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- ID:
- ivo://CDS.VizieR/J/ApJ/662/15
- Title:
- Abundances in extragalactic HII regions
- Short Name:
- J/ApJ/662/15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We determine the primordial helium mass fraction Yp using 93 spectra of 86 low-metallicity extragalactic HII regions. This sample constitutes the largest and most homogeneous high-quality data set in existence for the determination of Yp. For comparison, and to improve the statistics in our investigation of systematic effects affecting the Yp determination, we have also considered a sample of 271 low-metallicity HII regions selected from Data Release 5 of the Sloan Digital Sky Survey. Although this larger sample shows more scatter, it gives results that are consistent at the 2{sigma} level with our original sample. We have considered known systematic effects that may affect the ^4^He abundance determination.
- ID:
- ivo://CDS.VizieR/J/A+A/571/A40
- Title:
- Abundances in 2 extremely metal-poor stars
- Short Name:
- J/A+A/571/A40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- It has been noted that, in classical extremely metal-poor (EMP) stars, the abundance ratio of two well-observed neutroncapture elements, Sr and Ba, is always higher than [Sr/Ba]=-0.5, which is the value of the solar r-only process; however, a handful of EMP stars have recently been found with a very low Sr/Ba ratio. We try to understand the origin of this anomaly by comparing the abundance pattern of the elements in these stars and in the classical EMP stars. For a rigorous comparison with previous data, four stars with very low Sr/Ba ratios were observed and analyzed in the same way as in the First Stars Program: analysis within LTE approximation through 1D (hydrostatic) model atmosphere, providing homogeneous abundances of nine neutron-capture elements.
- ID:
- ivo://CDS.VizieR/J/AZh/93/49
- Title:
- Abundances in Galactic open clusters
- Short Name:
- J/AZh/93/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalog compiling the parameters of 346 open clusters, including their metallicities, positions, ages, and velocities has been composed. The elements of the Galactic orbits for 272 of the clusters have been calculated. Spectroscopic determinations of the relative abundances, [el/Fe], for 14 elements synthesized in various nuclear processes averaged over data from 109 publications are presented for 90 clusters. The compiled data indicate that the relative abundances of primary {alpha} elements (oxygen and magnesium) exhibit different dependences on metallicity, age, Galactocentric distance, and the elements of the Galactic orbits in clusters with high, elongated orbits satisfying the criterion (Z_max_^2^+4e^2^)^1/2^>0.40 and in field stars of the Galactic thin disk (Zmax is the maximum distance of the orbit from the Galactic plane in kiloparsec and e is the eccentricity of the Galactic orbit). Since no systematic effects distorting the relative abundances of the studied elements in these clusters have been found, these difference suggest real differences between clusters with high, elongated orbits and field stars. In particular, this supports the earlier conclusion, based on an analysis of the elements of the Galactic orbits, that some clusters formed as a result of interactions between high-velocity,metal-poor clouds and the interstellar medium of the Galactic thin disk. On average, clusters with high, elongated orbits and metallicities [Fe/H]<-0.1 display lower relative abundances of the primary {alpha} elements than do field stars. The low [O, Mg/Fe] ratios of these clusters can be understood if the high-velocity clouds that gave rise to them were formed of interstellar material from regions where the star-formation rate and/or the masses of Type II supernovae were lower than near the Galactic plane. It is also shown that, on average, the relative abundances of the primary {alpha} elements are higher in relatively metal-rich clusters with high, elongated orbits than in field stars. This can be understood if clusters with [Fe/H]>-0.1 formed as a result of interactions between metal-rich clouds with intermediate velocities and the interstellar medium of the Galactic disk; such clouds could form from returning gas in a so-called "Galactic fountain".
- ID:
- ivo://CDS.VizieR/J/AZh/72/864
- Title:
- Abundances in gamma Sge
- Short Name:
- J/AZh/72/864
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD spectra are used to analyse the abundances of chemical elements in the atmosphere of the MOIII giant gamma Sagittae. Its atmospheric atmospheric parameters were determined to be T(eff)=3970K, logg=1.3, and microturbulence v(t)=1.65km/s.
- ID:
- ivo://CDS.VizieR/J/A+A/506/729
- Title:
- Abundances in globular cluster Pal 3
- Short Name:
- J/A+A/506/729
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Chemical abundances of 25 alpha-, iron peak-, and neutron-capture elements in the remote (R=90kpc) outer halo globular cluster have been determined for 4 red giants observed with the Magellan/MIKE spectrograph and from integrated spectra of 19 stars obtained with the Keck/HIRES instrument. The resulting abundance ratios show that Pal 3 is very similar to globular clusters of the inner halo and very dissimilar from dwarf spheroidal galaxy stars. Its neutron capture element ratios are compatible with a pure r-process enrichment.
- ID:
- ivo://CDS.VizieR/J/A+A/326/1069
- Title:
- Abundances in globular clusters
- Short Name:
- J/A+A/326/1069
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Tables 5, 6, and 7 present details of the derived abundances for the stars observed in the globular clusters M2, M13, and M56, respectively. Table 9 gives the measured equivalent widths for the iron lines of the field stars. Table 10 gives the measured equivalent widths for the programme stars of this survey.
