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Some recent observations of the abundances of s-process, r-process, and alpha elements in metal-poor stars have led to a new scenario for their formation. According to this scenario, these stars were born in a globular cluster and accreted…

Astrophysics · Physics 2009-11-07 A. Thoul , A. Jorissen , S. Goriely , E. Jehin , P. Magain , A. Noels , G. Parmentier

Context. We investigate the stellar population and the origin of diffuse light around brightest cluster galaxies. Aims. We study the stellar population of the dynamically hot stellar halo of NGC 3311, the brightest galaxy in the Hydra I…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 L. Coccato , O. Gerhard , M. Arnaboldi , G. Ventimiglia

We derive abundance ratios for nine stars in the relatively high-metallicity bulge globular cluster NGC 6380. We find a mean cluster metallicity between [Fe/H]$= -0.80$ and $-0.73$, with no clear evidence for a variation in iron abundances…

We present a study of the spatial distribution of the stellar cluster populations in the star forming galaxy NGC 628. Using Hubble Space Telescope broad band WFC3/UVIS UV and optical images from the Treasury Program LEGUS (Legacy…

The process that leads to the formation and early evolution of low-mass stars is in a broad sense well understood theoretically and carefully traced observationally. The largest uncertainties in this framework reside in the poorly known…

Astrophysics · Physics 2007-05-23 Francesco Palla , Sofia Randich

The aim of the present work is to determine accurate metallicities for a group of red giant branch stars in the field of the bulge Globular Cluster NGC 6441. This is the third paper of a series resulting from a large project aimed at…

Astrophysics · Physics 2009-11-11 R. G. Gratton , S. Lucatello , A. Bragaglia , E. Carretta , Y. Momany , E. Pancino , E. Valenti

Lithium abundances are presented for a sample of 181 nearby F and G dwarfs with accurate {\it Hipparcos} parallaxes. The stars are on circular orbits about the Galactic centre and, hence, are identified as belonging to the thin disk. This…

Astrophysics · Physics 2009-11-10 David L. Lambert , Bacham E. Reddy

We present a cosmologically motivated model for the hierachical formation of the stellar halo which includes a semi-analytic treatment of galactic chemical enrichment coupled to numerical simulations that track the orbital evolution and…

Astrophysics · Physics 2009-11-13 Andreea S. Font , Kathryn V. Johnston , James S. Bullock , Brant Robertson

It is well-established that the vast majority of metal-poor Galactic halo stars shows evidence for enrichment by solely massive stars. Recent observations have identified more varied behavior in the pattern of elemental abundances measured…

Astrophysics · Physics 2016-08-30 Gerard Gilmore , Rosemary F. G. Wyse

The abundance patterns of the most metal-poor stars in the Galactic halo and small dwarf galaxies provide us with a wealth of information about the early Universe. In particular, these old survivors allow us to study the nature of the first…

Astrophysics of Galaxies · Physics 2010-06-15 Anna Frebel

We present the abundances of Li, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Zn, Sr, Y, Zr, and Ba in a wide metallicity range ($-2.8 \le$ [Fe/H] $\le -1.5$). Using the differential technique allowed us to obtain an unprecedented low…

Solar and Stellar Astrophysics · Physics 2017-12-06 Henrique Reggiani , Jorge Meléndez , Chiaki Kobayashi , Amanda Karakas , Vinicius Placco

Recent dynamical analysis based on Gaia data have revealed major accretion events in Milky Way's history. Nevertheless, our understanding of the primordial Galaxy is hindered because the bona fide identification of the most metal-poor and…

The lithium plateau observed in halo stars has long appeared as a paradox in the general context of the lithium abundance behavior in stellar outer layers. First, the plateau is flat, second, the lithium abundance dispersion is extremely…

Astrophysics · Physics 2009-11-06 Sylvie Theado , Sylvie Vauclair

Context: The metal-rich bulge globular cluster NGC6388 shows a blue horizontal branch (HB). Helium (He) enrichment, which is correlated with changes in other light elements, might explain this feature. The hot HB stars in the metal-poor…

Solar and Stellar Astrophysics · Physics 2024-12-03 Sabine Moehler

We investigate the origin of the abundance ratios and scatter of the neutron-capture elements Sr, Ba and Eu in the stellar halo of a Milky Way-mass galaxy formed in a hydrodynamical cosmological simulation, and compare them with those of…

Astrophysics of Galaxies · Physics 2022-09-21 Cecilia Scannapieco , Gabriele Cescutti , Cristina Chiappini

Stellar population models with abundance distributions determined from the analytic Simple model of chemical evolution fail to match observations of the nuclei of bulge-dominated galaxies in three respects. First, the spectral energy…

Astrophysics · Physics 2009-10-28 Guy Worthey , Ben Dorman , Lewis Jones

(Abridged) The hierarchical formation scenario for the stellar halo requires the accretion and disruption of dwarf galaxies, yet low-metallicity halo stars are enriched in alpha-elements compared to similar, low-metallicity stars in dwarf…

This paper explores the quantitative connection between globular clusters and the diffuse stellar population of the galaxies they are associated with. Both NGC 1399 and NGC 4486 (M87) are well suited for this kind of analysis due to their…

Astrophysics · Physics 2009-11-13 J. C. Forte , F. R. Faifer , D. Geisler

We present the abundance analysis for a sample of 7 red giant branch stars in the metal-poor globular cluster NGC 4372 based on UVES spectra acquired as part of the Gaia-ESO Survey. This is the first extensive study of this cluster from…

The new generation of 3D hydrodynamical model atmospheres have been employed to study the impact of a realistic treatment of stellar convection on element abundance determinations of globular cluster stars for a range of atomic and…

Astrophysics · Physics 2007-05-23 Martin Asplund
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