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181. Abundances in Milky Way's disk
ID:
ivo://CDS.VizieR/J/A+A/438/139
Title:
Abundances in Milky Way's disk
Short Name:
J/A+A/438/139
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have compiled a large catalogue of metallicities and abundance ratios from the literature in order to investigate abundance trends of several alpha and iron peak elements in the thin disk and the thick disk of the Galaxy. The catalogue includes 743 stars with abundances of Fe, O, Mg, Ca, Ti, Si, Na, Ni and Al in the metallicity range -1.30<[Fe/H]<+0.50. We have checked that systematic differences between abundances measured in the different studies were lower than random errors before combining them. Accurate distances and proper motions from Hipparcos, and radial velocities from several sources have been retrieved for 639 stars and their velocities (U,V,W) and galactic orbits have been computed. Ages of 322 stars have been estimated with the Bayesian method of isochrone fitting developed by Pont & Eyer (2004MNRAS.351..487P). Two samples kinematically representative of the thin and thick disks have been selected, taking into account the Hercules stream which is intermediate in kinematics, but with a probable dynamical origin. Our results show that the two disks are chemically well separated, they overlap greatly in metallicity and both show parallel decreasing trends of alpha elements with increasing metallicity, in the interval -0.80<[Fe/H]<-0.30. The Mg enhancement with respect to Fe of the thick disk is measured to be 0.14dex. An even larger enhancement is observed for Al. The thick disk is clearly older than the thin disk with a tentative evidence of an AMR over 2-3Gyr and a hiatus in star formation before the formation of the thin disk. We do not observe a vertical gradient in the metallicity of the thick disk. The Hercules stream have properties similar to that of the thin disk, with a wider range of metallicity. Metal-rich stars assigned to the thick disk and super metal rich stars assigned to the thin disk appear as outliers in all their properties.
182. Abundances in M71 (NGC 6838)
ID:
ivo://CDS.VizieR/J/A+A/486/941
Title:
Abundances in M71 (NGC 6838)
Short Name:
J/A+A/486/941
Date:
21 Oct 2021
Publisher:
CDS
Description:
Abundance variations in moderately metal-rich globular clusters can give clues about the formation and chemical enrichment of globular clusters. CN, CH, Na, Mg and Al indices in spectra of 89 stars of the template metal-rich globular cluster M71 are measured and implications on internal mixing are discussed.
183. Abundances in M15 RGB/RHB stars
ID:
ivo://CDS.VizieR/J/AJ/141/175
Title:
Abundances in M15 RGB/RHB stars
Short Name:
J/AJ/141/175
Date:
21 Oct 2021
Publisher:
CDS
Description:
The globular cluster M15 is unique in its display of star-to-star variations in the neutron-capture elements. Comprehensive abundance surveys have been previously conducted for handfuls of M15 red giant branch (RGB) and red horizontal branch (RHB) stars. No attempt has been made to perform a single, self-consistent analysis of these stars, which exhibit a wide range in atmospheric parameters. In the current effort, a new comparative abundance derivation is presented for three RGB and six RHB members of the cluster. The analysis employs an updated version of the line transfer code MOOG, which now appropriately treats coherent, isotropic scattering.
184. Abundances in NGC 2243 and Mel 66
ID:
ivo://CDS.VizieR/J/A+A/283/911
Title:
Abundances in NGC 2243 and Mel 66
Short Name:
J/A+A/283/911
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
185. Abundances in NGC 5053 and NGC 5634
ID:
ivo://CDS.VizieR/J/A+A/579/A104
Title:
Abundances in NGC 5053 and NGC 5634
Short Name:
J/A+A/579/A104
Date:
21 Oct 2021
Publisher:
CDS
Description:
The tidal disruption of the Sagittarius dwarf Spheroidal galaxy (Sgr dSph) is producing the most prominent substructure in the Milky Way (MW) halo, the Sagittarius Stream. Aside from field stars, the Sgr dSph is suspected to have lost a number of globular clusters (GC). Many Galactic GC are suspected to have originated in the Sgr dSph. While for some candidates an origin in the Sgr dSph has been confirmed due to chemical similarities, others exist whose chemical composition has never been investigated. NGC 5053 and NGC 5634 are two among these scarcely studied Sgr dSph candidate-member clusters. To characterize their composition we analyzed one giant star in NGC 5053, and two in NGC 5634. We analize high-resolution and signal-to-noise spectra by means of the MyGIsFOS code, determining atmospheric parameters and abundances for up to 21 species between O and Eu. The abundances are compared with those of MW halo field stars, of "unassociated" MW halo globulars, and of the metal poor Sgr dSph main body population. We derive a metallicity of [FeII/H]=-2.26+/-0.10 for NGC 5053, and of [FeI/H]=-1.99+/-0.075 and -1.97+/-0.076 for the two stars in NGC 5634. This makes NGC 5053 one of the most metal poor globular clusters in the MW. Both clusters display an alpha enhancement similar to the one of the halo at comparable metallicity. The two stars in NGC 5634 clearly display the Na-O anticorrelation widespread among MW globulars. Most other abundances are in good agreement with standard MW halo trends. The chemistry of the Sgr dSph main body populations is similar to the one of the halo at low metallicity. It is thus difficult to discriminate between an origin of NGC 5053 and NGC 5634 in the Sgr dSph, and one in the MW. However, the abundances of these clusters do appear closer to that of Sgr dSph than of the halo, favoring an origin in the Sgr dSph system.
