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241. Abundances of F-G main-sequence stars
ID:
ivo://CDS.VizieR/J/A+A/552/A6
Title:
Abundances of F-G main-sequence stars
Short Name:
J/A+A/552/A6
Date:
21 Oct 2021
Publisher:
CDS
Description:
Detailed chemical abundances of volatile and refractory elements have been discussed in the context of terrestrial-planet formation during in past years. The HARPS-GTO high-precision planet-search program has provided an extensive database of stellar spectra, which we have inspected in order to select the best-quality spectra available for late type stars. We study the volatile-to-refractory abundance ratios to investigate their possible relation with the low-mass planetary formation.
242. Abundances of field BHB star candidates
ID:
ivo://CDS.VizieR/J/A+A/364/102
Title:
Abundances of field BHB star candidates
Short Name:
J/A+A/364/102
Date:
21 Oct 2021
Publisher:
CDS
Description:
New spectroscopic observations are presented for a sample of thirty-one blue horizontal branch (BHB) star candidates that are sufficiently nearby to have reliable proper motions. Comments are given on a further twenty-five stars that have previously been suggested as BHB star candidates but which were not included in our sample. Moderately high-resolution spectra ({lambda}/{Delta}{lambda}=~15000) of twenty five of our program stars were taken with the coude feed spectrograph at Kitt Peak. Twelve of the program stars were also observed with the CAT spectrograph at ESO. Six of these program stars were observed from both hemispheres. IUE low-resolution spectra are available for most of our candidates and were used, in addition to other methods, in the determination of their T_eff_ and reddening. Abundances were obtained from these spectra using models computed by Castelli with an updated version of the ATLAS9 code (Kurucz, 1993, CD-ROM No. 13). All thirty one candidates are halo stars.
243. Abundances of field & GC RR Lyrae. I. NGC3201
ID:
ivo://CDS.VizieR/J/ApJ/864/57
Title:
Abundances of field & GC RR Lyrae. I. NGC3201
Short Name:
J/ApJ/864/57
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a detailed spectroscopic analysis of horizontal branch stars in the globular cluster NGC 3201. We collected optical (4580-5330{AA}), high-resolution (~34000), high signal-to-noise ratio (~200) spectra for 11 RR Lyrae stars and one red horizontal branch star with the multifiber spectrograph M2FS with the 6.5m Magellan telescope at the Las Campanas Observatory. From measured equivalent widths, we derived atmospheric parameters and abundance ratios for {alpha} (Mg, Ca and Ti), iron-peak (Sc, Cr, Ni and Zn), and s-process (Y) elements. We found that NGC 3201 is a homogeneous, monometallic ([Fe/H]=-1.47+/-0.04), {alpha}-enhanced ([{alpha}/Fe]=0.37+/-0.04) cluster. The relative abundances of the iron-peak and s-process elements were found to be consistent with solar values. In comparison with other large stellar samples, NGC 3201 RR Lyraes have similar chemical enrichment histories as do those of other old (t>=10Gyr) Halo components (globular clusters; red giants; blue and red horizontal branch stars; and RR Lyraes). We also provided a new average radial velocity estimate for NGC 3201 by using a template velocity curve to overcome the limit of single-epoch measurements of variable stars: Vrad=494+/-2km/s ({sigma}=8km/s).
244. Abundances of five open clusters
ID:
ivo://CDS.VizieR/J/A+A/511/A56
Title:
Abundances of five open clusters
Short Name:
J/A+A/511/A56
Date:
21 Oct 2021
Publisher:
CDS
Description:
The present number of Galactic open clusters that have high resolution abundance determinations, not only of [Fe/H], but also of other key elements, is largely insufficient to enable a clear modeling of the Galactic disk chemical evolution. To increase the number of Galactic open clusters with high quality measurements, we obtained high resolution (R~30000), high quality (S/N~50-100 per pixel), echelle spectra with the fiber spectrograph FOCES, at Calar Alto, Spain, for three red clump stars in each of five Open Clusters. We used the classical equivalent width analysis method to obtain accurate abundances of sixteen elements: Al, Ba, Ca, Co, Cr, Fe, La, Mg, Na, Nd, Ni, Sc, Si, Ti, V, and Y. We also derived the oxygen abundance using spectral synthesis of the 6300{AA} forbidden line.
245. Abundances of five red giants in M5
ID:
ivo://CDS.VizieR/J/AJ/139/2289
Title:
Abundances of five red giants in M5
Short Name:
J/AJ/139/2289
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present LTE chemical abundances for five red giants and one AGB star in the Galactic globular cluster (GC) M5 based on high-resolution spectroscopy using the Magellan Inamori Kyocera Echelle spectrograph on the Magellan 6.5m Clay telescope. Our results are based on a line-by-line differential abundance analysis relative to the well-studied red giant Arcturus.
