Related papers: Multiple Stellar Populations in Galactic GCs: Obse…
An increasing number of photometric observations of multiple stellar populations in Galactic globular clusters is seriously challenging the paradigm of GCs hosting single, simple stellar populations. These multiple populations manifest…
An increasing number of both photometric and spectroscopic observations over the last years have shown the existence of distinct sub-populations in many Galactic globular clusters and shattered the paradigm of globulars hosting single,…
We are coming to believe that stellar populations in globular clusters are not as simple as they were once thought to be. A growing amount of photometric and spectroscopic evidence shows that globular clusters host at least two different…
This paper presents a review of the characteristics of the multiple stellar populations observed in globular clusters, and of their possible origin. The current theoretical issues and the many open questions are discussed.
I report on some recent results in the framework of a complex project aimed to characterize the photometric properties of stellar populations in Galactic Globular Clusters.
An increasing amount of spectroscopic and photometric evidence is showing that the stellar populations of globular clusters are not as simple as they have been considered for many years. The presence of at least two different populations of…
Galactic globular clusters are not simple stellar populations. And nothing is simple in their study, basically because we try to reconstruct chains of events that occurred at redshift z > 2-3 by observing these objects at z=0, after a…
The majority of Galactic globular clusters (GCs) contain multiple stellar populations displaying specific chemical abundance variations. In particular, GCs generally contain a `primordial' population with abundances similar to field stars,…
It is now commonly accepted that globular clusters (GCs) have undergone a complex formation and that they host at least two stellar generations. This is a recent paradigm and is founded on both photometric and spectroscopic evidence. We…
We review the multiple population (MP) phenomenon of globular clusters (GCs): i.e., the evidence that GCs typically host groups of stars with different elemental abundances and/or distinct sequences in photometric diagrams. Most Galactic…
Observations revealed the presence of multiple stellar populations in globular clusters (GCs) that exhibit wide abundance variations and multiple sequences in Hertzsprung-Russell (HR) diagram. We present a scenario for the formation of…
Globular Clusters (GCs) exhibit star-to-star variations in specific elements (e.g., He, C, N, O, Na, Al) that bare the hallmark of high temperature H burning. These abundance variations can be observed spectroscopically and also…
The existence of star-to-star light-element abundance variations in massive Galactic and extragalactic star clusters has fairly recently superseded the traditional paradigm of individual clusters hosting stars with the same age, and uniform…
Recent progress in studies of globular clusters has shown that they are not simple stellar populations, being rather made of multiple generations. Evidence stems both from photometry and spectroscopy. A new paradigm is then arising for the…
We briefly summarize the impact of the chemical peculiarities associated to the multiple population phenomenon in Galactic Globular Clusters, on the evolutionary properties and spectral energy distribution of second generation stars, in…
Stellar populations contain the most important information about star clus- ter formation and evolution. Until several decades ago, star clusters were believed to be ideal laboratories for studies of simple stellar populations (SSPs).…
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…
Multiple stellar populations in the Milky Way globular clusters manifest themselves with a large variety. Although chemical abundance variations in light elements, including He, are ubiquitous, the amount of these variations is different in…
We take a closer look at our published results of determination of ages, metallicities, helium mass fractions and abundances of chemical elements in Galactic globular clusters in order to find possible signatures of the phenomenon of…
Until recently our knowledge of the Galactic Bulge stellar populations was based on the study of a few low extinction windows. Large photometric and spectroscopic surveys are now underway to map large areas of the bulge. They probe several…