- ID:
- ivo://CDS.VizieR/J/ApJ/736/87
- Title:
- Abundances in G-type stars with exoplanets
- Short Name:
- J/ApJ/736/87
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We confirm the difference in chemical abundance between stars with and without exoplanets and present the relation between chemical abundances and physical properties of exoplanets, such as planetary mass and the semimajor axis of planetary orbit. We obtained the spectra of 52 G-type stars from the Bohyunsan Optical Astronomy Observatory (BOAO) Echelle Spectrograph and carried out abundance analyses for 12 elements: Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Co, and Ni. We first found that the [Mn/Fe] ratios of planet-host stars are higher than those of comparison stars over the entire metallicity range, and we then found that in metal-poor stars of [Fe/H]<-0.4 the abundance difference was larger than in metal-rich samples, especially for the elements of Mg, Al, Sc, Ti, V, and Co. After examining the relation between planet properties and metallicities of planet-host stars, we observed that planet-host stars with low metallicities tend to have several low-mass planets (<M_J_) instead of a massive gas-giant planet.
- ID:
- ivo://CDS.VizieR/J/MNRAS/424/2316
- Title:
- Abundances in HII regions
- Short Name:
- J/MNRAS/424/2316
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We suggest a new way of determining abundances and electron temperatures in HII regions from strong emission lines. Our approach is based on the standard assumption that HII regions with similar intensities of strong emission lines have similar physical properties and abundances. A 'counterpart' for a studied HII region may be chosen among HII regions with well-measured abundances (reference HII regions) by comparison of carefully chosen combinations of strong-line intensities. Then the abundances in the investigated HII region can be assumed to be the same as those in its counterpart. In other words, we suggest to determine the abundances in HII regions 'by precedent'. To get more reliable abundances for the considered HII region, a number of reference HII regions are selected and then the abundances in the target HII region are estimated through extrapolation/interpolation. We will refer to this method of abundance determination as the counterpart method or, for brevity, the C method. We define a sample of reference HII regions and verify the validity of the C method. We find that this method produces reliable abundances. Finally, the C method is used to obtain the radial abundance distributions in the extended discs of the spiral galaxies M83, NGC 4625 and NGC 628.
- ID:
- ivo://CDS.VizieR/J/A+A/464/885
- Title:
- Abundances in 53 HII regions
- Short Name:
- J/A+A/464/885
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Continuing the systematic determination of the electron temperature of HII regions using the Balmer and/or Paschen discontinuities by Guseva et al. (2006ApJ...644..890G) we focus here on 3.6m ESO telescope observations of a large new sample of 69 HII regions in 45 blue compact dwarf (BCD) galaxies. This data set spans a wide range in metallicity (Z_{sun}_/60<Z<Z_{sun}_/3) and, combined with the sample of 47 HII regions from Guseva et al. (2006ApJ...644..890G), yields the largest spectroscopic data set ever used to derive the electron temperature in the H^+^ zone. In the same way as in Guseva et al. (2006ApJ...644..890G) we have used a Monte Carlo technique to vary free parameters and to calculate a series of model spectral energy distributions (SEDs) for each HII region. The electron temperature in the H^+^ zones was derived from the best fitting synthetic and observed SEDs in the wavelength range ~3200-5100{AA}, which includes the Balmer jump. On the base of the present large spectroscopic sample we find that in hot (Te(H^+^)>11000K) HII regions the temperature of the O^2+^ zone, determined from doubly ionised oxygen forbidden lines, does not differ statistically from the temperature of the H^+^ zone. Thus, we confirm and strengthen the finding by Guseva et al. (2006ApJ...644..890G). We emphasize that due to a number of modelling assumptions and the observational uncertainties for individual objects, only a large, homogeneous sample, as the one used here, can enable a conclusive study of the relation between Te(H^+^) and Te(OIII).
- ID:
- ivo://CDS.VizieR/J/A+A/521/A3
- Title:
- Abundances in HII regions and PNe of M81
- Short Name:
- J/A+A/521/A3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- M81 is an ideal laboratory to investigate the galactic chemical and dynamical evolution through the study of its young and old stellar populations. We analyze the chemical abundances of planetary nebulae and HII regions in the M81 disk for insight on galactic evolution, and compare it with that of other galaxies, including the Milky Way.
- ID:
- ivo://CDS.VizieR/J/A+A/567/A88
- Title:
- Abundances in HII regions of M81
- Short Name:
- J/A+A/567/A88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new set of weak-line abundances of HII regions in M81, based on Gemini Multi-Object Spectrograph (GMOS) observations. The aim is to derive plasma and abundance analysis for a sizable set of emission-line targets to study the galactic chemical contents in the framework of galactic metallicity gradients. We used the weak-line abundance approach by deriving electron density and temperatures for several HII regions in M81. Gradient analysis is based on oxygen abundances. Together with a set of HII region abundances determined similarly by us with Multi-Mirror Telescope (MMT) spectra, the new data yield to a radial oxygen gradient of -0.088+/-0.013dex/kpc, which is steeper than the metallicity gradient obtained for planetary nebulae (-0.044+/-0.007dex/kpc). This result could be interpreted as gradient evolution with time: Models of galactic evolution with inside-out disk formation associated to pre-enriched gas infall would produce such difference of gradients, although stellar migration effects would also induce a difference in the metallicity gradients between the old and young populations.
