- ID:
- ivo://CDS.VizieR/J/AJ/134/1216
- Title:
- Abundances of NGC 7142, 6939, and IC 4756 stars
- Short Name:
- J/AJ/134/1216
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of echelle spectra of stars in three open clusters obtained with the Hydra multiobject spectrograph on the WIYN 3.5m telescope. Abundances of Fe, O, Si, Ca, Na, Al, and Ni have been determined via equivalent width analysis and spectrum synthesis. Mean abundances for each cluster are compared to those of previous studies and of other clusters in the literature, with emphasis on exploring the enhancements of Na and Al seen in many open clusters. All three clusters show enhanced values of [Na/Fe] and [Al/Fe], while the abundances of Fe, O, Si, and Ca are consistent with their ages and locations in the Galactic disk.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/431/933
- Title:
- Abundances of NGC 7789 evolved stars
- Short Name:
- J/A+A/431/933
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-resolution spectra of six giants and three core-helium-burning "clump" stars in the open cluster NGC 7789 have been obtained with the SOFIN spectrograph on the Nordic Optical Telescope to investigate abundances of up to 20 chemical elements. Abundances of carbon were studied using the C_2_ Swan (0, 1) band head at 5635.5{AA}. The wavelength interval 7980-8130{AA} with strong CN features was analysed in order to determine nitrogen abundances and ^12^C/^13^C isotope ratios. The oxygen abundances were determined from the [O I] line at 6300{AA}.
- ID:
- ivo://CDS.VizieR/J/ApJ/824/73
- Title:
- Abundances of NGC 6362 member stars
- Short Name:
- J/ApJ/824/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first measure of Fe and Na abundances in NGC 6362, a low-mass globular cluster (GC) where first- and second-generation stars are fully spatially mixed. A total of 160 member stars (along the red giant branch (RGB) and the red horizontal branch (RHB)) were observed with the multi-object spectrograph FLAMES at the Very Large Telescope. We find that the cluster has an iron abundance of [Fe/H]=-1.09+/-0.01dex, without evidence of intrinsic dispersion. On the other hand, the [Na/Fe] distribution turns out to be intrinsically broad and bimodal. The Na-poor and Na-rich stars populate, respectively, the bluest and the reddest RGBs detected in the color-magnitude diagrams including the U filter. The RGB is composed of a mixture of first- and second-generation stars in a similar proportion, while almost all the RHB stars belong to the first cluster generation. To date, NGC 6362 is the least massive GC where both the photometric and spectroscopic signatures of multiple populations have been detected.
- ID:
- ivo://CDS.VizieR/J/A+A/490/625
- Title:
- Abundances of NGC 6121 red giants
- Short Name:
- J/A+A/490/625
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present abundance analysis based on high resolution spectra of 105 isolated red giant branch (RGB) stars in the Galactic Globular Cluster NGC 6121 (M4). The data have been collected with FLAMES+UVES, at the ESO/VLT@UT2 telescope. Spectroscopic data were coupled with high precision wide-field UBVI_C photometry from WFI@2.2m telescope and infrared JHK photometry from 2MASS. We derived an average [Fe/H]=-1.07+/-0.01, and an {alpha} enhancement of [{alpha}/Fe]=+0.39+/-0.05dex (internal errors). We confirm the presence of an extended Na-O anticorrelation, and find two distinct groups of stars with significantly different Na and O content. We find no evidence of a Mg-Al anticorrelation. By coupling our results with previous studies on the CN band strength, we find that the CN strong stars have higher Na and Al content and are more O depleted than the CN weak ones. The two groups of Na-rich, CN-strong and Na-poor, CN-weak stars populate two different regions along the RGB. In the U vs. U-B color magnitude diagram the RGB spread is present from the base of the RGB to the RGB-tip. Apparently, both spectroscopic and photometric results imply the presence of two stellar populations in M4. We briefly discuss the possible origin of these populations.
- ID:
- ivo://CDS.VizieR/J/A+A/565/A23
- Title:
- Abundances of NGC5897 red giants
- Short Name:
- J/A+A/565/A23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report for the first time on the chemical composition of the halo cluster NGC 5897 (R_{sun}_=12.5kpc), based on chemical abundance ratios for 27 {alpha}-, iron-peak, and neutron-capture elements in seven red giants. From our high-resolution, high signal-to-noise spectra obtained with theMagellan/MIKE spectrograph, we find a mean iron abundance from the neutral species of [Fe/H]=-2.04+/-0.01(stat.)+/-0.15(sys.), which is more metal-poor than implied by previous photometric and low-resolution spectroscopic studies. NGC 5897 is {alpha}-enhanced (to 0.34+/-0.01dex) and shows Fe-peak element ratios typical of other (metal-poor) halo globular clusters (GCs) with no overall, significant abundance spreads in iron nor in any other heavy element.
