Following a Kuiper belt Object
Buffy (designated 2004 XR190 in the International Astronomical Union's official announcement), was discovered during routine operation of the Canada-France Ecliptic Plane Survey (CFEPS) running as part of the Legacy Survey on the Canada France Hawaii Telescope.
Buffy was discovered in the mountain of Legacy Survey data (about 50 gigabytes per hour of operation) by powerful computers combing through the telescopic images and producing hundreds of candidates. Astronomers then sift through the candidates to identify the distant comets.
"It was quite bright compared to the usual Kuiper belt objects we find", said Dr. Jones, "but what was more interesting was how far away it was."
Astronomer Dr. Lynne Jones of the University of British Columbia (now at University of Washington) was the first to lay eyes on the new object, as she completed the initial identification in the course of processing CFEPS data from December 2004.
``We immediately realized that the object was about twice as far as Neptune from the Sun and that its orbit was potentially nearly circular,'' said UBC professor Brett Gladman, who noticed the unusual nature of the object when determining its orbit, ``but further observations were required.''
The object's brightness implies it is likely between 500 and 1000 kilometers (300 to 600 miles) in diameter. Buffy is thus a very large Kuiper belt object, but about half a dozen are larger.
One to two years of observations of a Kuiper belt object are required before their orbits can be precisely measured. The first additional observations of Buffy came in October 2005 when Dr. Brett Gladman and Dr. Phil Nicholson of Cornell University used the Hale 5-meter telescope to re-observe the object.
Measurement of Buffy's new position verified that the orbit was not only extremely tilted, inclined at 47 degrees to the plane of the planetary system (essentially tying the record for a Kuiper belt object) but confirmed that Buffy was unlike any other previously-known object because it was on a nearly circular orbit while at a very large distance.
"To find the first known object with a nearly circular orbit beyond 50 AU is indeed intriguing," reacted Brian Marsden, director of the MPC.
More measurements of Buffy's position on images from telescopes at Kitt Peak National Observatories in Arizona by team members Dr. Joel Parker (Southwest Research Institute), as well as Dr. JJ Kavelaars (National Research Council of Canada, Herzberg Institute of Astrophysics) and Mr. Wes Fraser (University of Victoria), through November 2005 refined the estimate for Buffy's closest approach to the Sun. Additional observations, to further confirm the orbit, where then provided by the CFHT Legacy Survey project.
The team have reported their find to the Minor Planet Center, the clearinghouse for astronomical measurements of new minor planets.