- ID:
- ivo://CDS.VizieR/J/ApJ/768/L12
- Title:
- Abundances in host stars XO-2S and XO-2N
- Short Name:
- J/ApJ/768/L12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- With the aim of connecting the compositions of stars and planets, we present the abundances of carbon and oxygen, as well as iron and nickel, for the transiting exoplanet host star XO-2N and its wide-separation binary companion XO-2S. Stellar parameters are derived from high-resolution, high signal-to-noise spectra, and the two stars are found to be similar in their T_eff_, log g, iron ([Fe/H]), and nickel ([Ni/H]) abundances. Their carbon ([C/H]) and oxygen ([O/H]) abundances also overlap within errors, although XO-2N may be slightly more C-rich and O-rich than XO-2S. The C/O ratios of both stars (~0.60+/-0.20) may also be somewhat larger than solar (C/O~0.50). The XO-2 system has a transiting hot Jupiter orbiting one binary component but not the other, allowing us to probe the potential effects planet formation might have on the host star composition. Additionally, with multiple observations of its atmosphere the transiting exoplanet XO-2b lends itself to compositional analysis, which can be compared to the natal chemical environment established by our binary star elemental abundances. This work sets the stage for determining how similar or different exoplanet and host star compositions are, and the implications for planet formation, by discussing the C/O ratio measurements in the unique environment of a visual binary system with one star hosting a transiting hot Jupiter.
- ID:
- ivo://CDS.VizieR/J/AZh/77/96
- Title:
- Abundances in Hyades red giants
- Short Name:
- J/AZh/77/96
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- CCD spectra are obtained in 1994-1997 on the 2.6-m telescope of the Crimean Astrophysical observatory in the first chamber of the Coude focus. The dispersion was 3{AA}/mm and the signal-to-noise ratios were 100-300.
- ID:
- ivo://CDS.VizieR/J/A+A/420/135
- Title:
- Abundances in intracluster medium with XMM
- Short Name:
- J/A+A/420/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- XMM-Newton observations of 19 galaxy clusters are used to measure the elemental abundances and their spatial distributions in the intracluster medium. The sample mainly consists of X-ray bright and relaxed clusters with a cD galaxy. Along with detailed Si, S and Fe radial abundance distributions within 300-700kpc in radius, the O abundances are accurately derived in the central region of the clusters. The Fe abundance maxima towards the cluster center, possibly due to the metals from the cD galaxy, are spatially resolved. The Si and S abundances also exhibit central increases in general, resulting in uniform Fe-Si-S ratios within the cluster. In contrast, the O abundances are in general uniform over the cluster. The mean O to Fe ratio within the cluster core is sub-solar, while that of the cluster scale is larger than the solar ratio. These measurements indicate that most of the Fe-Si-S and O in the intracluster medium have different origins, presumably in supernovae Ia and II, respectively. The obtained Fe and O mass are also used to discuss the past star formation history in clusters.
- ID:
- ivo://CDS.VizieR/J/MNRAS/234/583
- Title:
- Abundances in Magellanic Cloud planetary nebulae
- Short Name:
- J/MNRAS/234/583
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Optical spectroscopic data for 71 Planetary Nebulae (PN) in the Large and Small Magellanic Clouds have been analysed. The line fluxes have been used to determine nebular temperatures, densities, and the abundances of He, N, O, Ne and Ar, relative to H. In our sample there are 12 nebulae with N/O>=0.5, resembling Peimbert's Type I PN; six low-excitation objects [1<=I(5007)/I(H{beat})<=4], and four very-low excitation (VLE) nebulae [I(H{beta})>I(5007)], similar to the Galactic VLE class. Mean abundances have been calculated for the nebulae not in these special groups. After correction for collisional excitation contributions to the nebular He I lines, PN in the SMC and LMC yield mass fractions of Y=0.249+/-0.025 and Y=0.258+/-0.012, respectively.
- ID:
- ivo://CDS.VizieR/J/AJ/120/1364
- Title:
- Abundances in M3 and M13
- Short Name:
- J/AJ/120/1364
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze high-resolution, high signal-to-noise ratio spectra of six red giant branch (RGB) stars in the globular cluster M3 (NGC 5272) and three in M13 (NGC 6205) that were obtained with the 4 m Mayall Telescope and echelle spectrometer on Kitt Peak. The spectra include lines of O, Na, Mg, Al, Si, Ca, Ti, V, Mn, Fe, and Ni. We also analyze the [Al/Fe] values of 96 RGB stars in M13 covering the brightest 3.5 mag, which include 66 measurements that were derived from moderate-resolution, low signal-to-noise ratio spectra obtained with the WIYN 3.5 m telescope and Hydra multiobject spectrograph, also on Kitt Peak.
