Stars form in dense regions of molecular clouds of gas and dust. Most of these stars emerge as unbound associations and disperse rapidly to create the field star populations, while some stars emerge in bound open clusters. In addition to this coarse characterization of dynamical state, star formation in the disk of the Milky Way can be thought of as diverse in terms of richness (10-100s of stars per event up to ‘clusters’ as large as 10^5 members) and environment (e.g. triggered or not, range of ISM pressure, and many other parameters). Is dynamical state linked in some way to these other properties? In other words, what star-forming events contribute most to making up the field? In this talk, I will summarize recent results from our group concerning observations of young star clusters that help address these questions. In particular, our work is focussed on determining: a) whether the IMF is Universal or depends on star-forming environment; b) the property of binary stars in the field as compared to young clusters and associations; and c) assessing the dynamical state of young stars as they emerge from the clouds of gas and dust from which they were born.
Institute for Astronomy, Department of Physics, ETH, Zurich, Switzerland