Related papers: Pre-main sequence accretion and the formation of m…
The majority of the inhomogeneities in the chemical composition of Globular Cluster (GC) stars appear due to primordial enrichment by hot-CNO cycled material processed in stars belonging to a first stellar generation. Either massive AGB…
(abridged) We consider the effect of stellar remnants on the interstellar medium of a massive star cluster following the initial burst of star formation. We argue that accretion onto stellar-mass black holes (BHs) is an effective mechanism…
The cosmological lithium problem, that is, the discrepancy between the lithium abundance predicted by the Big Bang nucleosynthesis and the one observed for the stars of the 'Spite plateau', is one of the long standing problems of modern…
The formation mechanism of massive stars remains one of the main open problems in astrophysics, in particular the relationship between the mass of the most massive stars, and that of the cores in which they form. Numerical simulations of…
In order to investigate the origin of multiple stellar populations in the halo and bulge of the Milky Way, we have constructed chemical evolution models for the low-mass proto-Galactic subsystems such as globular clusters (GCs). Unlike…
We investigate the long-term dynamical evolution of two distinct stellar populations of low-mass stars in globular clusters in order to study whether the energy equipartition process can explain the high number of stars harbouring abundance…
We consider here the collective accretion of gas by globular clusters and dwarf galaxies moving through the interstellar medium. In the limit of high velocity and/or sound speed of the ISM, the collective potential of the cluster is…
Observations have revealed that most stars are born in clusters. As these clusters typically contain more mass in gas than in stars, accretion can play an important role in determining the final stellar masses. Numerical simulations of gas…
Star cluster formation is unlikely to be a sudden event: instead, matter will flow to a cluster's formation site over an extended period, even as stars form and inject energy to the region. A cluster's gaseous precursor must persist under…
Several scenarios have been proposed to explain the presence of multiple stellar populations in globular clusters. Many of them invoke multiple generations of stars to explain the observed chemical abundance anomalies, but it has also been…
Some globular clusters are observed to host a population of second generation (SG) stars which show chemical anomalies and must have formed from gas containing matter processed in the envelopes of first generation (FG) cluster stars. We…
We present a new approach to understanding star-to-star helium abundance variations within globular clusters. We begin with detailed radiation hydrodynamics simulations of cluster formation within giant molecular clouds, and investigate the…
Mergers of gas-rich galaxies lead to gravitationally driven increases in gas pressure that can trigger intense bursts of star and cluster formation. Although star formation itself is clustered, most newborn stellar aggregates are unbound…
This chapter reviews the dynamical processes in young stellar clusters. The accretion of gas by individual stars affects the dynamics of the cluster, and the masses of the stars. Dynamical mass segregation cannot explain the degree of mass…
A new scenario --early disc accretion-- has been recently proposed to explain the discovery of multiple stellar populations in Galactic globular clusters. According to this model, the existence of well defined (anti)-correlations amongst…
Hertzsprung-Russell diagrams of star forming regions show a large luminosity spread. This is incompatible with well-defined isochrones based on classic non-accreting protostellar evo- lution models. Protostars do not evolve in isolation of…
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:…
Grids of stellar models are useful tools to derive the properties of stellar clusters, in particular young clusters hosting massive stars, and to provide information on the star formation process in various mass ranges. Because of their…
Multiple Populations represent the standard for Globular Clusters (GC): a fraction (10-50%) of their stars have the same elemental abundances of halo stars of similar metallicity (first generation, or 1G), but the other stars (second…
In this contribution we review our recent numerical work discussing the essential role of the local cluster environment in assembling massive stars. First we show that massive stars are formed from low mass pre-stellar cores and become…