New planets discovered
15 Oct 2010 by qwwqdccwwm.d qwwqdccwwm.d
Two new planets confirmed and a third awaiting verification – it’s all happening at NASA’s Kepler Mission, which is looking for Earth-like planets outside our Solar System.
Two new planets confirmed and a third awaiting verification – it’s all happening at NASA’s Kepler Mission, which is looking for Earth-like planets outside our Solar System.
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Artists impression of the two Saturn-sized planets orbiting Kelper-9 Credit: NASA/Ames/JPL-Caltech |
After seven months of observation, scientists working at the Kepler Space Observatory announced the presence of two Saturn-sized planets – Kepler 9b and Kepler 9c – orbiting a sun-like star, dubbed Kepler-9.
“This is the first confirmed system of more than one planet transisting the same star,” said Matthew Holman, a Kepler scientist from the Harvard-Smithsonian Centre for Astrophysics.
Scientists used a new method of confirming the planets called transit timing variation. They looked for the signatures of planets by measuring tiny decreases in the brightness of stars when planets cross them. The size of the planet can be derived from the change in the star’s brightness.
“Using transit timing variations, astronomers have a new tool for confirming some planetary systems much more efficiently than before,” said Kepler scientist Eric Ford from the University of Florida.
Systems with multiple transisting planets – planets that pass in front of their stars – are rich in information that provides clues to their physical characteristics, said Holman. Scientists can measure the time between successive transits changes from orbit to orbit due to mutual gravity between the two worlds.
“We can actually see evidence of the gravitational interaction of these two planets through the deviation in their transit times,” he said, “This discovery is the first clear detection of transit timing variations.”
Scientists believe Kepler 9b orbits the star once every 19.2 days at a distance of 13 million miles and would weigh about the same as 80 Earths. Kepler 9c orbits once every 38.9 days at a distance of 21 miles and would weight about 54 Earth equivalents.
The observatory – which also receives information from the Hubble and Spitzer Space Telescopes –has so far identified over 700 planetary candidates, including five systems with more than one planet candidate. A third planet orbiting Kepler-9 – about one and a half times the size of the Earth – is still awaiting official confirmation.
