First Star in Universe Grew Fast

Aug. 1, 2008 -- Star light, star bright. The first star grew fast, but began slight. The first cosmological object formed in the universe was a tiny protostar with a mass of about 1 percent of our sun, according to U.S. and Japanese researchers who spent years developing a complex computer simulation of what it was like after the Big Bang that formed the universe.

This protostar was surrounded by a giant mass of gas and it grew to 100 times the sun's mass over about 10,000 years, according to Naoki Yoshida of Nagoya University in Japan. That is very rapid growth on a cosmic scale.

"The first stars were very different from stars like the sun," explained Harvard astronomy professor Lars Hernquist, co-author of a paper describing the findings in Friday's issue of the journal Science.

While the sun is mostly hydrogen, it also contains oxygen and carbon, he said. The early stars were primarily hydrogen and helium, and were much more luminous and had a shorter life.

"These differences have important implications for what happened afterward," he said at a teleconference.

"This general picture of star formation, and the ability to compare how stellar objects form in different time periods and regions of the universe, will eventually allow investigation into the origins of life and planets," Hernquist said.

The study may prove to be a "Cosmic Rosetta stone" suggested Volker Bromm, an assistant astronomy professor at the University of Texas.

Bromm, who was not part of the research team, said in a commentary that the findings could help researchers finally unlock the problem of understanding star formation, much as the Rosetta stone led to the understanding of ancient Egyptian writing.