相关论文: Gas expulsion vs gas retention: what process domin…
Young stars form on a wide range of scales, producing aggregates and clusters with various degrees of gravitational self-binding. The loose aggregates have a hierarchical structure in both space and time that resembles interstellar…
Recently de Marchi, Paresce & Pulone (2007) studied a sample of twenty globular clusters and found that all clusters with high concentrations have steep stellar mass-functions while clusters with low concentration have comparatively shallow…
We investigate the dissolution process of young embedded star clusters with different primordial mass segregation levels using fractal distributions by means of N-body simulations. We combine several star clusters in virial and subvirial…
Violent relaxation -- the protocluster dynamical response to the expulsion of its leftover star forming gas -- is a short albeit crucial episode in the evolution of star clusters and star cluster systems. In this contribution, I survey how…
Multiple stellar populations are observed in almost all globular-clusters, but the origin of this phenomenon is still debated. We investigate the role cool supergiants may have played. To do this, we combine two investigative methods:…
After the stars of a new, embedded star cluster have formed they blow the remaining gas out of the cluster. Especially winds of high mass stars and definitely the on-set of the first super novae can remove the residual gas from a cluster.…
The effect of gas ejection on the structure and binding energy of newly formed stellar clusters is investigated. The star formation efficiency (SFE), necessary for forming a gravitationally bound stellar cluster, is determined. Two sets of…
Based on kinematic data observed for very young, massive clusters that appear to be in dynamical equilibrium, it has recently been argued that such young systems set examples where the early residual gas-expulsion did not happen or had no…
The paper deals with the conditions required to form at least two stellar generations in globular clusters under the constraints generated by feedback from massive stars as well as radiative cooling and the metallicity of the primordial…
We examine the effects of gas expulsion on initially sub-structured and out-of-equilibrium star clusters. We perform $N$-body simulations of the evolution of star clusters in a static background potential before removing that potential to…
Most stars form as part of a star cluster. The most massive clusters in the Milky Way exist in two groups - loose and compact clusters - with significantly different sizes at the end of the star formation process. After their formation both…
Little is known about the origins of the giant star clusters known as globular clusters. How can hundreds of thousands of stars form simultaneously in a volume only a few light years across the distance of the sun to its nearest neighbor?…
During star cluster formation, ongoing mass accretion is resisted by stellar feedback in the form of protostellar outflows from the low-mass stars and photo-ionization and radiation pressure feedback from the massive stars. We model the…
The star-to-star differences in the abundance of light elements observed in the globular clusters (GCs) can be explained assuming that a second generation (SG) of stars form in the gas ejected by the asymptotic giant branch (AGB) stars…
Nearly all globular clusters (GCs) studied to date show evidence for multiple stellar populations, in stark contrast to the conventional view that GCs are a mono-metallic, coeval population of stars. Building on earlier work, we propose a…
Recent observational studies of the age distribution of star clusters in nearby merging galaxies and starburst (SB) galaxies indicate a premature death of the young clusters. The fate of an evolving star cluster crucially depends of its gas…
Stars mostly form in groups consisting of a few dozen to several ten thousand members. For 30 years, theoretical models provide a basic concept of how such star clusters form and develop: they originate from the gas and dust of collapsing…
We construct a family of semi-analytic models for young open clusters, including a gaseous component and varying assumptions about the distribution function for the stellar component. The parameters of these models are informed by observed…
Stars form predominantly in groups which display a broad spectrum of masses, sizes, and other properties. Despite this diversity there exist an underlying structure that can constrain cluster formation theories. We show how combining…
Star clusters stand at the intersection of much of modern astrophysics: the interstellar medium, gravitational dynamics, stellar evolution, and cosmology. Here we review observations and theoretical models for the formation, evolution, and…