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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…

Astrophysics of Galaxies · Physics 2011-05-26 Sarah L. Martell

We measure abundances of 12 elements (Na, Mg, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni) in a sample of 86 metal-poor ($-2 \lesssim \text{[Fe/H]} \lesssim -1$) subgiant stars in the solar neighborhood. Abundances are derived from…

We have previously reported on chemical abundance trends with evolutionary state in the globular cluster NGC 6397 discovered in analyses of spectra taken with FLAMES at the VLT. Here, we reinvestigate the FLAMES-UVES sample of 18 stars,…

Solar and Stellar Astrophysics · Physics 2012-09-24 T. Nordlander , A. J. Korn , O. Richard , K. Lind

Globular clusters (GCs) are key to understanding the formation and evolution of our Galaxy. While the abundances of light and Fe-peak elements in GCs have been widely studied, investigations into heavier, neutron-capture elements -- and…

Aims. The aim of this work is the study of abundances of the heavy elements Ba, La, Ce, Nd, and Eu in 56 bulge giants (red giant branch and red clump) with metallicities ranging from -1.3 dex to 0.5 dex. Methods. We obtained high-resolution…

Astrophysics of Galaxies · Physics 2016-01-20 M. Van der Swaelmen , B. Barbuy , V. Hill , M. Zoccali , D. Minniti , S. Ortolani , A. Gomez

We present results from a study of 94 red giant stars in the globular cluster M53. We use low-resolution spectra to measure the strength of CN and CH features at $\sim$3800 and 4300 \r{A}, respectively. The strengths of these features are…

Solar and Stellar Astrophysics · Physics 2021-06-09 Jeffrey M. Gerber , Eileen D. Friel , Enrico Vesperini

Spectroscopic surveys have identified significant numbers of metal-poor nitrogen-rich (N-rich) field stars. These stars are strong candidates for escapees from globular clusters (GCs), as their distinctive nitrogen enhancement mirrors the…

Evolutionary trends in the surface abundances of heavier elements have recently been identified in the globular cluster NGC 6397 ([Fe/H]=-2), indicating the operation of atomic diffusion in these stars. Such trends constitute important…

Astrophysics · Physics 2009-11-13 K. Lind , A. J. Korn , P. S. Barklem , F. Grundahl

We present a homogeneous photometric and spectroscopic analysis of 18 stars along the evolutionary sequence of the metal-poor globular cluster NGC 6397 ([Fe/H] = -2), from the main-sequence turnoff point to red giants below the bump. The…

We used FLAMES+GIRAFFE (Medusa mode) at the VLT to obtain moderately high resolution spectra for 30 red horizontal branch (RHB) stars, 4 RR Lyrae variables, and 17 blue horizontal branch (BHB) stars in the low-concentration, moderately…

Solar and Stellar Astrophysics · Physics 2014-12-24 R. G. Gratton , S. Lucatello , A. Sollima , E. Carretta , A. Bragaglia , Y. Momany , V. D'Orazi , M. Salaris , S. Cassisi , P. B. Stetson

We present abundances of Fe, Na, and O for 1409 red giant stars in 15 galactic globular clusters, derived from the homogeneous analysis of high resolution FLAMES/GIRAFFE spectra. Combining the present data with previous results, we obtained…

Sulphur is an important, volatile alpha element but its role in the Galactic chemical evolution is still uncertain. We derive the S abundances in RGB stars in three Galactic globular clusters (GC) that cover a wide metallicity range…

Astrophysics of Galaxies · Physics 2015-04-29 Nikolay Kacharov , Andreas Koch , Elisabetta Caffau , Luca Sbordone

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…

Astrophysics of Galaxies · Physics 2023-09-06 Eugenio Carretta , Angela Bragaglia

The abundance of fluorine in a few Galactic globular clusters is known to strongly vary from star-to-star. These unexpected chemical properties are an additional confirmation of the chemical inhomogeneities already found in several GC, and…

Solar and Stellar Astrophysics · Physics 2015-06-16 P. de Laverny , A. Recio-Blanco

Chlorine abundances are reported in 15 evolved giants and one M dwarf in the solar neighborhood. The Cl abundance was measured using the vibration-rotation 1-0 P8 line of H$^{35}$Cl at 3.69851 $\mu$m. The high resolution L-band spectra were…

Solar and Stellar Astrophysics · Physics 2016-12-05 Z. G. Maas , C. A. Pilachowski , K. Hinkle

Recent work has revealed two classes of Globular Clusters (GCs), dubbed Type-I and Type-II. Type-II GCs are characterized by a blue- and a red- red giant branch composed of stars with different metallicities, often coupled with distinct…

Solar and Stellar Astrophysics · Physics 2021-12-15 A. F. Marino , A. P. Milone , A. Renzini , D. Yong , M. Asplund , G. S. Da Costa , H. Jerjen , G. Cordoni , M. Carlos , E. Dondoglio , E. P. Lagioia , S. Jang , M. Tailo

We present Na, Mg and Al abundances in a set of 98 stars with known giant planets, and in a comparison sample of 41 ``single'' stars. The results show that the [X/H] abundances (with X = Na, Mg and Al) are, on average, higher in stars with…

Astrophysics · Physics 2009-11-10 P. Beirao , N. C. Santos , G. Israelian , M. Mayor

We present the abundance analysis of 82 red giant branch stars in the dense, metal-poor globular cluster NGC 6093 (M 80), the largest sample of stars analyzed in this way for this cluster. From high resolution UVES spectra of 14 stars and…

Astrophysics of Galaxies · Physics 2015-03-12 E. Carretta , A. Bragaglia , R. G. Gratton , V. D'Orazi , S. Lucatello , A. Sollima , Y. Momany , G. Catanzaro , F. Leone

We present an analysis of the multiple stellar populations of the globular cluster NGC 1851. We used lower resolution spectra of giant stars to measure CN, CH, and calcium H & K spectral indices, and determine elemental abundances for…

Solar and Stellar Astrophysics · Physics 2016-10-31 Jeffrey D. Simpson , Sarah L. Martell , Colin A. Navin

The inner disk of the Galaxy has a number of young star clusters dominated by red supergiants that are heavily obscured by dust extinction and observable only at infrared wavelengths. These clusters are important tracers of the recent star…

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