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211. Abundances in two Galactic bulge stars
ID:
ivo://CDS.VizieR/J/ApJ/699/66
Title:
Abundances in two Galactic bulge stars
Short Name:
J/ApJ/699/66
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present abundance analyses based on high dispersion and high signal-to-noise ratio Magellan spectra of two highly microlensed Galactic bulge stars in the region of the main-sequence turnoff with T_eff_~5650K. We find that MOA-2008-BLG-310S has [Fe/H]^8^=+0.41+/-0.09dex and MOA-2008-BLG-311S has +0.26+/-0.09dex. The abundance ratios for the ~20 elements for which features could be detected in the spectra of each of the two stars follow the trends with [Fe/H] found among samples of bulge giants. Combining these two bulge dwarfs with the results from previous abundance analysis of four other Galactic bulge turnoff region stars, all highly magnified by microlensing, gives a mean [Fe/H] of +0.29dex. This implies that there is an inconsistency between the Fe-metallicity distribution of the microlensed bulge dwarfs and that derived by the many previous estimates based on surveys of cool, luminous bulge giants, which have mean [Fe/H]~-0.1dex.
212. Abundances in zeta Scl open cluster
ID:
ivo://CDS.VizieR/J/A+A/293/75
Title:
Abundances in zeta Scl open cluster
Short Name:
J/A+A/293/75
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
213. Abundances of A-F stars
ID:
ivo://CDS.VizieR/J/A+A/398/1121
Title:
Abundances of A-F stars
Short Name:
J/A+A/398/1121
Date:
21 Oct 2021
Publisher:
CDS
Description:
Fundamental parameters and abundances of 140 A and F-type stars are presented. The barycentric Julian dates and signal-to-noise ratios are also given.
214. Abundances of 5 Ap/Bp stars of NGC 6475
ID:
ivo://CDS.VizieR/J/MNRAS/376/361
Title:
Abundances of 5 Ap/Bp stars of NGC 6475
Short Name:
J/MNRAS/376/361
Date:
21 Oct 2021
Publisher:
CDS
Description:
The connection between age, rotation and chemical abundance of magnetic Ap stars is poorly understood. Using open clusters, we are able to study samples of stars that are both coeval and co-environmental. By determining rotation and chemical abundance for Ap star members of clusters with various ages, the variations of these properties as a function of age and environment can be derived. All four probable Ap star members of the open cluster NGC 6475, as well as one normal late B star, were studied using detailed spectrum synthesis of high-resolution UVES-POP spectra. Probable cluster membership was confirmed for all five stars; however, chemical abundance anomalies only appear to be present in spectra of three. Projected rotational velocity and chemical abundances for 21 elements ranging from C to Eu are presented for the five stars. In the three peculiar stars, we find overabundances of Si, Cr, Mn, Fe and rare earths, such as Nd, characteristic of Ap stars. The set of chemically peculiar stars show fairly homogeneous abundance tables, however, notable differences exist for a few elements. There also exist appreciable differences in the vsini and main-sequence evolutionary stage of the chemically peculiar stars. This may hint at the underlying processes giving rise to the observed abundance anomalies. With this first detailed study of chemical abundances of a complete sample of magnetic Ap/Bp stars in an open cluster, we have initiated an exploration of the environmental and evolutionary influence on chemical peculiarity.
215. Abundances of Baade's Window K giants
ID:
ivo://CDS.VizieR/J/ApJ/636/821
Title:
Abundances of Baade's Window K giants
Short Name:
J/ApJ/636/821
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the first results of a new abundance survey of the Milky Way bulge based on Keck HIRES spectra of 27 K giants in the Baade's Window (l=1{deg},b=-4{deg}) field. The spectral data used in this study are of much higher resolution and signal-to-noise ratio than previous optical studies of Galactic bulge stars. The [Fe/H] values of our stars, which range between 1.29 and +0.51, were used to recalibrate large low-resolution surveys of bulge stars. Our best value for the mean [Fe/H] of the bulge is -0.10+/-0.04. This mean value is similar to the mean metallicity of the local disk and indicates that there cannot be a strong metallicity gradient inside the solar circle. The metallicity distribution of stars confirms that the bulge does not suffer from the so-called G dwarf problem. This paper also details the new abundance techniques necessary to analyze very metal-rich K giants, including a new Fe line list and regions of low blanketing for continuum identification.
