相关论文: Light Element Abundances and Multiple Populations …

Among stars in Galactic globular clusters the carbon abundance tends to decrease with increasing luminosity on the upper red giant branch, particularly within the lowest metallicity clusters. While such a phenomena is not predicted by…

We present stellar atmosphere and evolution models of main sequence stars in two stellar populations of the Galactic globular cluster NGC 6752. These populations represent the two extremes of light-element abundance variations in the…

We present detailed C, O, Na, Mg, Si, Ca, Ti, V, Fe, Zr, Ba, and Eu abundance measurements for 20 red giant branch (RGB) stars in the LMC star cluster NGC 1846 ([Fe/H] = -0.59). This cluster is 1.95 Gyr old and lies just below the supposed…

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…

Variations in chemical abundances with evolutionary phase have been identified among stars in globular and open clusters with a wide range of metallicities. In the metal-poor clusters, these variations compare well with predictions from…

We present analysis of high-resolution spectra of a sample of stars in the globular cluster M5 (NGC 5904). The sample includes stars from the red giant branch (seven stars), the red horizontal branch (two stars), and the asymptotic giant…

Since the discovery of chemically peculiar stars in globular clusters in the last century, the study of multiple populations has become increasingly important, given that chemical inhomogeneity is found in almost all globular clusters.…

We present the first results from the analysis of GIRAFFE spectra of more than 1200 red giants stars in 19 Galactic Globular Clusters (GCs), to study the chemical composition of second generation stars and their link with global cluster…

We present detailed abundance measurements for 45 globular clusters (GCs) in galaxies in (and, in one case, beyond) the Local Group. The measurements are based on new high-resolution integrated-light spectra of GCs in NGC 185, NGC 205, M31,…

Observations in integrated light (2200-4800 A, 8 to 11 A resolution, S/N > 20) of 4 M31 globular clusters and of the cores of six gE galaxies made with the HST/FOS are presented and analyzed. These data are supplemented by IUE observations…

We derived chemical abundances for C, N, O, Na, Mg and Al in 20 asymptotic giant branch (AGB) stars in the globular cluster NGC 6752. All these elements (but Mg) show intrinsic star-to-star variations and statistically significant…

Several recent studies have reported the detection of an anomalous color spread along the red giant branch (RGB) of some globular clusters (GC) that appears only when color indices including a near ultraviolet band (such as Johnson U or…

There is a growing body of evidence for the presence of multiple stellar populations in some globular clusters, including NGC 1851. For most of these peculiar globular clusters, however, the evidence for the multiple red giant-branches…

Recent pieces of evidence have revealed that most, and possibly all, globular star clusters are composed of groups of stars that formed in multiple episodes with different chemical compositions. In this sense, it has also been argued that…

Context. Globular clusters are known to host multiple stellar populations, which are a signature of their formation process. The globular cluster E3 is one of the few low-mass globulars that is thought not to host multiple populations.…

We perform a comparative study of the ex--situ second--parameter pair globular clusters (GCs) M30 and M92, having similar metallicities but different horizontal branch morphologies. We obtain the similar mean primordial carbon abundances…

The location of Galactic Globular Clusters' (GC) stars on the horizontal branch (HB) should mainly depend on GC metallicity, the "first parameter", but it is actually the result of complex interactions between the red giant branch (RGB)…

There is increasing evidence that some massive globular clusters (GCs) host multiple stellar populations having different heavy element abundances enriched by supernovae. They usually accompany multiple red giant branches (RGBs) in the…

We study the formation of multiple populations in globular clusters (GC), under the hypothesis that stars in the second generation formed from the winds of intermediate-mass stars, ejected during the asymptotic giant branch (AGB) phase,…

The Advanced Camera for Surveys on board the Hubble Space Telescope has been used to obtain deep high-resolution images of the giant early-type galaxy NGC 1316 which is an obvious merger remnant. These observations supersede previous,…