- ID:
- ivo://CDS.VizieR/J/ApJ/900/146
- Title:
- Abundances in 2 metal-poor GCs, M53 & NGC5053
- Short Name:
- J/ApJ/900/146
- Date:
- 02 Feb 2022 13:00:59
- Publisher:
- CDS
- Description:
- We search for extratidal stars around two metal-poor Galactic globular clusters, M53 and NGC 5053, using the near-infrared APOGEE spectra. Applying the t-distributed stochastic neighbor embedding (t-SNE) algorithm on the chemical abundances and radial velocities results in identification of two isolated stellar groups composed of cluster member stars in the t-SNE projection plane. With additional selection criteria of radial velocity, location in the color-magnitude diagram, and abundances from a manual chemical analysis, we find a total of 73 cluster member candidates; seven extratidal stars are found beyond the tidal radii of the two clusters. The extratidal stars around the clusters tend to be located along the leading direction of the cluster proper motion, and the individual proper motion of these stars also seems to be compatible to those of clusters. Interestingly, we find that one extratidal star of NGC 5053 is located on the southern outskirts of M53, which is part of common stellar envelope by the tidal interaction between two clusters. We discuss the nature of this star in the context of the tidal interaction between two clusters. We find apparent Mg-Al anticorrelations with a clear gap and spread (~0.9dex) in Al abundances for both clusters, and a light Si abundance spread (~0.3dex) for NGC 5053. Since all extratidal stars have Mg-enhanced and Al-depleted features, they could be first-generation stars of two globular clusters. Our results support that M53 and NGC5053 originated in dwarf galaxies and are surrounded by extended stellar substructures of more numerous populations of clusters.
- ID:
- ivo://CDS.VizieR/J/ApJ/857/2
- Title:
- Abundances in 6 metal-poor stars
- Short Name:
- J/ApJ/857/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new abundances derived from CuI, CuII, ZnI, and ZnII lines in six warm (5766<=T_eff_<=6427K), metal-poor (-2.50<=[Fe/H]<=-0.95) dwarf and subgiant (3.64<=logg<=4.44) stars. These abundances are derived from archival high-resolution ultraviolet spectra from the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope and ground-based optical spectra from several observatories. Ionized Cu and Zn are the majority species, and abundances derived from CuII and ZnII lines should be largely insensitive to departures from local thermodynamic equilibrium (LTE). We find good agreement between the [Zn/H] ratios derived separately from ZnI and ZnII lines, suggesting that departures from LTE are, at most, minimal (<~0.1dex). We find that the [Cu/H] ratios derived from CuII lines are 0.36+/-0.06dex larger than those derived from CuI lines in the most metal-poor stars ([Fe/H]{<}-1.8), suggesting that LTE underestimates the Cu abundance derived from CuI lines. The deviations decrease in more metal-rich stars. Our results validate previous theoretical non-LTE calculations for both Cu and Zn, supporting earlier conclusions that the enhancement of [Zn/Fe] in metal-poor stars is legitimate, and the deficiency of [Cu/Fe] in metal-poor stars may not be as large as previously thought.
- ID:
- ivo://CDS.VizieR/J/ApJ/675/1213
- Title:
- Abundances in M33 HII regions
- Short Name:
- J/ApJ/675/1213
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new determination of the metallicity gradient in M33, based on Keck LRIS measurements of oxygen abundances using the temperature-sensitive emission line [OIII] {lambda}4363 in 61 HII regions. These data approximately triple the sample of direct oxygen abundances in M33. We find a central abundance of 12+log(O/H)=8.36+/-0.04 and a slope of -0.027+/-0.012dex/kpc, in agreement with infrared measurements of the neon abundance gradient but much shallower than most previous oxygen gradient measurements. There is substantial intrinsic scatter of 0.11dex in the metallicity at any given radius in M33, which imposes a fundamental limit on the accuracy of gradient measurements that rely on small samples of objects. We also show that the ionization state of neon does not follow the ionization state of oxygen as is commonly assumed, suggesting that neon abundance measurements from optical emission lines require careful treatment of the ionization corrections.
- 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.
- 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.
- 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.
- 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)
- 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.
- 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)
- 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.
- 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_.
- 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.
- 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.
- ID:
- ivo://CDS.VizieR/J/A+A/427/231
- Title:
- Abundances in planetary nebulae
- Short Name:
- J/A+A/427/231
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new spectroscopic data (43 objects) and derived plasma diagnostics and abundances (164 objects) of a sample of planetary nebulae in the direction of the Galactic center. The spectra were obtained in July 2000 with the 1.9-m telescope at the South African Astronomical Observatory. The spectral coverage was 3500-7000{AA} with an average resolution of 1000.
- ID:
- ivo://CDS.VizieR/J/A+A/494/591
- Title:
- Abundances in planetary nebulae
- Short Name:
- J/A+A/494/591
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new plasma diagnostics and abundances of a sample of planetary nebulae located in the Galactic bulge (168 objects), the Galactic inner disk (61 objects) and in the LMC (110 objects).