216. Abundances of 26 barium stars. I.
ID:
ivo://CDS.VizieR/J/A+A/454/895
Title:
Abundances of 26 barium stars. I.
Short Name:
J/A+A/454/895
Date:
21 Oct 2021
Publisher:
CDS
Description:
The abundances for Na, Al, alpha-, iron-peak, s-, and r-elements have been derived by using spectrum synthesis for a sample of 26 barium stars, including dwarf barium stars. High-resolution spectra were obtained with the FEROS spectrograph at the ESO-1.52m Telescope, along with photometric data with Fotrap at the Zeiss telescope at the LNA.
217. Abundances of 26 barium stars. II.
ID:
ivo://CDS.VizieR/J/A+A/454/917
Title:
Abundances of 26 barium stars. II.
Short Name:
J/A+A/454/917
Date:
21 Oct 2021
Publisher:
CDS
Description:
The aim of this work is to quantify the contributions of the s-, r-, and p-processes for the total abundance of heavy elements from abundances derived for a sample of 26 barium stars. The abundances of the sample stars were compared to those of normal stars, thus identifying the fraction relative to the main component of the s-process s. The fittings of the sigmaN curves (neutron-capture cross-section times abundance, plotted against atomic mass number) for the sample stars suggest that the material from the companion asymptotic giant branch star had approximately the solar isotopic composition as concerns fractions of abundances relative to the s-process main component.
218. Abundances of BHB stars in NGC 1904
ID:
ivo://CDS.VizieR/J/A+A/434/235
Title:
Abundances of BHB stars in NGC 1904
Short Name:
J/A+A/434/235
Date:
21 Oct 2021
Publisher:
CDS
Description:
The abundance measurements are based on high-resolution optical spectroscopical data, obtained during 2 observing runs with the Ultraviolet and Visual Echelle Spectrograph mounted on Kueyen (Very Large Telescope UT2). Ten target stars in the extended blue horizontal branch of the Galactic globular cluster NGC 1904 (M79) have been analysed.
219. Abundances of 3 bright extremely metal-poor giants
ID:
ivo://CDS.VizieR/J/ApJ/864/43
Title:
Abundances of 3 bright extremely metal-poor giants
Short Name:
J/ApJ/864/43
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present detailed chemical abundances of three new bright (V~11), extremely metal-poor ([Fe/H]~-3.0), r-process-enhanced halo red giants based on high-resolution, high-S/N Magellan/MIKE spectra. We measured abundances for 20-25 neutron-capture elements in each of our stars. J1432-4125 is among the most r-process-rich r-II stars, with [Eu/Fe]=+1.44+/-0.11. J2005-3057 is an r-I star with [Eu/Fe]=+0.94+/-0.07. J0858-0809 has [Eu/Fe]=+0.23+/-0.05 and exhibits a carbon abundance corrected for an evolutionary status of [C/Fe]_corr_=+0.76, thus adding to the small number of known carbon-enhanced r-process stars. All three stars show remarkable agreement with the scaled solar r-process pattern for elements above Ba, consistent with enrichment of the birth gas cloud by a neutron star merger. The abundances for Sr, Y, and Zr, however, deviate from the scaled solar pattern. This indicates that more than one distinct r-process site might be responsible for the observed neutron-capture element abundance pattern. Thorium was detected in J1432-4125 and J2005-3057. Age estimates for J1432-4125 and J2005-3057 were adopted from one of two sets of initial production ratios each by assuming the stars are old. This yielded individual ages of 12+/-6Gyr and 10+/-6Gyr, respectively.
220. Abundances of bright metal-poor stars
ID:
ivo://CDS.VizieR/J/ApJ/797/13
Title:
Abundances of bright metal-poor stars
Short Name:
J/ApJ/797/13
Date:
21 Oct 2021
Publisher:
CDS
Description:
The chemical abundances of large samples of extremely metal-poor (EMP) stars can be used to investigate metal-free stellar populations, supernovae, and nucleosynthesis as well as the formation and galactic chemical evolution of the Milky Way and its progenitor halos. However, current progress on the study of EMP stars is being limited by their faint apparent magnitudes. The acquisition of high signal-to-noise spectra for faint EMP stars requires a major telescope time commitment, making the construction of large samples of EMP star abundances prohibitively expensive. We have developed a new, efficient selection that uses only public, all-sky APASS optical, 2MASS near-infrared, and WISE mid-infrared photometry to identify bright metal-poor star candidates through their lack of molecular absorption near 4.6 microns.

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