Wednesday 07 Dec 2016: The Dynamics of Star Clusters
Dr. Nick Wright - Keele University
Physics, 4th Floor 14:00-15:00
The formation and evolution of young star clusters is fundamental to our understanding of the star formation process, the conditions faced by young binary and plenty systems, and the formation of long-lived open and globular clusters. Despite this our understanding of the physical processes that drive this evolution has been limited by the static nature of most observations. This is all changing thanks to a revolution in kinematic data quality from large-scale radial velocity surveys and new astrometric facilities such as Gaia. I will present results from structural and kinematic studies of star clusters that constrain their past dynamical evolution. I will talk about recent kinematic observations of the massive OB association Cygnus OB2 that show it has considerable kinematic substructure and no evidence for the radial expansion pattern predicted by theories such as residual gas expulsion. This means that, contrary to the standard view of OB associations as expanded star clusters, Cygnus OB2 could never have been a dense star cluster in the past. This places strong constraints on the frequency of clustered vs non-clustered star formation and the origin of star clusters and OB associations.