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Top 10 Exoplanets: Weird Worlds in a Galaxy Not So Far Away [Slide Show]

A look at some of our extreme planetary neighbors right here in the Milky Way Galaxy

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BONUS: FIRST PROTOPLANET?:

Though no exoplanets have been confirmed around a star called UX Tauri A, scientists have spotted a huge gap in its protoplanetary disk indicating that a planet may be coalescing. These swirling disks of gas and dust (leftover material from star formation ) form around a star's equator and then extend outward into space.....[ More ]

1. PRIMORDIAL PLANET:

Exoplanet PSR B1620-26 b is believed to have formed an incredible 13 billion years ago, less than a billion years after the big bang . Aptly nicknamed Methuselah, this probable gas giant resides in an ancient type of galaxy known as a globular cluster, where it orbits two stellar hosts, a white dwarf star and a pulsar, both remnants of larger stars.....[ More ]

2. EARTH TIMES THREE:

The exoplanet MOA-192 b , which orbits a purplish star in this artist's impression, is the smallest discovered so far, measuring about 3.3 Earths in mass. It revolves about a dim star that is about one twentieth the mass of our sun, making this the planet with the teensiest host star, to boot.....[ More ]

3. IT'S A SMALL(ER) WORLD:

Besides being the first exoplanet ever directly observed from Earth as it transited in front of its host star, exoplanet HD 209458 b (aka Osiris) is also shrinking. Its proximity to the inferno of its host star superheats the planet to an estimated 18,000 degrees Fahrenheit (10,000 degrees Celsius), which researchers believe is causing it to sweat off about 10,000 tons (9,000 metric tons) of atmospheric hydrogen every second, forming a cometlike tail.....[ More ]

4. EXOHOTTIE:

HD 149026 b ranks as one of the hottest known exoplanets, with a lead-boiling surface temperature of around 3,700 degrees Fahrenheit (2,000 degrees Celsius). Tricky measurements of light reflecting from its surface suggest that this world may be pitch-black in color, perhaps because of a strangely high concentration of heavy, metallic elements in its atmosphere.....[ More ]

5. NOT TOO HOT OR TOO COLD?:

When astronomers spotted Gliese 581 c , it set off a flurry of reports that this exoplanet fell within the so-called "Goldilocks" zone where liquid water can exist on the planet's surface. Gliese 581 c orbits closer to its star than torrid Mercury orbits the sun, but the host is a red dwarf star 50 times cooler than our sun, which researchers thought placed it in that star's habitable zone.....[ More ]

6. FREAKISHLY FROZEN WORLD:

Scientists think Gliese 436 b (aka GJ 436 b), a Neptune -size exoplanet, is too heavy to be all gas but not heavy enough to be entirely rock. They surmise that in addition to gas and rock, it also contains a kind of pressurized, high-temperature ice that only exists on Earth in laboratories, where it goes by names like "ice VII" and "ice X." The high pressures deep inside the planet may stabilize this alternate solid state of water, similar to the way intense pressures in Earth's crust can squeeze carbon atoms into crystalline diamond .....[ More ]

7. POTPOURRI OF PLANETS:

Astronomers discovered a fifth planet around the sunlike star 55 Cancri in 2007, lending a familiar feel to this solar system and making it the most planet-populated one outside our own--so far. All five confirmed planets in the system are jumbo versions of Earth and its neighbors, including a rocky mega-Earth and a gas giant four times as massive as Jupiter.....[ More ]

8. SURVIVOR OF APOCALYPSE:

V391 Pegasi b distinguishes itself as the only planet known to orbit a star that has passed through its red giant phase . As stars like our sun age, they run low on nuclear fuel in their cores and swell to hundreds of times their original sizes.....[ More ]

9. TYPICAL STAR; EXTRAORDINARY PLANET:

The first exoplanet spotted around a typical or " main sequence " star similar to our sun, gaseous 51 Pegasi b completes an orbit around its host star every four days. Many exoplanets found after this one are very similar "hot Jupiters," named for their size and proximity to their star.....[ More ]

10. FIRST EXOWORLD:

The first solid evidence for an exoplanet (extrasolar planet) came in 1992 when scientists calculated that two bodies must be orbiting the pulsar PSR 1257. Pulsars are rapidly spinning neutron stars (the superdense remnants of massive stars that have exploded as supernovae ), which emit radio waves in pulses.....[ More ]

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