* Astronomy

Hum,
Seems that `Lila', and 'Xena' are not the names suggested to the IAU…

Mike Brown has updated his website about 2003UB313 and added some information about the other two big KBOs.

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The Gemini Observatory has obtained a spectrum of 2003UB313
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The observations were obtained on January 25, 2005 by Chad Trujillo, a Gemini staff member who is also on the discovery team for 2003 UB313, the existence of which was formally announced by the Minor Planet Centre in Cambridge, MA on July 29, 2005.


2003 UB313 spectrum (red, obtained at Gemini Observatory) and Pluto (blue). The "dips" characteristic of methane ice are indicated by red arrows and are present in both 2003 UB313 and Pluto.

The research team obtained spectra of the surface of the object also using the NIRI (the near-infrared spectrograph) on the much larger 8 meter Gemini North telescope on Mauna Kea, Hawaii.
The NIRI spectra show strong signatures of methane ice, remarkably similar to the spectrum of Pluto, which is also dominated by methane ice in near-infrared observations.

"We still do not know much about this object, however, it is clear that it is very similar to Pluto in both size and composition, at least upon first glance. If 2003 UB313 ever got close to the sun, all the methane ice would have boiled off immediately. To date, no one has seen methane on any other Kuiper Belt Object, only on Pluto and Neptune's moon Triton." - Chad Trujillo.

The presence of methane ice is unusual in that it indicates a primitive surface that has not likely been heated significantly since the solar system formed 4.5 billion years ago.
The team have also obtained spectra of the smaller mini-planet 2003 EL61. The object shows strong water-ice features, similar to what is seen on the surface of Pluto's moon Charon.

Source

Astronomers announced yesterday that they had found a lump of rock and ice that was larger than Pluto and the farthest known object in the solar system. The discovery will probably 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 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 from 2.7 billion miles to 4.6 billion.

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 E. Brown, a professor of planetary astronomy at the California Institute of Technology 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. Dr. Brown and the other members of the team - Chadwick A. Trujillo of the Gemini Observatory in Hawaii and David L. Rabinowitz of Yale University - then found that they had, unknowingly, taken images of the planet, using the observatory's 48-inch telescope, as far back as 2003.

Last year, the same team announced the discovery of a distant body they named Sedna, which, until the latest discovery, had held the title of farthest known object in the solar system. But Sedna, smaller than Pluto, is on a far stranger, 10,500-year orbit that takes it as far out as 84 billion miles.

Dr. Brown said they had a name they have proposed for the planet, but did not want to disclose it 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," Dr. Brown said.

The astronomers were not able to see 2003 UB313 using NASA's Spitzer Space Telescope, looking for infrared heat emitted by its minus-405 degree surface. That means the planet is less than 1,800 miles in diameter.

What is most surprising is that the orbit of the planet is sharply skewed to most of the rest of the solar system. The orbits of most planets lie close to the same plane as Earth's, known as the ecliptic plane.
The orbit of 2003 UB313 is tilted by 44 degrees.

"That blows my mind," said Harold Levison of the Southwest Research Institute in Boulder, Colo., who was not involved in the discovery.
"Getting something up that high is very hard."

The object is also the third brightest in the Kuiper Belt, a ring of icy bodies that circle beyond Neptune. The new planet could have been easily discovered much sooner if anyone had looked at that part of the sky.

"It's because no one looks that far off the ecliptic," Dr. Brown said.
"No one expects to have an inclination that high."

Another group of astronomers led by José-Luis Ortiz at the Sierra Nevada Observatory in Spain announced Thursday that they had found a large Kuiper Belt object, designated 2003 EL61, that they thought could be Pluto-size or larger. Dr. Brown's group had been observing the same body, but had not announced it, and their observations had already pinpointed a moon circling 2003 EL61, which constrained the size of the body to 30 percent the mass of Pluto and about 70 percent the diameter.

On his Web site, Dr. Brown wrote that the Spanish group deserved credit, saying his group had gambled that no one else would find the planet.
"We were wrong!" he said.

Dr. Brown had still hoped to hold back announcements of 2003 UB313 and another large Kuiper Belt object, 2005 FY9, until October, but his hand was tipped by Brian G. Marsden, director of the International Astronomical Union's Minor Planet Centre in Cambridge, Mass., who urged him to make the announcement as soon as possible.

Dr. Marsden said that it was possible by looking on the Internet at the logs of one of the telescopes Dr. Brown's team had been using to find out where they had been pointed. He had, he said, reason to think someone had done that, "presumably" in preparation for their own observations.

"I was shocked to find this kind of information was available on the Web," Dr. Marsden said.

He urged Dr. Brown to announce his findings. "I was suspicious and I warned him," he said. "We try to give credit where credit is due."

Astronomers suddenly have three large bodies, and with one of them larger than Pluto, they will probably revive their debate over what makes a planet.

Astronomers do not have a formal definition of what a planet is, and many have said that if Pluto had been discovered today, it would not have been called a planet. The first of the smaller Kuiper Belt objects were discovered in 1992, 62 years after Clyde Tombaugh found Pluto.

The Minor Planet Centre proposed in 1999 that Pluto, while maintaining its position among the major planets, be given a designation among the Kuiper Belt objects. The centre dropped the proposal after outcry from those who saw it as a demotion.

Gareth V. Williams, associate director of the centre, said he still supported a dual status for Pluto, but did not think 2003 UB313 should be added to the registry of major planets. Mr. Williams said astronomers should "leave it as a minor planet permanently."

Mark V. Sykes, a defender of Pluto's planetary status, said his initial inclination would be to classify 2003 UB313 as a planet. He wondered whether it had an atmosphere and what sort of geological processes generated its apparently bright surface. "The kinds of questions we would ask about this object would be planet like questions," said Dr. Sykes, director of the Planetary Sciences Institute, a research institution in Tucson.

Astronomers will also have to figure out how the body made it to its current skewed orbit. "It makes Pluto seem less weird," Dr. Sykes said.

Dr. Brown said he used to support Mr. Williams's view of Pluto as a minor planet, but "I've given up on that." If Pluto, for historical reasons, has been grandfathered in as a planet, "this one, I would say, counts out as the 10th planet," Dr. Brown said.

Five and a half years ago, Dr. Brown bet an astronomer friend, Sabine Airieau, five bottles of good Champagne that he would find a Kuiper Belt object larger than Pluto by the end of last year. In December, having failed, he bought the five bottles of Champagne to send to her. Then 2003 UB313 turned up on Jan. 8.

"I lost the bet by eight days," Dr. Brown said, but "she graciously decided she would let that window slide and I would win the bet."

"That means I get to drink 10 bottles of good Champagne," he said, "and I think I will."

http://www.nytimes.com/2005/07/30/science/30planet.html?pagewanted=all

The planet , with the current temporary name 2003UB313, was discovered using the Samuel Oschin Telescope at Palomar Observatory near San Diego, California, by astronomers Mike Brown (Caltech), Chad Trujillo (Gemini Observatory), and David Rabinowitz (Yale University).
The team had been scanning the skies with the 1.2 metre (48-inch) telescope for five years, searching for large bodies orbiting in higher planes than that of the Earth and other planets.
The discovered object is the farthest-known object in the solar system, orbiting the sun once every 560 years. It is so far away that an observer standing on its surface could cover the view of the sun with the head of a pin.

The object was first photographed on Oct. 31, 2003, but it was so far away that its motion was not detected until data was analyzed again in January 8 2005.
A proposed name for the new found planet is Lila – though it will require approval from the IAU.
The word on the street is that Lila is the name of Mike Brown's newborn daughter

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