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02-01-09 Did Dark Matter Power Early Stars?

The first stars to light the early universe may have been powered by dark matter,according to a new study.Researchers from the University of Michagan,Ann Arbor call these very first stars "Dark Stars,"and propose that dark matter heating provided the energy for these stars instead of fusion.The researchers propose that with a high concentration of dark matter in the early Universe,the theoretical particles called Weakly Interacting Massive Particles(WIMPs),collected inside the first stars and annihilated themselves to produce a heat source to power the stars."We studied the behavior of WIMPs in the first stars,"said Katherine Freese and her team in their paper,"and found that they can radically alter the stellar evolution.The annihilation products of the dark matter inside the star can be trapped and deposit enough energy to heat the star and prevent it from further collapse."The philosophy behind this research is that 95% of the mass in galaxies and clusters of galaxies is in the form of an unknown type matter,dark matter.The researchers say,"The first stars to form in the universe are a natural place to look for significant amounts of dark matter annihilation,because they form at the right place and the right time.They form at high redshifts,when the universe was still substantially denser than it is today,and at the high density centers of dark matter haloes."