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Chemical composition of the stellar cluster Gaia1: No surprise behind Sirius

Mucciarelli, A.; Monaco, L.; Bonifacio, P.; Saviane, I. (EDP Sciences, 2017-07)

We observed six He-clump stars of the intermediate-Age stellar cluster Gaia1 with the MIKE/Magellan spectrograph. A possible extra-galactic origin of this cluster, recently discovered thanks to the first data release of ...

Disentangling the Galactic Halo with APOGEE. I. Chemical and Kinematical Investigation of Distinct Metal-poor Populations

Hayes, C.R.; Majewski, S.R.; Shetrone, M.; Fernández-Alvar, E.; Prieto, C.A.; Schuster, W.J.; Carigi, L.; Cunha, K.; Smith, V.V.; Sobeck, J.; Almeida, A.; Beers, T.C.; Carrera, R.; Fernández-Trincado, J.G.; García-Hernández, D.A.; Geisler, D.; Lane, R.R.; Lucatello, S.; Matthews, A.M.; Minniti, D.; Nitschelm, C.; Tang, B.; Tissera, P.B.; Zamora, O. (Institute of Physics Publishing, 2018)

We find two chemically distinct populations separated relatively cleanly in the [Fe/H]-[Mg/Fe] plane, but also distinguished in other chemical planes, among metal-poor stars (primarily with metallicities [Fe H] < -0.9) ...

Disentangling the Galactic Halo with APOGEE. II. Chemical and Star Formation Histories for the Two Distinct Populations

Fernández-Alvar, E.; Carigi, L.; Schuster, W.J.; Hayes, C.R.; Ávila-Vergara, N.; Majewski, S.R.; Allende Prieto, C.; Beers, T.C.; Sánchez, S.F.; Zamora, O.; García-Hernández, D.A.; Tang, B.; Fernández-Trincado, J.G.; Tissera, P.; Geisler, D.; Villanova, S. (Institute of Physics Publishing, 2018)

The formation processes that led to the current Galactic stellar halo are still under debate. Previous studies have provided evidence for different stellar populations in terms of elemental abundances and kinematics, ...

Gauging the Helium Abundance of the Galactic Bulge RR Lyrae Stars

Marconi, M.; Minniti, D. (Institute of Physics Publishing, 2018)

We report the first estimate of the He abundance of the population of RR Lyrae stars in the Galactic bulge. This is done by comparing the recent observational data with the latest models. We use the large samples of ab-type ...

A spectroscopic study of the globular Cluster NGC 4147

Villanova, S.; Monaco, L.; Moni Bidin, C.; Assmann, P. (OXFORD UNIV PRESS, 2016-08)

We present the abundance analysis for a sample of 18 red giant branch stars in the metal-poor globular cluster NGC 4147 based on medium- and high-resolution spectra. This is the first extensive spectroscopic study of this ...

The Gaia-ESO Survey: Inhibited extra mixing in two giants of the open cluster Trumpler 20?

Smiljanic, R.; Franciosini, E.; Randich, S.; Magrini, L.; Bragaglia, A.; Pasquini, L.; Vallenari, A.; Tautvaišienė, G.; Biazzo, K.; Frasca, A.; Donati, P.; Delgado Mena, E.; Casey, A. R.; Geisler, D.; Villanova, S.; Tang, B.; Sousa, S. G.; Gilmore, G.; Bensby, T.; François, P.; Koposov, S. E.; Lanzafame, A. C.; Pancino, E.; Recio-Blanco, A.; Costado, M. T.; Hourihane, A.; Lardo, C.; de Laverny, P.; Lewis, J.; Monaco, L.; Morbidelli, L.; Sacco, G. G.; Worley, C. C.; Zaggia, S.; Martell, S. (EDP SCIENCES, 2016-06)

Aims. We report the discovery of two Li-rich giants, with A(Li) ~ 1.50, in an analysis of a sample of 40 giants of the open cluster Trumpler 20 (with turnoff mass ~1.8 M⊙). The cluster was observed in the context of the ...

TOPoS: IV. Chemical abundances from high-resolution observations of seven extremely metal-poor stars

Bonifacio, P.; Caffau, E.; Spite, M.; Spite, F.; Sbordone, L.; Monaco, L.; François, P.; Plez, B.; Molaro, P.; Gallagher, A.J.; Cayrel, R.; Christlieb, N.; Klessen, R.S.; Koch, A.; Ludwig, H.-G.; Steffen, M.; Zaggia, S.; Abate, C. (EDP Sciences, 2018-04)

Context. Extremely metal-poor (EMP) stars provide us with indirect information on the first generations of massive stars. The TOPoS survey has been designed to increase the census of these stars and to provide a chemical ...

Investigation of a sample of carbon-enhanced metal-poor stars observed with FORS and GMOS

Caffau, E.; Gallagher, A.J.; Bonifacio, P.; Spite, M.; Duffau, S.; Spite, F.; Monaco, L.; Sbordone, L. (EDP Sciences, 2018-06)

Aims. Carbon-enhanced metal-poor (CEMP) stars represent a sizeable fraction of all known metal-poor stars in the Galaxy. Their formation and composition remains a significant topic of investigation within the stellar ...

On the Chemical Abundances of Miras in Clusters: V1 in the Metal-rich Globular NGC 5927

D'Orazi, V.; Magurno, D.; Bono, G.; Matsunaga, N.; Braga, V.F.; Elgueta, S.S.; Fukue, K.; Hamano, S.; Inno, L.; Kobayashi, N.; Kondo, S.; Monelli, M.; Nonino, M.; Przybilla, N.; Sameshima, H.; Saviane, I.; Taniguchi, D.; Thevenin, F.; Urbaneja-Perez, M.; Watase, A.; Arai, A.; Bergemann, M.; Buonanno, R.; Dall'Ora, M.; Da Silva, R.; Fabrizio, M.; Ferraro, I.; Fiorentino, G.; Francois, P.; Gilmozzi, R.; Iannicola, G.; Ikeda, Y.; Jian, M.; Kawakita, H.; Kudritzki, R.P.; Lemasle, B.; Marengo, M.; Marinoni, S.; Martínez-Vázquez, C.E.; Minniti, D.; Neeley, J.; Otsubo, S.; Prieto, J.L.; Proxauf, B.; Romaniello, M.; Sanna, N.; Sneden, C.; Takenaka, K.; Tsujimoto, T.; Valenti, E.; Yasui, C.; Yoshikawa, T.; Zoccali, M. (Institute of Physics Publishing, 2018-03)

We present the first spectroscopic abundance determination of iron, α-elements (Si, Ca, and Ti), and sodium for the Mira variable V1 in the metal-rich globular cluster NGC 5927. We use high-resolution (R ∼ 28,000), high ...

Ages and Heavy Element Abundances from Very Metal-poor Stars in the Sagittarius Dwarf Galaxy

Hansen, C.J.; El-Souri, M.; Monaco, L.; Villanova, S.; Bonifacio, P.; Caffau, E.; Sbordone, L. (Institute of Physics Publishing, 2018-03)

Sagittarius (Sgr) is a massive disrupted dwarf spheroidal galaxy in the Milky Way halo that has undergone several stripping events. Previous chemical studies were restricted mainly to a few, metal-rich ([Fe/H] ) stars that ...