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NASA Finds Six-Planet Solar System
By IBT Staff Reporter, Feb. 3, 2011
A NASA team has found multiple planets in a distant solar system - dubbed Kepler-11 - transiting a sun-like star located about 2,000 light years away from Earth. "This is the largest group of transiting planets orbiting a single star yet discovered outside our solar system," NASA said. With temperatures hotter than Venus - likely more than 400 to 1,400 degrees Fahrenheit, the six planets range in size from twice to four and a half times Earth’s diameter, astronomers said.
.Kepler Mission News
The five confirmed planets are larger in mass but less dense than Earth, and closely packed, taking from 10 to 47 days to orbit the star. Astonomers said there is almost certainly a sixth planet orbiting nearly twice as far away, but its distance from the star makes its confirmation more difficult. According to NASA, all of the planets orbiting Kepler-11 are larger than Earth, with the largest ones being comparable in size to Uranus and Neptune. The innermost planet, Kepler-11b, is ten times closer to its star than Earth is to the sun. Moving outward, the other planets are Kepler-11c, Kepler-11d, Kepler-11e, Kepler-11f, and the outermost planet, Kepler-11g, which is half as far from its star as Earth is from the sun.
The planets Kepler-11d, Kepler-11e and Kepler-11f have a significant amount of light gas, which indicates that they formed within a few million years of the system's formation, NASA said. These six planets are mixtures of rock and gases, possibly including water. The new planets were found by tracking the dimming of a star’s light when planets pass between the star and the telescope, astronomers said.
The astronomers said the next step will be to determine mass and orbits of the planets more precisely, providing clues to how the planets formed. "Much of the scientific community thought that multiple planets transiting the same star would be unlikely," said Eric Ford of NASA team and University of Florida associate professor. "That idea has been completely overturned by this new discovery. Without the transit-timing method, these planets might have gone unconfirmed for years." The discoveries are part of several hundred new planet candidates identified in new Kepler mission science data, released on Tuesday. The findings increase the number of planet candidates identified by Kepler to-date to 1,235. (
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.Kepler.gov:
NASA Finds Earth-size Planet Candidates in Habitable Zone, Six Planet System
Moffett Field, Calif. -- NASA's Kepler mission has discovered its first Earth-size planet candidates and its first candidates in the habitable zone, a region where liquid water could exist on a planet's surface. Five of the potential planets are near Earth-size and orbit in the habitable zone of smaller, cooler stars than our sun. Candidates require follow-up observations to verify they are actual planets. Kepler also found six confirmed planets orbiting a sun-like star, Kepler-11. This is the largest group of transiting planets orbiting a single star yet discovered outside our solar system.
"In one generation we have gone from extraterrestrial planets being a mainstay of science fiction, to the present, where Kepler has helped turn science fiction into today's reality," said NASA Administrator Charles Bolden. "These discoveries underscore the importance of NASA's science missions, which consistently increase understanding of our place in the cosmos." The findings are based on the results of observations conducted May 12 to Sept. 17, 2009, of more than 156,000 stars in Kepler's field of view, which covers approximately 1/400 of the sky. "The fact that we've found so many planet candidates in such a tiny fraction of the sky suggests there are countless planets orbiting sun-like stars in our galaxy," said William Borucki of NASA's Ames Research Center in Moffett Field, Calif., the mission's science principal investigator. "We went from zero to 68 Earth-sized planet candidates and zero to 54 candidates in the habitable zone, some of which could have moons with liquid water."
Among the stars with planetary candidates, 170 show evidence of multiple planetary candidates. Kepler-11, located approximately 2,000 light years from Earth, is the most tightly packed planetary system yet discovered. All six of its confirmed planets have orbits smaller than Venus, and five of the six have orbits smaller than Mercury's. The only other star with more than one confirmed transiting planet is Kepler-9, which has three. The Kepler-11 findings will be published in the Feb. 3 issue of the journal Nature. Kepler, a space telescope, looks for planet signatures by measuring tiny decreases in the brightness of stars caused by planets crossing in front of them. This is known as a transit. Since transits of planets in the habitable zone of sun-like stars occur about once a year and require three transits for verification, it is expected to take three years to locate and verify Earth-size planets orbiting sun-like stars. (
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