Groundbreaking study sheds new light on first star formation 13 bln years ago
Washington | September 14, 2007 11:17:32 AM IST
Cosmologists from Durham University, England, have provided new insights into the way the first stars were formed at the start of the Universe, some 13 billion years ago.
The groundbreaking study states that the formation of the first stars depends crucially on the nature of 'dark matter', the strange material that makes up most of the mass in the universe.
For their research, the scientists from the University's Institute for Computational Cosmology carried out sophisticated computer simulations of the formation of these early stars with accepted scientific models of so-called 'cold' as well as 'warm' dark matter.
The computer model found that for slow moving 'cold dark matter' particles, the first stars formed in isolation, with just a single, larger mass star forming per developing spherical dark matter concentration.
In contrast, for faster-moving 'warm dark matter', a large number of stars of differing sizes formed at the same time in a big burst of star formation. The bursts occurred in long and thin filaments.
Dr Liang Gao, one of the researchers said: "These filaments would have been around 9000 light years long, which is about a quarter of the size of the Milky Way galaxy today. The very luminous star burst would have lit-up the dark universe in spectacular fashion."
The study further revealed that stars forming in the cold dark matter were massive.
"The larger a star is, the shorter its life span, so these larger mass stars would not have survived until today. However the warm dark matter model predicts the formation of low mass stars as well as larger ones and the scientists say the low mass stars would survive until today," the research said.
Co-researcher, Dr Tom Theuns, said, the study has paved the way for observational studies which could bring scientists closer to finding out more about the nature of dark matter.
"The discovery has taken scientists a step further to determining the nature of dark matter, which remains a mystery since it was first discovered more than 70 years ago. It also suggests that some of the very first stars that ever formed can still be found in the Milky Way galaxy today," Dr Theuns said.
"A key question that astronomers often ask is 'where are the descendants of the first stars today'? The answer is that, if the dark matter is warm, some of these primordial stars should be lurking around our galaxy," he said in his study in the journal Science.
The scientists also give new insights into the way that black holes could be formed.
Most galaxies harbour in their centres monster black holes, some with masses more than a billion times the mass of the Sun.
The team has hypothesised that collisions between stars in the dense filament in the warm dark matter scenario lead to the formation of the seeds for such black holes.
"Our results raise the exciting prospect of learning about the nature of dark matter from studying the oldest stars. Another telltale sign could be the gigantic black holes that live in centres of galaxies like the Milky Way. They could have formed during the collapse of the first led by warm dark matter," said Dr Theuns.(ANI)
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