| Surface regions | 26 regions, named after Egyptian deities[4] |
| Spacecraft | ESA Rosetta (orbited 2014–2016) and Philae lander (landed Nov. 12, 2014)[2] |
Discovery
The comet was discovered on October 22, 1969, at the Alma-Ata Observatory, when Klim Churyumov examined a photographic plate exposed by Svetlana Gerasimenko on September 11, 1969, while she was observing a different comet.[1] The comet carries both of their names.
A cosmic rubber duck
67P has two lobes joined by a narrower neck — a shape often compared to a rubber duck. The larger lobe is about 4.1 × 3.3 × 1.8 km and the smaller about 2.6 × 2.3 × 1.8 km.[4] Exposed layers point in different directions in each lobe, indicating that two objects gently collided and fused to form a contact binary.[4]
The nucleus is very porous, with a density about half that of water.[3][1]
Orbit and history
67P is a Jupiter-family comet that circles the Sun about every 6.4 years, between about 1.24 and 5.68 AU.[3] Its orbit has been reshaped by Jupiter: an encounter in 1840 sent it deeper into the inner Solar System, and another in 1959 moved its perihelion inward to about 1.3 AU, close to where it remains today.[1][4]
Rosetta and Philae
ESA's Rosetta launched on March 2, 2004, and after a ten-year journey reached 67P on August 6, 2014, becoming the first spacecraft to orbit a comet.[5] On November 12, 2014, its Philae lander made the first landing on a comet.[5] Rosetta followed the comet through its closest approach to the Sun and ended its mission on September 30, 2016, with a controlled descent onto the surface.[5][1]
What we learned
NASA lists among Rosetta's key findings the first detection of molecular nitrogen and molecular oxygen at a comet, exposed water ice on the surface, and the amino acid glycine and the element phosphorus.[1] When heated by the Sun, the comet is thought to emit about twice as much dust as gas.[1]
Read more about comets and space
Rosetta's story — a decade-long chase, a bouncing lander, a comet shaped like a duck — is the kind of adventure that makes a great book. Try our space book finder for picks for every age.
Read more
Rosetta's ten-year chase to catch a comet
Earth and Mars flybys, two asteroids, 31 months of hibernation — and the first orbit around a comet.
Read →Philae, the bouncing lander
How the first comet landing went wrong, went right, and ended in a dark crevice found two years later.
Read →What Rosetta found at Comet 67P
A duck-shaped contact binary, oxygen, glycine and a twist in the story of Earth's water.
Read →Sources
- 67P/Churyumov-Gerasimenko — NASA Science
- Rosetta — European Space Agency
- Small-Body Database Lookup: 67P/Churyumov-Gerasimenko — NASA JPL Solar System Dynamics
- 67P/Churyumov–Gerasimenko — Wikipedia
- Rosetta (spacecraft) — Wikipedia
- Philae (spacecraft) — Wikipedia
- Planetary Fact Sheet (orbit comparison) — NASA NSSDCA
Figures are rounded; where sources differ we note it. Spotted an error? Tell us.