186. Abundances in normal late-B and HgMn stars
ID:
ivo://CDS.VizieR/J/A+A/274/335
Title:
Abundances in normal late-B and HgMn stars
Short Name:
J/A+A/274/335
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
187. Abundances in OGLE-2007-BLG-349S
ID:
ivo://CDS.VizieR/J/ApJ/682/1029
Title:
Abundances in OGLE-2007-BLG-349S
Short Name:
J/ApJ/682/1029
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an abundance analysis based on high-dispersion and high signal-to-noise ratio Keck spectra of a very highly microlensed Galactic bulge dwarf, OGLE-2007-BLG-349S, with Teff~5400K. The amplification at the time the spectra were taken ranged from 350 to 450. This bulge star is highly enhanced in metallicity with [Fe/H]=+0.51+/-0.09dex. The abundance ratios for the 28 species of 26 elements for which features could be detected in the spectra are almost all solar. In particular, there is no evidence for enhancement of any of the {alpha}-elements, including O and Mg. We conclude that the high [Fe/H] seen in this star, when combined with the equally high [Fe/H] derived in previous detailed abundance analysis of two other Galactic bulge dwarfs, both also highly magnified by microlensing, implies that the median metallicity in the Galactic bulge is very high. We thus infer that many previous estimates of the metallicity distribution in the Galactic bulge have substantially underestimated the mean Fe metallicity there due to sample bias, and suggest a candidate mechanism for such. If our conjecture proves valid, it may be necessary to update the calibrations for the algorithms used by many groups to interpret spectra and broadband photometry of the integrated light of very metal-rich old stellar populations, including luminous elliptical galaxies.
188. Abundances in 23 open clusters. I.
ID:
ivo://CDS.VizieR/J/ApJ/824/75
Title:
Abundances in 23 open clusters. I.
Short Name:
J/ApJ/824/75
Date:
21 Oct 2021
Publisher:
CDS
Description:
Neutron-capture elements, those with Z>35, are the least well understood in terms of nucleosynthesis and formation environments. The rapid neutron-capture, or r-process, elements are formed in the environments and/or remnants of massive stars, while the slow neutron-capture, or s-process, elements are primarily formed in low-mass AGB stars. These elements can provide much information about Galactic star formation and enrichment, but observational data are limited. We have assembled a sample of 68 stars in 23 open clusters that we use to probe abundance trends for six neutron-capture elements (Eu, Gd, Dy, Mo, Pr, and Nd) with cluster age and location in the disk of the Galaxy. In order to keep our analysis as homogeneous as possible, we use an automated synthesis fitting program, which also enables us to measure multiple (3-10) lines for each element. We find that the pure r-process elements (Eu, Gd, and Dy) have positive trends with increasing cluster age, while the mixed r- and s-process elements (Mo, Pr, and Nd) have insignificant trends consistent with zero. Pr, Nd, Eu, Gd, and Dy have similar, slight (although mostly statistically significant) gradients of ~0.04dex/kpc. The mixed elements also appear to have nonlinear relationships with R_GC_.
189. Abundances in outer parts of Fornax dSph
ID:
ivo://CDS.VizieR/J/A+A/572/A82
Title:
Abundances in outer parts of Fornax dSph
Short Name:
J/A+A/572/A82
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present radial velocities and [Fe/H] abundances for 340 stars in the Fornax dwarf spheroidal from R~16000 spectra. The targets were obtained in the outer parts of the galaxy. Our sample shows a wide range in [Fe/H], between -0.5 and -3.0dex, in which we detect three subgroups. Removal of stars belonging to the most metal-rich population produces a truncated metallicity distribution function that is identical to Sculptor, indicating that these systems shared a similar early evolution. The derived age-metallicity relation shows a fast increase in [Fe/H] at early ages, after which the enrichment flattens significantly for stars younger than ~8Gyr. Additionally, the data indicate a strong population of stars around 4Gyr, followed by a second rapid enrichment in [Fe/H]. Our dynamical analysis reveals an increasing velocity dispersion with decreasing [Fe/H] from sigma_sys_=7.5km/s to 14km/s. The large velocity dispersion at low metallicities is possibly the result of a non-Gaussian velocity distribution among stars older than ~8Gyr. Our sample also includes members from the Fornax globular clusters H2 and H5. In agreement with past studies we find [Fe/H]=-2.04+/-0.04 and a mean radial velocity RV=59.36+/-0.31km/s for H2 and [Fe/H]=-2.02+/-0.11 and RV=59.39+/-0.44km/s for H5. Overall, we find high complexity in the chemical and dynamical properties, with signatures that additionally vary with galactocentric distance.
190. Abundances in planetary nebulae
ID:
ivo://CDS.VizieR/J/A+A/500/1089
Title:
Abundances in planetary nebulae
Short Name:
J/A+A/500/1089
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present new spectroscopic data (90 objects) and derived plasma diagnostics and abundances of a sample of planetary nebulae in the direction of the Galactic center. The spectra were obtained in 2001/2002 with the 4-m class telescope at the Cerro Tololo Interamerican Observatory and the European Southern Observatory.

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