We will need to find something friendlier to call themthan GJ 667Cc.
By:Denise Chow
Published: 02/02/2012 10:16 AM EST on SPACE.com
A potentially habitablealien planet — one that scientists say is the best candidate yet to harborwater, and possibly even life, on its surface — has been found around a nearbystar.
The planet is located in the habitablezone of its host star, which is a narrowcircumstellar region where temperatures are neither too hot nor too cold forliquid water to exist on the planet's surface.
"It's the Holy Grail of exoplanetresearch to find a planet around a star orbiting at the right distance so it'snot too close where it would lose all its water and boil away, and not too farwhere it would all freeze," Steven Vogt, an astronomer at the Universityof California, Santa Cruz, told SPACE.com. "It's right smack in thehabitable zone — there's no question or discussion about it. It's not on theedge, it's right in there."
Vogt is one of the authorsof the new study, which was led by Guillem Anglada-Escudé and Paul Butler ofthe Carnegie Institution for Science, a private, nonprofit researchorganization based in Washington, D.C.
"This planet is the newbest candidate to support liquid water and, perhaps, life aswe know it," Anglada-Escudé said in astatement.
However, in my opinion, addressing them as“Super-Earth” places us in an overly subservient, diminished posture.
Analien super-Earth
The researchers estimate that the planet, called GJ 667Cc, is atleast 4.5 times as massive as Earth, which makes it a so-calledsuper-Earth. It takes roughly 28 daysto make one orbital lap around its parent star, which is located a mere 22light-years away from Earth, in the constellation Scorpius (the Scorpion).
"This is basically ournext-door neighbor," Vogt said. "It's very nearby. There are onlyabout 100 stars closer to us than this one."
Interestingly enough, the host star, GJ 667C, is a member of atriple-star system. GJ 667C is an M-class dwarf star that is about a third ofthe mass of the sun, and while it is faint, it can be seen by ground-basedtelescopes, Vogt said. [Gallery:The Strangest Alien Planets]
"The planet is around onestar in a triple-star system," Vogt explained. "The other stars arepretty far away, but they would look pretty nice in the sky."
Hey, Mr. Spaceman
The discovery of a planetaround GJ 667C came as a surprise to the astronomers, because the entire starsystem has a different chemical makeup than our sun. The system has much lowerabundances of heavy elements (elements heavier than hydrogen and helium), suchas iron, carbon and silicon.
"It's pretty deficient inmetals," Vogt said. "These are the materials out of which planetsform — the grains of stuff that coalesce to eventually make up planets — so weshouldn't have really expected this star to be a likely case for harboringplanets."
The fortuitous discovery could mean that potentially habitable alien worlds couldexist in a greater variety of environments than was previously thoughtpossible, the researchers said.
Won’t you please take me along, I won’t doanything wrong.
"Statistics tell us weshouldn't have found something this quickly this soon unless there's a lot ofthem out there," Vogt said. "This tells us there must be an awful lot of these planets out there. Itwas almost too easy to find, and it happened too quickly."
Thedetailed findings of the study will be published in the Astrophysical JournalLetters.
Anintriguing star system
Another super-Earth thatorbits much closer to GJ 667C was previously detected in 2010, but the findingwas never published, Vogt added. This planet, called GJ 667Cb, takes 7.2 daysto circle the star but its location makes it far too hot to sustain liquidwater on its surface.
It's basically glowingcinders, or a well-lit charcoal," Vogt said. "We know about a lot ofthese, but they're thousands of degrees and not places where you could live."
But, the newly detected GJ667Cc planet is a much more intriguing candidate, he said.
Eight miles high, and when you touch down,you’ll find that it’s stranger than known.
"When a planet gets biggerthan about 10 times the size of the Earth,there's a runaway process that happens, where it begins to eat up all the gasand ice in the disk that it's forming out of and swells quickly into somethinglike Uranus, Jupiter or Saturn," Vogt explained. "When you have asurface and the right temperature, if there's water around, there's a goodchance that it could be in liquid form. This planet is right in that sweet spotin the habitable zone, so we've got the right temperature and the right massrange."
Preliminary observationsalso suggest that more planets could exist in this system, including a gasgiant planet and another super-Earth that takes about 75 days to circle the star.More research will be needed to confirm these planetary candidates, as well asto glean additional details about the potentially habitable super-Earth, thescientists said.
Findingnearby alien planets
To make their discovery,the researchers used public data from the European Southern Observatorycombined with observations from the W.M. Keck Observatory in Hawaii and the newCarnegie Planet Finder Spectrograph at the Magellan II Telescope in Chile.
Follow-up analyses were also made using a planet-huntingtechnique that measures the small dips, or wobbles, in a star's motion causedby the gravitational tug of a planet.
...Off somewhere, just beingtheir own.
"With the advent of a newgeneration of instruments, researchers will be able to survey many M dwarfstars for similar planets and eventually look for spectroscopic signatures oflife in one of these worlds," Anglada-Escudé said in a statement.Anglada-Escudé was with the Carnegie Institution for Science when he conductedthe research, but has since moved on to the University of Gottingen in Germany.
With the GJ 667C systembeing relatively nearby, it also opens exciting possibilities for probingpotentially habitable alien worlds in the future, Vogt said, which can't easilybe done with the planets that are being found by NASA's prolific Keplerspacecraft.
I often find myself thinking, “I’m happy to bepast draft age.”
"The planets coming out of Kepler aretypically thousands of light-years away and we could never send a space probeout there," Vogt said. "We've been explicitly focusing on very nearbystars, because with today's technology, we could send a robotic probe outthere, and within a few hundred years, it could be sending back picturepostcards."
Picture Postcard fromSpace: "Having a lovely time, wish you were here."
1. The Byrds: Eight Miles High (link)
2. The Byrds: Mr.Spaceman (link)
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