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From ESO VLT/FLAMES/GIRAFFE spectra, abundance measurements of Zn have been made in $\approx$100 individual red giant branch (RGB) stars in the Sculptor dwarf spheroidal galaxy. This is the largest sample of individual Zn abundance…

Astrophysics of Galaxies · Physics 2017-10-18 Ása Skúladóttir , Eline Tolstoy , Stefania Salvadori , Vanessa Hill , Max Pettini

CONTEXT: Extragalactic globular clusters have been studied in elliptical galaxies and in a few luminous spiral galaxies, but little is known about globular clusters in low-luminosity spirals. AIMS: Past observations with the ACS have shown…

Astrophysics · Physics 2009-11-13 Marcelo D. Mora , Soeren S. Larsen , Markus Kissler-Patig

From detailed abundance analysis of >100 Hamburg/ESO candidate extremely metal-poor (EMP) stars we find 45 with [Fe/H] < -3.0 dex. We identify a heretofore unidentified group: Ca-deficient stars, with sub-solar [Ca/Fe] ratios and the lowest…

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 use Hubble Space Telescope imaging to show that the nearby dwarf starburst galaxy NGC 4449 has an unusual abundance of luminous red star clusters. Joint constraints from integrated photometry, low-resolution spectroscopy, dynamical…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Jay Strader , Anil C. Seth , Nelson Caldwell

We present an abundance analysis for the extremely metal poor star HE1424-0241 based on high dispersion spectra from HIRES at Keck. This star is a giant on the lower red giant branch with [Fe/H] ~ -4.0 dex. Relative to Fe, HE1424-0241 has…

We present the analysis of four new extremely metal poor turn-off stars thanks to high-resolution spectra obtained with the Subaru/HDS spectrograph. We determined the abundances and upper limits of Li, C, Mg, Ca, Sr, and Ba. Metallicities…

Solar and Stellar Astrophysics · Physics 2025-07-01 Takuma Suda , Patrick Francois , Shinya Wanajo , Elisabetta Caffau , Wako Aoki , Piercarlo Bonifacio

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 $\gtrsim 15,000$ metal-rich (${\rm [Fe/H]}>-0.2$dex) A and F stars whose surface abundances deviate strongly from Solar abundance ratios and cannot plausibly reflect their birth material composition. These stars are identified by…

Abundance ratios relative to iron for carbon, nitrogen, strontium and barium are presented for a metal-rich main sequence star ([Fe/H]=--0.74) in the globular cluster omega Centauri. This star, designated 2015448, shows depleted carbon and…

Astrophysics · Physics 2009-11-11 Laura M. Stanford , G. S. Da Costa , John E. Norris , Russell D. Cannon

We have collected spectra of about 2000 red giant branch (RGB) stars in 19 Galactic globular clusters (GC) using FLAMES@VLT (about 100 star with GIRAFFE and about 10 with UVES, respectively, in each GC). These observations provide an…

Astrophysics of Galaxies · Physics 2015-05-14 Eugenio Carretta , Angela Bragaglia , Raffaele Gratton , Valentina D'Orazi , Sara Lucatello

Long-slit medium-resolution spectra of the Galactic globular clusters (GCs) NGC6229 and NGC6779, obtained with the CARELEC spectrograph at the 1.93-m telescope of the Haute-Provence observatory, have been used to determine the age, helium…

Solar and Stellar Astrophysics · Physics 2015-09-15 Khamidullina D. A. , Sharina M. E. , Shimansky V. V. , Davoust E

We present, for the first time, a detailed abundance analysis of the carbon star HE 1104$-$0957 based on high resolution (R${\sim}$ 50\,000) spectra. Our analysis shows that the object is an extremely metal-poor star with [Fe/H] $\sim$…

Solar and Stellar Astrophysics · Physics 2023-12-05 Meenakshi Purandardas , Aruna Goswami , Sridharan Rengasamy

We present the helium abundance of the two metal-poor clusters M30 and NGC6397. Helium estimates have been obtained by using the high-resolution spectrograph FLAMES at the ESO Very Large Telescope and by measuring the HeI line at 4471 A in…

Solar and Stellar Astrophysics · Physics 2015-06-19 A. Mucciarelli , L. Lovisi , B. Lanzoni , F. R. Ferraro

NGC1851 possibly shows a spread in [Fe/H], but the relation between this spread and the division in the SGB is unknown. We obtained blue (3950-4600 A) intermediate resolution (R~8,000) spectra for 47 stars on the bright and 30 on the faint…

Solar and Stellar Astrophysics · Physics 2015-06-05 R. G. Gratton , S. Villanova , S. Lucatello , A. Sollima , D. Geisler , E. Carretta , S. Cassisi , A. Bragaglia

NGC1851 is surrounded by a stellar component that extends more than ten times beyond the tidal radius. Although the nature of this stellar structure is not known, it has been suggested to be a sparse halo of stars or associated with a…

NGC 3311, the central cD galaxy in the Hydra cluster, was previously thought to host the most metal-rich globular cluster system known. Ground-based Washington photometry had indicated the almost complete absence of the population of…

Astrophysics · Physics 2009-10-31 Jean P. Brodie , Soeren S. Larsen , Markus Kissler-Patig

We present preliminary abundance analyses of a group of high-velocity metal-poor stars. This report describes our work in progress. We examine the derived abundances in the context of previous studies of metal-poor stars with unusual…

Astrophysics · Physics 2007-05-23 Inese I. Ivans , Bruce Carney , Luisa de Almeida , Chris Sneden

We present a first systematic investigation of the iron abundance in very hot (Teff>50,000K) hydrogen-deficient post-AGB stars. Our sample comprises 16 PG1159 stars and four DO white dwarfs. We use recent FUSE observations as well as HST…

Astrophysics · Physics 2009-11-07 S. Miksa , J. L. Deetjen , S. Dreizler , J. W. Kruk , T. Rauch , K. Werner

We present an abundance analysis based on high resolution spectra of 8 stars selected to span the full range in metallicity in the Draco dwarf spheroidal galaxy. We find [Fe/H] for the sample stars ranges from -1.5 to -3.0 dex. Combining…

Astrophysics of Galaxies · Physics 2009-08-05 Judith G. Cohen , Wenjin Huang