- ID:
- ivo://CDS.VizieR/J/A+A/279/567
- Title:
- Abundances of non-type I PNe in LMC
- Short Name:
- J/A+A/279/567
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectroscopic observations, plasma diagnostics and chemical composition of 15 non-type I planetary nebulae (PNe) in the Large Magellanic Cloud (LMC) are reported. Abundances of He, O, N, S, and Ar are determined and compared with recently obtained data for nebulae both in the Magellanic Clouds and in the Galaxy.
- ID:
- ivo://CDS.VizieR/J/AJ/140/1694
- Title:
- Abundances of non-variable red and blue HB stars
- Short Name:
- J/AJ/140/1694
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new detailed abundance study of field red horizontal branch (RHB) and blue horizontal branch (BHB) non-variable stars. High resolution and high signal-to-noise ratio echelle spectra of 11 RHB and 12 BHB were obtained with the McDonald 2.7m telescope, and the RHB sample was augmented by reanalysis of spectra of 25 stars from a recent survey. We derived stellar atmospheric parameters based on spectroscopic constraints and computed relative abundance ratios for 24 species of 19 elements.
- ID:
- ivo://CDS.VizieR/J/ApJ/660/1462
- Title:
- Abundances of ONC X-ray PMS stars
- Short Name:
- J/ApJ/660/1462
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Following the Chandra Orion Ultradeep Project (COUP) observation, we have studied the chemical composition of the hot plasma in a sample of 146 X-ray-bright pre-main-sequence stars in the Orion Nebula Cluster (ONC). We report measurements of individual element abundances for a subsample of 86 slightly absorbed and bright X-ray sources, using low-resolution X-ray spectra obtained from the Chandra ACIS instrument.
- ID:
- ivo://CDS.VizieR/J/MNRAS/428/2321
- Title:
- Abundances of open cluster stars
- Short Name:
- J/MNRAS/428/2321
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The first generation of large-scale chemical tagging surveys, in particular the High Efficiency and Resolution Multi-Element Spectrograph (HERMES)/Galactic Archaeology with HERMES million star survey, promises to vastly expand our understanding of the chemical and dynamical evolution of the Galaxy. This, however, is contingent on our ability to confidently perform chemical tagging on such a large data set. Chemical homogeneity has been observed across a range of elements within several Galactic open clusters, yet the level to which this is the case globally, and particularly in comparison to the scatter across clusters themselves, is not well understood. The patterns of elements in coeval cluster members, occupying a complex chemical abundance space, are rooted in the evolution, ultimately the nature of the very late stages, of early generations of stars. The current astrophysical models of such stages are not yet sufficient to explain all observations, combining with our significant gaps in the understanding of star formation, makes this a difficult arena to tackle theoretically. Here, we describe a robust pair-wise metric used to gauge the chemical difference between two stellar components. This metric is then applied to a data base of high-resolution literature abundance sources to derive a function describing the probability that two stars are of common evolutionary origin. With this cluster probability function, it will be possible to report a confidence, grounded in empirical observational evidence, with which clusters are detected, independent of the group finding methods. This formulation is also used to probe the role of chemical dimensionality, and that of individual chemical species, on the ability of chemical tagging to differentiate coeval groups of stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/655/1046
- Title:
- Abundances of {phi} Her
- Short Name:
- J/ApJ/655/1046
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of the mercury-manganese star phi Her with the Navy Prototype Optical Interferometer (NPOI) conclusively reveal the previously unseen companion in this single-lined binary system. The NPOI data were used to predict a spectral type of A8 V for the secondary star phi Her B. This prediction was subsequently confirmed by spectroscopic observations obtained at the Dominion Astrophysical Observatory. phi Her B is rotating at 50+/-3km/s, in contrast to the 8 km/s lines of phi Her A. Recognizing the lines from the secondary permits one to separate them from those of the primary. The abundance analysis of phi Her A shows an abundance pattern similar to those of other HgMn stars, with Al being very under-abundant and Sc, Cr, Mn, Zn, Ga, Sr, Y, Zr, Ba, Ce, and Hg being very overabundant.
