Open Clusters

Clusters and evolution

Clusters of star occupy a focal position in studies of stellar evolution because they can usually be considered to contain stars that were all born at the same time. They come in two basic types; there are open clusters like the Pleiades, which are usually young and situated near the plane of our Galaxy; and there are globular clusters, like M3, which are very old, compact and distributed in a halo around the Galaxy.

Cool stars in clusters

I use observations of young open clusters to investigate the evolution of rotation, magnetic activity and lithium depletion in stars that are as or less massive than the sun. This programme of research is pursued by undertaking X-ray and optical observations of open clusters like NGC 2516, which has an age of 150 million years and is shown at the top of the page.

Rob Jeffries
Department of Physics
University of Keele
Staffordshire ST5 5BG, UK
19th October 1995