Scientists have found evidence that seven stars in our Milky Way galaxy may be orbited by planets, NASA announced Thursday.
In the past decade, researchers have claimed to discover evidence of planets around some two dozen stars. But so far, scientists have not conclusively established the existence of any planetary system outside our own.Using a new method that involves analyzing infrared light from space, astrophysicists Kenneth Marsh and Michael J. Mahoney at NASA's Jet Propulsion Laboratory found nine sun-like stars that appear to be orbited by companion bodies.
Two of those stars were found to be orbited by faint stars, Mahoney said. But the seven other stars may be orbited by planets, faint stars or "brown dwarfs," gaseous bodies too big to be planets but too small to become stars.
Other scientists praised the new method but said they aren't yet convinced the astrophysicists found planets outside our solar system.
"The landscape of previous efforts to detect planets is littered with the corpses of claims that haven't been substantiated," said David Black, director of the Lunar and Planetary Institute in Houston.
"It's way too soon to tell" if Marsh and Mahoney really discovered other worlds, he said, but the method used is "very interesting . . . very creative."
Marsh was scheduled to present the findings Thursday at a meeting of the American Astronomical Society in Columbus, Ohio.
Existing telescopes cannot detect objects as small as planets outside our solar system. So scientists have searched for planets by looking for wobbles in a star's motion or variations in its radiowave pulses that might indicate the gravitational tug of a body nearby.
Marsh and Mahoney instead analyzed the infrared light emitted by the swirling disks of gas, dust and debris surrounding stars. It was in such a disk surrounding the sun that matter is believed to have clumped together to form Earth and other planets in our solar system 4.6 billion years ago.
Even if the bodies found by the NASA scientists prove not to be planets, the study is significant because "it's a whole new way of looking for planets," said Steve Maran, spokesman for the American Astronomical Society.