Sunlike Star Vibrations Seen for First Time

October 23, 2008

A first look at the surfaces of three nearby stars shows that the hot bodies are vibrating faster than our sun and have smoother exteriors, according to new research.

The work could help astronomers get a better picture of minute changes in stellar vibrations, which would improve our understanding of how sunlike stars operate inside.

Also, knowing more about subtle changes in the surfaces of other stars can help scientists better predict sun storms, which can damage orbiting satellites and interrupt power lines on Earth.

Studies of the sun's vibrations, or helio-seismology, have been yielding clues about our star's interior structure for decades. (Related: "Sun Gets Fatter 'Waist' During Magnetic Peaks" [October 2, 2008].)

Granulation, or bubbling, of the stellar surface can reveal how heat is being transported through the uppermost layers of gas.

But until recently, vibrations and surface features in more distant stars have been too hard to detect, so scientists have relied on computer simulations based on data from the sun.

"In the last few years, observers have started to see acoustic spectra from solar-type stars that are comparable in quality to what was seen in the sun nearly 30 years ago," said Rachel Howe, a scientist at the National Solar Observatory in Tucson, Arizona, who was not involved with the new study.

"These measurements will allow observers to probe the rotation and other properties of stars that are similar to our sun but of different sizes and ages."

Lead study author Eric Michel, a stellar physicist with France's National Center for Scientific Research, said his team's data should help refine previous computer predictions.

"The phenomena we observe are of the order of what we expected, and we will be able to measure them with precision," Michel said via email. "We are now looking into the stars!"

Margin of Error

All three stars observed for the new study are within 200 light-years of Earth. They are similar to the sun but are hotter and slightly more massive.

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