Sun-like stars brighten and dim

IOWA STATE (US) — Five hundred stars similar to our sun in size, age, composition, and location in the Milky Way are bringing to new light how stars evolve.

The oscillations, observed by NASA’s Kepler Mission, are offering hints about star basics such as mass, radius, and age, as well as clues about their internal structure.

Details are reported in the journal Science. The lead author is Bill Chaplin of the University of Birmingham.

“This helps us understand more about the formation of stars and how they evolve,” says Steve Kawaler, professor of physics and astronomy at Iowa State University and a co-author of the paper.

“These new observations allow us to measure the detailed properties of stars at an accuracy that wasn’t possible before.”

The Kepler spacecraft is orbiting the sun carrying a photometer, or light meter, to measure changes in star brightness that includes a telescope 37 inches in diameter connected to a 95 megapixel CCD camera.

The instrument is continually pointed at the Cygnus-Lyra region of the Milky Way and is expected to continuously observe about 170,000 stars for at least three and a half years.

The spacecraft’s primary job is to use tiny variations in the brightness of the stars within its view to find Earth-like planets that might be able to support life.

The Kepler Asteroseismic Investigation is using Kepler data to study different kinds of stars and has provided astronomers with so much new information, researchers say they are “entering a golden era for stellar physics.”

Data from 500 sun-like stars gives astronomers a much better understanding of the stars, their properties and their evolution, provides data to test theories, models, and predictions about the stars and the galaxy, and also gives astronomers enough data to make meaningful statistical studies.

“But this is just the start of things,” Kawaler says. “This is a first broad-brush analysis of the data we’ve seen. This is a preview of this new tool and the kind of detailed census that we’ll be able to do.”

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A star like our sun is shown with an orbiting planet in the foreground. NASA’s Kepler Mission is studying these sun-like stars by tracking changes in their brightness. (Credit Gabriel Perez Diaz, Instituto de Aastrofisica de Canarias/(MultiMedia Service)