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Related papers: Abundance variations in the globular cluster M71 (…

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We present abundances of C, N, O, F, Na, and Fe in six giant stars of the tidally disrupted globular cluster NGC 6712. The abundances were derived by comparing synthetic spectra with high resolution infrared spectra obtained with the…

Recent work has shown that most globular clusters have at least two chemically distinct components, as well as cluster-to-cluster differences in the mean [O/Fe], [Mg/Fe], and [Si/Fe] ratios at similar [Fe/H] values. In order to investigate…

Solar and Stellar Astrophysics · Physics 2015-06-05 Don A. VandenBerg , Peter A. Bergbusch , Aaron Dotter , Jason W. Ferguson , Georges Michaud , Jacques Richer , Charles Proffitt

We have made observations with the Keck I telescope and HIRES at a resolution of $\sim$45,000 of five nearly identical stars at the turn-off of the metal-rich globular cluster M 71. Our mean Fe abundance, [Fe/H]=-0.80 +-0.02, is in…

We present ages, [Fe/H] and abundances of the alpha elements Ca I, Si I, Ti I, Ti II, and light elements Mg I, Na I, and Al I for 31 globular clusters in M31, which were obtained from high resolution, high signal-to-noise ratio (SNR$>60$)…

Astrophysics of Galaxies · Physics 2015-06-23 J. E. Colucci , R. A. Bernstein , J. Cohen

We obtained spectra of some 140 globular clusters (GCs) associated with the Virgo central cD galaxy M87 with the Subaru/FOCAS MOS mode. The fundamental properties of GCs such as age, metallicity and $\alpha$-element abundance are…

Astrophysics of Galaxies · Physics 2021-09-29 Sooyoung Kim , Suk-Jin Yoon , Sang-Yoon Lee , Chul Chung , Sangmo Tony Sohn

We have determined Al, $\alpha$, Fe-peak, and neutron capture elemental abundances for five red giant branch (RGB) stars in the Galactic globular cluster M10. Abundances were determined using equivalent width analyses of moderate resolution…

We present the homogeneous reanalysis of Mg and Al abundances from high resolution UVES/FLAMES spectra for 31 red giants in the globular cluster NGC 2808. We found a well defined Mg-Al anticorrelation reaching a regime of subsolar Mg…

Solar and Stellar Astrophysics · Physics 2015-06-23 Eugenio Carretta

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

Self-enrichment processes occurring in the early stages of a globular cluster lifetime are generally invoked to explain the observed CNONaMgAl abundance anticorrelations within individual Galactic globulars.We have tested, with fully…

Astrophysics · Physics 2009-11-11 Maurizio Salaris , Achim Weiss , Jason W. Ferguson , David J. Fusilier

Recent theoretical yields and chemical evolution models demonstrate that intermediate-mass AGB stars cannot reproduce the observed abundance distributions of O, Na, Mg, and Al. As a further observational test of this finding, we present…

We used the multifiber spectrograph FLAMES on the ESO Very Large Telescope UT2 to derive atmospheric parameters, metallicities and abundances of O and Na for 79 red giant stars in the Galactic globular cluster NGC 6218 (M 12). We analyzed…

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…

Astrophysics of Galaxies · Physics 2015-05-20 C. Lardo , M. Bellazzini , E. Pancino , E. Carretta , A. Bragaglia , E. Dalessandro

Globular Clusters are among the oldest objects in the Galaxy, thus their researchers are key to understanding the processes of evolution and formation that the galaxy has experienced in early stages. Spectroscopic studies allow us to carry…

Astrophysics of Galaxies · Physics 2021-03-24 Carolina Montecinos , S. Villanova , C. Muňoz , C. C. Cortés

We used the UVES spectrograph on Kueyen (VLT UT2) to perform the abundance analysis of stars at the base of the giant branch (RGB) and at the main sequence turn-off in the globular cluster 47 Tuc (NGC 104). High dispersion spectra (R ~…

There is increasing evidence for the presence of multiple red giant branches (RGBs) in the color-magnitude diagrams of massive globular clusters (GCs). In order to investigate the origin of this split on the RGB, we have performed new…

The globular cluster M 2 has a photometrically detected double red giant branch (RGB) sequence. We investigate here the chemical differences between the two RGBs in order to gain insight in the star formation history of this cluster. The…

Solar and Stellar Astrophysics · Physics 2015-06-15 C. Lardo , E. Pancino , A. Mucciarelli , M. Bellazzini , M. Rejkuba , S. Marinoni , G. Cocozza , G. Altavilla , S. Ragaini

In the past decade, the notion that globular clusters (GCs) are composed of coeval stars with homogeneous initial chemical compositions has been challenged by growing evidence that they host an intricate stellar population mix, likely…

We have observed ten red giant stars in four old Large Magellanic Cloud globular clusters with the high-resolution spectrograph MIKE on the Magellan Landon Clay 6.5-m telescope. The stars in our sample have up to 20 elemental abundance…

Astrophysics · Physics 2009-11-13 Jennifer A. Johnson , Inese I. Ivans , Peter B. Stetson

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…

Solar and Stellar Astrophysics · Physics 2018-10-17 Nate Bastian , Carmela Lardo

We performed low-resolution spectroscopy for the red giant stars in the Galactic globular cluster (GC) NGC 5286, which is known to show intrinsic heavy element abundance variations. We found that the observed stars in this GC are clearly…

Astrophysics of Galaxies · Physics 2017-07-26 Dongwook Lim , Seungsoo Hong , Young-Wook Lee