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141. Abundances for all seven stars in Latham 1
ID:
ivo://CDS.VizieR/J/AJ/152/176
Title:
Abundances for all seven stars in Latham 1
Short Name:
J/AJ/152/176
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present elemental abundances for all seven stars in Moving Group W11450 (Latham 1) to determine if they may be chemically related. These stars appear to be both spatially and kinematically related, but no spectroscopic abundance analysis exists in literature. Abundances for eight elements were derived via equivalent width analyses of high-resolution (R~60000), high-signal-to-noise ratio (<S/N> ~100) spectra obtained with the Otto Struve 2.1m telescope and the Sandiford Echelle Spectrograph at McDonald Observatory. The large star-to-star scatter in metallicity, -0.55{<=}[Fe/H]{<=}0.06dex ({sigma}=0.25), implies these stars were not produced from the same chemically homogeneous molecular cloud, and are therefore not part of a remnant or open cluster as previously proposed. Prior to this analysis, it was suggested that two stars in the group, W11449 and W11450, are possible wide binaries. The candidate wide binary pair show similar chemical abundance patterns with not only iron but with other elements analyzed in this study, suggesting the proposed connection between these two stars may be real.
142. Abundances for lines of n-capture in 19 stars
ID:
ivo://CDS.VizieR/J/A+A/287/927
Title:
Abundances for lines of n-capture in 19 stars
Short Name:
J/A+A/287/927
Date:
21 Oct 2021
Publisher:
CDS
Description:
(no description available)
143. Abundances for 4 metal-poor stars
ID:
ivo://CDS.VizieR/J/A+A/627/A173
Title:
Abundances for 4 metal-poor stars
Short Name:
J/A+A/627/A173
Date:
21 Oct 2021
Publisher:
CDS
Description:
Very metal-poor halo stars are the best candidates for being among the oldest objects in our Galaxy. Samples of halo stars with age determination and detailed chemical composition measurements provide key information for constraining the nature of the first stellar generations and the nucleosynthesis in the metal-poor regime. Age estimates are very uncertain and are available for only a small number of metal-poor stars. Here we present the first results of a pilot program aimed at deriving precise masses, ages and chemical abundances for metal-poor halo giants using asteroseismology, and high-resolution spectroscopy. We obtained high-resolution UVES spectra for four metal-poor RAVE stars observed by the K2 satellite. Seismic data obtained from K2 light curves helped improving spectroscopic temperatures, metallicities and individual chemical abundances. Mass and ages were derived using the code PARAM, investigating the effects of different assumptions (e.g. mass loss, [alpha/Fe]-enhancement). Orbits were computed using Gaia DR2 data. {The stars are found to be "normal" metal-poor halo stars (i.e. non C-enhanced), with an abundance pattern typical of old stars (i.e. alpha and Eu-enhanced), and with masses in the 0.80-1.0M_{sun}_ range. The inferred model-dependent stellar ages are found to range from 7.4 to 13.0Gyr, with uncertainties of ~30%-35%. We also provide revised masses and ages for metal-poor stars with Kepler seismic data from APOGEE survey and a set of M4 stars. The present work shows that the combination of asteroseismology and high-resolution spectroscopy provides precise ages in the metal-poor regime. Most of the stars analysed in the present work (covering the metallicity range of [Fe/H]~-0.8 to -2dex), are very old >9Gyr (14 out of 19 stars), and all of them are older than >5Gyr (within the 68 percentile confidence level).
144. Abundances for 6 million stars from LAMOST DR5
ID:
ivo://CDS.VizieR/J/ApJS/245/34
Title:
Abundances for 6 million stars from LAMOST DR5
Short Name:
J/ApJS/245/34
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the determination of stellar parameters and individual elemental abundances for 6 million stars from ~8 million low-resolution (R~1800) spectra from LAMOST DR5. This is based on a modeling approach that we dub the data-driven Payne (DD-Payne), which inherits essential ingredients from both the Payne and the Cannon. It is a data-driven model that incorporates constraints from theoretical spectral models to ensure the derived abundance estimates are physically sensible. Stars in LAMOST DR5 that are in common with either GALAH DR2 or APOGEE DR14 are used to train a model that delivers stellar parameters (Teff, log g, Vmic) and abundances for 16 elements (C, N, O, Na, Mg, Al, Si, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, and Ba) over a metallicity range of -4dex<[Fe/H]<0.6dex when applied to the LAMOST spectra. Cross-validation and repeat observations suggest that, for S/N_pixel_>=50, the typical internal abundance precision is 0.03-0.1dex for the majority of these elements, with 0.2-0.3dex for Cu and Ba, and the internal precision of Teff and logg is better than 30K and 0.07dex, respectively. Abundance systematics at the ~0.1dex level are present in these estimates but are inherited from the high-resolution surveys' training labels. For some elements, GALAH provides more robust training labels, for others, APOGEE. We provide flags to guide the quality of the label determination and identify binary/multiple stars in LAMOST DR5.
