67P/Churyumov-Gerasimenko

67P/Churyumov-Gerasimenko is the designation of a comet with a current orbital period of 6.6 years. It is the destination of the European Space Agency's Rosetta spacecraft mission, launched on March 2, 2004.

Comet parameters

Diameter:	4 km
Orbital period:	6.6 years
Orbital eccentricity:	0.6
Orbital inclination:	7.1 degrees
Discovered:	1969

Hubble pictures

As preparation for the Rosetta mission Hubble Space Telescope pictures taken on March 12, 2003, were closely analyzed. An overall 3-D model was constructed and computer generated images from various view angles are shown in this composite picture.

Discovery

This comet was discovered by Klim Ivanovic Churyumov who examined a photograph exposed for periodic comet 32P/Comas Solá by Svetlana Ivanovna Gerasimenko on September 11, 1969 at the Alma-Ata Astrophysical Institute. He found a cometary object near the edge of the plate, but assumed that this was Comas Solá. After returning to his home institute in Kiev, all photographic plates were investigated closely. About a month after the photograph was taken (October 22), it was discovered that the object could not be the assumed comet, because it was about 1.8 degrees off the expected position. Further scrutiny produced a faint picture of Comas Solá at its expected position on the plate, thus proving that the other object was a newly discovered comet.

Orbital history

Churyumov-Gerasimenko has a rather interesting orbital history. Comets are regularly nudged from one orbit to another when they encounter Jupiter or Saturn in close proximity. For this comet it was calculated, that before the year 1840 it was completely unobservable due to its perihelion distance of about 4.0 AU. At this time Jupiter shifted that distance to about 3.0 AU. Later on, in the year 1959, another encounter with Jupiter pushed it to about 1.28 AU, where it is now.

References

Preprint at astro-ph

External links

Detailed description of 67P with light curves and pictures