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The origin of {\omega} Centauri remains one of the key open problems in stellar dynamics and chemical evolution. Its large abundance spreads and multiple populations suggest a formation history more complex than that of a typical globular…

Astrophysics of Galaxies · Physics 2026-05-21 G. Pagnini , P. Bianchini , P. Di Matteo , A. Mastrobuono-Battisti

The most massive star clusters include several generations of stars with a different chemical composition (mainly revealed by an Na-O anti-correlation) while low-mass star clusters appear to be chemically homogeneous. We are investigating…

Astrophysics of Galaxies · Physics 2015-06-12 A. Bragaglia , R. G. Gratton , E. Carretta , V. D'Orazi , C. Sneden , S. Lucatello

The spreads in chemical abundances inferred by recent precision observations suggest that some or possibly all globular clusters can no longer be considered as simple stellar populations. The most striking case is omega Cen in the sense…

Astrophysics of Galaxies · Physics 2009-03-18 Sukyoung K. Yi

AIMS. In this paper we present the chemical abundance analysis from high resolution UVES spectra of seventeen bright giant stars of the Globular Cluster M~22. RESULTS. We obtained an average iron abundance of [Fe/H]=-1.76\pm0.02 (internal…

Solar and Stellar Astrophysics · Physics 2015-05-13 A. F. Marino , A. P. Milone , G. Piotto , S. Villanova , L. R. Bedin , A. Bellini , A. Renzini

Previous surveys in a few metal-poor globular clusters (GCs) showed that the determination of abundances for Li and proton-capture elements offers a key tool to address the intracluster pollution scenario. In this Letter, we present Na, O,…

Solar and Stellar Astrophysics · Physics 2015-05-18 Valentina D'Orazi , Sara Lucatello , Raffaele Gratton , Angela Bragaglia , Eugenio Carretta , Zhixia Shen , Simone Zaggia , .

Context. Globular clusters are known to host multiple stellar populations, which are a signature of their formation process. The globular cluster E3 is one of the few low-mass globulars that is thought not to host multiple populations.…

Solar and Stellar Astrophysics · Physics 2018-09-12 L. Monaco , S. Villanova , G. Carraro , A. Mucciarelli , C. Moni Bidin

We report the discovery of a unique collection of metal-poor giant-stars, that exhibit anomalously high levels of $^{28}$Si, clearly above typical Galactic levels. Our sample spans a narrow range of metallicities, peaking at $-1.07\pm…

We present the first result of the Ital-FLAMES survey of red giant branch (RGB) stars in omega Cen. Radial velocities with a precision of ~0.5 km/s are presented for 650 members of omega Cen observed with FLAMES-Giraffe at the Very Large…

Astrophysics · Physics 2009-11-13 E. Pancino , A. Galfo , F. R. Ferraro , M. Bellazzini

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

The origin of multiple stellar populations in Globular Clusters (GCs) is one of the greatest mysteries of modern stellar astrophysics. N-body simulations suggest that the present-day dynamics of GC stars can constrain the events that…

Using current observational data and simple dynamical modeling, we demonstrate that Omega Cen is not special among the Galactic globular clusters in its ability to produce and retain the heavy elements dispersed in the AGB phase of stellar…

The globular cluster omega Centauri contains the largest known population of very hot horizontal branch (HB) stars. We have used the Hubble Space Telescope to obtain a far-UV/optical color-magnitude diagram of three fields in omega Cen. We…

The high-quality OmegaCAM photometry of the 3x3 deg around the Orion Nebula Cluster (ONC) in r, and i filters by Beccari et al.(2017) revealed three well-separated pre-main sequences in the color-magnitude diagram (CMD). The objects…

It is well known that newly formed planetary systems undergo processes of orbital reconfiguration and planetary migration. As a result, planets or protoplanetary objects may accrete onto the central star, being fused and mixed into its…

We present multi-wavelength observations of the northern population of Omega Cen from the main-sequence turn-off to high on the red giant branch. We show that the best information about the metallicity and age of the stars can be gained…

Astrophysics · Physics 2016-08-30 Joanne Hughes , George Wallerstein , Floor van Leeuwen

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

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 recently identified an upturn in [Na/Fe] for the population of Solar-type stars in the Galactic young thick disc ($-0.3 < \mathrm{[Fe/H]} < +0.3$) at super-Solar metallicity in data from the GALactic Archaeology with HERMES (GALAH)…

Determining the metal content of low-mass members of young associations provides a tool that addresses different issues, such as triggered star formation or the link between the metal-rich nature of planet-host stars and the early phases of…

Solar and Stellar Astrophysics · Physics 2015-05-13 V. D'Orazi , S. Randich , E. Flaccomio , F. Palla , G. G. Sacco , R. Pallavicini

Our understanding of multiple populations in globular clusters (GCs) largely comes from photometry and spectroscopy: appropriate photometric diagrams can disentangle first and second populations (1P and 2P)-1P having chemical signatures…