Rosetta's target: comet 67P/Churyumov-Gerasimenko
There are hundreds of comets flying around the Solar
System, each of them a potential target for ESA's comet-chasing Rosetta
mission. As the mission took shape, the science team was faced with the
difficult task of sifting through these candidates until they
identified a handful of suitable objects.
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Rosetta's twelve-year journey in space. Credit: ESA. (Click here for further details and larger versions of this video.) |
Of particular interest were comets that had been observed over at
least several orbits of the Sun, and which were known to be fairly
active. Ideally, they had to follow orbital paths near the ecliptic
plane, so that a rendezvous, prolonged survey and landing would be
easier to achieve. Furthermore, the comet's flight into the inner Solar
System had to coincide with the mission timeline of Rosetta, so that
they both arrived in the right place at the right time for the historic
rendezvous.
The favoured target for Rosetta was the periodic comet 46P/Wirtanen,
but, after the launch was delayed, another regular visitor to the inner
Solar System, 67P/Churyumov-Gerasimenko, was selected as a suitable
replacement.
Like all comets, Churyumov-Gerasimenko is named after its
discoverers. It was first observed in 1969, when several astronomers
from Kiev visited the Alma-Ata Astrophysical Institute in Kazakhstan to
conduct a survey of comets.
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Astronomer Klim Churyumov, ESA Director General Jean-Jacques Dordain and astronomer Svetlana Gerasimenko, pictured in 2004. Credit: Christian Sotty |
On 20 September, Klim Churyumov was examining a photograph of comet
32P/Comas Solá, taken by Svetlana Gerasimenko, when he noticed another
comet-like object. After returning to Kiev, he studied the plate very
carefully and eventually realised that they had indeed discovered a new
comet.
Comet 67P is one of numerous short period comets which have orbital
periods of less than 20 years and a low orbital inclination. Since their
orbits are controlled by Jupiter's gravity, they are also called
Jupiter Family comets
http://sci.esa.int/rosetta/14615-comet-67p/
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