It's astronomical: stars produce like rabbits Intergalactic excitement, way out into space.

July 02, 1992|By Tom Siegfried | Tom Siegfried,Dallas Morning News

COLUMBUS, Ohio -- Astronomers are anxiously studying a bright galaxy that seems to be giving birth to stars faster than rabbits produce bunnies.

"It's the most spectacular object in the universe," says Philip Solomon of the State University of New York at Stony Brook. "It's truly a fantastic starburst."

The galaxy is so far away -- a 12 billion-year journey at the speed of light -- that powerful telescopes show it as a small smudge. But it is actually one of the brightest objects ever discovered, as radiant as 100 trillion suns.

Some astronomers believe that rapid star production can explain the tremendous brightness of this object, which glows mainly with infrared rays. Studies presented in June confirm that the galaxy, known by the intergalactic zip code 10214724, is full of the raw gas and dust from which stars form.

Study of this dust and gas is providing clues about the origin of chemical elements in young galaxies. Astronomers hope more such spectacular galaxies may be found so that those clues can be pursued.

"My guess is the universe is filled with these galaxies, and this is going to change our whole understanding of how galaxies form," said astronomer Eric Becklin of the University of California, Los Angeles. "I think this is a fantastic discovery."

The spectacular galaxy, in the constellation Ursa Major, was discovered in the 1980s during analysis of observations made by NASA's Infrared Astronomical Satellite. Only last year, though, did British astronomers discover how distant and powerful that galaxy is.

Michael Rowan-Robinson, of Queen Mary and Westfield College in London, and colleagues made the discovery while measuring distances to 1,400 galaxies emitting infrared rays. 10214724 turned out to be more than 12 billion light-years away. Rowan-Robinson and colleagues suspected that it might be a protogalaxy -- a galaxy in the process of formation, giving birth to many new stars. But they said it might also be a dust-covered quasar.

Astronomers still don't know for sure which explanation is correct. The latest evidence, reported at a meeting of the American Astronomical Society, indicates that the galaxy is a scene of rapid star production.

The galaxy is loaded with carbon monoxide gas. With colleagues from France, Mr. Solomon measured radio signals emitted from carbon monoxide molecules and found those signals to be surprisingly strong, indicating that massive amounts of gas in this galaxy are enough to make many new stars.

New stars would give off ultraviolet rays that should destroy some of the carbon monoxide molecules, liberating carbon and oxygen atoms. Observations using telescopes in Arizona and Spain have found evidence of such carbon atoms, astronomers Paul Vanden Bout and Robert Brown reported.

If baby stars are responsible for this galaxy's tremendous brightness, the rate of star birth must be fantastically high, 1,000 times faster than the rate of star production in the Milky Way, Earth's home.

"There's kind of a stellar birth control," Mr. Solomon said., "What I think is happening in this fantastic object is a huge scaled-up version of what's happening in our galaxy."

A new star nursery should glow brightly with infrared light because the baby stars heat up surrounding dust, which glows at infrared wavelengths. But to produce the bright glow from this galaxy, the baby stars must be the massive variety known as OB stars, which live fairly short lives and then explode, producing supernovas.

"We think probably a hundred supernova a year form in this galaxy as a result of this star formation," Mr. Solomon said.

But, Mr. Becklin said, "There's no evidence that the luminosity is star formation. It could be a buried quasar very easily."

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