EL61

falkor · 2005-07-31 09:47:21

http://fullcoverage.yahoo.com/s/space/2 … tune]Large New World Discovered Beyond Neptune

A newfound object in our solar system's outskirts may be larger than any known world after Pluto, scientists said today.

It also has a moon.

http://fullcoverage.yahoo.com/s/space/20050729/sc_space/largenewworlddiscoveredbeyondneptune] EL61 with it's moon

Designated as 2003 EL61, the main object in the two-body system is 32 percent as massive as Pluto and is estimated to be about 70 percent of Pluto's diameter.

Other news reports that the object could be twice as big as Pluto are false, according to two astronomers who found the object in separate studies and another expert who has analyzed the data.

If the mass is only one-third that of Pluto, then theory holds that it can't be larger than Pluto, according to Brian Marsden of the Minor Planet Center, which serves as a clearinghouse for data on all newfound objects in the solar system.

Marsden, who was not involved in the discovery but has reviewed the data, told SPACE.com that the mass estimate is very firm, within 1 or 2 percent. "I don’t think it is bigger than Pluto," he said.

Where it fits in

This is still a big world, once again raising the prospect that something larger than Pluto might still lurk out there.

Scientists base their size calculations in part on the object's reflectivity. Since they don't know exactly how much the surface brightness of distant objects varies, there is some wiggle room in their size estimates.

A team led by Mike Brown of Caltech has been observing 2003 EL61 for a year but was seeking more data before announcing the discovery. Brown said today it may possibly be larger than Sedna, which has been the largest known world beyond Neptune other than Pluto.

Sedna is between 800 and 1,100 miles in diameter. Pluto is about 1,400 miles across.

Brown figures 2003 EL61 has a diameter of around 930 miles.

Is there any chance it is bigger than Pluto?

"No," Brown said in a telephone interview. "Definitely not."

In fact, Brown's team got the new data they had been waiting for, from the Spitzer Space Telescope, last week. While not fully analyzed, he said the Spitzer observations show "absolutely" that the object is not bigger than Pluto.

Who gets credit?

The object was spotted independently by a group led by Jose-Luis Ortiz of the Sierra Nevada Observatory in Spain. Ortiz' team announced the finding in astronomy circles recently and the finding, including the claim that it might be twice as big as Pluto, was reported by an online news site today.

Ortiz said that based on his team's observations, there was one outlying theory could allow 2003 EL61 to be larger than Pluto, but he does not think it is right.

"I do not think it is larger than Pluto," Ortiz told SPACE.com today.

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#1 2005-07-31 09:47:21

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