相关论文: Manganese Abundances in Cluster and Field Stars

In this work we present and discuss the observations of the Mn abundances for 247 FGK dwarfs, located in the Galactic disc with metallicity -1<Fe/H]<+0.3. The observed stars belong to the substructures of the Galaxy thick and thin discs,…

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…

CONTEXT: Manganese is an iron-peak element and although the nucleosynthesis path that leads to its formation is fairly well understood, it remains unclear which objects, SN II and/or SN Ia, that contribute the majority of Mn to the…

We present magnesium abundances derived from high resolution spectra using several Mg I and two high excitation Mg II lines for 19 metal-poor stars with [Fe/H] values between -1.1 and +0.2. The main goal is to search for systematic…

Manganese is mainly produced in type II SNe during explosive silicon burning, in incomplete Si-burning regions, and depends on several nucleosynthesis environment conditions, such as mass cut beween the matter ejected and falling back onto…

We investigate aluminum abundance variations in the stellar populations of globular clusters using both literature measurements of sodium and aluminum and APOGEE measurements of nitrogen and aluminum abundances. For the latter, we show that…

We present a chemical composition analysis of 36 giant stars in the mildly metal-poor globular cluster M5 (NGC 5904). The analysis makes use of high resolution data acquired at the Keck I telescope as well as a re-analysis of high…

We derive [Cu/Fe] for 117 giant stars in ten globular clusters (M3, M4, M5, M10, M13, M15, M71, NGC 7006, NCG 288, and NGC 362) and find that globular cluster Cu abundances appear to follow [Cu/Fe] trends found in the field. This result is…

We present abundances of globular clusters in the Milky Way and Fornax from integrated light spectra. Our goal is to evaluate the consistency of the integrated light analysis relative to standard abundance analysis for individual stars in…

We report the first high spectral resolution study of 17 M giants kinematically confirmed to lie within a few parsecs of the Galactic Center, using R=24,000 spectroscopy from Keck/NIRSPEC and a new linelist for the infrared K band. We…

We present a study of the stellar parameters and iron abundances of 18 giant stars in 6 open clusters. The analysis was based on high-resolution and high-S/N spectra obtained with the UVES spectrograph (VLT-UT2). The results complement our…

Following our solar work, we perform NLTE calculations of the Mn abundance for fourteen stars with [Fe/H] from 0 to -2.5, mainly to show how NLTE affects Mn abundances in cool stars of different metallicities.The spectrum synthesis and Mn…

Assuming that in the atmospheres of low-mass, metal-poor red giant stars, 1-D models based on LTE accurately predict the abundance of iron from Fe II, we derive a globular cluster metallicity scale based on the equivalent widths of Fe II…

We investigate sulphur abundance in 74 Galactic stars by using high resolution spectra obtained at ESO VLT and NTT telescopes. For the first time the abundances are derived, where possible, from three optical multiplets: Mult. 1, 6, and 8.…

We investigate the impact of hyperfine splitting on stellar abundance analyses of Mn and Sc, and find that incorrect hfs treatment can lead to spurious abundance trends with metallicity. We estimate corrections to a recent study by Nissen…

We have obtained high-res, high S/N ratio CCD echelle spectra of 10 bright red giants in 3 GCs (47Tuc, NGC6752 and NGC6397) roughly spanning the range of metallicities of the galactic GC system; they reveal no evidence of star to star…

We have obtained [Mg/Fe] measurements for 76.3% of the stars in the MILES spectral library used for understanding stellar atmospheres and stellar populations in galaxies and star clusters. These abundance ratios were obtained through (1) a…

We present a detailed study of the composition of 20 M giants in the Galactic center with 15 of them confirmed to be in the Nuclear Star Cluster. As a control sample we have also observed 7 M giants in the Milky Way Disk with similar…

We present Mn, Co and Eu abundances for a sample of 20 disk F and G dwarfs and subgiants with metallicities in the range -0.8 <= [Fe/H] <= +0.3. We investigate the influence of hyperfine structure (HFS) on the derived abundances of Mn and…

We measure chemical abundances for over 20 elements of 15 N-rich field stars with high resolution ($R \sim 30000$) optical spectra. We find that Na, Mg, Al, Si, and Ca abundances of our N-rich field stars are mostly consistent with those of…