UVES Observes Stellar Abundance Anomalies in Globular Clusters

"Globular clusters are very massive assemblies of stars. More than 100 are known in the Milky Way galaxy and most of them harbour several million stars. They are very dense - at their centers, the typical distance between individual stars is comparable to the size of the Solar System, or 100 to 1000 times closer than the corresponding distances between stars in the solar neighborhood. Globular clusters are among the oldest objects known , with estimated ages of 11 to 15 billion years [1]. All stars in a globular cluster were formed at nearly the same moment, and from the same parent cloud of gas and dust. The original chemical composition of all stars is therefore the same. But now, an international group of astronomers [2], working with the UVES Spectrograph at the ESO Very Large Telescope (VLT), have obtained some unexpected results during a detailed analysis of dwarf stars in some globular clusters . Such stars have about the same mass as our Sun and like it, they evolve very slowly. Thus they still ought to have about the same abundances of most chemical elements." Read the complete ESO Science Release.