Tracing comet 67P/Churyumov-Gerasimenko back to its likely origins
ESA's Rosetta unmanned deep-space probe may have made comet 67P/Churyumov-Gerasimenko its final resting place, but researchers are tracing things back to where it all began. Using statistical computer analysis, astronomers Mattia Galiazzo and Paul Wiegert of Western University in Ontario, Canada have reconstructed the orbit of the comet as it's changed over hundreds of thousands of years. Their findings indicate the comet is a recent visitor to the inner Solar System and had its origins out in the Kuiper Belt beyond Pluto.
According to the team, comet 67P only showed up in our part of the Solar System about 10,000 years ago and is therefore a Jupiter Family comet. That is, a comet that originates much farther away from the Sun, but whose orbit has been disturbed by Jupiter's gravity, knocking it into an eccentric orbit. Galiazzo and Wiegert say such comets have unstable orbits and usually only hang around the inner Solar System for about 12,000 years before departing again for the outer regions.
Jupiter Family comets are believed to come from the Kuiper Belt, which is about 2.5 to 4.5 billion miles (4.5 to 7.4 billion km) from the Sun. The scientists contend 67P spent millions of years at the outer edge of the Belt – twice the distance of Neptune from the Sun or about 5 billion mi (9 billion km). If this is the case, it could contain material dating back to the birth of the Solar System.
"These results come from computations of the comet's orbit from the present to the past, which is computationally difficult due to the chaosity of the orbit caused by close encounters with Jupiter," says Galiazzo. "Thus the details are obscure but we can establish a dynamical pathway from its current orbit back to the Kuiper Belt."
The research was presented at the joint 48th annual meeting of the Division for Planetary Sciences of the American Astronomical Society (AAS) and 11th annual European Planetary Science Congress in Pasadena, California.
The video below shows how the orbit of 67P has changed over the eons.
Source: Western University