Related papers: The Initial Mass Function and the Dynamical Evolut…
We use N-body simulations to explore the influence of orbital eccentricity on the dynamical evolution of star clusters. Specifically we compare the mass loss rate, velocity dispersion, relaxation time, and the mass function of star clusters…
Both simulations and observations indicate that stars form in filamentary, hierarchically clustered associations, most of which disperse into their galactic field once feedback destroys their parent clouds. However, during their early…
The total mass of a distant star cluster is often derived from the virial theorem, using line-of-sight velocity dispersion measurements and half-light radii, under the implicit assumption that all stars are single (although it is known that…
The evolution of a protostellar binary system is investigated while it is embedded in its parent molecular cloud core and acted upon by gas drag due to dynamical friction. Approximate analytical results are obtained for the energy and…
The "in-situ" formation of very wide binaries is hard to explain as their physical separations are beyond the typical size of a collapsing cloud core ($\approx$5000-10,000 au). Here we investigate the formation process of such systems. We…
Most stars with birth masses larger than that of our Sun belong to binary or higher order multiple systems. Similarly, most stars have stellar winds. Radiation pressure and multiplicity create outflows of material that remove mass from the…
We present velocity dispersion measurements of 20 Local Group stellar clusters (7 < log(age [yrs]) < 10.2) from integrated light spectra and examine the evolution of the stellar mass-to-light ratio, Upsilon_*. We find that the clusters…
We performed populations synthesis calculations of single stars and binaries and show that binary evolution is extremely important for Galactic astronomy. We review several binary evolution models and conclude that they give quite different…
Massive binary evolution models are needed to predict massive star populations in star forming galaxies, the supernova diversity, and the number and properties of gravitational wave sources. Such models are often computed using so called…
We revisit the issue of the recent dynamical evolution of clusters of galaxies using a sample of ACO clusters with z<0.14, which has been selected such that it does not contain clusters with multiple velocity components nor strongly merging…
We examine the statistics of main-sequence / main-sequence, main-sequence / white-dwarf and white-dwarf / white-dwarf wide binaries at 10^2.5-10^4 AU separations in Gaia data. For binaries containing a white dwarf, we find a complex…
(abridged) The case can be made for a rather universal stellar IMF form that can be approximated by a two-part power-law function in the stellar regime. However, there exists a possible hint for a systematic variation with metallicity. A…
The massive (13,000-26,000 Msolar), young (15-30 Myr) Large Magellanic Cloud star cluster NGC 1818 reveals an unexpected increasing binary frequency with radius for F-type stars (1.3-2.2 Msolar). This is in contrast to many older star…
We review recent work that investigates the formation of stellar clusters, ranging in scale from globular clusters through open clusters to the small scale aggregates of stars observed in T associations. In all cases, recent advances in…
A concordance model for angular momentum evolution has been developed by multiple investigators. This approach postulates that star forming regions and clusters are an evolutionary sequence which can be modeled with assumptions about the…
Dynamical models of star clusters are maturing in the sense that effects other than simple point particle dynamics are taken into account. We summarize the relevance of and prospects for this new generation of N-body models.
Observations and theory suggest that star clusters can form in a subvirial (cool) state and are highly substructured. Such initial conditions have been proposed to explain the level of mass segregation in clusters through dynamics, and have…
We investigate a population of primordial binaries during the initial stage of evolution of a star cluster. For our calculations we assume that equal mass stars form rapidly in a tidally truncated gas cloud, that $\sim10$\% of the stars are…
Red giants are increasingly used as stellar population tracers due to their well-understood evolution and the availability of asteroseismic observables. However, stellar binarity can alter observable properties and introduce strong biases.…
We have studied the dynamical evolution of rotating globular clusters with direct $N$-body models. Our initial models are rotating King models; we obtained results for both equal-mass systems and systems composed out of two mass components.…