Planets with potential for life 'more common than thought'
Monday, 18 Feb 2008 10:24
Artist concept of a montage of terrestrial worlds that may form around neighboring sun-like stars
Science In Focus
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Planets with the potential for life may be more common in the Milky Way than scientists previously thought, a new study suggests.
Researchers found that terrestrial planets might form around many of the nearby sun-like stars in the disk of the Earth's galaxy.
University of Arizona astronomer Michael Meyer told the annual meeting of the American Association of Science that at least 20 per cent, and possibly as many as 60 per cent, of stars similar to the sun are candidates for forming rocky planets.
His team surveyed six groups of stars similar to the sun using Nasa's Spitzer space telescope.
Each star was grouped by age ranging from three-million-years-old to three-billion-years-old.
The researchers then studied the evolution of the gas and dust around the stars and compared the results with what they think the solar system looked like at earlier stages during its evolution.
They found evidence of dust from terrestrial planet formation in stages similar to "the time scales thought to span the formation and dynamical evolution of our own solar system".
Scott Kenyon of the Smithsonian Astrophysical Observatory and Ben Bromley of the University of Utah have developed planet formation models that suggest the warm dust detected in Dr Meyer's study exists as rocky bodies collide and merge, creating larger rocky bodies.
"Our work suggests that the warm dust Meyer and colleagues detect is a natural outcome of rocky planet formation," said Dr Kenyon.
"We predict a higher frequency of dust emission for the younger stars, just as Spitzer observes."
Further research on the possibility of terrestrial planets around stars like the sun will be undertaken from next year with the launch of Nasa's Kepler mission.