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Related papers: Magnesium Isotope Ratios in omega Centauri Red Gia…

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We present abundances of several light, alpha, Fe-peak, and neutron-capture elements for 66 red giant branch (RGB) stars in the Galactic globular cluster Omega Centauri. Our observations lie in the range 12.0<V<13.5 and focus on the…

Solar and Stellar Astrophysics · Physics 2011-02-11 Christian I. Johnson , Catherine A. Pilachowski , R. Michael Rich , Jon P. Fulbright

Near-infrared spectra of 21 giants in omega Centauri, spanning the whole range of metallicities observed in this cluster, are presented. This work is part of a coordinated photometric and spectroscopic campaign in the optical and in the…

Astrophysics · Physics 2009-11-07 L. Origlia , F. R. Ferraro , M. Bellazzini , E. Pancino

Carbon-12 and carbon-13 abundances are measured in eleven red-giant members of the globular cluster Omega Centauri via observations of first-overtone CO bands near 2.3 microns. The mean value for the entire sample is <12C/13C>= 4.3 +/-0.4,…

Astrophysics · Physics 2009-11-07 Verne V. Smith , Donald M. Terndrup , Nicholas B. Suntzeff

We present radial velocities, Fe, and Al abundances for 180 red giant branch (RGB) stars in the Galactic globular cluster Omega Centauri ($\omega$ Cen). The majority of our data lie in the range 11.0$<$V$<$13.5, which covers the RGB from…

Omega Centauri is no longer the only globular cluster known to contain multiple stellar populations, yet it remains the most puzzling. Due to the extreme way in which the multiple stellar population phenomenon manifests in this cluster, it…

We derive abundances of Fe, Na, O, and s-elements from GIRAFFE@VLT spectra for more than 200 red giant stars in the Milky Way satellite Omega Centauri. Our preliminary results are that: (i) we confirm that Omega Centauri exibiths large…

Solar and Stellar Astrophysics · Physics 2015-05-14 A. F. Marino , G. Piotto , R. Gratton , A. P. Milone , M. Zoccali , L. R. Bedin , S. Villanova , A. Bellini

High spectral resolution and high signal-to-noise ratio optical spectra of red giants in the globular cluster Omega Centauri are analysed for stellar parameters and chemical abundances of 15 elements including helium by either line…

Solar and Stellar Astrophysics · Physics 2020-05-20 Arumalla B. S. Reddy

We present elemental abundances for 855 red giant branch (RGB) stars in the globular cluster Omega Centauri (w Cen) from spectra obtained with the Blanco 4m telescope and Hydra multifiber spectrograph. The sample includes nearly all RGB…

Solar and Stellar Astrophysics · Physics 2015-05-19 Christian I. Johnson , Catherine A. Pilachowski

Medium resolution spectra of more than 400 subgiant and turn-off region stars in Omega Centauri were analysed. The observations were performed at the VLT/Paranal with FORS2/MXU. In order to determine the metallicities of the sample stars,…

Astrophysics · Physics 2007-05-23 Andrea Kayser , Michael Hilker , Tom Richtler , Philip G. Willemsen

We present spectroscopic abundances and radial velocities for giant stars in the Galactic globular cluster omega Centauri based on the CaII infrared triplet. Two samples of stars were observed: 234 stars at M_V = 1.25 on the lower giant…

Astrophysics · Physics 2009-10-05 Nicholas B. Suntzeff , Robert P. Kraft

A revised metallicity calibration of the Stroemgren (b-y),m_1 diagram, based on a sample of globular cluster and field red giant stars, is presented. This new calibration has been used to determine Stroemgren metallicities ([Fe/H]_phot) for…

Astrophysics · Physics 2007-05-23 M. Hilker , T. Richtler

We present manganese abundances in 10 red-giant members of the globular cluster Omega Centauri; 8 stars are from the most metal-poor population (RGB MP and RGB MInt1) while two targets are members of the more metal rich groups (RGB MInt2…

Astrophysics of Galaxies · Physics 2015-05-19 Katia Cunha , Verne V. Smith , Maria Bergemann , Nicholas B. Suntzeff , David L. Lambert

We present results of an extensive spectroscopic survey of Subgiant stars in the stellar system omega Centauri. Using infrared CaII triplet lines, we derived metallicities and radial velocities for more than 250 stars belonging to different…

Astrophysics · Physics 2009-11-13 A. Sollima , E. Pancino , F. R. Ferraro , M. Bellazzini , O. Straniero , L. Pasquini

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

Abundances relative to iron for carbon, nitrogen, strontium and barium are presented for 33 stars on the red giant branch of the globular cluster omega Centauri. They are based on intermediate-resolution spectroscopic data covering the blue…

Solar and Stellar Astrophysics · Physics 2015-05-18 Laura M. Stanford , Gary S. Da Costa , John E. Norris

Isotopic abundance ratios 24^Mg:25^Mg:26^Mg are derived for 20 stars from high- resolution spectra of the MgH A-X 0-0 band at 5140AA. With the exception of the weak g-band giant HR 1299, the stars are dwarfs that sample the metallicity…

Astrophysics · Physics 2009-10-31 Pamela Gay , David L. Lambert

For the first time, the abundances of a large sample of subgiant and turn-off region stars in omega Centauri have been measured, the data base being medium resolution spectroscopy from FORS2 at the VLT. Absolute iron abundances were derived…

Astrophysics · Physics 2009-11-10 Michael Hilker , Andrea Kayser , Tom Richtler , Philip Willemsen

We present a chemical-composition analysis of 77 red-giant stars in Omega Centauri. We have measured abundances for carbon and nitrogen, and combined our results with abundances of O, Na, La, and Fe that we determined in our previous work.…

Solar and Stellar Astrophysics · Physics 2015-06-03 A. F. Marino , A. P. Milone , G. Piotto , S. Cassisi , F. D'Antona , J. Anderson , A. Aparicio , L. R. Bedin , A. Renzini , S. Villanova

In this study, we report the results of Fe, Mg, Al, and Si abundances analysis for a sample of 439 stars in Omega Centauri, using high-resolution spectra obtained with the VLT/FLAMES multi-object spectrograph. Our analysis reveals the…

Solar and Stellar Astrophysics · Physics 2024-01-10 Deimer Antonio Alvarez Garay , Alessio Mucciarelli , Michele Bellazzini , Carmela Lardo , Paolo Ventura

We analysed high-resolution UVES spectra of six stars belonging to the subgiant branch of omega Centauri, and derived abundance ratios of 19 chemical elements (namely Al, Ba, C, Ca, Co, Cr, Cu, Fe, La, Mg, Mn, N, Na, Ni, Sc, Si, Sr, Ti, and…

Solar and Stellar Astrophysics · Physics 2015-05-20 E. Pancino , A. Mucciarelli , L. Sbordone , M. Bellazzini , L. Pasquini , L. Monaco , F. R. Ferraro
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