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Stellar mass and metallicity are factors that affect the neutron-capture process. Due to this, the enrichment of the ISM and the abundance of neutron-capture elements vary with time, making them suitable probes for the Galactic chemical…

星系天体物理 · 物理学 2019-11-06 Rebecca Forsberg , Henrik Jönsson , Nils Ryde , Francesca Matteucci

Determining elemental abundances of bulge stars can, via chemical evolution modeling, help to understand the formation and evolution of the bulge. Recently there have been claims both for and against the bulge having a different…

星系天体物理 · 物理学 2017-02-08 H. Jönsson , N. Ryde , M. Schultheis , M. Zoccali

The stellar origin of the elements molybdenum (Mo, Z=42) and ruthenium (Ru, Z=44) is still a matter of debate. Studying their abundances provides valuable insights into nucleosynthesis processes and the broader evolution of neutron-capture…

We present new observational data for the heavy elements molybdenum (Mo, Z = 42) and ruthenium (Ru, Z = 44) in F-, G-, and K-stars belonging to different substructures of the Milky Way. The range of metallicity covered is --1.0 $<$ [Fe/H]…

Context. Recent observations of the Bulge, e.g., its X-shape, cylindrical stellar motions, and a potential fraction of young stars propose that it formed through secular evolution of the disk and not through gas dissipation and/or mergers,…

星系天体物理 · 物理学 2019-05-29 M. Lomaeva , H. Jönsson , N. Ryde , M. Schultheis , B. Thorsbro

This work presents a large consistent study of molybdenum (Mo) and ruthenium (Ru) abundances in the Milky Way. These two elements are important nucleosynthetic diagnostics. In our sample of 71 Galactic metal-poor field stars, we detect Ru…

太阳与恒星天体物理 · 物理学 2014-09-05 Camilla J. Hansen , Anja C. Andersen , Norbert Christlieb

The galactic bulge is a significant part of our galaxy, but it is hard to observe, being both distant and covered by dust in the disk. Therefore there do not exist many hi-res optical spectra of bulge stars with large wavelength coverage,…

星系天体物理 · 物理学 2017-02-08 H. Jönsson , N. Ryde , T. Nordlander , A. Pehlivan , H. Hartman , P. Jönsson , K. Eriksson

Measuring the abundances of neutron-capture elements in Galactic disk stars is an important part of understanding key stellar and galactic processes. In the optical wavelength regime a number of different neutron-capture elements have been…

星系天体物理 · 物理学 2022-09-28 M. Montelius , R. Forsberg , N. Ryde , H. Jönsson , M. Afşar , A. Johanssen , K. F. Kaplan , H. Kim , G. Mace , C. Sneden , B. Thorsbro

The aim of this work is to determine abundances of neutron-capture elements for thin- and thick-disc F, G, and K stars in several sky fields near the north ecliptic pole and to compare the results with the Galactic chemical evolution…

It is debated whether the Milky Way bulge has the characteristics of a classical bulge sooner than those of a pseudobulge. Detailed abundance studies of bulge stars is a key to investigate the origin, history, and classification of the…

We compare abundance ratio trends in a sample of $\sim 11,000$ Milky Way bulge stars ($R_{\rm GC} < 3$ kpc) from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) to those of APOGEE stars in the Galactic disk ($5$ kpc $<…

The Milky Way bulge is an important tracer of the early formation and chemical enrichment of the Galaxy. The abundances of different iron-peak elements in field bulge stars can give information on the nucleosynthesis processes that took…

太阳与恒星天体物理 · 物理学 2020-08-19 H. Ernandes , B. Barbuy , A. Friaça , V. Hill , M. Zoccali , D. Minniti , A. Renzini , S. Ortolani

This study probes the chemical abundances of the neutron-capture elements cerium and neodymium in the inner Milky Way from an analysis of a sample of $\sim$2000 stars in the Galactic Bulge/bar spatially contained within $|X_{Gal}|<$5 kpc,…

In previous works, we computed abundances for the red giant in nearly four dozen S-type symbiotic systems (SySt). The abundances provide information about metallicity, evolutionary status, and possible memberships in Galactic stellar…

太阳与恒星天体物理 · 物理学 2023-10-20 Cezary Gałan , Joanna Mikołajewska , Kenneth H. Hinkle , Richard R. Joyce

Aims. The aim of this work is the study of abundances of the heavy elements Ba, La, Ce, Nd, and Eu in 56 bulge giants (red giant branch and red clump) with metallicities ranging from -1.3 dex to 0.5 dex. Methods. We obtained high-resolution…

星系天体物理 · 物理学 2016-01-20 M. Van der Swaelmen , B. Barbuy , V. Hill , M. Zoccali , D. Minniti , S. Ortolani , A. Gomez

Metal-poor stars in the Galactic halo often show strong enhancements in carbon and/or neutron-capture elements. However, the Galactic bulge is notable for its paucity of carbon-enhanced metal-poor (CEMP) and/or CH-stars, with only two such…

星系天体物理 · 物理学 2019-02-13 A. Koch , M. Reichert , C. J. Hansen , M. Hampel , R. J. Stancliffe , A. Karakas , A. Arcones

Molybdenum abundances in the stars from 13 different open clusters were determined. High-resolution stellar spectra were obtained using the VLT telescope equipped with the UVES spectrograph on Cerro Paranal, Chile. The Mo abundances were…

星系天体物理 · 物理学 2020-06-09 Mishenina , Tamara , Shereta , Elena , Pignatari , Marco , Carraro , Giovanni , Gorbaneva , Tatyana , Soubiran , Caroline

We present radial velocities and chemical abundances of O, Na, Mg, Al, Si, Ca, Cr, Fe, Co, Ni, and Cu for a sample of 156 red giant branch stars in two Galactic bulge fields centered near (l,b)=(+5.25,-3.02) and (0,-12). The (+5.25,-3.02)…

太阳与恒星天体物理 · 物理学 2015-06-22 Christian I. Johnson , R. Michael Rich , Chiaki Kobayashi , Andrea Kunder , Andreas Koch

In a recent study, based on homogeneous barium abundance measurements in open clusters, a trend of increasing [Ba/Fe] ratios for decreasing cluster age was reported. We present here further abundance determinations, relative to four other…

太阳与恒星天体物理 · 物理学 2015-05-28 E. Maiorca , S. Randich , M. Busso , L. Magrini , S. Palmerini

The formation and evolution of the Milky Way bulge is not yet well understood and its classification is ambiguous. Constraints can, however, be obtained by studying the abundances of key elements in bulge stars. The aim of this study is to…

太阳与恒星天体物理 · 物理学 2009-11-13 Nils Ryde , Bengt Edvardsson , Bengt Gustafsson , Kjell Eriksson , Hans Ulrich Kaufl , Ralf Siebenmorgen , Alain Smette
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