- ID:
- ivo://CDS.VizieR/J/ApJS/218/25
- Title:
- Abundances in PNe. III: Se and Kr
- Short Name:
- J/ApJS/218/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The detection of neutron(n)-capture elements in several planetary nebulae (PNe) has provided a new means of investigating s-process nucleosynthesis in low-mass stars. However, a lack of atomic data has inhibited accurate trans-iron element abundance determinations in astrophysical nebulae. Recently, photoionization (PI) and recombination data were determined for Se and Kr, the two most widely detected n-capture elements in nebular spectra. We have incorporated these new data into the photoionization code Cloudy (Ferland et al. 2013RMxAA..49..137F). To test the atomic data, numerical models were computed for 15 PNe that exhibit emission lines from multiple Kr ions. We found systematic discrepancies between the predicted and observed emission lines that are most likely caused by inaccurate PI and recombination data. These discrepancies were removed by adjusting the Kr^+^-Kr^3+^ PI cross sections within their cited uncertainties and the dielectronic recombination rate coefficients by slightly larger amounts. From grids of models spanning the physical conditions encountered in PNe, we derive new, broadly applicable ionization correction factor (ICF) formulae for calculating Se and Kr elemental abundances. The ICFs were applied to our previous survey of near-infrared [KrIII] and [SeIV] emission lines in 120 PNe. The revised Se and Kr abundances are 0.1-0.3dex lower than former estimates, with average values of [Se/(O,Ar)]=0.12+/-0.27 and [Kr/(O,Ar)]=0.82+/-0.29, but correlations previously found between their abundances and other nebular and stellar properties are unaffected. We also find a tendency for high-velocity PNe that can be associated with the Galactic thick disk to exhibit larger s-process enrichments than low-velocity PNe belonging to the thin-disk population.
- ID:
- ivo://CDS.VizieR/J/PASJ/59/1127
- Title:
- Abundances in 5 post-AGB candidates
- Short Name:
- J/PASJ/59/1127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A detailed non-LTE study on the abundances of C, N, O, S, and Zn was carried out for five F-G supergiants of suspected post-AGB candidates with IR excesses (HD 112374, HD 148743, HD 161796, HD 163506, and HD 187203), since these volatile elements can provide the key to inferring the original metallicity as well as an evolution-induced change due to mixing, given that they are free from depletion caused by dust-gas separation.
- ID:
- ivo://CDS.VizieR/J/ApJ/682/1217
- Title:
- Abundances in red giants in 7 globular clusters
- Short Name:
- J/ApJ/682/1217
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a technique that applies spectral synthesis to medium-resolution spectroscopy (MRS; R~6000) in the red (6300{AA}<{lambda}<9100{AA}) to measure [Fe/H] and [{alpha}/Fe] of individual red giant stars over a wide metallicity range. We apply our technique to 264 red giant stars in seven Galactic globular clusters and demonstrate that it reproduces the metallicities and {alpha}-enhancements derived from high-resolution spectroscopy (HRS). The MRS technique excludes the three CaII triplet lines and instead relies on a plethora of weaker lines. Unlike empirical metallicity estimators, such as the equivalent width of the CaII triplet, the synthetic method presented here is applicable over an arbitrarily wide metallicity range and is independent of assumptions about the {alpha}-enhancement.
- ID:
- ivo://CDS.VizieR/J/AJ/110/2319
- Title:
- Abundances in RR Lyr variables
- Short Name:
- J/AJ/110/2319
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used moderately high-resolution, high S/N spectra to study the chemical composition of ten field ab-type RR Lyrae stars. Variables having accurate photometric and radial-velocity data were selected, in order to derive a precise estimate of the atmospheric parameters independently of excitation and ionization equilibria. A new temperature scale was determined from literature "Infrared Flux Method" measures of subdwarfs and the Kurucz (1992) (priv. com.) model atmospheres, and used to calibrate colors for both dwarfs and RR Lyraes. Photometric reddening estimates for the program stars were carefully examined, and compared with other determinations. The applicability of Kurucz (1992) (priv. com.) model atmospheres in the analysis of RR Lyraes at minimum light was analyzed: we found that they are able to reproduce colors, excitation, and ionization equilibria as well as the wings of Halpha. The comparison solar abundances were carefully determined. From a new analysis of weak Fe I lines with accurate gfs [Bard & Kock, A&A, 282, 1014 (1994)] we derived log epsilon(Fe)_Sun=7.52, in agreement with the Fe abundances determined from meteorites and Fe II lines. We derived abundances for 21 species. Main results are: The metal abundances of the program stars span the range -2.50<[Fe/H]<+0.17. Lines of most elements are found to form in LTE conditions. Fe lines satisfy very well the excitation and ionization equilibria. A comparison with statistical equilibrium computations shows that rather large collisional cross sections are required to reproduce observations. If these cross sections are then used in the analysis of the formation of Fe lines in subdwarfs and RGB stars, no significant departures from LTE are found for these stars, thus validating the very numerous LTE analyses. RR Lyraes share the typical abundance pattern of other stars of similar [Fe/H]: alpha-elements are overabundant by ~0.4dex and Mn is underabundant by ~0.6dex in stars with [Fe/H]<-1. Solar scaled abundances are found for most of the other species, except for the low Ba abundance in the