145. Abundances for red giants in NGC 6342 and NGC 6366
ID:
ivo://CDS.VizieR/J/AJ/152/21
Title:
Abundances for red giants in NGC 6342 and NGC 6366
Short Name:
J/AJ/152/21
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present radial velocities and chemical abundances for red giant branch stars in the Galactic bulge globular clusters NGC6342 and NGC6366. The velocities and abundances are based on measurements of high-resolution (R>~20000) spectra obtained with the MMT-Hectochelle and WIYN-Hydra spectrographs. We find that NGC6342 has a heliocentric radial velocity of +112.5km/s ({sigma}=8.6km/s), NGC6366 has a heliocentric radial velocity of -122.3km/s ({sigma}=1.5km/s), and both clusters have nearly identical metallicities ([Fe/H]~-0.55). NGC6366 shows evidence of a moderately extended O-Na anti-correlation, but more data are needed for NGC6342 to determine if this cluster also exhibits the typical O-Na relation likely found in all other Galactic globular clusters. The two clusters are distinguished from similar metallicity field stars as having larger [Na/Fe] spreads and enhanced [La/Fe] ratios, but we find that NGC6342 and NGC6366 display {alpha} and Fe-peak element abundance patterns that are typical of other metal-rich ([Fe/H]>-1) inner Galaxy clusters. However, the median [La/Fe] abundance may vary from cluster-to-cluster.
146. Abundances for stars in 18 open clusters
ID:
ivo://CDS.VizieR/J/MNRAS/490/1821
Title:
Abundances for stars in 18 open clusters
Short Name:
J/MNRAS/490/1821
Date:
21 Oct 2021
Publisher:
CDS
Description:
The study of open-cluster chemical abundances provides insights on stellar nucleosynthesis processes and on Galactic chemo-dynamical evolution. In this paper we present an extended abundance analysis of 10 species (Fe, Ni, Cr, V, Sc, Si, Ca, Ti, Mg, O) for red giant stars in 18 OCCASO clusters. This represents a homogeneous sample regarding the instrument features, method, line list and solar abundances from confirmed member stars. We perform an extensive comparison with previous results in the literature, and in particular with the Gaia FGK Benchmark stars Arcturus and mu Leo. We investigate the dependence of [X/Fe] with metallicity, Galactocentric radius (6.5kpc<RGC<11kpc), age (0.3Gyr<Age<10Gyr), and height above the plane (|z|<1000pc). We discuss the observational results in the chemo-dynamical framework, and the radial migration impact when comparing with chemical evolution models. We also use APOGEE DR14 data to investigate the differences between the abundance trends in RGC and |z| obtained for clusters and for field stars.
147. Abundances for stars in Plaut's window
ID:
ivo://CDS.VizieR/J/ApJ/749/175
Title:
Abundances for stars in Plaut's window
Short Name:
J/ApJ/749/175
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report chemical abundances of Na, Al, Zr, La, Nd, and Eu for 39 red giant branch (RGB) stars and 23 potential inner disk red clump stars located in Plaut's low-extinction window. We also measure lithium for a super Li-rich RGB star. The abundances were determined by spectrum synthesis of high-resolution (R{approx}25000), high signal-to-noise (S/N ~ 50-100/pixel) spectra obtained with the Blanco 4m telescope and Hydra multifiber spectrograph. For the bulge RGB stars, we find a general increase in the [Na/Fe] and [Na/Al] ratios with increasing metallicity, and a similar decrease in [La/Fe] and [Nd/Fe]. Additionally, the [Al/Fe] and [Eu/Fe] abundance trends almost identically follow those of the {alpha}-elements, and the [Zr/Fe] ratios exhibit relatively little change with [Fe/H]. The consistently low [La/Eu] ratios of the RGB stars indicate that at least a majority of bulge stars formed rapidly (<~1Gyr) and before the main s-process could become a significant pollution source. In contrast, we find that the potential inner disk clump stars exhibit abundance patterns more similar to those of the thin and thick disks. Comparisons between the abundance trends at different bulge locations suggest that the inner and outer bulges formed on similar timescales. However, we find evidence of some abundance differences between the most metal-poor and metal-rich stars in various bulge fields. The data also indicate that the halo may have had a more significant impact on the outer bulge initial composition than the inner bulge composition. The [Na/Fe], and to a lesser extent [La/Fe], abundances further indicate that the metal-poor bulge, at least at ~1 kpc from the Galactic center, and thick disk may not share an identical chemistry.
