| Abstract: |
Old stars in the halo of our Galaxy preserve the chemical abundance pattern of the gas clouds from which they formed. The oldest halo stars known to date are ~13 Gyr old, and in some of them the fraction of elements heaver than helium (i.e., metals) is a factor of <1/100,000 compared to the fraction of metals in the Sun. Therefore, these stars have presumably formed from gas clouds that were enriched by the nucleosynthesis products of a few, or in some cases perhaps only one, supernova/e. The most metal-poor stars can therefore be used for studying the properties of the first generation(s) of stars in the Universe (e.g., their initial mass function, or rotation), and the physics of star formation in an extremely metal-poor environment. |