extremely metal-poor star X Ari ([Fe/H]~-2.5). Significant departures from LTE are found for a few species: Nd II, Ce II, Y II, and Sc II are severely underabundant (~0.5dex) in metal-rich variables; Ti I and Cr I are slightly (~0.1-0.2dex) underabundant in metal-poor stars. These effects are attributed to overionization. We suggest that the photoionization of the alkaline earth-like ions is due to Lyman lines emission produced by the shock waves that propagate in the atmosphere of these variables [Fokin (1992MNRAS.256...26F)]. Departures from LTE were considered in detail in the derivation of abundances for the light elements (O and Na). Significant corrections were required for the O I IR triplet and the Na D lines. The resulting pattern reproduces that observed in less evolved field stars. We did not find any evidence for an O-Na anticorrelation among these field HB stars, suggesting that the environment is likely to be responsible for the anticorrelation found in metal-poor globular cluster stars [Sneden et al. =1992AJ....104.2121S]. We used our new [Fe/H] abundances, as well as values from Butler and co-workers (corrected to our system), and from high- resolution spectroscopy of globular clusters giants, to obtain a revised calibration of the low-resolution metallicity index Delta(S) [Preston =1959ApJ...130..507P]: [Fe/H]=-0.194(+/-0.011)Delta(S)-0.08(+/-0.18). Our new metallicity scale is stretched on both low and high metallicity ends with respect to Butler's [1975ApJ...200...68B]. The error in [Fe/H] by Delta(S) observations is 0.16dex, well of the same order of high-resolution metallicity determinations. The slope of the calibration obtained considering only stars with 4<Delta(S)<10 is slightly smaller than that obtained using all stars. While this difference is only barely significant, it might point out the presence of a nonlinearity of the Delta(S) vs [Fe/H] relation, as suggested by Manduca [ApJ, 245, 258 (1981)]. The new [Fe/H] values were used to update the metallicity calibration of the Ca II K line index [Clementini et al. =1991AJ....101.2168C]. Using the present new metallicities, and W'(K) values and relative errors from Clementini et al. (1991), a least-squares fit weighted both in W'(K) and [Fe/H] gives [Fe/H]=0.65(+/-0.17)W'(K)-3.49(+/-0.39). Finally, our new metallicity scale was used to revise the metallicity dependence of the absolute magnitude of RR Lyrae stars, M_V. Using M_V values from Fernley [1994A&A...284L..16F] for the field stars, and estimates from Liu & Janes [1990ApJ...360..561L] and Storm et al. [1994A&A...290..443S] for the cluster variables, we found M_V=0.20(+/-0.03) [Fe/H]+1.06(+/-0.04) and M_V=0.19(+/-0.03)[Fe/H]+0.96(+/-0.04), the last being obtained by using M_V estimates derived for a value of the conversion factor between observed and true pulsation velocity p=1.38 (Fernley 1994). The adoption of the new metallicity scale does not yield significant changes in the slope or zero point of the M_V vs [Fe/H] relation. Observations do not rule out the possibility that the slope of the M_V vs [Fe/H] relation might be different for metal-poor and metal-rich variables. However, a larger sample of Baade-Wesselink M_V determinations is required to definitely settle this question.
- ID:
- ivo://CDS.VizieR/J/A+A/508/L17
- Title:
- Abundances in solar analogs
- Short Name:
- J/A+A/508/L17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We derive the abundance of 19 elements in a sample of 64 stars with fundamental parameters very similar to solar, which minimizes the impact of systematic errors in our spectroscopic 1D-LTE differential analysis, using high-resolution (R~60000), high signal-to-noise ratio (S/N~200) spectra. The estimated errors in the elemental abundances relative to solar are as small as ~0.025dex. The abundance ratios [X/Fe] as a function of [Fe/H] agree closely with previously established patterns of Galactic thin-disk chemical evolution.
- ID:
- ivo://CDS.VizieR/J/AZh/75/586
- Title:
- Abundances in solar atmosphere
- Short Name:
- J/AZh/75/586
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- An analysis of the chemical composition of the solar atmosphere is performed using spectrograms of the daylight sky obtained on the ZTS telescope (dispersion 3{AA}/mm, signal-to-noise ration, S/N>100). The chemical composition derived in the framework of a Holweger-Muller atmosphere model are in excellent agreement with the generally accepted values. Analysis based on the models of Bell et al. (1976A&AS...23...37B) and Kurucz (1992RMxAA..23..181K) with Teff=5770K and logg=4.44 failed to give satisfactory results.
- ID:
- ivo://CDS.VizieR/J/AZh/88/750
- Title:
- Abundances in stars of galactic sub-structures
- Short Name:
- J/AZh/88/750
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have determined abundances of copper, zinc, sodium, and aluminium in the atmospheres of 172 F, G, and K dwarf stars (-1.0<[Fe/H]<0.3) belonging to the Galaxy's thin and thick disks and to the Hercules moving group. Our observations were performed with the ELODIE echelle spectrometer on the 1.93-m telescope of the Haute ProvenceObservatory, with a resolving power of R=42000 and signal-to-noise ratio S/N>100. The Na, Al, Cu, and Zn abundances were derived in an LTE approximation; the synthetic spectrum for the copper lines was calculated taking into account super-fine structure of the lines. We analyzed the abundances of these elements as a function of metallicity [Fe/H] for stars of the thin and thick disks of the Galaxy and the Hercules moving group. The Cu abundances and their trends with metallicity are essentially the same in the three studied sub-structures. The mean Al and Zn abundances for stars of the thin and thick disks differ significantly.
