相关论文: Spectroscopy of Main Sequence Stars in Globular Cl…

It is now clear that abundance variations from star-to-star among the light elements, particularly C, N, O, Na and Al, are ubiquitous within galactic globular clusters; they appear seen whenever data of high quality is obtained for a…

There is vast evidence from observations of multiple stellar populations (MPs) in globular clusters (GCs). To explore the issue theoretically, this work considers two subsolar metallicities, two ages, and two initial abundance patterns: a…

There is compelling observational evidence that globular clusters (GCs) are quite complex objects. A growing body of photometric results indicate that the evolutionary sequences are not simply isochrones in the observational plane -as…

Globular Cluster (GC) formation seems to be a widespread mode of star formation in extreme starbursts triggered by strong interactions and mergers of massive gas-rich galaxies. We use our detailed chemically consistent evolutionary…

Star-to-star variations in abundances of the light elements carbon, nitrogen, oxygen, and sodium have been observed in stars of all evolutionary phases in all Galactic globular clusters that have been thoroughly studied. The data available…

Abundance patterns of the elements C, N, and O are sensitive probes of stellar nucleosynthesis processes and, in addition, O abundances are an important input for stellar age determinations. Understanding the nature of the observed…

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…

For several decades, globular clusters have been considered the best example of simple stellar populations, hosting coeval and chemical homogeneous stars. The last decade of spectroscopic and photometric studies has revealed a more complex…

Stars in globular clusters (GCs) exhibit a peculiar chemical pattern with strong abundance variations in light elements along with a constant abundance in heavy elements. These abundance anomalies can be explained by a primordial pollution…

Studies during the last decade have revealed that nearly all Globular Clusters (GCs) host multiple populations (MPs) of stars with a distinctive chemical patterns in light elements. No evidence of such MPs has been found so far in…

Galactic globular cluster stars exhibit abundance patterns which are not shared by their field counterparts. It is clear from recent spectroscopic observations of GC turnoff stars that these abundance anomalies were already present in the…

Thanks to the large amount of spectroscopic and photometric data assembled in the last couple of decades, the assumption that all globular clusters (GCs) contain a simple mono-metallic stellar population has been modified. Besides the…

The spectroscopic and photometric signals of the star-to-star abundance variations found in globular clusters seem to be correlated with global parameters like the cluster's metallicity, mass and age. Understanding this behaviour could…

Spectra with a high signal-to-noise ratio of 50 stars which are just below the main sequence turnoff and are members of M13 are presented. They yield indices for the strength of the CH and the ultraviolet CN band. There is no evidence for a…

Spreads in light element abundances among stars (a.k.a. multiple populations) are observed in nearly all globular clusters. One way to map such chemical variations using high-precision photometry is to employ a suitable combination of…

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…

Using the 2dF multi-fibre instrument on the AAT, moderate resolution spectra have been obtained for a large sample of stars on the main sequence and at the turnoff in the unusual globular cluster omega Centauri. We investigate the behaviour…

I summarize the results of 15 years of research on the surface abundances of stars in globular clusters. Globular-cluster stars afford a unique view of the physical processes that shape the surface abundances of stars on and beyond the…

Globular clusters contain many stars with surface abundance patterns indicating contributions from hydrogen burning products, as seen in the anti-correlated elemental abundances of e.g. sodium and oxygen, and magnesium and aluminium.…

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…