Study Continues on 10th Planet

Scientists from the Jet Propulsion Laboratory and Caltech are continuing this week to review data related to the recent discovery of the tenth known planet in our solar system.

Astronomers announced in a press conference held at JPL July 29 that a planet larger than Pluto has been discovered in one of the most distant regions of our solar system.

JPL scientists will begin observing the new planet through the Spitzer telescope soon, according to a lab spokesperson.

Caltech planetary scientist Mike Brown announced the planet’s discovery, the tenth in our solar system. It was discovered during an ongoing survey at Palomar Observatory’s Samuel Oschin telescope by Brown and colleagues Chad Trujillo (Gemini Observatory) and David Rabinowitz (Yale University).

Brown and Trujillo first photographed the planet in October 2003; however, the planet, 97 times farther away from the sun than the Earth, was so far away that its motion was not detected until they reanalyzed the data in January of this year. The last seven months have been devoted to reviewing data to better estimate the planet’s size and motions.

“We have gotten together the A-team [of the Spitzer telescope scientists],” said Brown.

The planet is temporarily named 2003UB313 by the International Astronomical Union (IAU). A new name has been submitted by Brown but has yet to be approved. Some have speculated that the planet might be named after Brown’s four-week-old daughter, Lilah.

But according to Brown’s website, that is just a speculation. He has not released the name submitted, but does give a hint that they followed the IAU rules set up for new body discoveries in the solar system. According to those rules, they must name the planet after some figure in creation mythology. The other nine planets are named after Greek and Roman gods. Some science websites have been reporting that Brown has submitted the name, Xena, for the planet.

“That is one of the code words we used,” said Brown, who added that they often use code words like Santa and Easter Bunny for other projects but do not intend on submitting those as names either.

Backyard astronomers, using very high-end amateur equipment, can see the new planet, which is high in the morning sky a few hours before the sun comes, up in the Cetus constellation.

“It’s definitely bigger than Pluto,” stated Brown in a Caltech press release.

According to Brown’s website it is the largest object found in orbit around the sun since the discovery in 1846 of Neptune and its moon Triton. The new planet, like Pluto, is a member of the Kuiper belt, a swarm of icy bodies beyond Neptune in orbit around the sun. Scientists can determine the size of a solar-system object by its brightness. It is not yet possible to tell how much light from the sun is reflected away, but the amount of light the planet reflects puts a lower limit on its size.

“Even if it reflected 100 percent of the light reaching it, it would still be as big as Pluto,” said Brown. “I’d say it’s probably one-and-a-half times the size of Pluto, but we’re not sure yet of the final size.”

Pluto and the new planet are made of ice and rock and have very eccentric orbits. Although Pluto and the new planet have commonalities, they are not identical. Pluto’s surface is moderately red; the new planet appears almost gray.

According to Brown, scientists decided to make the announcement without all the desired data for fear the discovery would be made public by someone who had gained information by accident or with intent through the website containing the planet’s location.

“We already were hacked in to,” said Brown of the Internet intrusion.

JPL Spitzer scientists will be busy scanning the sky for the planet.

“Within a month or two we will know the size of this guy [planet],” said Brown of determining the planet’s exact size. Other astronomers will be looking at the planet, creating a competition for information. “The race is on,” said Brown.