Many, perhaps most, nearby sun-like stars may form rocky planets

A UA astronomer and his Spitzer team find that at least 1 in 5 neighboring solar-mass stars may form terrestrial worlds

Artist concept showing a montage of terrestrial worlds that may form around neighboring sun-like stars. Click here for more information.

Astronomers have discovered that terrestrial planets might form around many, if not most, of the nearby sun-like stars in the disk of our galaxy. These new results suggest that worlds with potential for life might be more common than thought.

University of Arizona astronomer Michael Meyer led a Legacy Science Program with NASA's Spitzer Space Telescope to determine whether planetary systems like ours are common or rare in the Milky Way galaxy. Meyer and his colleagues found that at least 20 percent, and possibly as many as 60 percent, of stars similar to the sun are candidates for forming rocky planets.

Meyer is presenting the findings at the annual meeting of the American Association for the Advancement of Science tomorrow. The results appear in the Feb. 1, 2008, issue of Astrophysical Journal Letters.

Members of the research team include John Carpenter of the California Institute of Technology, Eric Mamajek of the Harvard-Smithsonian Center for Astrophysics and 11 other astronomers from the United States and Germany.

The astronomers surveyed six groups of stars with masses comparable to our sun using Spitzer, which includes an instrument built at UA's Steward Observatory by a team led by Professor George Rieke. The stars were grouped by age, ranging from three-to-10 million years, 10-to-30 million years, 30-to-100 million years, 100-to-300 million years, 300 million to one billion years and one-to-three billion years old.

"We wanted to study the evolution of the gas and dust around stars similar to the sun and compare the results with what we think the solar system looked like at earlier stages during its evolution," Meyer said. The sun is about 4.6 billion years old.