The ABC of population III

The authors discuss the circumstances in which one would expect Population III stars to form and examine their cosmological consequences. Consideration of their production of light, metals, and remnants places a strong constraint on their formation epoch and mass spectrum. However, these constraints would still allow Population III stars to provide the dark matter in galactic halos, a helium abundance of around 25%, a detectable background of gravitational waves, a possible infrared background, and the generation of large-scale cosmological structure throughout explosions. All of these features could be achieved by VMOs in the range 10/sup 2/ to 10/sup 5/M/sub Θ/. On the other hand, the Population III scenario would be most compatible with the standard Big Bang picture if the stars were SMOs with mass around 10/sup 6/M/sub Θ/. Such stars could still provide the dark matter and detectable gravitational waves