April 28, 2011

Early Stars Spun Faster Than Current Stars

A new study found that the first stars in the universe were not only massive, but also fast-spinning.

These stars died out long ago, but astronomers are able to see what they were like by looking at later generations of stars.

Cristina Chiappini of the Astrophysical Institute Potsdam in Germany, and colleagues reanalyzed data from the Very Large Telescope of a 12-billion-year-old star cluster.  The team found high levels of metal in the stars.

These levels suggest earlier generations were massive and rotated much faster than present day stars.

According to current theory, the universe was born out of an explosion about 13.7 billion years ago.

The first stars were different than current stars because they were primarily made up of hydrogen and helium.  They also lived fast and die young.

The stars exploded as brilliant supernova and fed the universe with basic elements from which the current stars were created.

The scientists said that if the first stars were fast-spinning, then they most likely died as gamma-ray bursts.  This would mean that scientists today would have a better chance of detecting them.

The researchers said that the ancestral stars that spawned the eight stars observed in the study were likely to have been spinning at 310-miles-per-second at the surface.   This is 250 times as fast as the Sun.

NASA' Swift satellite has the ability to spy gamma-ray bursts.

Jason Tumlinson of the Space Telescope Science Institute in Maryland, who was not a part of the study, said in a statement that this "increases the chances we'll directly observe the death of massive stars during that epoch."

"A higher frequency of bursts increases the chances of seeing the first generations directly," he says.

The study was published on Wednesday in the journal Nature.


Image Caption: Simulation of the formation of the first stars showing fast rotation (Credits: A. Stacy, University of Texas).


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