148. Abundances for 3 stars in Sgr dSph
ID:
ivo://CDS.VizieR/J/ApJ/778/149
Title:
Abundances for 3 stars in Sgr dSph
Short Name:
J/ApJ/778/149
Date:
21 Oct 2021
Publisher:
CDS
Description:
From chemical abundance analysis of stars in the Sagittarius dwarf spheroidal galaxy (Sgr), we conclude that the {alpha}-element deficiencies cannot be due to the Type Ia supernova (SN Ia) time-delay scenario of Tinsley. Instead, the evidence points to low [{alpha}/Fe] ratios resulting from an initial mass function (IMF) deficient in the highest mass stars. The critical evidence is the 0.4 dex deficiency of [O/Fe], [Mg/Fe], and other hydrostatic elements, contrasting with the normal trend of r-process [Eu/Fe]_r_ with [Fe/H]. Supporting evidence comes from the hydrostatic element (O, Mg, Na, Al, Cu) [X/Fe] ratios, which are inconsistent with iron added to the Milky Way (MW) disk trends. Also, the ratio of hydrostatic to explosive (Si, Ca, Ti) element abundances suggests a relatively top-light IMF. Abundance similarities with the LMC, Fornax, and IC 1613 suggest that their {alpha}-element deficiencies also resulted from IMFs lacking the most massive SNe II. The top-light IMF, as well as the normal trend of r-process [Eu/Fe]_r_ with [Fe/H] in Sgr, indicates that massive SNe II (>~30M_{sun}_) are not major sources of r-process elements. High [La/Y] ratios, consistent with leaky-box chemical evolution, are confirmed but ~0.3 dex larger than theoretical asymptotic giant branch (AGB) predictions. This suggests that a substantial increase in the theoretical ^13^C pocket in low-mass AGB stars is required. Sgr has the lowest [Rb/Zr] ratios known, consistent with pollution by low-mass (<~2M_{sun}_) AGB stars near [Fe/H]=-0.6, likely resulting from leaky-box chemical evolution. The [Cu/O] trends in Sgr and the MW suggest that Cu yields increase with both metallicity and stellar mass, as expected from Cu production by the weak s-process in massive stars. Finally, we present an updated hyperfine splitting line list, an abundance analysis of Arcturus, and further develop our error analysis formalism.
149. Abundances for 79 Sun-like stars within 100pc
ID:
ivo://CDS.VizieR/J/ApJ/865/68
Title:
Abundances for 79 Sun-like stars within 100pc
Short Name:
J/ApJ/865/68
Date:
21 Oct 2021
Publisher:
CDS
Description:
The compositions of stars are a critical diagnostic tool for many topics in astronomy such as the evolution of our Galaxy, the formation of planets, and the uniqueness of the Sun. Previous spectroscopic measurements indicate a large intrinsic variation in the elemental abundance patterns of stars with similar overall metal content. However, systematic errors arising from inaccuracies in stellar models are known to be a limiting factor in such studies, and thus it is uncertain to what extent the observed diversity of stellar abundance patterns is real. Here we report the abundances of 30 elements with precisions of 2% for 79 Sun-like stars within 100pc. Systematic errors are minimized in this study by focusing on solar twin stars and performing a line-by-line differential analysis using high-resolution, high-signal-to-noise spectra. We resolve [X/Fe] abundance trends in galactic chemical evolution at precisions of 10^-3^dex/Gyr and reveal that stars with similar ages and metallicities have nearly identical abundance patterns. Contrary to previous results, we find that the ratios of carbon-to-oxygen and magnesium-to-silicon in solar-metallicity stars are homogeneous to within 10% throughout the solar neighborhood, implying that exoplanets may exhibit much less compositional diversity than previously thought. Finally, we demonstrate that the Sun has a subtle deficiency in refractory material relative to >80% of solar twins (at 2{sigma} confidence), suggesting a possible signpost for planetary systems like our own.
150. Abundances for 6 transiting planet host stars
ID:
ivo://CDS.VizieR/J/A+A/458/997
Title:
Abundances for 6 transiting planet host stars
Short Name:
J/A+A/458/997
Date:
21 Oct 2021
Publisher:
CDS
Description:
We used the UVES spectrograph (VLT-UT2 telescope) to obtain high-resolution spectra of 6 stars hosting transiting planets, namely for OGLE-TR-10, 56, 111, 113, 132, and TrES-1. These spectra are now used to derive and discuss the chemical abundances for C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, and Zn.

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