相关论文: Pre-main sequence accretion and the formation of m…

We investigated the possibility of producing helium enhanced stars in globular clusters by accreting polluted matter during the pre-main sequence phase. We followed the evolution of two different classes of pre-main sequence accreting…

Globular clusters (GCs), once thought to be well approximated as simple stellar populations (i.e. all stars having the same age and chemical abundance), are now known to host a variety of anomalies, such as multiple discrete (or spreads in)…

The various scenarios proposed for the origin of the multiple, helium-enriched populations in massive globular clusters are critically compared to the relevant constraining observations. Among accretion of helium-rich material by…

Globular clusters host complex stellar populations whose chemical signatures suggest early (3 Myr - 1 Gyr) retention and reprocessing of stellar ejecta, yet direct evidence for intracluster gas is lacking. Here we present a unified…

We investigate the contraction of accreting protoclusters using an extension of n-body techniques that incorporates the accretional growth of stars from the gaseous reservoir in which they are embedded. Following on from Monte Carlo studies…

The formation of star clusters involves the growth of smaller, gas-rich subclusters through accretion of gas from the giant molecular cloud within which the subclusters are embedded. The two main accretion mechanisms responsible for this…

I simulate the evolution of a stellar system hosting two stellar populations whose initial set up is defined according to the two main scenarios proposed for the origin of multiple populations in Galactic globular clusters: (i) formation of…

We investigate the accretion of globular cluster stars on early cosmological timescales through detailed N-body simulations of theoretical GC models to assess the role of this mechanism in Milky Way-like galaxies. For the dynamical…

Globular clusters exhibit abundance variations, defining `multiple populations', which have prompted a protracted search for their origin. Properties requiring explanation include: the high fraction of polluted stars ($\sim…

Some recent observations of the abundances of s-process, r-process, and alpha elements in metal-poor stars have led to a new scenario for their formation. According to this scenario, these stars were born in a globular cluster and accreted…

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…

We investigate the possibility that multiple populations in globular clusters arise as a natural by-product of massive star-cluster formation. We use 3D radiative hydrodynamics simulations for the formation of young massive clusters to…

Globular clusters (GCs) are known to harbor multiple stellar populations. To explain these observations Bastian et al. suggested a scenario in which a second population is formed by the accretion of enriched material onto the low-mass stars…

Models aiming to explain the formation of massive black hole seeds, and in particular the direct collapse scenario, face substantial difficulties. These are rooted in rather ad hoc and fine-tuned initial conditions, such as the simultaneous…

[Abridged] A new scenario --early disc accretion-- has been proposed very recently to explain the origin of the multiple population phenomenon in Galactic globular clusters. It envisages the possibility that a fraction of low- and very…

We present a model for the formation of massive ($M > 10 M_\odot$) stars through accretion-induced collisions in the cores of embedded dense stellar clusters. This model circumvents the problem of accreting onto a star whose luminosity is…

We present a simple physical mechanism that can account for the observed stellar mass spectrum for masses $\ms \simgreat 0.5 \solm$. The model depends solely on the competitive accretion that occurs in stellar clusters where each star's…

In this review, I present the case for how massive stars may form through stellar collisions. This mechanism requires very high stellar densities, up to 4 orders of magnitude higher than are observed in the cores of dense young clusters. In…

The formation of stars with light-element abundance variations in globular clusters and the subsequent dynamical evolution of these multiple populations remains an open question. One of the most widely discussed is the AGB scenario, in…