New planet discovered in solar system
This time-lapse image, provided by NASA's Jet Propulsion Laboratory, of a newfound planet in our solar system, called 2003 UB313, was taken on Oct. 21, 2003, using the Samuel Oschin Telescope at the Palomar Observatory near San Diego, Calif. The planet, circled, is seen moving across a field of stars. The three images were taken about 90 minutes apart. Scientists did not discover the planet until Jan. 8.
Astronomers announced Friday that they have found a lump of rock and ice that is larger than Pluto and the farthest known object in the solar system.
The discovery will likely rekindle debate over the definition of "planet" and whether Pluto still merits the designation. The new object — as yet unnamed, but temporarily known as 2003 UB313 — is now 9 billion miles away from the sun, or 97 times as far away as the Earth and about three times Pluto's current distance from the sun. Its 560-year elliptical orbit brings it as close as 3.3 billion miles. Pluto's orbit ranges between 2.7 billion and 4.6 billion miles.
The astronomers do not have an exact size for the new planet, but its brightness and distance tell them that it is larger than Pluto, the smallest of the nine known planets.
"It is guaranteed bigger than Pluto," said Michael Brown, a professor of planetary astronomy at Caltech and a member of the team that made the discovery. "Even if it were 100 percent reflective, it would be larger than Pluto. It can't be more than 100 percent reflective."
The discovery was made Jan. 8 at Palomar Observatory in California. Brown and the other members of the team — Chadwick Trujillo of the Gemini Observatory in Hawaii and David Rabinowitz of Yale University — found then that they had, unknowingly, taken images of the planet, using the observatory's telescope, as far back as 2003.
Brown said they had a name they have proposed for the planet, but did not want to disclose it publicly until it had been formally approved by the International Astronomical Union. "We have a name we really like, and we want it to stick," he said.
Informally, the astronomers have been calling it "Xena" after the television series about a Greek warrior princess, which was popular when the astronomers began their systematic sweep of the sky in 2000. "Because we always wanted to name something Xena," Brown said.