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NASA's prolific planet-hunting spacecraft has hit the jackpot again,
discovering 11 new planetary systems with 26 confirmed alien planets
among them. 
 
The findings nearly double the number of bona fide planets found
outside our solar system by the Kepler space observatory.
 
"Prior to the Kepler mission, we knew of perhaps 500 exoplanets across
the whole sky," Doug Hudgins, Kepler program scientist at NASA
headquarters in Washington, said in a statement. "Now, in just two
years staring at a patch of sky not much bigger than your fist, Kepler
has discovered more than 60 planets and more than 2,300 planet
candidates. This tells us that our galaxy is positively loaded with
planets of all sizes and orbits."
 


The week's best images of our solar system, the galaxy and everything
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The newly detected worlds vary in size from 1.5 times the radius of
Earth to larger than Jupiter; 15 of the 26 planets fall between Earth
and Neptune in size. While all of the planets tightly orbit their
parent stars, more research will be required to determine which worlds
are rocky like Earth, and which have thick, gaseous atmospheres like
Neptune, the scientists said.
 
Still, all of the 26 new planets orbit closer to their stars than
Venus does to our sun. This means that their orbital periods — or the
time it takes for them to complete one orbital lap around the star —
range from  six days to 143 days, according to the researchers.
[Gallery: A World of Kepler Planets ]
 
By studying these different planetary systems, scientists can glean
valuable information about how planets form.
 
Hunting for planets
 
The Kepler spacecraft, which orbits the sun, stares at a patch of sky
that contains 150,000 stars and locates potential alien planets by
measuring the tiny change in brightness that occurs when a planet
transits — that is, passes in front of — a star.
 
Once a planetary candidate is identified, further observations are
conducted by ground-based observatories to weed out the false
positives.
 
"Confirming that the small decrease in the star's brightness is due to
a planet requires additional observations and time-consuming
analysis," Eric Ford, associate professor of astronomy at the
University of Florida, explained in a statement.
 
Ford is the lead author of a study that confirms two of the new
systems, Kepler-23 and Kepler-24.
 
"We verified these planets using new techniques that dramatically
accelerated their discovery," Ford said.
 
Each of the newly found planetary systems holds two to five closely
spaced transiting planets, the researchers said. Since these systems
are tightly packed, the planets exert gravitational forces on one
another, speeding up or slowing down their orbits. The orbital period
of each planet is altered in the process.
 
By measuring the orbital changes, Kepler can identify potential
planets in the system. This method, known as Transit Timing Variation,
can be used to verify alien planets without extensive ground-based
observations. The technique also increases Kepler's ability to confirm
planetary systems around fainter and more distant stars, the
researchers said. [Video: Kepler Reveals Lots of Planets: Some
Habitable?]
 
"By precisely timing when each planet transits its star, Kepler
detected the gravitational tug of the planets on each other, clinching
the case for 10 of the newly announced planetary systems," Dan
Fabrycky, of the University of California, Santa Cruz, said in a
statement.
 
Fabrycky is the lead author of the paper that confirms the Kepler-29,
-30, -31 and -32 systems.
 
Alien planets and their host stars
 
Five of the systems (Kepler-25, -27, -30, -31 and -33) contain a pair
of planets, the inner one circling its star twice in the time it takes
the outer planet to make one lap.
 
Four of the systems (Kepler-23, -24, -28 and -32) are home to a pair
of planets where the outer one orbits the star twice for every three
times the inner planet circles the parent star.
 
"These configurations help to amplify the gravitational interactions
between the planets, similar to how my sons kick their legs on a swing
at the right time to go higher," Jason Steffen, a postdoctoral fellow
at Fermilab Center for Particle Astrophysics in Batavia, Ill., said in
a statement. Steffen is the lead author of a paper confirming the
Kepler-25, -26, -27 and -28 systems.

The system with the most planets is Kepler-33. The star, which is
older and more massive than the sun, hosts five planets that range in
size from 1.5 to five times that of Earth. All of these planets orbit
closer to their star than any planet circles our sun.
 
Once the properties of a star are understood, such as the telltale
light signature of a planet crossing in front, it becomes easier to
eliminate false positives, the researchers said.

"The approach used to verify the Kepler-33 planets shows the overall
reliability is quite high," said Jack Lissauer, planetary scientist at
NASA Ames Research Center at Moffett Field, Calif., and lead author of
the paper on Kepler-33. "This is a validation by multiplicity."
 
The newly discovered planets increase the Kepler mission's tally of
confirmed planets to 61, with 2,326 other planetary candidates.
 
The four separate papers appear in the Astrophysical Journal and the
Monthly Notices of the Royal Astronomical Society.
 The Strangest Alien Planets
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 Gallery: First Earth-Size Alien Planets Discovered


Read more:
http://www.foxnews.com/scitech/2012/01/27/alien-worlds-abound-nasa-scope-finds-26-alien-planets/#ixzz1khQSbNC0


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