Study says stellar bar is at center of Milky Way

MADISON, Wis. -- From the Earth, the Milky Way galaxy is a band of stars that lights up the night sky. From outside the galaxy looking in, astronomers say it's an entirely different picture.

After creating a detailed analysis, astronomers say a long bar of stars cuts on an angle through the center of the galaxy that includes the sun and Earth.

The team of astronomers used NASA's Spitzer space telescope to survey more than 30 million stars in the center of the Milky Way. The orbiting infrared telescope allowed the astronomers to see bright stars through clouds of interstellar dust to draw a vivid portrait of the center of the galaxy.

"We're pretty certain of the extent and orientation of this bar because we got more data than anybody else that has ever brought to bear on the problem by a long shot," said Ed Churchwell, a University of Wisconsin-Madison professor of astronomy who collaborated on the project.

Robert Benjamin, a UW-Whitewater professor of physics and lead author of the study, said the new portrait will help astronomers understand the inner regions of the galaxy and then apply that knowledge to other galaxies in the universe.

Astrophysical Journal Letters has accepted the paper for future publication, the researchers said.

The study should put to rest the idea held by some astronomers that an ellipse is at the center of the galaxy's swirling arms, Churchwell said.

Martin Weinberg, a professor of astronomy at University of Massachusetts who was not involved in the study, said the telescope allowed the researchers to see details that were previously unknown. The findings, he said, "are fairly consistent with what people have found before."

"I don't think this result is hugely surprising," he said. "On the other hand, it's very interesting."

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