The data collected so far from NASA's new planet-hunting spacecraft has allowed an international team of scientists -- including a Boulder researcher -- to characterize hundreds of stars in unprecedented detail.

Kepler, built by Ball Aerospace in Boulder and commanded by University of Colorado students, was designed to find Earth-like planets orbiting other stars. To detect the planets, Kepler's digital eyes are now staring at thousands of stars, measuring the intensity of their light and recording any dips in brightness, which could signify that a planet has just traveled across the star in its orbit.

But the keen stare of Kepler, which launched in March 2009, is taking in far more information than just an occasional dimming of starlight, and that information has proved to be a cosmic gold mine for scientists who study asteroseismology -- the study of stellar oscillations or "starquakes."

"It was recognized that if we had the sensitivity to detect an Earth-sized planet, we also had the capability of transforming our knowledge of the stars themselves," Natalie Batalha, an astronomer at San Jose State University, said during a Tuesday news conference.


"Doing seismology of the star is like taking an ultrasound image ... sound waves travel down into the star and then come back to the surface where Kepler can see it," said Travis Metcalfe, a scientist at the National Center for Atmospheric Research. "Larger stars naturally flicker in lower tones, while smaller stars flicker in higher tones."

The work being done by Metcalfe and his colleagues, led by the Danish Asteroseismology Centre at the University of Aarhus, will also be useful to the scientists hunting planets.

"The method that Kepler uses to study exoplanets, the transit method, only reveals the size of the planet relative to the size of the star," Metcalfe said. "By measuring the size of the star, we can determine the absolute size of the planet."

And because planets are formed at the same time as their stars, knowing the age of the star also reveals the age of the planet, Metcalfe said.

Kepler will continue to stare at the same 100,000 stars for at least another two years. So far, the spacecraft has discovered more than 700 possible planets, but only seven have been confirmed by ground observations.
