Trans-Neptunian Object 2003 UB313 vying with Pluto in Size

IAU Circular 8577 announced on July 29, 2005 the discovery of three relatively bright Trans-Neptunian objects by M. E. Brown, C. A. Trujillo, and D. Rabinowitz using the Palomar 1.2-m Schmidt telescope. One of these objects, 2003 UB313, appears to be as big as or slightly bigger than the planet Pluto. The object's distance from the Sun varies between about 38 AU (1 AU is 150 million kilometers) and 98 AU, which is also close to its current distance. Its orbit has a period of about 560 years and is even more elongated and more inclined than the orbit of Pluto (let us here make a link to: http://www.gps.caltech.edu/~mbrown/planetlila/index.html).

Definition of a Planet

The IAU will publish beginning of September 2006 the definition of a "Planet".