Astronomers found another planet? (Yawn)

The firsts and superlatives
In addition to finding new worlds, the burgeoning field has achieved many firsts.

In 2001, a team led by David Charbonneau of the Harvard-Smithsonian Center for Astrophysics used the Hubble Space Telescope and NASA's infrared-detecting Spitzer Space Telescope to detect for the first time the atmosphere of an extrasolar hot Jupiter called HD 189733b.

Another hot Jupiter, Upsilon Andromeda b, revealed for the first time an exoplanet with a temperature variation across its surface: One side has temperatures rivaling those found deep in a volcano while the other face could plunge below freezing.

Superlatives abound as well, with discoveries gaining fame as the windiest, tiniest, most massive and fastest orbiter.

Shortest orbital period in catalog: HD 41004 B b completes a full orbit in 1.328 days. Longest orbit: HD 154345 b takes 13,100 days to orbit its parent star. Lightest planet: Gliese 581 C weighs just five Earth masses.

Planet organizer
In an effort to keep track of the rapidly increasing list of exoplanets, a group of astronomers published a catalog of nearby exoplanets within 652 light-years of Earth in a 2006 issue of the Astrophysical Journal, though they realize updates will be a must on a routine basis.

"Without question, the catalog presented here will become out of date before it is printed," the researchers say in the published report of the catalog.

But with such a huge sample of relatively nearby planets, theorists now have the chance to test out their theories in the "real world."

"This whole business of extrasolar planets has been a real boon for theorists because so far they had only one planetary system to study-and that was ours," Mandushev said in a telephone interview.

For instance, when does an object stop being a planet and become a star, a threshold that theory places at 10 to 15 Jupiter masses and beyond which an object can ignite hydrogen fusion to power a stellar glow'

The real goal
The ultimate goal, say many planet hunters, is to find Earth-like planets, or those with similar masses, orbits and rocky compositions to Earth. And beyond finding the physical Earth-like attributes would be to find life. So far no "Earths" have been identified, though observatories are coming online with the sensitivity to detect small objects that orbit far from their host stars, as our planet does.

"The hunt is still on for rocky, Earth-like planets," said Jason Wright, an astronomer at the University of California, Berkeley, who was part of the team compiling the exoplanet catalog.

And astronomers have identified the first Earth-like planet that could support liquid water and harbor life. The "super Earth," Gliese 581 C, weighs about five Earth masses and is either a rocky planet or one covered entirely by oceans, astronomers speculate.

Multi-planet systems are also a goal. So far about 25 multi-planet systems have been identified with two such systems supporting four planets.

"We haven't found a clone of the solar system yet," Boss said. "But that's only ruling out maybe 10 percent of the stars. The other 90 percent could have exact solar system analogs and we wouldn't know it because we haven't been able to take data for long enough to actually find their planetary systems."

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