246. Abundances of Gaia DR2 wide binaries
ID:
ivo://CDS.VizieR/J/MNRAS/492/1164
Title:
Abundances of Gaia DR2 wide binaries
Short Name:
J/MNRAS/492/1164
Date:
21 Oct 2021
Publisher:
CDS
Description:
One of the high-level goals of Galactic archaeology is chemical tagging of stars across the Milky Way to piece together its assembly history. For this to work, stars born together must be uniquely chemically homogeneous. Wide binary systems are an important laboratory to test this underlying assumption. Here we present the detailed chemical abundance patterns of 50 stars across 25 wide binary systems comprised of main-sequence stars of similar spectral type identified in Gaia DR2 with the aim of quantifying their level of chemical homogeneity. Using high-resolution spectra obtained with McDonald Observatory, we derive stellar atmospheric parameters and precise detailed chemical abundances for light/odd-Z (Li, C, Na, Al, Sc, V, Cu), alpha (Mg, Si, Ca), Fe-peak (Ti, Cr, Mn, Fe, Co, Ni, Zn), and neutron capture (Sr, Y, Zr, Ba, La, Nd, Eu) elements. Results indicate that 80% (20 pairs) of the systems are homogeneous in [Fe/H] at levels below 0.02dex. These systems are also chemically homogeneous in all elemental abundances studied, with offsets and dispersions consistent with measurement uncertainties. We also find that wide binary systems are far more chemically homogeneous than random pairings of field stars of similar spectral type. These results indicate that wide binary systems tend to be chemically homogeneous but in some cases they can differ in their detailed elemental abundances at a level of [X/H]~0.10dex, overall implying chemical tagging in broad strokes can work.
247. Abundances of Galactic Bulge red giants
ID:
ivo://CDS.VizieR/J/A+A/465/799
Title:
Abundances of Galactic Bulge red giants
Short Name:
J/A+A/465/799
Date:
21 Oct 2021
Publisher:
CDS
Description:
This paper investigates the peculiar behaviour of the light elements (even, e.e. alpha-elements, and odd atomic numbers) in red giants of the galactic bulge, both in terms of the chemical evolution of the bulge, and in terms of possible deep-mixing mechanisms in these evolved stars. Abundances of the four light elements O, Na, Mg, and Al are measured in 13 core He-burning giant stars (red clump stars) and 40 red giant branch stars in four 25' fields spanning the bulge from -3 to -12{deg} galactic latitude. Special care was taken in the abundance analysis, performing a differential analysis with respect to the metal-rich solar-neighbourhood giant mu Leo, which best resembles our bulge sample stars. This approach minimises systematic effects that can arise in the analysis of cool metal-rich stars due to continuum definition issues and blending by molecular lines (CN) and, cancels out possible model atmosphere deficiencies.
248. Abundances of Galactic G dwarfs
ID:
ivo://CDS.VizieR/J/AJ/131/431
Title:
Abundances of Galactic G dwarfs
Short Name:
J/AJ/131/431
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have studied 23 long-lived G dwarfs that belong to the thin disk and thick disk stellar populations. The stellar data and analyses are identical, reducing the chances for systematic errors in the comparisons of the chemical abundance patterns in the two populations. Abundances have been derived for 24 elements: O, Na, Mg, Al, Si, Ca, Ti, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, La, Ce, Nd, and Eu.
249. Abundances of Galactic red giants
ID:
ivo://CDS.VizieR/J/A+A/513/A35
Title:
Abundances of Galactic red giants
Short Name:
J/A+A/513/A35
Date:
21 Oct 2021
Publisher:
CDS
Description:
The formation and evolution of the Galactic bulge and its relationship with the other Galactic populations is still poorly understood. To establish the chemical differences and similarities between the bulge and other stellar populations, we performed an elemental abundance analysis of alpha- (O, Mg, Si, Ca, and Ti) and Z-odd (Na and Al) elements of red giant stars in the bulge as well as of local thin disk, thick disk and halo giants. We use high-resolution optical spectra of 25 bulge giants in Baade's window and 55 comparison giants (4 halo, 29 thin disk and 22 thick disk giants) in the solar neighborhood. All stars have similar stellar parameters but cover a broad range in metallicity (-1.5<[Fe/H]<+0.5). A standard 1D local thermodynamic equilibrium analysis using both Kurucz and MARCS models yielded the abundances of O, Na, Mg, Al, Si, Ca, Ti and Fe. Our homogeneous and differential analysis of the Galactic stellar populations ensured that systematic errors were minimized.
250. Abundances of giants in five Galactic clusters
ID:
ivo://CDS.VizieR/J/A+A/480/79
Title:
Abundances of giants in five Galactic clusters
Short Name:
J/A+A/480/79
Date:
21 Oct 2021
Publisher:
CDS
Description:
To constrain the formation and chemical evolution of the Galactic disk, we surveyed open clusters of different ages, metal contents, and distances form the Galactic centre. We employed FLAMES on VLT-UT2 to collect UVES spectra of five to ten giant stars in each of the selected clusters, and used them to derive the iron abundance and the detailed chemical composition. Equivalent widths were measured and abundance analysis was performed using the MOOG code and Kurucz model atmospheres on all stars accepted as cluster member on the basis of their radial velocity. We derived the atmospheric parameters and the abundance of Fe for NGC 2324 and NGC 2477 (average [Fe/H]=-0.17 with rms 0.05dex, and +0.07 with rms 0.03dex, respectively), two clusters never analyzed using high resolution spectroscopy. We also derived the abundances of Mg, Al, Ca, Si, Ti, Cr, Ni, and Ba for these two clusters and for NGC 2660, NGC 3960, and Berkeley 32, whose atmospheric parameters and metallicities were measured in a previous paper. We determined the reddening values for the five clusters, based on the spectroscopically determined temperatures, literature photometry, and a colour-temperature relation. All clusters show solar-scaled abundances for alpha- and Fe-peak elements, while [Na/Fe] appears slightly enhances and and [Ba/Fe] significantly enhanced. Our findings were compared to thin-disk stars and other open clusters, and no significant deviation from the standard behavior was found.

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