相关论文: Potassium in globular cluster stars: comparing nor…

Context. NGC 1851 is one of several globular clusters for which multiple stellar populations of the subgiant branch have been clearly identified and a difference in metallicity detected. A crucial piece of information on the formation…

A combined effort utilizing spectroscopy and photometry has revealed the existence of a new globular cluster class. These "anomalous" clusters, which we refer to as "iron-complex" clusters, are differentiated from normal clusters by…

We present a multiple stellar population (MSP) study of the globular cluster (GC) NGC~6752. We show that our new photometric CN index accurately traces the CN and the nitrogen abundances in cool giants, finding the discrete double red giant…

Galactic globular clusters (GC) are known to have multiple stellar populations and be characterised by similar chemical features, e.g. O-Na anti-correlation. While second-population stars, identified by their Na overabundance, have been…

NGC 2420 is a $\sim$2 Gyr-old well-populated open cluster that lies about 2 kpc beyond the solar circle, in the general direction of the Galactic anti-center. Most previous abundance studies have found this cluster to be mildly metal-poor,…

NGC3201 is a globular cluster (GC) which shows very peculiar kinematic characteristics including an extreme radial velocity and a highly retrograde orbit, strongly suggesting an extraGalactic origin. Our aims are to study NGC3201 in the…

We present metallicities for red giant stars in the globular cluster NGC 6273 based on intermediate resolution GMOS-S spectra of the calcium triplet region. For the 42 radial velocity members with reliable calcium triplet line strength…

We review the properties of globular clusters which make them useful for studying the Galactic halo, Galactic chemical evolution, and the early stages of the formation of the Milky Way. We review the evidence that GCs have a chemical…

We present an analysis of optical and ultraviolet Hubble Space Telescope photometry for evolved stars in the core of the distant massive globular cluster NGC 2419. We characterize the horizontal branch (HB) population in detail including…

(Abridged) Globular clusters host multiple stellar populations showing different sodium enrichments. These various populations can be observed along the main sequence, red giant and horizontal branch phases. Recently it was shown, however,…

We have derived Mn abundances for more than 200 stars in 19 globular clusters. In addition, Mn abundance determinations have been made for a comparable number of halo field and disk stars possessing an overlapping range of metallicities and…

We present a potassium (K) abundance analysis in extremely metal-poor (EMP) stars based on high-resolution ($R\sim 60000$) spectra obtained with the High Dispersion Spectrograph on the Subaru Telescope, covering the K I resonance lines at…

We measure the C+N+O abundance sum in red giant stars in two Galactic globular clusters, NGC 1851 and NGC 6752. NGC 1851 has a split subgiant branch which could be due to different ages or C+N+O content while NGC 6752 is representative of…

We have observed 15 red giant stars in the relatively massive, metal-poor globular cluster NGC 4833 using the Magellan Inamori Kyocera Echelle spectrograph at Magellan. We calculate stellar parameters for each star and perform a standard…

We present the homogeneous abundance analysis for a combined sample of 185 giants in the bulge globular cluster (GC) NGC 6388. Our results are used to describe the multiple stellar populations and differences or analogies with bulge field…

Globular clusters (GCs) are the oldest stellar systems in the Milky Way. Long time considered as simple stellar populations, nowadays we recognize their complex star formation history through precise abundance analysis of a variety of…

The presence of multiple populations in globular clusters has been well established thanks to high-resolution spectroscopy. It is widely accepted that distinct populations are a consequence of different stellar generations: intra-cluster…

The view of globular clusters (GCs) as simple systems continues to unravel, revealing complex objects hosting multiple chemical peculiarities. Using differential abundance analysis, we probe the chemistry of the Type I GC, NGC 288 and the…

Globular Clusters (GCs) are natural laboratories where stellar and chemical evolution can be studied in detail. In addition, their chemical patterns and kinematics can tell us wich Galactic structure (Disk, Bulge, Halo or extragalactic) the…

We report chemical abundances obtained by SDSS-III/APOGEE for giant stars in five globular clusters located within 2.2 kpc of the Galactic centre. We detect the presence of multiple stellar populations in four of those clusters (NGC 6553,…