- ID:
- ivo://CDS.VizieR/J/ApJS/191/352
- Title:
- Abundances in stars of Milky Way dwarf satellites
- Short Name:
- J/ApJS/191/352
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of Fe, Mg, Si, Ca, and Ti abundances for 2961 stars in eight dwarf satellite galaxies of the Milky Way (MW): Sculptor, Fornax, Leo I, Sextans, Leo II, Canes Venatici I, Ursa Minor, and Draco. For the purposes of validating our measurements, we also observed 445 red giants in MW globular clusters and 21 field red giants in the MW halo. The measurements are based on Keck/DEIMOS medium-resolution spectroscopy (MRS) combined with spectral synthesis. We estimate uncertainties in [Fe/H] by quantifying the dispersion of [Fe/H] measurements in a sample of stars in monometallic globular clusters (GCs). We estimate uncertainties in Mg, Si, Ca, and Ti abundances by comparing to high-resolution spectroscopic abundances of the same stars. For this purpose, a sample of 132 stars with published high-resolution spectroscopy in GCs, the MW halo field, and dwarf galaxies has been observed with MRS. The standard deviations of the differences in [Fe/H] and <[{alpha}/Fe]> (the average of [Mg/Fe], [Si/Fe], [Ca/Fe], and [Ti/Fe]) between the two samples is 0.15 and 0.16, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/438/251
- Title:
- Abundances in stars with giant planets
- Short Name:
- J/A+A/438/251
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Na, Mg and Al abundances in a set of 98 stars with known giant planets, and in a comparison sample of 41 "single" stars. The results show that the [X/H] abundances (with X = Na, Mg and Al) are, on average, higher in stars with giant planets, a result similar to the one found for iron. However, we did not find any strong difference in the [X/Fe] ratios, for a fixed [Fe/H], between the two samples of stars in the region where the samples overlap. The data was used to study the Galactic chemical evolution trends for Na, Mg and Al and to discuss the possible influence of planets on this evolution. The results, similar to those obtained by other authors, show that the [X/Fe] ratios all decrease as a function of metallicity up to solar values. While for Mg and Al this trend then becomes relatively constant, for Na we find indications of an upturn up to [Fe/H] values close to 0.25dex. For metallicities above this value the [Na/Fe] becomes constant.
- ID:
- ivo://CDS.VizieR/J/A+A/416/1117
- Title:
- Abundances in the early Galaxy
- Short Name:
- J/A+A/416/1117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the framework of the ESO Large Programme "First Stars", very high-quality spectra of some 70 very metal-poor dwarfs and giants were obtained with the ESO VLT and UVES spectrograph. These stars are likely to have descended from the first generation(s) of stars formed after the Big Bang, and their detailed composition provides constraints on issues such as the nature of the first supernovae, the efficiency of mixing processes in the early Galaxy, the formation and evolution of the halo of the Galaxy, and the possible sources of reionization of the Universe. This paper presents the abundance analysis of an homogeneous sample of 35 giants selected from the HK survey of Beers et al. (1992, Cat. <J/AJ/103/1987>, 1999, Cat. <J/AJ/117/981>), emphasizing stars of extremely low metallicity: 30 of our 35 stars are in the range -4.1<[Fe/H]<-2.7, and 22 stars have [Fe/H]<-3.0. Our new VLT/UVES spectra, at a resolving power of R~45000 and with signal-to-noise ratios of 100-200 per pixel over the wavelength range 330-1000 nm, are greatly superior to those of the classic studies of McWilliam et al. (1995AJ....109.2757M) and Ryan et al. (1996ApJ...471..254R).
- ID:
- ivo://CDS.VizieR/J/A+A/410/527
- Title:
- Abundances in the Galactic disk
- Short Name:
- J/A+A/410/527
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In table 3 we list all spectral lines that have been used in the determination of abundances. Column 1 gives the wavelength (in Angstrom), column 2 the lower excitation potential (in eV), column 3 the correction factor to the classical Unsoeld damping constant, and column 5 the radiation damping constant. An "S" in column 4 indicates that the broadening by collisions have been taken from Anstee & O'Mara (1995MNRAS.276..859A), Barklem & O'Mara (1997MNRAS.290..102B, 1998MNRAS.300..863B), and Barklem et al. (1998MNRAS.296.1057B, 2000, Cat. <J/A+AS/142/467>), instead of the classical Unsoeld broadening (indicated by a "U"). The solar abundance that is given for each element is the photospheric value from Grevesse & Sauval (1998SSRv...85..161G ). Column 6 gives our adopted log gf - values and column 7 the references. In table 6 we give the derived abundances for all individual elements (atoms and ions). The results for each star consist of three rows. The top row gives the mean abundance, the middle row gives the (1 sigma) standard deviation around the mean, and the third row gives the number of spectral lines that was used in computing the mean. All abundances are given relatively our solar values, which in turn is normalized to the standard photospheric values in Grevesse & Sauval (1998SSRv...85..161G ).
- ID:
- ivo://CDS.VizieR/J/A+A/419/469
- Title:
- Abundances in the galaxy HS 0837+4717
- Short Name:
- J/A+A/419/469
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of high S/N long-slit spectroscopy with the Multiple Mirror (MMT) and the SAO 6-m (BTA) telescopes, optical imaging with the Wise 1-m telescope and HI observations with the Nancay Radio Telescope of the very metal-deficient (12+log(O/H)=7.64) luminous (M_B_=-18.1mag) blue compact galaxy (BCG) HS 0837+4717.
