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(ABRIDGED) The origin of the globular cluster (GC) NGC3201 is under debate. Its retrograde orbit points to an extragalactic origin, but no further chemical evidence supports this idea. Light-element chemical abundances are useful to tag GCs…

Astrophysics of Galaxies · Physics 2018-07-04 Bruno Dias , Ignacio Araya , João Paulo Nogueira-Cavalcante , Leila Saker , Ahmed Shokry

We recently discovered that NGC 3201 has characteristics that set it outside the current twofold classification scheme for Galactic globular clusters (GCs). Most GCs are mono-metallic and show light-element abundance variations (e.g., Na-O…

Solar and Stellar Astrophysics · Physics 2020-03-18 Bruno Dias , Ignacio Araya , João Paulo Nogueira-Cavalcante , Leila Saker , Ahmed Shokry

We propose a new chemical evolution model aimed at explaining the chemical properties of globular clusters (GC) stars. Our model depends upon the existence of (i) a peculiar pre-enrichment phase in the GC's parent galaxy associated with…

Astrophysics of Galaxies · Physics 2009-11-13 Andrea Marcolini , Brad K. Gibson , Amanda I. Karakas , Patricia Sanchez-Blazquez

We present the first comprehensive abundance study of the massive, outer halo globular cluster (GC) M 75 (NGC 6864). This unique system shows a very extended trimodal horizontal branch (HB), but no other clues for multiple populations have…

Astrophysics of Galaxies · Physics 2013-01-11 Nikolay Kacharov , Andreas Koch

NGC 2419 is the most distant massive globular cluster in the outer Galactic halo. It is unusual also due to the chemical peculiarities found in its red giant stars in recent years. We study the stellar population of this unusual object…

Astrophysics of Galaxies · Physics 2015-06-12 M. E. Sharina , V. V. Shimansky , E. Davoust

NGC 1851 is an intriguing Galactic globular cluster, with multiple stellar evolutionary sequences, light and heavy element abundance variations and indications of a surrounding stellar halo. We present the first results of a spectroscopic…

Solar and Stellar Astrophysics · Physics 2015-08-26 Colin A. Navin , Sarah L. Martell , Daniel B. Zucker

The outskirts of globular clusters (GCs) simultaneously retain crucial information about their formation mechanism and the properties of their host galaxy. Thanks to the advent of precision astrometry both their morphological and kinematic…

Astrophysics of Galaxies · Physics 2020-01-08 P. Bianchini , R. Ibata , B. Famaey

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…

Astrophysics of Galaxies · Physics 2015-06-05 Nikolay Kacharov , Andreas Koch

We present the abundance analysis of a sample of more than 120 red giants in the globular cluster (GC) NGC 1851, based on FLAMES spectra. We find a small but detectable metallicity spread. This spread is compatible with the presence of two…

We present a detailed spectroscopic analysis of horizontal branch stars in the globular cluster NGC 3201. We collected optical (4580-5330 A), high resolution (~34,000), high signal-to-noise ratio (~200) spectra for eleven RR Lyrae stars and…

Solar and Stellar Astrophysics · Physics 2018-09-05 D. Magurno , C. Sneden , V. F. Braga , G. Bono , M. Mateo , S. E. Persson , M. Dall'Ora , M. Marengo , M. Monelli , J. R. Neeley

We present the abundance analysis of stars from the tip of the red giant branch (RGB) to below the RGB-bump in the globular cluster NGC 2808, based on high resolution echelle spectra. We derived abundances of Al, alpha-process elements (Si…

Astrophysics · Physics 2009-11-11 Eugenio Carretta

We present chemical abundance analysis of a sample of 15 red giant branch (RGB) stars of the Globular Cluster NGC~1851 distributed along the two RGBs of the (v, v-y) CMD. We determined abundances for C+N+O, Na, $\alpha$, iron-peak, and…

Astrophysics of Galaxies · Physics 2015-05-19 Sandro Villanova , Douglas Geisler , Giampaolo Piotto

Detailed chemical abundances for twenty one elements are presented for four red giants in the anomalous outer halo globular cluster Palomar 1 ($R_{\rm{GC}} = 17.2$ kpc, $Z=3.6$ kpc) using high-resolution (R=36000) spectra from the High…

Astrophysics of Galaxies · Physics 2015-05-28 Charli M. Sakari , Kim A. Venn , Mike Irwin , Wako Aoki , Nobuo Arimoto , Aaron Dotter

The chemical composition of multiple populations in the massive globular cluster (GC) NGC~2808 is addressed with the homogeneous abundance re-analysis of 140 red giant branch (RGB) stars. UVES spectra for 31 stars and GIRAFFE spectra for…

Solar and Stellar Astrophysics · Physics 2015-09-23 Eugenio Carretta

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…

Solar and Stellar Astrophysics · Physics 2023-12-18 T. Nordlander , P. Gruyters , O. Richard , A. J. Korn

Globular clusters (GCs) in the outer Milky Way halo are important tracers of the assembly history of our Galaxy. Only a few of these objects show spreads in heavier elements beyond the canonical light-element variations that have…

Astrophysics of Galaxies · Physics 2019-07-05 Andreas Koch , Siyi Xu , R. Michael Rich

Context: M 75 is a relatively young Globular Cluster (GC) found at 15 kpc from the Galactic centre at the transition region between the inner and outer Milky Way halos. Aims: Our aims are to perform a comprehensive abundance study of a…

Astrophysics of Galaxies · Physics 2015-06-15 Nikolay Kacharov , Andreas Koch , Andrew McWilliam

NGC 6229 is a relatively massive outer halo globular cluster that is primarily known for exhibiting a peculiar bimodal horizontal branch morphology. Given the paucity of spectroscopic data on this cluster, we present a detailed chemical…

Solar and Stellar Astrophysics · Physics 2017-09-27 Christian I. Johnson , Nelson Caldwell , R. Michael Rich , Matthew G. Walker

NGC 5053 provides a rich environment to test our understanding of the complex evolution of globular clusters (GCs). Recent studies have found that this cluster has interesting morphological features beyond the typical spherical distribution…

Astrophysics of Galaxies · Physics 2015-05-20 Owen M. Boberg , Eileen D. Friel , Enrico Vesperini

We present new Keck/HIRES observations of six red giants in the globular cluster NGC 2419. Although the cluster is among the most distant and most luminous in the Milky Way, it was considered chemically ordinary until very recently. Our…

Astrophysics of Galaxies · Physics 2013-02-04 Judith G. Cohen , Evan N. Kirby
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