9 Wildest Exoplanets Ever Spotted
A team of European astronomers found 32 new exoplanets last week, bringing the total of planets found outside our solar system to 403. These extreme worlds continue to shape astronomer's ideas about how planets form. Here, we've combed through the hundreds to pick the 9 hottest, biggest, most eccentric alien worlds ever found.
A team of European planet hunters has uncovered a bonanza of 32 new exoplanets, planets outside our solar system. Using a precise spectrograph at the Very Large Telescope in northern Chile, the astronomers spotted enough planets to bring the total number of known exoplanets up by nearly 10 percent—to 403. Most of these hundreds of exoplanets are gas giants, but in the mix there are also super-Earths, planets with masses that are up to 20 times that of Earth. These are especially difficult to find because they are so much smaller than the giant Jupiter-like gaseous planets.
Scientists usually spot exoplanets by detecting changes in the motion of the star the planets are orbiting. But because the gravity of an orbiting super-Earth tugs so weakly on its star, the changes are harder to observe. The spectrograph that made this discovery possible was the first instrument able to detect the tiny changes from these planets. These 32 exoplanets have also supported the idea that super-Earths are much more common than they were once thought to be. Scientists now think that super-Earths may be found near more than 60 percent of stars similar to our sun. At that rate, Stephane Udry, an astronomer at the University of Geneva in Switzerland who announced the discovery, believes it is very likely that life exists on other planets. The elements that make up rocky planets can only be made in stars, and some of these elements are also the elements needed for life. "There are many planets," he says, "and I am convinced we will find life."
The Most Massive:
HD 43848
Discovered in 2008, this exoplanet has a mass that is 25 times the mass of Jupiter. Orbiting around a star that is a just a bit smaller than our sun, HD43848 is nearly 8000 times as massive as Earth.
The Smallest:
CoRoT-7b
This planet is less than twice the size of Earth, and its density is similar to Earth's. Discovered in February 2009, CoRoT-7b takes 20.4 hours to orbit a star that is slightly smaller, cooler and younger than our sun.
The Most Likely to Have Life:
Gl 581 e
Of the four planets that orbit the star called Gliese 581, two are near the edges of what astronomers called the habitable zone, where liquid water may exist. One of these planets is near the cool edge of the zone, but Gl 581 e, spotted in April 2009, is in a warmer spot.
The Biggest Radius:
CT Cha b
This gas giant has a radius that is more than twice as large as our largest planet, Jupiter, and 17 times as massive.
The Hottest:
WASP-18b
Although the data is still preliminary, this 2009 discovery may be the hottest, says University of Central Florida professor Joseph Harrington, stealing the title from another planet that Harrington calculated to be the hottest in 2007. This speedy planet, which is 10 times the size of Jupiter, hauls its mass around its star in less than an Earth day. But title of "hottest" may still be under contention—because it is so close to its star, WASP-18b is likely to spiral into it within the next million years.
The Most Eccentric Orbit:
VB 10 b
A planet that orbits its star in a perfect circle would have an eccentricity designated as 0. The eccentricity of Earth's orbit is 0.0167—a very slight oval. The orbit of VB 10 b is the most elliptical orbit known—with an eccentricity of nearly 0.98, it is even more stretched out than the orbit of Haley's comet.
The Baby:
Fomalhaut b
Only 25 light-years away, Fomalhaut is a neighbor of our sun. In 2005, astronomers discovered the exoplanet Fomalhaut b hiding amid the interstellar dust surrounding Fomalhaut. The presence of the dust means that the system is still very young and is likely to have more planets form within it—Fomalhaut b may be just the first-born. And just like a baby, this planet is crawling; it takes about 876 years to orbit its star, even though it is closer than Mercury is to our sun.
The Farthest From its Star:
UScoCTIO 108 b
This planet, which has 14 times the mass of Jupiter, spends its days at about 670 astronomical units—about 64 billion miles—away from its star. That's about 17 times farther away than dwarf planet Pluto is from our sun.
The Farthest from Earth:
OGLE-05-390L b
At 21,450 light-years away, this is the furthest exoplanet scientists have found. It is five times the mass of the Earth and twice the distance from its star and it trundles slowly around, taking 3500 days to orbit.