- ID:
- ivo://CDS.VizieR/J/AJ/133/694
- Title:
- Abundances in the HR 1614 moving group
- Short Name:
- J/AJ/133/694
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present abundances for a sample of F, G, and K dwarfs of the HR 1614 moving group based on high-resolution, high signal-to-noise ratio spectra from the Anglo-Australian Telescope UCLES instrument. Our sample includes stars from Feltzing and Holmberg, as well as from Eggen. Abundances were derived for Na, Mg, Al, Si, Ca, Mn, Fe, Ni, Zr, Ba, Ce, Nd, and Eu.
- ID:
- ivo://CDS.VizieR/J/AJ/150/88
- Title:
- Abundances in the local region. I. G and K giants
- Short Name:
- J/AJ/150/88
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Parameters and abundances for 1133 stars of spectral types F, G, and K of luminosity class III have been derived. In terms of stellar parameters, the primary point of interest is the disagreement between gravities derived with masses determined from isochrones, and gravities determined from an ionization balance. This is not a new result per se, but the size of this sample emphasizes the severity of the problem. A variety of arguments led to the selection of the ionization-balance gravity as the working value. The derived abundances indicate that the giants in the solar region have Sun-like total abundances and abundance ratios. Stellar evolution indicators have also been investigated with the Li abundances and the [C/Fe] and C/O ratios, indicating that standard processing has been operating in these stars. The more salient result for stellar evolution is that the [C/Fe] data across the red-giant clump indicates the presence of mass-dependent mixing in accord with standard stellar evolution predictions.
- ID:
- ivo://CDS.VizieR/J/AJ/153/21
- Title:
- Abundances in the local region. II. F, G, and K dwarfs
- Short Name:
- J/AJ/153/21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Parameters and abundances have been derived for 1002 stars of spectral types F, G, and K, and luminosity classes IV and V. After culling the sample for rotational velocity and effective temperature, 867 stars remain for discussion. Twenty-eight elements are considered in the analysis. The {alpha}, iron-peak, and Period 5 transition metal abundances for these stars show a modest enhancement over solar averaging about 0.05dex. The lanthanides are more abundant, averaging about +0.2dex over solar. The question is: Are these stars enhanced, or is the Sun somewhat metal-poor relative to these stars? The consistency of the abundances derived here supports an argument for the latter view. Lithium, carbon, and oxygen abundances have been derived. The stars show the usual lithium astration as a function of mass/temperature. There are more than 100 planet-hosts in the sample, and there is no discernible difference in their lithium content, relative to the remaining stars. The carbon and oxygen abundances show the well-known trend of decreasing [x/Fe] ratio with increasing [Fe/H].
- ID:
- ivo://CDS.VizieR/J/AJ/155/111
- Title:
- Abundances in the local region. III. Southern dwarfs
- Short Name:
- J/AJ/155/111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stellar parameters and abundances have been derived from a sample of 907 F, G, and K dwarfs. The high-resolution, high signal-to-noise spectra utilized were acquired with the HARPS spectrograph of the European Southern Observatory. The stars in the sample with -0.2<[Fe/H]<+0.2 have abundances that strongly resemble that of the Sun, except for the lithium content and the lanthanides. Near the solar temperature, stars show two orders of magnitude range in lithium content. The average content of stars in the local region appears to be enhanced at about the +0.1 level relative to the Sun for the lanthanides. There are over 100 planet hosts in this sample, and there is no discernible difference between them and the non-hosts regarding their lithium content.
- ID:
- ivo://CDS.VizieR/J/A+A/414/503
- Title:
- Abundances in the Sgr dSph
- Short Name:
- J/A+A/414/503
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on abundances of O, Mg, Si, Ca and Fe for 10 giants in the Sgr dwarf spheroidal derived from high resolution spectra obtained with UVES at the 8.2m Kueyen-VLT telescope. The iron abundance spans the range -0.8<~[Fe/H]<~0.0 and the dominant population is relatively metal-rich with [Fe/H]~-0.25.
- ID:
- ivo://CDS.VizieR/J/ApJ/870/83
- Title:
- Abundances in the ultra-faint dwarf gal. GruI & TriII
- Short Name:
- J/ApJ/870/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-resolution spectroscopy of four stars in two candidate ultra-faint dwarf galaxies (UFDs), GrusI (GruI) and TriangulumII (TriII). Neither object currently has a clearly determined velocity dispersion, placing them in an ambiguous region of parameter space between dwarf galaxies and globular clusters (GCs). No significant metallicity difference is found for the two GruI stars, but both stars are deficient in neutron-capture elements. We verify previous results that TriII displays significant spreads in metallicity and [{alpha}/Fe]. Neutron-capture elements are not detected in our TriII data, but we place upper limits at the lower envelope of Galactic halo stars, consistent with previous very low detections. Stars with similarly low neutron-capture element abundances are common in UFDs but rare in other environments. This signature of low neutron-capture element abundances traces chemical enrichment in the least massive star-forming dark matter halos and further shows that the dominant sources of neutron-capture elements in metal-poor stars are rare. In contrast, all known GCs have similar ratios of neutron-capture elements to those of halo stars, suggesting that GCs do not form at the centers of their own dark matter halos. The low neutron-capture element abundances may be the strongest evidence that GruI and TriII are (or once were) galaxies rather than GCs, and we expect future observations of these systems to robustly find nonzero velocity dispersions or signs of tidal disruption. However, the nucleosynthetic origin of this low neutron-capture element floor remains unknown.